The Temperature Response of Single-Truss Tomatoes

SummaryTomato varieties Potella and Potentate, sown respectively in October and November, were subjected to combinations of high temperature and low winter light intensity. Floral development was arrested in plants grown on a single stem of indeterminate length, but removal of the apical shoot above the first inflorescence caused floral development to be resumed.The variety Potella was sown on two dates in January 1963 and the effects of three day-time air temperatures, 62°, 68° and 74° F. (17°, 20°, 23° C.), were compared during each of four periods in the development of the plants, the night-time air temperature being 62° F. for all.There were effects on the branching of the inflorescence and on the number of flowers, but none on the final weight of ripe fruit, which exceeded 2 lb. per plant in all treatments. The average weight of the individual fruits on a plant was inversely proportional to the total number it carried.The start of harvest was delayed slightly by high day temperatures in the period be...