Estimating combining ability for yield and yield contributing traits in cucumber

A study was conducted on a 8 × 8 diallel set of cucumber excluding reciprocals to find out the extent of combining ability for yield and yield attributing characters. The magnitudes of variance due to general as well as specific combining ability were highly significant indicating the importance of both additive and non-additive gene action. Among parents, gynoecious line GBS-1(P1) showed maximum g.c.a effects in desirable direction for node number of first female flower, days to first female flower anthesis, days to fruit set from opening of first female flower, days to first fruit harvest, number of fruits per plant, and vine length. The parent P5 (Pusa Uday) exhibited highest positive g.c.a effect for fruit length, fruit diameter, average fruit weight and yield per plant. In order of merit the gynoecious hybrids P1 × P5 (GBS-1 × Pusa Uday) and P1 × P6 (GBS-1 × Punjab Naveen) followed by monoecious hybrid P3 × P5 (GS-4 × Pusa Uday), which exhibited highest s.c.a effects for number of characters including total fruit yield per plant. In case of yield and other yield contributing characters like node number of first female flower, days to first female flower anthesis, days to fruit set from opening of first female flower, days to first fruit harvest, number of fruits per plant and yield per plant where specific combining ability component of variance (s2s) is more than general combining ability component of variance (s2g), which indicated preponderance of non-additive gene action. Hence, an improvement programme based on heterosis breeding would be appropriate for improving different traits under study.