Differential Cultivar Responses of Tomato Transplants to Ethephon1

Abstract Cultivars of tomato ( Lycopersicon esculentum Mill.) responded differently when (2-chloroethyl)phosphonic acid (ethephon) was applied at 300 ppm in the transplant stage. The amount of stem root proliferation and the length of these roots were the largest on ‘Ohio 7663’ transplants. ‘Heinz 2653’, ‘Libby 2981’, ‘Heinz 414’, ‘Knox’ and ‘Campbell 28’ showed major stem root proliferation from ethephon, whereas ‘Peto 80’, ‘Campbell 37’, ‘Hunt 62’, and ‘Hunt 208 F’ had a very small amount of stem root proliferation. The average stem diameter for the 18 cultivars treated with ethephon increased from 0.50 to 0.63 cm in 21 days.