Staple crops are those which are most common in people's diets. Large expanses of land are dedicated to growing these foods, compared to the smaller areas planted in fruits and vegetables. In the third world, the staples are often a starch (grain or root crop) and a pulse (dried legume seed, beans). The starch gives energy and a feeling of fullness in the stomach, while the pulse provides protein.
These crops are so important to so many people that many have spread far beyond their centers of origin; many types of cassava, corn, rice, soybeans, and pigeon peas are grown around the world. Major research centers devote much of their resources to studying and improving these crops. Other crops, such as amaranth, quinoa, and tepary beans remain localized, but they hold great potential for thriving in other places with similar conditions. ECHO's focus is on these little-known plants and some varieties of the common crops which have special characteristics.
AMARANTH SEED. Amaranth grain, corn and beans were probably the primary foods of the Aztecs. The Aztecs unfortunately practiced a religious observance in which they would mix blood from a human sacrifice with popped amaranth grain. They formed this into a statue of a war god, worshiped the statue, then ate it. The Conquistadors considered this a mockery of the eucharist (communion) so banned both the religion and cultivation of the grain in 1517. Amaranth has existed primarily as a wild weed since that time.
Amaranth received much research attention in the 1970s and 80s because: (1) it is more resistant to drought than corn, (2) it does fairly well in nutrient deficient soil, (3) it produces yields that compare favorably with corn and rice, (4) the grain is high in protein of unusually high quality, and (5) the leaves also have a good balance of proteins and may be cooked like spinach. Much of the research was done by Rodale Institute (known for their many publications, including Organic Gardening magazine). They enlisted thousands of readers to do backyard experiments with different varieties of amaranth that they brought in from around the world. (This is a model for the kind of world-wide data we hope to gather as you report back to us on the seeds we send you.)
The protein is high in lysine, which accounts for 5% of total protein. It also has a very high "chemical score," a calculated value in which the higher numbers are the more perfect match for ideal human nutrition. For example, the chemical score for amaranth is 75-87, corn 44, wheat 57, sorghum 48, peanut 52, soybean 68, cow's milk 72. However, I have read results of feeding trials with rats where they did not do well at all on a corn/amaranth diet compared to corn and soybean. There are some anti- nutritional factors in raw amaranth that limits its use as a feed. Cooking improves this. Other drawbacks include small size of the seed that makes it difficult to thresh by machine and oxalic acid in the leaves that might tie up too much dietary calcium if eaten frequently in high amounts. You may request a summary of nutritional and cultivation information from ECHO. (See the chapter on Human Health for a perspective on nutritional limitations of amaranth.)
When evaluating amaranth for your area, you should try more than one species and variety, because the variability is considerable. A few of those we grew this year looked absolutely horrible, while others were truly beautiful crops. Amaranthus cruentus and A. hypochondriacus are grown primarily for their grain and A. tricolor for its leaves. Leaves of any variety can be eaten, however. Doug and Ruth Welcha are trying several of these varieties in Zaire. They just wrote that one variety (ECHO's #81-039) that they received earlier from Rodale grew 7 to 8 feet in composted soil. "Most of our neighbors demanded seeds, so it has been distributed near and far. But they are using it as a vegetable." This was one of the most prolific grain types for us.
Lloyd Rowlands sent us these comments from Zaire: "I planted two varieties of Amaranthus cruentus that I got from ECHO. I was pleasantly surprised by the yield. I gave a small quantity to my workman to try cooking. He tried it roasted-awful. Then he tried cooking it like rice-and asked me for seed! Variety 81-037 out-yielded 81-039. They were sown December 3 and harvested in March." ECHO has many varieties of amaranth seed, both types grown primarily for grain and those grown for their edible leaves. Please indicate with your order which type of amaranth you wish to try; we will send several varieties.
BUCKWHEAT: EDIBLE LEAVES, SEED SET, SUCCESS, AND A RECIPE. In the chapter on Domestic Animals we mention the experience with buckwheat, Fagopyrum esculentum, reported by John Trossel. He said this quick-maturing crop can be harvested two months after planting. Seed that we sent to a lower elevation (about 4,000 feet) in Honduras also reportedly did well. The newsletter HortIdeas quotes from an Indian journal that the leaves of this "broad-leaved 'grain' with remarkable soil-building abilities are edible. In fact, they are eaten regularly by people living in the higher ranges of the Himalayas. They are simply cooked with seasonings in boiling water for a short time. The leaves contain 4.5% protein on a fresh weight basis and are reasonably high in calcium and iron."
Buckwheat does best in cool and humid climates and is definitely not suited for the tropical lowlands. If you work at an appropriate site, we can send you a small packet to get started. Poultry can eat the seeds whole, but for other animals it must be ground. Some of our readers, wanting to make a flour for human use, have given up on buckwheat because it is difficult to prepare into a pure flour when grinding. (If you have had experience preparing buckwheat flour, please share it with us.)
Kevin Hendricksen with the Peace Corps in Honduras wrote, "I planted buckwheat at 1500 m in early June in an area that receives 1000 mm rainfall. The plants grew quickly, flowered in about five weeks, reached a height of 12-15 inches. But the seeds produced were empty and did not sprout when planted. I made another planting of the original seed from ECHO in July with the same results." We asked Dr. Obendorf at Cornell University for some ideas on what may have caused the empty seed. He said that the optimal temperature for flowering and early seed set of buckwheat is 18 C; at 25 C, there is 40% loss of seed set and seed weight. The plants flower over a period of about 6 weeks, but most of the seed set is during the first 2-3 weeks of flowering. Hollow seeds are probably those which are set late and form seeds which do not fill in. Under temperature stress, the early flowers will abort. Later flowers, however, may set seed, but it will be sterile. Other possibilities include inadequate pollination by bees or drought sensitivity.
Bill Lewis from Ethiopia visited ECHO and gave a good report on buckwheat seeds he obtained from our seedbank. When his family left Ethiopia, they left some plants nearly ready for harvest, and they were eager to see how the plant was used in their absence. He returned to Africa and sent this update: "We only had a few months to try it at about 5000 feet. We left our seed with church members when we went on furlough. We found that they love it. By adding a little wheat flour or oil they say it is as good as anything they have. I have some church property now with water available, so I will grow buckwheat continuously until the next rainy season for seed. We are really excited about the possibilities! The buckwheat here matures in 9-10 weeks and is prolific. The bees really love it. We will also be trying other things-even your chaya!" He also asked for recipes.
Martin Price offers this family recipe for buckwheat pancakes. Growing up in Ohio, we had buckwheat pancakes almost every morning from the time the weather cooled down in the fall until it became warm again in the spring. The reason it required cool weather is that we fermented the buckwheat on the cool porch or in the sparsely heated kitchen. To start, we mixed buckwheat 50:50 with wheat flour, then added some yeast and enough water to make a thick paste. By the next morning it had expanded to 2-3 times its original size. We then added enough water for a nice consistency for pouring pancakes. We never liked it the first morning, but ate it anyway. That night we added more of the buckwheat/wheat flour mix (but no more yeast) and the process was repeated. After the third day, the pancakes were absolutely delicious and gave a wonderful aroma when cooking. People who have eaten buckwheat pancakes from a mix (not fermented) do not know how good the sourdough approach can be. It is like a totally different food, and it is very filling in a pleasant way.
NEW VARIETIES OF HIGH-LYSINE CORN SHOW PROMISE FOR THE SMALL FARM. A variety of corn that contains much higher concentrations of the amino acid lysine than normal corn was developed by Dr. Ed Mertz at Purdue University in the 1960s. Lysine is the essential amino acid that is most limiting in diets composed mainly of cereals. One way to get extra lysine is to mix cereals with beans. The high-lysine corn, however, would be much more nutritious than regular corn for folks or animals that do not have a good mixture of legumes with their corn.
The high-lysine corn has not been widely accepted because its yields were inferior and the texture was not as acceptable for human diets in many countries. Dr. Mertz visited ECHO on his way home from the International Center for Improvement of Wheat and Maize (CIMMYT) in Mexico. He was quite excited because CIMMYT had just completed yield trials in several countries with some new varieties that have equaled or outperformed the best open-pollinated varieties and which have the preferred texture.
Open-pollinated corn is the kind farmers plant year after year using seed that they harvest (as opposed to purchased hybrid corn). Most of you know that if farmers save and plant their own seed the next year from hybrid varieties, subsequent yields can be variable and much less productive. CIMMYT is to be congratulated for concentrating on open-pollinated corn, which is more appropriate than hybrid corn for those farming at near subsistence levels. If there is no sacrifice of yield, high-lysine varieties should be seriously considered for the small farm. Human and animal health would both be improved. Some farmers in the United States claim that they save $2-10 per hog when they feed high-lysine corn, mainly because it allows them to reduce the amount of soybeans in the diet by up to 25%. They also claim fewer veterinarian expenses. (I have seen no scientific studies on either point.)
If you want to try the new corn, you should be cautious about a few things. First, an unusual trait of the high- lysine corn is that if it is pollinated by normal corn the crop that is harvested will not be high in lysine. Therefore, if it were introduced to an occasional small farm which is immediately surrounded by fields of regular corn, the extra nutritional benefits might not be present. All farmers in an area should agree to grow the high- lysine crop unless fields were somewhat isolated. Second, there is risk in changing all of a farmer's crop to a single new variety. Quite likely the local varieties have developed resistances to disease and insects common to the area. Although the new varieties have no doubt been developed with resistance to common tropical stresses, there is some risk (and scientific loss) if the old varieties are no longer grown.
The director of the Maize program at CIMMYT told us that it would be best if ECHO's network would write CIMMYT for seed, rather than sending seed to ECHO for redistribution. This would enable them to send appropriate types. They have both highland and lowland varieties and also different grain types and maturities, so tell them something about your climate, altitude, length of season and any preferences as to type and texture of the corn so they can make the best choice. Write CIMMYT, Londres 40, Apdo. Postal 6-641, Col. Juarez Deleg. Cuauhtemoc, 06600 Mexico, D.F. MEXICO.
