Inheritance of Tolerance to Chloramben Methyl Ester in Cucumber1

Two tolerant and 2 susceptible lines of cucumber ( Cucumis sativus L.) and their progenies were evaluated for tolerance to the herbicide methyl 3-amino-2,5-dichlorobenzoic acid (chloramben methyl ester). Gene action was primarily additive; however, partial dominance of genes controlling tolerance was noted. Evidence for transgressive segregation was observed in segregating populations of the cross tolerant x tolerant. The minimum number of effective factor pairs varied from 1 to 5 depending on the evaluation criterion and the method of calculation employed. Heritability estimates from crosses involving tolerant MSU 0612 were consistently higher than those involving tolerant MSU 3207, suggesting that the tolerance of these 2 lines may be conditioned by different genes. Estimates of heritability indicated that considerable progress can be made in selection for tolerance when the criterion used is epinasty or reduction in plant dry weight and height.