Genetic behavior of some economic characteristics of cucumber (Cucumis sativus L.) under high temperature conditions

Abstract: This study was conducted at the research facilities of the Horticulture Research Institute, Agriculture Research Center in Egypt during the period from 2017 to 2019 to develop cucumber (Cucumis sativus L.) inbred lines and hybrids tolerant to high temperature to reduce losses in quality and yield and evaluate them under greenhouse conditions. Twenty two inbred lines and twenty hybrids were evaluated in the two successive summer plantings of 2017/18 and 2018/19 under greenhouse conditions along with the hybrid Lamar as a control. Total yield reflected great variation among the inbred lines and ranged from 5.50 to 0.53 kg^-1. P₁₀ gave the greatest total yield and it was at par with P₁₉. Narrow range (3.20 to 2.50 cm) was observed among hybrids for fruit diameter. The highest value was recorded in P₂×P₅. Fruit weight reflected great variation among the hybrids and the hybrid, P₂×P₅ gave the heaviest fruit weight. Data showed significant differences among hybrids for total yield and hybrid P₁×P₃ gave the highest value of total yield and was at par with hybrid Lamar (control). The cross P₁×P₄ achieved high specific combining ability (SCA) effects for all traits in this study which means comparing the general combining ability effects (GCA) of the parents to their corresponding crosses’ SCA indicate that the GCA effects of the parents were reflected in the SCA effects of the crosses for the most studied traits. The reciprocal effects in F₁ diallel crosses were significant for most of the traits studied and the cross P₅×P₁ achieved high SCA effects for all traits.