DROUGHT-TOLERANT CORNS FROM 'PLANTS OF THE SOUTHWEST' CATALOG. Posole Corn: "Large, plump ears on vigorous, drought-tolerant plants. The traditional variety of dry dent corn for making posole, the hominy and one of the finest dishes of the Southwest. 100 days." Papago: "Small, slender cream- colored ears on this drought-tolerant corn adapted to the extremely arid region of southern Arizona. Larger in wetter climates or with regular irrigation. Grind into meal for tamales. Excellent for harsh, dry sites. 80 days." Buhrow's White Desert Sweet Corn (ask for it even if not listed in their catalog): "A new cross of papago with a white corn to produce a sweet corn that will open pollinate between 90-100 F. It is remarkably drought tolerant and has been known to bear when deeply watered only 3 times in a season, but your yield will be greater with more frequent waterings. Grows 5-9 feet with 6-9 inch ears." [NOTE ON CORN: We bought this from a commercial seed company, so it should be disease free. If corn is important in your area, be watchful and destroy the plants if any new disease should ever appear.] ECHO can send you a small packet to evaluate. Though you can save your own seed, it is best to have a minimum population of perhaps 200 plants in a field to prevent inbreeding. You can later order larger quantities from Plants of the Southwest, Agua Fria, Rt. 6 Box 11A; Santa Fe, NM 87505, USA; phone 505/471-2212; phone orders 800/788-7333; fax orders 505/438-8800 ($20 minimum). Their catalog features many other drought-tolerant corns and plants you may wish to try.
DOING YOUR OWN CORN (MAIZE) IMPROVEMENT. Bob Short in Mexico teaches farmers to improve their own open-pollinated (not hybrid) corn varieties. The people already select the best ears for seed, but the selection is made from a pile after the harvest. Selection based on ear size only can cause more problems than you might think. This brings up an interesting story.
In the early 1900s in the United States a popular magazine, "Wallace's Farmer," and a professor at Iowa State University promoted corn competitions. These became annual events all over the midwest. Judging was based on a vision of the ideal corn: uniform ears, 10 inches long, with even rows and deep kernels shaped like a keystone. At one of the professor's talks a 16-year-old boy (the editor's son) asked whether seed from the ideal ear would produce more corn than any other. "Of course," he replied, though he had not tried it. The boy's persistence made him nervous, so he collected 25 ears of the best show corn and 25 of the poorest. The highest yield came from an ear no corn-show judge would look at twice. As a whole, the highest-ranked show ears produced less than those that ranked lowest. The boy went on to school and later formed what became the largest corn seed company in the world, Pioneer Hybrid, and eventually was Secretary of Agriculture.
Bob finds that even after selecting the best ears for seed, about half of the plants produce a poor ear, if any at all. Bob decided that the basic traits that he wanted were present in one plant or another in the field of "criollo" corn, though not necessarily on the same plant. He wrote, "Our method of selection is simple. The first thing we do is de-tassle the poor plants before pollination. This ensures that reasonably good plants will be the male parents of the corn. Then we select the ears to be kept for seed in the field. We take from the best plants which produce a good ear, taking into account the quality of the roots, stem, disease resistance, leaf area, etc." The important difference in this method is that good ears come from plants that are also known to be good.
"We have seen problems of inbreeding, so now recommend that seed come from fields that are at least half a hectare in size and that a minimum of 400 ears be selected. The selected ears are shelled and the seeds are thoroughly mixed together and saved for the next planting."
Bob says that they have definitely improved the quality of their own corn. It is difficult to convince farmers to change to it though because improvement is too slow to be seen quickly. A few are beginning to try it and he hopes that in 5-10 years it may be widespread.
I asked Dr. David Unander, a plant breeder on ECHO's Board of Directors, to comment. Highlights of his reply follow. "How many ears should one save to avoid inbreeding? Plant breeding texts and research suggest a minimum of 30 plants to avoid serious inbreeding, but much more is better. Unneeded seed can always be eaten. The extent of inbreeding is a function of the percentage of the population saved and will increase substantially if much less than 10% of the harvest is saved and mixed in the seed bin."
Dave suggests a way to further improve the technique. "Because differences among plants depend on the local spot in which the corn plant is grown, mentally divide the field into little blocks of 10-20 plants each (or more in a larger field). Be sure to select the best ear or ears from each of these imaginary blocks. Plants with mediocre genetic traits may have done well just because they grew in an unusually fertile spot, and plants that are outstanding may have done poorly if they grew in a poor part of the field." [This would also help to keep in your pool of seeds traits that would enable the best performance possible in those poor parts of the field.]
A special merit of Bob's method is "that he has thought out exactly what he wants to select: he has a mental picture of what a good corn plant would be like for his area. This is one of the most important things to establish before beginning any breeding program."
QUINOA, CHENOPODIUM QUINOA, IS A NUTRITIOUS GRAIN FROM THE ANDES.
"While no single food can supply all of the essential life-sustaining nutrients, quinoa comes as close as any other.... It holds exceptional promise as a weaning food."1 This crop was a staple in ancient times, second in importance only to corn in the Incan empire, and it is still an important grain crop in Bolivia, Chile, Ecuador, Peru, and Colombia. "Its grain is rich in protein and contains a better amino acid balance than the protein in most cereals. ...Today it is made into flour for baked goods, breakfast cereals, beer, soups, desserts and even livestock feed. When cooked in water, it swells and becomes almost transparent. It has a mild taste and a firm texture like that of wild rice.... Traditionally, quinoa is prepared like common rice or is used to thicken soups, but some varieties are also popped like popcorn."
"Quinoa has demonstrated value as a partial wheat-flour substitute for enriching unleavened bread, cakes, and cookies. Blends of 70% wheat and 30% quinoa flour produce fully acceptable loaf breads."2 Quinoa is called a "pseudocereal" because its use is similar to that of cereals but the plant is not in the grass family. Seeds are produced in large sorghum-like clusters and may shatter easily. They contain 58% starch, 5% sugar, 12-23% protein and 4-5% fat. It is a hardy plant, growing to 0.5-3 meters tall, maturing in 5-6 months with short day length. A drawback is that seeds of most varieties contain saponins, which impart a bitter flavor unless washed out in cold water or milled out.
Quinoa has an exceptionally nutritious balance of protein, fat, oil and starch
"Quinoa has an exceptionally nutritious balance of protein, fat, oil and starch. The embryo takes up a greater proportion of the seeds than in normal cereals, so the protein content is high. Quinoa seeds average 16% protein but can contain up to 23%, more than twice the level in common cereals." According to Underexploited Tropical Plants with Promising Economic Value, quinoa may prove to be a better protein source than most of the true cereals. It is "high in the essential amino acids lysine, methionine and cystine, making it complementary both to other grains (which are notably deficient in lysine) and to legumes such as beans (which are deficient in methionine and cystine). Quinoa is higher than wheat, corn or white rice in iron (6.6 mg, 4.6, 3.7, and 0 mg respectively.), phosphorus (449, 224, 207 and 143 mg), and calcium (141, 36, 6 and 8 mg)."
Quinoa's large seedheads and broad leaves make it look something like a cross between sorghum and spinach. Visitors who see quinoa at ECHO before seed heads form almost always think it is the (edible) weed lambsquarter, to which it is closely related. The leaves are eaten fresh or cooked. Nitrates and oxalates, high enough in some greens to be a health concern, are very low in quinoa leaves.
Quinoa has been grown almost exclusively in the Andean countries which were formerly part of the Incan empire. In the Andes, it is primarily a food of campesinos, although in some areas it is gaining popularity among wealthier urban classes who realize its nutritional benefits. The increased interest in these countries of origin is due in part to efforts of local governments and increasing interest in healthful foods, and in part to its growing popularity in western countries, where new, tasty and healthful foods bring a premium price.
Quinoa is known for its resistance to tough conditions. It will grow where corn will not because of cool weather and dry conditions. During a devastating drought in the altiplano in 1982-83, 66% of Bolivia's potato crop was lost, 25% of corn, 54% of barley, 44% of wheat, 34% of cassava but only 7% of quinoa. In Peru the figures were 27% potato, 6% corn, 26% barley, and 0% for quinoa.
There is great diversity in plant characteristics. "A classification based on ecotype recognizes five basic categories. (1) Valley type, grown in valleys from 2,000-3,600 m. Tall, branched, long growth periods. (2) Altiplano type, frost hardy, short, unbranched, short growth periods and compact seedheads. (3) Salar type, native to the salt flats in the Bolivian altiplano. (4) Chilean type, grown at low elevation sites between 34 S and 41 S in Chile, will flower even with long days. (5) Subtropical, located in intermontane valleys in Bolivia, intensely green plants that turn orange at maturity and have small, white or yellow-orange seeds."
Farmers and scientists in parts of the industrialized world where weather in the summer months resembles weather in the Andes have been trying to develop quinoa as a crop since the early 1980s. Because they originated near the equator where days are short, most varieties are daylength sensitive (require short days to flower) and do not do well. However, there are varieties which grow near sea level in Chile where days are long. These have proved more adaptable to high latitudes.
A drawback to quinoa production and use on a small scale is that the seeds contain saponins in the seed coat, which cause the grain to be extremely bitter. They can easily be mechanically removed with appropriate equipment. Lacking such equipment, the grain can be rinsed or soaked in water to dissolve the saponins. However, it is more difficult to get a uniform product this way. I spoke with Dr. Duane Johnson at Colorado State University about quinoa and its potential. He had just returned from harvesting his experimental plots of quinoa in Colorado.
Q. We know that the equatorial types require short days to produce seed but that Chilean types do not. Do Chilean quinoas actually require long days or are they day-neutral (produce in any daylength)?
A. They are day-neutral. That means that if ECHO sends Chilean seed to its network, it should not fail because of daylength. However, people in equatorial highlands would probably prefer equatorial types. They tend to have larger, white seeds; Chilean quinoas are smaller and colored. White seeds are generally softer and it is easier to remove the bitter saponins. Chilean types are harder and more extensive work is required to remove the saponins.
Q. The Chilean types are unbranched. Does that mean they should be planted more densely than equatorial types?
A. Yes. We plant 2 pounds/acre of equatorial seed but 5 pounds/acre with Chilean. That corresponds to a plant spacing of 3-4 inches (7.6-10 cm) and 2 inches (5 cm) respectively. Most farmers in Colorado use rows 16 inches (40 cm) wide, but some use 8 and others 20 inches (20 and 50 cm), depending on moisture. (If rainfall is limiting, having fewer plants with wider spacing will require less water.)
