Studies on combining ability in cucumber

Abstract

Thirty six F1 hybrids were developed from nine diverse parental cucumber lines, through half diallel mating system. The hybrids along with their parents were evaluated for their combining ability for ten important quantitative traits. The parent P3 (CHC-1) was the best general combiner for days to first fruit harvest, whereas, parent P1 (Pusa Uday) was the best general combiner for yield per plant and its contributing traits like average fruit weight & diameter and number of fruits per plant. The hybrid P6 × P7 (Poona Khira × Sel. 97-7) exhibited significant s.c.a effects for earliness (days to first female flower anthesis, node number of first female flower and days to first fruit harvest) while the highest s.c.a effect for yield per plant were exhibited by F1 crosses P2 × P4 (DC-1 × Himangi), followed by P1 × P9 (Pusa Uday × Pant Khira). The specific combining ability component of variance (σ2s) was higher than general combining ability component of variance (σ2g) for all the characters, which indicated the importance of non-additive gene action for improvement. The predictability ratio was observed to be < 0.5 for all the traits except node number of first female flower, which further confirmed the predominant role of non-additive component of variance for improvement of these traits.