Direct seeding of hydroponically grown tomatoes (Solanum lycorpersicum) is not a common practice in South Africa, and most growers use transplants. Seedlings for hydroponic production of fresh market tomatoes are commonly transplanted at 6 to 7 weeks after sowing or at the six-leaf stage (Niederwieser, 2001). Some advantages of transplants, compared with direct seeding, include more efficient use of costly hybrid seed, avoidance of unfavorable cool soils, increased crop uniformity, and early harvest (Liptay et al., 1982; NeSmith, 1997, 1999; Orzolek, 1996).
Effects of transplant age on growth and development have been reported for several vegetable species under soil cultivation. Kratky et al. (1982) reported similar yield for Chinese cabbage (Brassica rapa L. ssp. pekinenis) plants developed from transplants of 3 to 6 weeks old. Tomato transplants of among 4, 5, or 6 weeks old did not exhibit significant differences in growth (Leskovar and Cantliffe, 1991). Hall (1989) reported that transplants produced higher late and total yields than direct-seeded plants for one of two watermelon (Citrullus lanatus Thunb.) cultivars. Transplants of bell pepper (Capsicum annuum L.) resulted in increased basal roots, advanced maturity, increased shoot allocation, improved fruit set, and fruiting efficiency compared with direct-seeded plants (Leskovar and Cantliffe, 1993). Leskovar and Cantliffe (1994) also reported that transplants of fresh-market tomatoes resulted in earlier and higher yields compared with direct-seeded plants when grown in soil.
Various studies have been conducted in open-field cultivation on direct seeding vs. transplants (Leskovar and Cantliffe, 1991, 1993), but there is limited information for tomatoes grown hydroponically. The selection of a planting system depends on the economics of plant establishment, plant performance after establishment, and the value of subsequent yield (Hall, 1989; Leskovar and Cantliffe, 1993, 1994). The effect of transplant stage and direct seeding on yield and biomass production of hydroponically grown tomatoes has not been reported. This study was conducted to determine the yield of two locally produced tomato cultivars as affected by transplant stage and direct seeding.
Hall, M.R. 1989 Cell size of seedling containers influences early vine growth and yield of transplanted watermelons HortScience 24 771 773
Kratky, B.A., Wang, J.K. & Kubojiri, K. 1982 Effects of container size, transplant age, and plant spacing on Chinese cabbage J. Amer. Soc. Hort. Sci. 107 345 347
Leskovar, D.I. & Cantliffe, D.J. 1991 Growth and yield of tomato plants in response to age of transplants J. Amer. Soc. Hort. Sci. 116 416 420
Leskovar, D.I. & Cantliffe, D.J. 1993 Comparison of plant establishment method, transplant or direct-seeding, on growth and yield of bell pepper J. Amer. Soc. Hort. Sci. 118 17 22
Leskovar, D.I. & Cantliffe, D.J. 1994 Transplant production systems influence growth and yield of fresh-market tomatoes J. Amer. Soc. Hort. Sci. 119 662 668
Leskovar, D.I. & Stoffella, P.J. 1995 Vegetable seedling root system: Morphology, development, and importance HortScience 30 1153 1159
Liptay, A., Bolton, E.F. & Dirks, V.A. 1982 A comparison of field-seeded and transplanted tomatoes grown on a clay soil Can. J. Plant Sci. 62 483 487
Luitel, B.P., Adhikari, P.B., Yoon, C.S. & Kang, W.H. 2012 Yield and fruit quality of tomato (Lycorpersicon esculentum Mill.) cultivars established at different planting bed size and growing substrates Hort. Environ. Biotechnol. 53 102 107
Maboko, M.M., du Plooy, C.P. & Bertling, I. 2011 Comparative performance of tomato cultivars cultivated in two hydroponic production systems S. Afr. J. Plant Soil 28 97 102
Maboko, M.M., du Plooy, C.P. & Bertling, I. 2012 Comparison of performance of tomato Cultivars in temperature vs. non-temperature controlled plastic tunnel Acta Hort. 927 405 411
NeSmith, D.S. 1997 A comparison of yields and yield components from different muskmelon (Cucumis melo L.) production systems J. Veg. Crop. Prod. 3 37 45
Niederwieser, J.G. 2001 Guide to hydroponic vegetable production. 2nd ed. Agricultural Research Council, Roodeplaat, Vegetable and Ornamental Plant Institute. Pretoria, South Africa
Payne, R.W., Murray, D.A., Harding, S.A., Baird, D.B. & Soutar, D.M. 2008 GenStat for Windows®. 11th ed. Introduction. VSN International, Hemel Hempstead, UK
Peterson, T.A., Reinscl, M.D. & Krizek, D.T. 1991 Tomato (Lycopersicon esculentum Mill. cv ‘Better Bush’) plant response to root restriction. Root respiration and ethylene generation J. Expt. Bot. 42 1241 1249
Snedecor, G.W. & Cochran, W.G. 1980 Statistical methods. 7th ed. Iowa State University Press, Ames, IA