Q. What are the climatic boundaries beyond which quinoa has little potential? Will Chilean sea level types do well in tropical lowlands?
A. They have the greatest heat tolerance, but we don't recommend them where temperatures exceed 92 F/33 C, especially during the flowering period (July here in Colorado). We have quinoa growing from Finland to Australia, but mostly in temperate regions. Quinoa is very susceptible to downy and powdery mildew. It likes low humidity. Cool nights are probably important, though I have no data to prove that. It does well here where temperatures average 80 F day, 45 F night (27 C and 7 C). It does not do as well in broad valleys where night temperatures remain rather high, though at 7,000 feet it does great even in valleys.
[NOTE: Because it flourishes at high altitudes (2500-4000 m), we thought we might have a chance of growing quinoa at ECHO in southern Florida during the cool winter season. It has exceeded our expectations in some years, growing quite vigorously and forming grain. We are interested in examining it more closely to determine whether it has potential for a much wider range of climates. Dr. Russell Seibert at the Marie Selby Gardens told me that he thinks he has heard reports of it growing quite successfully in Alaska. An association, Sierra Blanca Associates, 2560 S. Jackson, Denver, CO 80210, USA, has been formed for its promotion and trial. It grows best where maximum temperatures do not exceed 90 F (32 C) and night temperatures are cool.]
Q. Are there subtropical quinoas?
A. There are related species, mainly back garden types. They grow, for example, in parts of Mexico. [Ed: Can anyone give ECHO some seed?]
Q. I read that the equatorial quinoas grow so well in Colorado
that they might make good forage.
A. Equatorial types produce tremendous biomass here, but we get no seed production. It could be used for forage only if we imported seeds.
Q. How complex is it to remove saponins at the "village"
A. It is pretty simple. Pillsbury Co. gave us a $7,000 rice dehuller (a carborundum stone that spins and knocks the coating off, designed for 3rd world countries). It works even with the harder Chilean types, though they require 2 passes. Once dehulled it tastes just as good. Actually I prefer the Chilean varieties, which to me have a richer, nuttier flavor. I find the equatorial types somewhat bland.
Q. Do the saponins give the color to the seed coat? If so, can you learn anything important by noting the color of the grain, e.g. whether birds might avoid it?
A. The saponins are buried in a pericarp, like the rind on an orange. Color does not really tell you anything useful. There is no correlation between color and bird resistance.
Q. What is the status of saponin-free varieties? Are they more
prone to insect and disease loss?
A. We are currently investigating these varieties, but I have some hesitation after this year's results. Birds were definitely a more serious problem with saponin-free varieties-I'd estimate 30% loss to bird damage. This is in middle of a 150-mile valley with no trees within 2 miles of the plots. But migrating birds found it (other grain fields had been harvested). [Ed: Has anyone noticed whether bird damage is a more serious problem in general on farms making heavy use of agroforestry techniques?]
Q. I read that in early trials in Colorado improved, selected varieties from South America did not do as well as less selected varieties. Presumably the loss in variability during the selection process lost some traits that were important in Colorado. So should I offer your selected varieties to ECHO's network or will they likewise perform less well than the original seed might have done?
A. We find that selected lines from South America aren't as good for us. The same may be true of our varieties when tried elsewhere. We have selected two: Apelawa and Colorado 407. I maintained the old original material, which would probably be better for widespread preliminary trials.
Q. Is quinoa becoming commercialized outside the Andes?
A. About 500 acres are grown in Colorado and 200 each in Washington and Wyoming. It is processed and sold to health food industries. Until this year 50% was sold here and 50% went to Europe. This year 99% will be sold in the USA. Europeans are now buying from South America. Nestle invested $5,000,000 in Ecuador in research in quinoa. Starch from quinoa is being used in synthetic cream products. The market for quinoa is increasing. Canada is becoming a dominant force, growing 2,000 acres last year.
Q. Where are the main places for seed of diverse types? Are Andean countries hesitant to share seed?
A. Ecuador and Bolivia are very helpful in exchanging seeds with us. INIAP in Ecuador has equatorial types; write Estacin Experimental Sta. Catalina, Km 14, Panamericana Sur, Quito, ECUADOR; fax 593 2 504 240. For Bolivia you should go and see what you can find. [NOTE: ECHO has many of the lines used in breeding by INIAP, if you want to select from domesticated but widely varying strains. Dr. John McCamant, Sierra Blanca Associates, 2560 S. Jackson, Denver, CO 80210, USA, also gladly shares from his sizeable quinoa collection.]
Q. Do you have any final comments?
A. There is a southern Bolivian type that I like very much. But it requires a longer season than we have in Colorado (105 days). I like it because it has larger seed and a softer pericarp, but is day-neutral.
If you want to try growing quinoa in your area, write to ECHO for sample packets. Dr. Johnson sent ECHO enough Chilean quinoa seed to send small introductory packets to our overseas network. These should bloom under the broadest range of day lengths (assuming that temperature and other conditions are right). We also have the virtually saponin-free commercial variety 'Tunkahun' from the highlands of Ecuador. Our seedbank has several other varieties you may try, if you are interested in doing a broad trial with quinoa. We do not consider quinoa worth trying in hot, humid lowlands nor where high temperatures are much over 92 F/33 C.
[This article relied heavily on the book 2Lost Crops of the Incas, the National Academy Press, 1989, and an article 1"Quinoa: Grain of the Incas" by David Cusack, in The Ecologist Vol 14: 21-31, 1984. David, an early member of ECHO's network, was shot and killed during a 1984 trip to South America to collect quinoa seed.]
A FARMER'S PRIMER ON GROWING RICE. This book was written at the International Rice Research Institute (IRRI) to help the progressive rice farmer understand "why and how the improved rice varieties and farm technology increase production." The book answers questions such as why more fertilizer should be used in the dry season and how water depth affects seedling growth. It is clear and concise. The major part of each page is an illustration or diagram. Only a few words of explanation and clarification occur on the page. Some knowledge of rice production is assumed. For example, the mechanics of planting a seed bed, transplanting, harvesting, pest control and disease prevention are not covered. It does cover the life cycle of the rice plant in great detail and tells how the treatment of the rice plant at each stage will affect the final yield. Selected topics in the book are when and why to add fertilizers, factors affecting growth, factors affecting lodging, how to use yield components, control of weeds, carbohydrate production by the plant, use of herbicides and how to judge a rice crop at flowering. The book should be extremely helpful to an agriculturalist who is involved in training farmers. The illustrations and diagrams could be enlarged and used in teaching. The revised 1992 edition (219 pp.) costs US$3.25 plus postage. (The 1979 edition is available in Kiswahili for US$2.75 plus postage.) Order catalog from Information Center, IRRI, P.O. Box 933, 1099 Manila, PHILIPPINES. Their catalog lists local suppliers around the world which charge less postage and give faster delivery. IRRI has an excellent catalog and is your best contact for questions related to rice. ECHO does not carry rice seed.
GIZA SORGHUM FOR FOOD AND FUEL. Dr. Axtell at Purdue University gave us a packet of seed of this special Egyptian grain sorghum and explained that in Egypt the stalks sometimes sold for more than the grain because of its superior burning characteristics. The grain is of good quality, though it can be damaged by rains near harvest. (As we have threshed it by hand, it seems that it is hard to remove all the "glumes" from the grain too.) Though we sent out several packets of seed in subsequent years, it was a long time before anyone in our network reported any excitement over it. Paul Butz's report from Peru is both encouraging and humorous.
ECHO was only able to send a small packet. Paul wrote that only 6 of 16 seeds germinated. Then two of these died of some disease. Later goats got in and ate half of the remaining four. The two that were left produced seed heads-then birds ate most of the seeds. By covering the heads with plastic bags he managed to get 200 seeds. Unlike in temperate climates where sorghum is an annual, a stalk that is cut back in the tropics may tiller (send up new stalks). Each of the two plants sent up 3-5 new stalks which in turn produced seed.
The immediate purpose of Paul's work is to "produce fuel for firing bricks in this area" as well as for cooking. They were expecting to plant a hectare which they calculated would produce enough fuel for the brick operation, giving at least three cuttings a year. Write ECHO if you would like to try seed of this sorghum.
"BIRD-RESISTANT" GRAIN SORGHUM. I [MLP] am especially pleased to make this offer because it relates to the subject of my three years post-doctoral research at Purdue University. Grain sorghum is one of the world's major cereals, grown primarily in locations which are just a bit too dry for reliable yields of corn. The plant looks like corn when young. Then a stalk emerges from the top of the plant on which a head of grain develops. Unlike corn, where the grain is protected by a husk, the sorghum grains are fully exposed. In some cases an entire field can be lost to birds.
bird-resistant" grain sorghum
There are two ways to protect the grain, neither very acceptable. One is to have the children or older people stay by the fields during the most susceptible weeks and scare the birds away. The other is to grow varieties which have a high tannin content. I once led a trial in Puerto Rico in which regular and high-tannin sorghums were grown on 3 acres. My plans for measuring degrees of damage by birds were discarded because there was 100% destruction of the kind with no tannin. The high-tannin varieties scarcely lost a grain.
So why is tannin not a good option? Tannin is the substance in green fruits (e.g. persimmons or banana) that causes your mouth to pucker up. The tannin binds with proteins, causing them to come out of solution. If this happens in your mouth, the lubricating proteins of saliva are removed, resulting in the puckery sensation. In the digestive tract they may tie up proteins in the diet or, worse yet, digestive enzymes. The consequences are serious. In feeding trials with rats and chickens, the animals grow much slower, or sometimes even lose weight, with rations based on high-tannin sorghum compared to varieties with no tannin.
Farmers face a terrible choice. Grow regular sorghum and risk low yields due to bird damage or high-tannin sorghum and get good yields of grain that is very bad nutritionally.
Dr. Larry Butler at Purdue gave me the good news that Dr. John York at the University of Arkansas and Roger Bullard with the U. S. Fish and Wildlife Service have a sorghum with no tannin that birds seldom bother. Dr. Butler's feeding trials showed that it was as good a feed as any other sorghum.
