Genetic Parameters for Traits Related to Mechanized Harvesting in a Cucumber (Cucumis sativus L.) Population

Sex expression (SE), stem length (SL), and number of laterals plant (NL) are important morphological traits of a cucumber plant ideotype adapted for machine harvesting. Two inbred lines, the determinate, gynoecious G-421, possessing high fruit quality, and the monoecious H-19, with multiple lateral branching and sequential fruiting habit, and their F1 and F3 (100) progenies were planted in Wisconsin and Georgia. Data on SE, SL, and NL were recorded on individual plant basis. Genetic parameters were estimated using all generations. Phenotypic correlations were calculated from the trait means, and genotypic correlations were estimated from the analysis of variance of F3 progeny. The additive genetic variance was the highest of the variance components for SL and NL. Dominance genetic variance was more important than the additive variance for the control of SE. Narrow-sense heritability were 0.41, 0.83, and 0.85 for SE, SL, and NL, respectively. The genotypic (g) and phenotypic (p) correlation coefficients (r) indicated negative association between SE and SL (rg = –0.57, rp = –0.45**) and between SE and NL (rg = –0.56, rp = –0.27**). The association between SL and NL was positive (rg = 0.63, rp = 0.35**). Results suggest that gain from selection can be made for this plant ideotype.