Combining Ability, Heterosis and Inbreeding Effects in Faba Bean (Vicia faba L.)

The present investigation was carried out under insect free cage during 2011/12, 2012/13 and open field in 2013/14 growing seasons. A diallel-cross including reciprocals among six parents of faba bean (Giza 843, Nubaria 1, Cairo 25, Cairo 5, Cairo 33 and Misr 3) was utilized to study the heterotic and inbreeding effects, as well as general and specific combining ability. Results showed significant differences between parents, F1's and F2's for all studied traits and these differences may be mainly due to the genetic diversity of the parents. The parents and their crosses would be interesting and prospective for improving seed yield and its components in faba bean. Based on the two estimates of heterotic effects (over mid and better parent), 6, 10,14, 28, 27, 25 and 8 crosses exhibited significantly positive heterotic effects for days to flowering, plant height, number of branches/plant, number of pods/plant, number of seeds/plant, seed yield/plant and 100-seed weight, respectively. The parental genotype Misr3 was a good combiner for days to flowering, number of pods/plant, number of seeds/plant and seed yield/plant. On the other hand, the parental genotype Cairo 25 was a good combiner for days to flowering, plant height, number of pods/plant, number of seeds/plant and seed yield/plant over F1 and F2 generations. Parent Nubaria 1 was good combiner for 100-seed. The cross (Cairo 5 x Misr 3) had significant or highly significant positive SCA effects for number of pods/plant, number of seeds/ plant, seed yield/plant and 100-seed weight. Reciprocal-cross differences occurred frequently in the F1. Inbreeding gain was found in some F2 materials and selection may be practiced to secure transgressive segregates with higher yield and heaver seed index.