Dr. Butler says, "In trials in Indiana for two summers the new variety was not damaged at all, whereas susceptible lines in the same fields were totally destroyed. However, one planting in Puerto Rico, where the sorghum was planted next to some millet (a common ingredient in bird feed), was wiped out. So in special cases it can still be damaged."
Trials have been conducted in Brazil, Kenya and Tanzania. You might want to wait until a lot more research has been done. But if you would like to get in on a tiny trial yourself, Dr. Butler gave us enough seed to send you a trial packet. Plant a row in the same field as your other sorghum and see if there is a difference. I asked if it was important to plant in a separate location, thinking that perhaps the birds needed to learn that a particular patch of grain was not "tasty." He said that birds seem to be able to distinguish individual resistant sorghums right in the row. Be sure to let us know what you find. We will pass the results on to Dr. Butler.
Dr. York has just released the variety, called AR 3048. He said that no yield trials have been done. (I think it was released primarily for use by plant breeders.) It is a triple dwarf, which means it may only get to be knee high. The plants are just now blooming at ECHO at a height of about 3 feet (1 m). That does not mean yields will necessarily be low, as many commercial varieties are dwarf. Although the short stalks mean that there is less danger of lodging (falling over) in wind, there will not be long stalks after harvest for other uses.
Dr. York reported a trial in which 2% of grain was lost during the "milk" stage of grain development to birds with AR 3048 and 86% for a control. There was some loss in that case after the grain was more mature ("dough" stage). He had earlier released another variety which proved to be resistant some years and not in others. There are a lot of mysteries in just what is happening and what is responsible for this "bird resistance."
If you are inclined a bit toward plant breeding, note that this bird resistance is a recessive trait. If you cross with another variety the seed will produce plants that are not resistant.
Saidou Jallow in the Gambia reported: "The bird resistant dwarf sorghum did absolutely well. I find no fault in it. Both the people in my village and surrounding villages like it. I hope in the near future it will be widespread in the area because it has the following advantages: short duration, wind resistance, and less or no disease."
Dr. Butler did send this caution about the bird-resistant sorghum. In some parts of the world people roast sorghum, as with corn (roasting ears) in the United States. Larry cautions about consuming this variety fresh roasted. "The roasting would not detoxify the cyanogenic glycoside dhurrin, which seems to be responsible for its bird resistance. The levels of dhurrin are higher at the dough stage than in the mature grain. The conventional processing method (grinding and wetting and cooking) does eliminate the cyanide." He adds that in both Kenya and India he "was told that if food supplies are scarce it is better to have a small amount of sorghum than maize, because one is more satisfied and can work longer on sorghum. I presume slower digestibility is the reason." This would assure a slow release of nutrients to the body over a longer period of time.
FOOD LEGUMES (1979) is an exceptionally useful book to which we frequently refer. We turn several times each month to this 435-page book to find alternate names, main uses, preferred climate, possible toxicity, etc. Let us look at Vigna unguiculata (cowpea) for an example of their treatment. Seven major common names and three botanical names are given at the top, followed by 119 other common names and the countries where these names are used. The next 14 pages cover a detailed botanical description, origin and distribution, cultivation conditions, planting procedure, pests and diseases, growth period, harvesting and handling, primary product, yield, main use, subsidiary uses, secondary and waste products, special features, processing, and products and trade, followed by 13 pages of bibliography.
Twenty-seven legumes are covered: adzuki bean, asparagus bean, bambara groundnut, broad bean, chick pea, cluster bean, cowpea, grass pea, haricot bean, horse gram, hyacinth bean, jack bean, Kersting's groundnut, lentil, lima bean, moth bean, mung bean, pea, pigeon pea, rice bean, runner bean, sword bean, tepary bean, urd bean, velvet bean, and winged bean. No charge is made for single copies requested by government, research, educational, or and non-profit groups in countries eligible for British Government Aid (most developing countries). Write on official letterhead. Available to others for £15 including surface postage. Order from Publications Distribution Office, Natural Resources Institute, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK; phone 44-1634-880088.
DROUGHT-TOLERANT, EARLY-MATURING 'CRIMSON' LENTIL. The Arid Lands Newsletter of the University of Arizona recently featured the new 'Crimson' variety of lentil (Lens culinaris), now available to farmers in the U.S. This particular variety is derived from Egyptian germplasm and is particularly well adapted to low rainfall, an early bloomer, tall and upright in growth habit, and a good yielder. Pods contain 2 or 3 seeds, seed coats are light brown with some darkly mottled spots, cotyledons are bright red-orange. The USDA registration article states that "these seed quality traits are distinguishing features of the cultivar and should appeal to international markets." In field trials no serious insect or disease problems were noted. Write ECHO if you would like a trial packet.
"SWEET" LUPIN (LUPINUS ALBUS) SEED. Dave Sweere and Gary Riestenberg with the United States Agricultural Development Corporation contacted ECHO and offered us seed of "sweet" lupin. The following is based on material written by Drs. Fred and Nancy Elliott, who developed the varieties for the company. Most North Americans know lupins as an ornamental or as a wildflower in the Rocky Mountains that can make cattle and sheep sick. But Europeans know it as a commercial crop which, for generations, has provided nutritious feed for their farm animals. In the South American Andes, people have eaten a lupin called tarwi for centuries. Lupins contain alkaloids, which cause a bitter taste and toxic effect when eaten. Andean people soak the beans for several days in running water to remove the alkaloids, then make a gruel which is often fed to babies or into a flour used in many breads and noodle recipes. The same procedure was described by Florentinus in 218 A.D. and is still used in Egypt and Italy to prepare lupins for animal feed. Lupins were grown for human and animal food centuries before Christ. The Roman author Varro reported that every Roman inn had a "labrum lupinarum," a basin used to soak out the alkaloids.
In this century "sweet" varieties of lupins have been developed which lack the bitter alkaloids. In many countries these are now grown like soybeans. The quality of the protein is similar to the soybean. In the processing of soybean meal the oils are removed and the meal is heated to inactivate the trypsin inhi- bitors and other compounds that inhibit digestion. Such processing is not necessary with the sweet lupins. They can be fed directly to animals, including poultry, pigs, cattle and sheep. Because no heat treatment is needed they are a natural for the small farmer in remote areas. Getting enough protein to maintain good egg production is often a problem. Dr. Elliott says that studies at the University of Minnesota and Tufts University indicate that lupins can provide an adequate poultry diet.
Another advantage over many legumes is that the lupins do not produce gas in the intestines (technically one says they do not produce flatulence). Many beans contain the complex sugars raffinose, stachyose and xylose which are not digestible by humans and many other animals. However, after they have moved into the intestine they are attacked by microorganisms which can break them down. In the process they produce gas. This could be a special consideration if you are looking for a legume to put in baby food. Gerry sent us several kinds of pasta that they sell commercially (too early for a report on taste). Their recipes are proprietary, but he suggested that up to 30% lupin flour could be used.
Who should try lupins? Lupins would be a good crop to try at higher elevations, depending on your latitude. The book Food Legumes says that they are successful in Kenya between 5000-8000 feet (1500-2400 meters). In fact they can tolerate temperatures down to 16 F (-9 C). The tropical lowlands would not be suitable for lupins because the seeds will not set if the temperature is high during flowering (over 90 F or 30 C). Farmers can grow a crop of lupins in the cool season and, because it is a legume, it will add nitrogen to the soil for the next crop. Lupins may be thought of as suited to the more northerly parts of the temperate region. This is because breeders have had success in adapting them to cold regions. Remember, though, that they originated in the Mediterranean. The variety ECHO was given should be one of the more adaptable. The same book says that this particular species (there are several other species) will tolerate mildly acid to mildly alkaline soils of only moderate fertility. They have been grown on saline (i.e. salty) soils in the Sudan and Egypt. I asked whether it would work to save your own seed. The answer is a qualified yes. Every time you grow the crop, roughly 2-10 plants per thousand mutate back to the alkaloid type. Because this is a dominant trait, the quality gradually diminishes. Gerry says that this variety, "altra," is one of the more stable. They have had excellent results through 7 years and expect they can go for 14 years. They have a clean-up program in which a large number of people go through one of the smaller fields tasting a seed from each plant. If the taste is bitter the plant is pulled out. The harvest is then used to start a new lot of seed that can be increased for about 10 years. You could either buy new seed every so often or go through the same exercise yourself.
MARAMA BEAN, TYLOSEMA ESCULENTUM, FOR VERY ARID REGIONS. Thanks to several people in ECHO's network, we are able to offer marama bean seed to those working in very arid regions. But what is a marama bean? I rely on the book Tropical Legumes: Resources for the Future for the following discussion. It is a wild plant prized by people living in and around the Kalahari in southern Africa. In Botswana and Namibia it is an important part of the diet in remote regions. It is a rich source of protein and energy in regions where few conventional crops can survive. It grows in some areas that receive up to 800 mm rainfall (32 inches) and in others where rainfall is so slight and erratic that in some years almost no rain falls at all.
The plant has long viny stems, but it is a creeper rather than a climber. They hug the ground, presumably avoiding drying winds. Seed pods contain 1-6 seeds about the diameter of a thumb nail. They are never eaten raw. After roasting they have a delicious nutty flavor that has been compared to roasted cashew nuts. Europeans in southern Africa grind the roasted seeds and use them as a culinary substitute for almonds. Africans boil them with cornmeal or grind them to a powder that is boiled in water to make either a porridge or a cocoa-like beverage. Raw seeds store well and remain edible for years. Protein content of seeds range from 30-39% (comparable to soybean). Oil content is 36-43% (about twice that of soybean). Like other legumes, the protein is rich in the amino acid lysine (5%) and deficient in methionine (0.7%).
