Abstract:The present study was undertaken on cucumber in a Line x tester was undertaken with the study of combining ability variances and their effect. The 36 F
1 hybrid along with their twelve line and three testers were crossed in line x tester fashion to obtained 36 F
1 and evaluated in randomized block design in three replications having each experimental unit of single row with spacing of 2.5 m x 0.5 m at Vegetable Research Farm, Kalyanpur, C. S. Azad University of Agriculture and Technology, Kanpur during zaid and summer - 2018-19.The selected parental lines areconsisted 12 lines (No-100, No.-512, No.- 40, No.-1, 5- URC-11-1, Panjab Naveen, Pusa Barkha, Poinsett-76, Pahari Barsati, Poinsett, Swarn Ageti, Pusa Uday with 3 testers (PCUC-8, Swarna Poona and Boro Patana). Observations were recorded on all the six plants maintained for 20 metric traits
viz. day to first male flower initiation day to first female flower initiation, number of node for first male flower, number of node for first female flower, number of branches per plant, vine of length @ 60das, number of fruit per plant, day to first fruit set, number of fruit per vine @ 60das, length of fruit (cm.), number of node/wine, duration of crop average weight of fruit diameter of fruit, fruit yield (kg.)/plant, day to first fruit picking, T.S.S, specific gravity of fruit, dry matter (%).
Highly significant variances were observed for general as well as specific combining ability for all the 19 traits studied during both the seasons and pooled which suggested that both additive and non-additive gene action were important in the expression of all the characters. Parents, L9 and L10 in E1, E2 and pooled had showed significant positive GCA effects indicating their good general combining ability for fruit yield per plant. Parent, (L9, L11), and (T2) were also found good general combiners for days to first picking during both the seasons and pooled. The crosses with top sca as well as per se performance were L3×T1, L6×T3 and L12×T3.