Appropriate planting dates and plastic mulch for increasing common tomato varieties yield in South Texas

In South Texas, most of tomato (Lycopersicon esculentum Mill.) crops are produced on plastic mulch due to the elevated temperatures and solar radiations. The study objectives were to; determine the suitable planting dates for increasing tomato varieties production under different planting dates in early spring and late winter, and evaluate the influence of using the plastic mulch (black and white. In the Spring season, nine tomato varieties (four rounds and five roma) were grown. The round varieties were the Torero, Mykonos, Shourouq, and TAM Hot-Ty, and the roma varieties were Prunus, Rio Grande, Seri, DRP-8551, and SV8579TE. The best five varieties from the spring season and two more varieties were selected for evaluation in the fall including; SV8579ET, Mykonos, DRP-8551, TAM-HOT-T4, Shourouq, Tycoon, and Everglade. All the tomato varieties were evaluated during the Spring season under three different planting dates (from late-February till late-March) and three mulching treatments (black, white plastic mulch, and bare soil); and during the fall season during two planting dates (from early to mid-September) and two mulching treatments (black and white plastic mulch). Higher average marketable yields were observed in the spring season than the fall season. The best varieties during the spring season were DRP-8551, SV8597TE, Shourouq, and Seri with yields ranging from 68,630 to 57,237 kg/ha, whereas the best varieties in the fall; were DRP-8551, SV8597TE, and Tycoon with yields ranging from 47,123 to 60,674 kg/ha. In both seasons, white plastic mulch resulted in higher yields compared to the black and bare tomato yields.    Key words: Planting dates, plastic mulch, tomato yield.