During cooler months stems die back, but the underground tuber produces new stems when warm weather returns. The tuber can attain a weight of over 10 kg after a few years. (The plant at ECHO produced a tuber larger than a basketball.) Young tubers are dug in the Kalahari at about 1 kg. Tubers more than 2 years old are fibrous and/or astringent. Baked, boiled or roasted they have a sweet, pleasant flavor. They contain up to 90% water (important to surviving the dry periods) and are an important emergency source of water. [A bit of trivia: I have been told that it is the tuber from which water is squeezed in the movie "The Gods Must Be Crazy."] Tubers contain 9% protein on a dry weight basis. Tropical Legumes states that "of all the plants described in this book, the marama bean is perhaps the least developed" in scientific study or plant breeding efforts to improve it.
Dr. Stanford sent the following hints on germinating the seeds. Keep them warm (they come from the Kalahari Desert). Seeds germinate after a rainstorm has swept the land, and the soil has moistened deeply, but the surface is drying. The thick shell, almost 1 mm, is extremely hard. When wetted, it swells tremendously. Then the germ and endosperm will absorb water, and germination starts. But for that to occur, you must first scratch the outside with a file. Do NOT try to hasten germination by dropping the bean into water. Be patient-let it imbibe slowly by planting it in moist (not wet) soil or potting medium. Plants prefer neutral to acid soil or sand.
Galen Sauder in Botswana supplied us with some seed and wrote, "I was excited to receive your request for marama beans. The day before it arrived I was helping some people harvest these beans. They were growing by the side of the road in an area that had received rains. I could have filled my pick-up if I had all day. The beans seem to like the gutters of the road where water collects. Last year I had some of these beans. After they were roasted the woody shell cracked off and inside is a delicious nut tasting like a hickory smoked cashew."
NUTRITIVE VALUE OF NUAS (POPPING BEANS). An article by van Beem et. al., in the April-June 1992 issue of Economic Botany addresses this topic. But first, what are popping beans?
Nuas are varieties of (American) common beans, Phaseolus vulgaris, which burst when toasted. In spite of the common name "popping beans," they do not actually pop. Rather, when heated in hot oil or on a hot dry pan, they expand and split open. This is all the cooking they require. "The resulting product has a powdery texture with a taste between that of popcorn and roasted peanuts." Most of our staff very much enjoyed the very few beans that we could spare for eating as a snack.
Nuas are cultivated in the highlands of Ecuador and Bolivia between 2,000 and 3,000 meters. In regions where firewood is scarce, the benefit of these beans obviously extends much beyond their unique taste. Most beans must normally be boiled for a long time to be adequately softened. This time is even longer in the mountains where the boiling point of water is well below 100 C. Nuas require only 3-4 minutes of cooking.
The plants are the "pole bean" type. They seem to be susceptible to common bean diseases. We can only keep the plants alive in the winter months here in southern Florida, so I doubt very much if you would succeed with them in any area where common beans do not grow well. They are also daylength sensitive. ECHO sent seed to several gardeners across the United States. Although the plants often did well, they bloomed and produced only in those few locations where they were still alive in late fall and winter when the days were short.
"The unique texture and taste of popped nuas appears to be related to their high starch content. The high starch levels may also explain the 'filling effect' [appetite satisfied] nuas have after consuming 15-20 seeds, as bean starches have been reported as being less digestible than cereal starches." [Ed: His thinking may be that materials that cannot be digested remain longer in the gut so the person feels full.]
There is no difference in moisture content between nuas and other common beans, but in nuas there is less space for steam to diffuse upon heating. "The steam forced expansion of these [limited] spaces is thought to contribute to the popping mechanism." Protein content is slightly lower in nuas than in other common beans (20.0% vs. 22.2%); starch (40.9% vs 35.5%) and amylose (18.1% vs 17.2%) are higher. The percentage of protein which can be digested was slightly lower in popped than in boiled nuas (76.6% vs 79.1%). "Nuas stored at optimum conditions retain indefinitely their ability to pop. However, under market place conditions, nuas lose their popping ability 2-3 months after harvest due to seed hardening. ... shop owners then will try to sell them as a dry bean cultivar. However, when nuas are boiled, they take a long time to reach an edible state and the broth in which they are cooked is 'watery' when compared to the thick broth of dry bean varieties."
The authors were concerned as to whether the short cooking time might be inadequate to destroy the antinutritional factors in common beans, especially tannins and lectins. Tannin levels in beans are low, though they do slightly reduce digestibility of protein. Lectins, the principle toxins in common beans, are more worrisome, as they interfere with absorption of nutrients from food. Lectins are themselves proteins, comprising about 10% of the total bean protein. Fortunately lectins appear to be denatured by the higher temperatures of roasting because popped beans had a similar or lower level than boiled beans.
Individuals working in areas where common beans are an important crop might well want to take a look at nuas. They probably have some export potential to the States because of the publicity they have received in recent years and the limited locations where they can be grown. In fact, one variety of seed that we are offering we purchased from a health food store in California. If you work where these beans are common and have helpful insights (especially as to how varieties may differ from each other), please write. These have grown very vigorously at ECHO through the years.
RESEARCH ON NUAS (POPPING BEANS). The international research center CIAT in Cali, Colombia is working (on a small scale) with nuas. Dr. Jeffery White, CIAT bean physiologist, says the beans do not produce well and are susceptible to most bean diseases, so farmers grow them less and less. "In fact, the crop is probably disappearing." Dr. Julia Kornegay at CIAT has crossed popping bean varieties with disease-resistant common beans and sent the progeny to Peru for testing. But when crossed with ordinary beans, the offspring lose their popping ability. Special breeding techniques are needed to recover that trait.
"There are about 30 types of nuas that differ in seed size, shape and color, but all taste similar. ...They retain their popping ability for years if stored at low temperature and low humidity. But they lose the popping trait in a few months if stored improperly." Dr. Kornegay would like to see popping beans marketed internationally.
PIGEONPEA VARIETIES FROM ICRISAT. We often tell people that ECHO specializes in growing food under difficult conditions. The pigeonpea, Cajanus cajan, is a prime example of a tough but nutritious plant for just such cases. This article is directed toward two audiences. For some of you, pigeonpea is already an important crop. You will mainly be interested in the information about and seeds for the vegetable pigeonpea varieties. For others who are not familiar with pigeonpea at all, the general discussion of pigeonpea is for you.
THE PIGEONPEA. (The following information is gleaned from a very helpful book, Pigeonpeas: a Valuable Crop of the Tropics, by Julia Morton, Roger Smith, A. Lugo- Lopez and R. Abrams, available for about US$7 from Dr. Eduardo Schroder; BNF Laboratory; Dept. of Agronomy and Soils; Univ. of Puerto Rico; Mayaguez, PR 00709- 5000. They also have a similar book on mung beans at the same price.) Why might you wish to grow pigeonpeas? I think of three principal reasons. (1) They grow under poor soil conditions. (2) They are tolerant of dry weather. (3) They are a nutritious, high- protein pulse crop. Other reasons include: (4) Leaves can be used for animal feed. (5) The fast-growing plants make good shade for other crops, e.g. vegetables, herbs, vanilla. (6) Plants are perennial for up to 5 years. (7) Woody parts can be used for firewood. (8) Water and nutrients from deep in the soil can be caught by its deep taproot.
The pigeonpea is a shrub that grows from one to a few meters tall and perhaps two meters wide, unless special short-season varieties are chosen. Most types flower when the days are 11 to 11 1/2 hours long, but varieties responding to both shorter and longer day lengths are available, and some will flower at any time of the year. Usually flowering begins in 120-150 days and seed maturity in 250 days, but these figures can be as early as 60 and 100 days respectively.
It is often advisable on a small farm to have one area for higher value crops, where the soil has been improved by concentrating the limited amount of manure and mulch, and where some irrigation is available. On the remaining, larger part of the farm, plants which yield in less fertile soil and require only normal rainfall are desired. Plants such as cassava, sweet potato and pigeonpeas fall into this later category. A few pigeonpeas are also often grown near the house for ease of harvest. For household use "indeterminate" varieties are wanted because they will produce a few pods each day over a long season. I recall visiting a dry part of the Dominican Republic during the dry season. Very little was green in the gardens, but pigeonpeas were green and providing a small daily harvest. They do best where annual rainfall ranges from 500-1,500 mm (20-60 inches) a year. The range of suitable elevations depends on latitude. In Venezuela they are grown up to 3,000 meters, in Jamaica up to 1,100 meters. In Hawaii they failed to set seed at 1,000 meters.
"When cultivated for the seeds, pigeonpeas are grown as an annual or biennial because the productivity declines after the first year and drops considerably after the third year. When grown for forage or green manure, it is usually maintained no more than five years. The plant will die in about 10-12 years."
"No regrowth occurs when plants are cut off at ground level, but regrowth is satisfactory with cutting heights ranging from 0.15 to 1.5 meters. Vigor declines and plant mortality increases somewhat after a first cutting and more markedly after a second cutting."
"The pigeonpea is noted for greater soil adaptability than other legumes [nitrogen fixing plants]. ... It performs well in a wide range of soil types. It can endure soil salinity of 0.0005 g NaCl/g. It seems well adapted to a soil pH as low as 5 and as high as 8." Plants also are rather resistant to nematodes.
VEGETABLE PIGEONPEA. (The following is taken from a booklet by the same title by ICRISAT, the International Crops Research Institute for the Semi-Arid Tropics, Pantancheru, Andhra Pradesh 502 324, INDIA. The booklet has four interesting and complicated recipes which are in the Indian tradition.)
Pigeonpeas are most commonly used as a pulse crop. (Pulses are leguminous crops, the dried seeds of which are used as human food.) When used as a "vegetable," the pea is picked when the seeds have reached physiological maturity, that is, when they are fully grown but just before they lose their green color. At this stage the green seed is more nutritious than the dry seed because it has more protein, sugar and fat. In addition, its protein is more digestible. "There are considerably lower quantities of the sugars that produce gas (flatulence) in the green seeds." The dried seeds contain somewhat more minerals. See Table I.
Table I. Comparison of some nutritional constituents of green and mature pigeonpeas on a dry-weight basis.
Protein digestibility (%)
Trypsin inhibitor (units/mg)
Amylase inhibitor (units/mg)
Flatulence factors (g/100g sol. sugar)
Crude fiber (%)
Minerals and trace elements (mg/100g)
In comparison with green peas, the vegetable pigeonpea takes longer to cook and is not as sweet, but is much more nutritious. On a fresh weight basis, it has greater edible portion (72% vs 53%), more protein, carbohydrates, fiber and fat than green pea. It also has more minerals and much more of some vitamins (469 vs. 83 vit. A/100g; 0.3 vs. 0.01 vit. B2; 25 vs. 9 vit. C).
