Combining Ability of Haricot Bean Varieties for Yield

Thirty-six genotypes (8 parents and their 28 F1 diallel crosses) were grown in 2 replications of randomized complete block design, during Nov. 2005- Feb. 2006 at Mandura, Metekel zone, Northwestern Ethiopia. The objective of the study was to determine general combining ability (GCA) of the parents and specific combining ability (SCA) of their crosses. Parents were significantly different for Days to flowering, Internod length, Number of nods on the main stem, Plant Height, Pod length, Number of Seeds per Pod, and Thousand Seed Weight. GCA Mean Square was statistically significant for number of seeds per pod, Thousand seed weight, number of seeds per plant, number of nods on the main stem, Plant height, pod length, pod diameter, number of pods per plant, internod length, days to flowering and days to maturity, indicating the existence of sufficient additive genetic variance which can be exploited. SCA Mean Square was statistically significant for plant height, number of seeds per pod, days to flowering and days to maturity. The b2 component of SCA was statistically significant only for plant height indicating the existence of gene asymmetry among the parents.