Heterosis, Combining Ability and Components of Genetic Variance in Faba Bean (Vicia faba L.)

Abstract

The present investigation was carried out at the Agricultural Research Station, Faculty of Agriculture, Alexandria University to evaluate seven faba bean varieties (four local and three introduced) in the diallele cross set. Twenty one crosses were constituted in the winter season of 2006/2007, whereas parents and crosses were evaluated in a yield trial, in winter season of 2007/2008, in a randomized complete block design of three replications. Results revealed highly significant variations within parents and F1 genotypes indicating a wide genetic variability for the studied characters and the possibility of genetic improvement using such genetic pools of faba bean. Several crosses recorded significant positive heterosis percentages relative to mid parent and better parent for seed yield per plant and 100-seed weight ranging from 17.46-84.95%, 22.47- 68.49%, 8.53-23.26% and 10.43-18.64% relative to MP and BP for each character, respectively. Both general (GCA) and specific (SCA) combining abilities were significant for all studied characters revealing the important role of both additive and dominant components in the inheritance of the studied characters. Giza Blanca proved to be a good combiner for all studied characters except number of pods per plant and maturity time. Several crosses exhibited significantly positive SCA effects for studied characters especially Giza 716 × ILB 450 and ILB 450 × Giza Blanca which exhibited highly significant and positive SCA effects for seed yield per plant and 100-seed weight. Heritability in narrow sense was high for 100- seed weight (0.54) and short plant height (-0.51) while it was low for seed yield per plant.