"The best vegetable pigeonpea cultivars have long pods, with as many as 9 large sweet seeds which are easily removed from the shell." Sweetness is also desirable. In contrast, what is usually sold in Indian markets for use as a vegetable are small pods with small seeds. "Consumers prefer vegetable pigeonpea with green pods, ... but tests ... have shown that differences in pod color are not related to cooking time, taste or quality." However, cultivars grown from white seeds leave clear rather than colored cooking water. The large pods are especially attractive to insects. Insect damage can also be greater in cultivars that have the pods clustered in bunches at the tops of the plants, but these varieties are also shorter and are easier to spray with insecticides and easier to harvest. If the rainy season is long, or the field is irrigated, pods may be produced as long as the plant remains free of disease and the mean temperature remains about 15-30 degrees C. A yield of 11 t/ha of green pods in five pickings was obtained on one plot. Harvest the pods just before the seeds start to lose their bright green color. Because pod color at this stage will be different with different varieties, you will need to sample seeds to find when it is best to harvest. In the Caribbean, harvesting has been mechanized by adapting green bean pickers.
If you would like to try pulse-type or vegetable pigeonpea, ECHO can send you a small variety trial. If you are already familiar with pigeonpea and wish to do a major trial, write to ICRISAT; Patancheru, Andhra Pradesh 502 324, INDIA, and tell them details of the trial you intend to undertake.
SOYBEAN CROP PRODUCTION BULLETIN AVAILABLE FROM ECHO. Dr. Frank Martin wrote this bulletin because soybean is one of the most important food plants of the world and is growing in importance in Third World countries. It produces more protein and oil per unit of land than almost any other crop and can substitute for meat and to some extent for milk. In 7 pages he discusses cooking/processing methods, climatic and soil needs, varieties and their differences, care of seed, and culture of soybean. (Write ECHO to receive the complete bulletin.) Many of you no doubt share my skepticism as to whether you would personally enjoy eating soybean and whether it would be accepted in your community. Yet I have seen examples where it has become much appreciated in a new community. The trick is that soybean must have special processing and be used in special ways. Here are some basic processing methods from the bulletin.
SHELLED GREEN SEEDS are boiled until tender (boil pods first for easier shelling). Cooked beans can be eaten as is or used in other dishes. Frank describes their flavor as "unique but very good."
PREBOILED BEANS. Normal boiling of dry soybeans results in an "off flavor." This can be avoided by destroying the enzyme that causes the problem by preboiling the beans. Bring to a boil two parts water, add one part soybeans and boil for 5 minutes. Meanwhile, boil four parts water. Remove seeds from the first water, rinse, and boil in the second water for 5 minutes. Discard the water and rinse. These are called "preboiled soybeans."
BOILED SOYBEANS are made by boiling preboiled beans until soft. Use as desired. Alternatively the soft beans can be mashed and used to enrich baked products.
SOYBEAN NUTS are made by deep frying preboiled soybeans for 12 minutes at 350 F. Drain and salt.
SOYBEAN MILK. Grind preboiled soybeans as fine as possible, using a home blender, a hand mill, or an electric mill. The ground soybeans should be low in grittiness. Mix one part ground, preboiled beans to two parts water. Filter with a cloth or colander. The liquid is left to stand one hour and is then decanted or filtered. The liquid portion is then boiled gently for one hour. This is soybean milk.
FRIED BEAN CAKE. The residue from filtering (or the precipitate from letting the filtrate settle) can be used for fried bean cake. Mix 4 parts residue with 1 part flour. Fry slowly in an oiled frying pan.
CHEESE (TOFU). Soak beans (not preboiled beans) overnight in water. Discard water and rinse. Grind as fine as possible (see above). Mix three parts water to one part ground soybean. Filter through a cheese cloth. Heat to boiling, stirring to avoid scorching. While the milk is still boiling, add one part of a precipitating solution as follows: 1% solution of MgSO4 (Epsom salts)-one part solution to 8 parts milk, or vinegar-one part solution to 66 parts milk. Curd formation occurs immediately. After 15 minutes filter through cheesecloth, discarding the solution. Wash curd twice. Press to shape and to remove water. Use this as a cheese substitute in cooked dishes.
ECHO sometimes has seed of the soybean varieties Davis (subtropical) and Duocrop (tropical) mentioned in the Soybean Crop Production Bulletin. We also have two other subtropical/temperate varieties developed for the southeastern United States, Braxton and Wright. We can send only enough to see how a small row will perform. If you are at low to moderate latitudes in the tropics, request Duocrop; at high elevations or in the subtropics request the other three.
If soybeans have not been grown in an area before, it is more important than with some legumes that the seeds be inoculated with rhizobia. Without this they may be inefficient at fixing their own nitrogen. ECHO does not carry inoculants; we refer you to the Haile-Dean Seed Co., P.O. Box 1458, Winter Garden, FL 32787, USA; phone 800/423-7333. They generally have bulk inoculant year-round, as they supply many tropical regions. If you start growing soybeans, finding inoculant may be a big problem for many of you. The good news is that a little bit goes a long way (a small $2 packet treats 2 bushels of seed). If there is a local farm supply store, perhaps they can order inoculant for you.
TEPARY BEANS RESIST DROUGHT. (We relied on the books Tropical Legumes: Resources for the Future by NAS, 1979, and Food Legumes by Daisy E. Kay, 1979, in preparing this note.) A frequent question ECHO receives from people working in the semi-arid tropics is, "It is so dry here! What plants can we grow with so little rain?" The tepary bean, Phaseolus acutifolius, is a promising crop for semi-arid to arid regions with infrequent but heavy rains and extreme heat.
This native plant of the Sonoran desert in western North America has been an important cultivated food of native Americans for over 5,000 years. When planted toward the end of the rainy season, tepary beans may receive sufficient moisture in a few heavy rains early in their growth to mature and produce quickly, even when conditions at the end of their life cycle are extremely hot and dry. Sometimes, when planted in recently water- logged soils of certain types, production is possible without any additional rain. Richard Pratt at Purdue University had results of yield trials where he compared the effect of drought on teparies and on common beans. As he cut back on water, the yield of common beans decreased steadily whereas the yield of tepary beans actually increased up to a point before they also eventually dropped off. Tepary beans have good potential to yield when very little other food is available.
The countless landraces and local varieties vary widely in color, seed size, and growth habit, but most yield their high-protein crop just 60-90 days after planting. The leaves and young pods are a leguminous forage nutritionally comparable to alfalfa. Dried pods may also be fed to animals. Plants are bushy to semi-vining on dry land, with more extensive vining and foliage growth when water is plentiful. The seeds and trifoliate leaves are a bit smaller than in the common bean. Because they are extremely resistant to common bacterial blight, which affects other beans in the tropics, they are used in breeding programs to impart this resistance to the (American) common bean Phaseolus vulgaris.
Tepary beans can thrive in areas with as little as 500-600mm (20-24 in) rain per year, and seed production drops with over 1000mm/year (40 in). Seeds are generally planted 10-20 cm (4-8 in) deep to utilize the lower water reserves. Plants often receive 3 or 4 irrigations in the early stages of growth. (Continued irrigation can actually lead to increased vegetative growth and lower seed yield.) Teparies prefer well-drained soils and are fairly tolerant of alkaline or saline soils. They may mature more quickly at mid elevations than coastal regions.
We consider them one of the more promising plants for arid regions. For example, Peter Welle got quick and heavy yields in Haiti in spite of hot, dry weather and calcareous soils. Robert Hargrave from Kenya wrote, "I wanted to report on the tepary beans I picked up when I visited ECHO in 1989. They have proved very promising. During the last rainy season (Nov. 1990 to January 1991) I recorded yields up to 1500 kg/ha on the yellow tepary beans. Admittedly we had higher than average rainfall (over 200 mm, 8 inches), but common field beans would not have produced. Some of my Kenyan friends have also grown and eaten the (brown) tepary beans, and reported favorably on them. I also conducted some inoculant trials with Rhizobium donated by a professor from Trier University in Germany who is conducting studies in this area. It appears that, at least here, there is no need for special inoculant." Dr. Leon at CATIE says that tepary beans can be found in the market on the Pacific coast of Mexico. He has read that they were introduced as a cover crop in the Sahel of Africa, and that people on their own initiative began eating the bean. (We would appreciate more information on this from our African readers.) Dr. Hidalgo at CIAT believes the relatively low yield and a flavor that is inferior to common beans are the main problems with commercialization. But he added that, "As a crop for subsistence farming, its potential is excellent. It doesn't stop growing even when it flowers. So if a stress occurs after the first flowers, it has a high capacity to recuperate."
Despite tepary bean's apparent potential to produce food quickly in semi-arid regions, not much attention has been given to research and improvement of this species by the scientific community. Some obstacles to introduction into new areas include disease problems (in climates where it is not adapted), sensitivity to some salty soils of semi-arid zones, poor productivity in humid regions, tendency toward short-day flowering, frost damage (nighttime temperatures must be above 8 C/46 F), unusually small and flat appearance of the bean, a sweet taste different from the common bean, and long cooking time after long periods of storage. (According to Linda MacElwee of Native Seeds/SEARCH in Arizona, they can take up to 4 hours of boiling, even after soaking, if they have been stored for some time. Even fresh teparies can take longer to cook than many common beans.) Teparies may also cause flatulence and therefore are not recommended as food for babies under one year old.
Agronomists at the United States Department of Agriculture in Mayagez, Puerto Rico, chose 11 cultivated lines from 70 accessions of tepary after evaluating and selecting under varying environmental conditions. They studied yield, seed size, protein and anti-nutritive factors, and resistance of each line to six diseases.
They found that tepary beans performed best and yielded more than the common bean under higher temperatures in dry regions. (Linda MacElwee says they will produce at 46 C/115 F.) The seed protein concentration for the tested varieties ranged from 17.8 to 26.8%, and anti-nutrients that interfere with protein digestibility were on average less than in the common bean. All lines were resistant to common bacterial blight and susceptible to the bean common mosaic virus, but the lines had varying resistance or tolerance to rust, ashy stem blight, bean golden mosaic virus, and Fusarium wilt.
The seeds supplied to ECHO are photoperiod-insensitive, virus-free, and selected for high yield and disease resistance; in addition, they may be more tolerant of excess rain than other tepary varieties.
We planted the tepary beans in our own semi-arid greenhouse as a trial. They germinated immediately and grew impressively well with none of the disease problems usually evident on tepary beans at ECHO [note: we do not send out the tepary seed grown at ECHO because of the risk of transmitting diseases common here]. In two months, most of the varieties already have pods and continue to flower. There is quite a bit of variation in foliage produced, flowering time, and leaf size. We asked Dr. Phillip Miklas, who sent us the disease-resistant varieties, the following questions on the potential of tepary beans:
Q. In what climates have you found tepary beans to outperform
A. Tepary beans are outstanding for hot climates, in some cases yielding over three times as much as dry beans when high temperatures cause common bean flowers to abort. They are well-suited to areas which suffer periodic drought. For example, in places which often, but not always, receive enough rain for common beans, you might plant a few plots of tepary beans as an insurance crop. However, in extremely rainy periods, tepary beans will produce a lot of vegetation, but very little or no seed.
Q. The seeds of the disease-resistant beans you supplied are smaller than the seeds we receive from Arizona. Can a grower select for larger seed and, if so, will that affect protein levels?
A. These are true-breeding lines of tepary beans; the plants produced should be genetically similar. It is not likely that you will find wide variation in seed size. Any selection of that nature, though, would not significantly affect other characteristics of the bean.
Q. Are the diseases observed in the study usually a major problem in arid to semi-arid zones, or are they primarily present in humid areas? Is there an advantage for people in extremely arid zones in using the selected disease-resistant varieties over other (larger-seeded) ones?
A. The diseases are present in many tropical climates. For example, common bacterial blight occurs mainly in hot, humid areas, and ashy stem blight occurs in hot, dry areas. One thing to remember is that the strains of each pathogen vary in each region; in other words, we were only able to select for resistance to the strains in our area, but different strains may be present in a new area.
Q. Do you have any comments concerning unique cultural
A. Fertilization should not be necessary. If you fertilize before the plants have emerged from the soil, nitrogen- fixing nodules may not form. So delay any fertilization until after the seeds have sprouted. [Tepary beans can nodulate with the broad cowpea/lima bean/Canavalia/mung bean group of rhizobia. Under very hot or dry conditions, the nitrogen-fixing bacteria will not persist strongly from one season to the next. In such conditions it may be best to inoculate the seeds.]
It is very important with tepary beans to try them at different times in the season to determine their best "window" in the local climate. Do not give up on them if they don't succeed on the first try; planting again at a different time may produce better results.
Q. How easily can tepary beans be crossed with other local beans
to impart disease resistance?
A. This is not possible at the field level.
Q. Are there other reasons why someone might want to grow tepary beans if they could grow common beans?
A. Tepary beans often produce at a different time of year than other beans, when it is too hot or dry to grow common beans. In addition, they are an excellent crop for drought insurance in areas with occasional dry years; people in such areas may want to maintain a plot of tepary beans in case the common beans do not receive enough rain. They may also be used as a green manure in some areas, although that is not their primary use now.
Q. Do tepary beans have potential as a green manure/cover crop for arid zones? (ECHO has heard of this in the Caribbean.)
A. Since tepary bean is a short-lived annual, it doesn't have as much potential as a cover crop as some other plants would. One of its great potential uses may be in an intercropping system with sorghum during the dry season.
Dr. Miklas has sent ECHO seed of these eleven varieties to distribute to our network. We have combined them according to color (white, grey, black, yellow-brown, and red). When ordering seed, please indicate the dry bean color preferences (if any) for your region.
We and Dr. Miklas (USDA-ARS, P.O. Box 70, Mayagez, Puerto Rico 00681) are very eager to hear how these varieties perform for you and are accepted in your area. ECHO also has larger-seeded virus-free native varieties from Arizona (white and yellow). Our source is Native Seeds/SEARCH, 2509 N. Campbell Ave. #325, Tucson, AZ 85719, USA. They carry 18 varieties of tepary bean; write for their seed catalog for more information on these and many other dryland plants. Please note that people with year-round humid weather would probably be wasting their time with this trial. For example, we cannot grow tepary beans at ECHO in the summer.
WINGED BEANS. See pages 70-71.
CAUSES OF BEAN BLOSSOM DROP. James Chrisantus in Kenya asked why all the blossoms fell off his winged beans, thus producing no beans. ECHO asked Dr. Andrew Duncan of Oregon State University. His reply concerns beans in general. "The two major causes of bean blossom drop are high temperatures over 90 F (32 C) and drought. Beans selected for temperate zones are more sensitive than those native to the humid tropics and sub-tropics. If beans have been growing under moderate (very favorable) conditions, then the imposition of stresses is even more damaging." Drought stress can occur even when the soil holds considerable water. For example, when soil moisture levels are at half of the field capacity [soils contain half as much water as they can hold without being flooded], and relative humidity is low (<25%), even a 5 mile per hour (8 km/h) breeze can cause moisture stress. "Root damage by diseases, insects or deep cultivation should also be checked. A long shot is improper use of pesticides. Beans are very sensitive to the 2,4-D type herbicides, even the vapors from a distance. Solvents included in insect sprays can damage blossoms and leaves."
SWEET POTATO CROP PRODUCTION BULLETIN, by Dr. Frank Martin. Dr. Martin is one of the leading sweet potato breeders, so it is fitting that he treat the subject of his first scientific love. The following is a condensed version; write ECHO for the complete bulletin.
Sweet potatoes (Ipomoea batatas) are the sixth or seventh most-produced food crop in the world. What makes it such a great crop? It is relatively easy to grow, is relatively free of pests and diseases, has relatively high produc- tivity, and is always good food, principally starch, some protein and vitamin C, and, in orange varieties, rich in vitamin A. In addition, the young leaves, rich in protein and most vitamins, are also good food. Furthermore, both sweet potato tubers and vines are excellent animal food.
Its ability to produce in poor soils make it an especially good crop for poor tropical soils where fertilizer is not available. If the leaves are also used as food, sweet potato will probably produce more nutrients per acre than any other crop under those conditions. (Cassava also produces well on poor soils and also has both edible roots and leaves. Its main advantage over sweet potato is drought tolerance. Sweet potato has the advantage in nutrients because polyphenolics in the cassava leaf combine with protein during cooking and reduce the amount of protein that is digestible.)
PRINCIPLE USES OF SWEET POTATOES. Leaves can be harvested during the second and third months of production. Only the tender stem and young, not-fully-developed leaves should be taken. The leaves and stems are boiled for 15-20 minutes. You are already familiar with recipes for boiled or baked sweet potatoes. (By the way, baking converts part of the starch to the sugar maltose, thus increasing sweetness.) There are other, less familiar, uses. The mashed pulp of boiled sweet potato can also be used as a partial substitute for wheat flour in baked products such as pancakes, cakes, flat breads, cookies, pies, fritters, or even bread. It can also be processed further, as you will see.
To make osmotically modified boiled sweet potato, the peeled and trimmed sweet potatoes are cut into thin (1/8") slices, placed in water 2 hours (moved once in a while) and then boiled. The products will be clearer, less sweet, and milder than those made from untreated sweet potatoes. (What is happening chemically is that the enzymes and substrates responsible for polyphenolic oxidation are partially lost, as well as some of the sugars.)
Sweet potato flour is much more difficult to make than potato flour because the reducing sugars readily released from the starch combine with free amino acids to produce disagreeable colors, odors, and flavors. To avoid this the peeled sweet potato can be shredded, and the shreds immersed in water 2 hours. This process works better if the water is changed 2-3 times. The shreds are drained and then dried, first in the shade (with air movement or wind) and later in the sun (in some cases, drying over the stove or in an oven will be necessary). The brittle shreds are easily crushed to flour, or this can be done rapidly in a household blender. The flour can be stored for 6 months or more in sealed containers. It can be used as a substitute for wheat flour in the following amounts: 100% in white sauces, 25-50% in cookies, cakes and flat breads, and 15-20% in breads. From the water, starch can be recovered (see below).
Starch can be produced by grinding the peeled sweet potato in a mill or blender as finely as possible, and mixing with 5-10 times its weight in water. The starch settles out, and the water is carefully poured away (this can be used as pig feed). The starch is then mixed with water 1-3 times more and the process is repeated. After the last settling the water is carefully drained and the starch is dried on a metal surface in the sun. It can be used as is any starch, such as corn or potato starch, and can be stored in sealed containers for a year or more.
A breakfast food similar to "cereal" can be made from any sweet potato. The sweet potato is grated (not as finely ground as for starch), suspended in water, and filtered through a cloth. The liquid is saved for starch, the residue is suspended 1-3 times more in water, and filtering is repeated. The portion of the sweet potato that does not pass through the filter is then dried and lightly toasted on a hot plate (over the fire). The toasting is very delicate. The product must be stirred and turned almost continuously, and should not become sticky and jellified. The toasted product can be stored in sealed containers and eaten with milk without further cooking, or can be used much like starch or flour, imparting its characteristic flavor.
CULTURE OF THE SWEET POTATO. Sweet potato is a hot weather crop. It is difficult to imagine an earthly environment that is too hot for sweet potato. In general, hot temperatures only speed up its growth. On the other hand sweet potatoes will survive at any temperature above freezing, and are very productive at temperatures that are comfortable for humans as well.
Depending upon variety, sweet potatoes may be ready for harvest after 10 weeks or may require up to 9 months in the field. The majority of the varieties can be harvested after 4 1/2 months in the field. Cool conditions can extend the needed growth period to 8-9 months. Early varieties (10 weeks) are in the process of development. Sweet potatoes from an individual planting may be harvested as needed over a three to four month harvest season.
If the soil is well aerated with medium texture the sweet potatoes need not be planted on ridges. They can be produced in heavy soils if formed into ridges for drainage and increased aeration. Sweet potatoes are often grown in sandy soils. Too much nitrogen results in abundant foliage and low and/or late yields. They can tolerate light drought in the second and third month of growth, and often fairly severe drought in the fourth or fifth month.
There are too many varieties to try to describe them all. Because of all this variation it may well be worth your while to collect several varieties within your country for local variety trials and preference tests. It is probably more useful to talk about some of the differences found. Internal color is the first difference you will see: white varieties (no vitamin A), yellow (little vitamin A) and orange (high vitamin A). Most varieties are chosen for sweetness, though Dr. Martin has developed non-sweet varieties which people that do not care for sweet potatoes may enjoy. [Ed: this was the case with me.] Texture ranges from dry (least preferred) to intermediate (often preferred) and moist (common in orange roots). Most plants are running (vining), a few are bunch varieties.
For practical purposes, in the tropics sweet potatoes are produced from cuttings of existing vines. (Only in the temperate zone is it necessary to conserve storage roots during the winter and stimulate them to grow in the spring as a source of sprouts for planting.) Where sweet potatoes are not grown year round, special plantings will have to be made as sources of cuttings, in which case it may be possible to obtain as many as 30 cuttings per plant. Usually best results are obtained by planting cuttings at an angle with about 2/3 of the cutting below the soil.
Cuttings should be 12-18 inches long. Shorter cuttings can be used if the distance between nodes is not excessive. The vines should be vigorous but not too soft and succulent. Old thickened, diseased, and leafless cuttings should be avoided. It is not necessary to remove any leaves from the cuttings. Cuttings should be gathered together in convenient-sized bundles, tied, or wrapped in burlap. These bundles should be held 1-3 days in a shady, protected area and maintained moist. This will stimulate root production, and even though the initial roots may be broken on transplanting the cutting will be more ready to establish itself if allowed to pre-root as described. If weevils are a problem, immerse cuttings for 5 minutes in a drum containing 0.1% carbofuran. Use gloves. Plant within 24 hours. This treatment eliminates weevils within the cuttings.
The area selected for planting should be as far from previous sweet potato plantings and its morning glory relatives as possible. One foot (30cm) between plants in a row is a minimum. Individual plants will yield more if given up to 1 square yard (meter) of space, but many roots will be excessively large. These large roots are edible but likely to be irregular in shape and unsightly. The layout of rows or beds will depend on the machinery or methods used for soil preparation.
Newly planted cuttings need watering frequently for 1-3 weeks. Once new growth begins water only when visible wilting is seen. Very little water will be necessary the fourth and fifth months. Remember, too much foliage means poor or late storage-root growth. Excessive foliage with poor yields is usually due to too heavy fertilization, especially with nitrogen. Any method that destroys part of the foliage tends to decrease this problem. Try feeding a portion of the vines to animals. [Dr. Martin told me of seeing men drag thorn bushes through the patch to tear up some of the leaves.]
There is no perfect time for harvests. Early harvest results in less yield, smaller roots, less insect damage, less cracking, milder flavors, and poor storeability. Late harvest results in the reverse. If insects are not a problem, partial or periodic harvest from 3 to 8 months may be possible. Cut away the vines before harvest. These can be fed to animals. As soon as possible after digging, remove the sweet potatoes from the sun. The roots should be sorted. Very small roots can be fed to animals. Damaged roots can be used immediately or processed as previously described. Sound roots can be stored at cool temperatures (minimum 55 F, 13 C) for 2-8 weeks. Rot of roots in storage is reduced by curing at high (80-90%) humidity and high (90-95 F) temperature for 4-5 days. Cured roots can be stored at the recommended temperature for up to 1 year.
SWEET POTATO CULTIVARS AVAILABLE. We grew and compared several of Dr. Frank Martin's sweet potatoes, both the non-sweet and sweet varieties. We selected six superior cultivars based on a combination of traits, including: uniqueness (not available elsewhere), yield, sugar content, ease of processing, texture, shape, color, time to maturity and reliable yield. These are the ones we will distribute from now on.
Cuttings are typically available July through October. Please send $5 to help with postage and handling if that is possible. Since the danger of introducing a new disease or insect is so much greater with fresh plant tissue than with seeds, we will only send them after receiving a government plant import permit from you. Be sure to designate which varieties you would like. If a phytosanitary certificate (certified disease and insect free) is required by the permit, enclose an additional $20 per order. If you use a USA address, check with us first. Many states in the US have restrictions on shipping sweet potatoes into the state. It is much better to pick up the cuttings on a visit to ECHO en route to your country, as cuttings may not survive very well in shipping.
Varieties selected were: "Topaz" (orange and sweet, closest to typical US varieties but 50% higher yielding for us, somewhat less uniform, some drought resistance; "Ivoire" (non-sweet, "Irish" potato substitute, very dry if harvested after 12 weeks); "Viola" (purple skin, white flesh, sweet, good flavor, has done well everywhere); "Colorette" (low in sweetness, high yielding, light orange flesh, light purple outside); "Suabor" (large, sweet, smooth, early maturing, yellow when cooked); and "Toquecita" (good yield, white skin and flesh, sweet, large tuber, but highly lobed, excellent for processing).
SWEET POTATO COOKBOOK. We have appreciated contributions from Dr. Frank Martin on many topics over the years. His main professional interest, however, is the breeding of sweet potatoes. When his technical expertise and personal interest in cooking was teamed with the skills of writer and agriculturalist Ruth Rubert and amateur gourmet cook (and professional engineer) Jos Herrera, this unique and valuable cookbook resulted.
Frank's personal acquaintance with scientists and sweet potato enthusiasts from many countries has made him aware of many delightful recipes that make this book an outstanding addition to the kitchen library. But it is his familiarity with the different kinds of sweet potatoes that makes the book especially unique. The type of sweet potato influences its cooking. Each type is better for some purposes than for others. The cookbook includes recipes designed to take advantage of these different types: dessert, tropical, white staple or orange staple types.
Dessert type sweet potatoes are very sweet, usually moist in the mouth, and almost always orange. On cooking in any manner, sweetness increases markedly. The flavor may seem carrot-like or even oily to some people. Tropical type sweet potatoes are less sweet, often dry in the mouth, and white, cream or yellow. Flavor is highly variable. These are the kinds of sweet potatoes most often found in the tropics, but a few are grown in the USA (Yellow Jersey, Rojoblanca and the Cuban boniatos of Florida). Cooking in any form increases sweetness. White staple "non-sweet" types were developed by Frank just before he retired. They are not sweet or are only very slightly sweet. Sweetness does not increase, or increases only slightly, upon cooking. They are often, but not necessarily, dry and need to be mashed to make them attractive to most palates. The flavor is usually neutral. They are white, whitish, cream, or pale yellow in color. Yellow staple type sweet potatoes is the orange-colored equivalent of the white staple type. They have a large amount of provitamin A and may taste like a carrot to some people.
Sweet potatoes are one of the world's most important food crops, surpassed only by wheat, rice, corn, Irish potato, and barley. Frank says they have the potential to be an even more important crop for peasant farmers (and the rest of us for that matter). The key to increasing their usefulness may surprise you-get rid of the sweetness! "Irish" potatoes (which really came from South America) are a temperate crop and poorly adapted to the hot, humid tropics. Yet their taste and cooking versatility are appreciated around the world. Dr. Martin believes that "bland" sweet potatoes, which could be used like Irish potatoes, could become a major part of tropical diets in a way more traditional varieties never could. These non-sweet or staple type sweet potatoes are almost a new crop. I have never cared much for sweet potatoes, but I very much enjoy the non-sweet varieties (with butter and chopped onion). Both taste and texture more similar to the potato, though still different.
Sweet potatoes are easy to grow, relatively free of pests, highly productive, and always good food. They produce in poor tropical soils without the benefit of fertilizers, tolerate drought once established, and thrive in tropical heat. Americans are often surprised to learn that sweet potato leaves are a popular vegetable in many countries. When both leaves and tubers are used for food, sweet potatoes will probably produce more nutrition per acre than any other crop. This all adds up to one fantastic crop for small land-holders in the tropics and sub-tropics. The cost of the book from ECHO is $6.00 plus postage.
LIVING SUPPORT POLES FOR YAMS (Diascorea spp.). [From "The Garden to Kitchen Newsletter" quoting Mike Benge with USAID.] This process is being used by farmers near the University of the Philippines at Los Baos. Fast-growing, nitrogen-fixing trees such as leucaena, gliricidia, or calliandra are planted ahead of time to shade out grasses. Yams are planted near the base of the tree after weeds are controlled. When the tuber begins to form, the tree bark is removed about 40 cm from the ground. This causes leaves to drop, giving full sun, mulch, fertilizer and support for the vine and eventually provides firewood. One strong sucker is left from the new tree growth below the girdled area to produce another tree.
Peter Afekoro in Nigeria writes that a lot of farmers are now using the growing branches of the moringa tree as a source of stake material for yam vines. The interesting aspect to him is that when you cut the young tree for the stake, it sends up 6-10 new trunks for use next year. [It tends to be weak, fast-rotting wood, however.] We discovered quite by accident here at ECHO that yams love to grow right up living moringa trees. The light shade does not seem to harm them at all, nor do the vines seem to harm the moringa tree.
The April 1990 issue of Agroforestry Today reports that farmers in Kenya's eastern highlands are using a local tree, Commiphora zimmermannii, (local names: mutunguka, mururi, kitungati) as stakes for both yam and passion fruit. It is drought tolerant, easily rooted from green stakes, slow growing with few lateral roots that might compete with crops, has no large dense canopy to shade crops, and thrives under frequent pollarding. (Pollarding is cutting back severely to a certain height, then letting new branches form near the top.) "Heavy vines would kill many trees, but Kenyan farmers claim that the mururi, once established, is permanent." A picture shows a farmer with yams on living stakes that appear to be about head high and were planted 20 years ago. "Few species could survive under these dense and heavy vines." It is also popular as living fences and is legally recognized as boundary markers because it is so permanent. If any of our Kenyan readers can supply ECHO with enough seed (if it produces seed) to make up 30 or so packets to offer to our network in other countries, please send details including postage costs and any insights you may have about growing the tree.