Heterosis, GCA and SCA Effects of Diallel-cross among Six Faba Bean (Vicia faba L.) Genotypes

The present investigation was carried out under insect free cage during 2011/12, 2012/13 growing seasons at Giza Research Station, Egypt. 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 effects, as well as general and specific combining ability. Results showed significant differences between parents and F1's for all studied traits and these differences may be mainly due to the genetic diversity of the parents. Based on the two estimates of heterotic effects (over mid and better parent), 5, 12, 7, 10, 13, 8 and 8 crosses exhibited significantly positive heterotic effects for plant height, number of branches/plant, number of pods/plant, number of seeds/plant, seed yield/plant and 100-seed weight, respectively. The ratio of both estimates GCA/SCA exceeded the unity for all traits indicating the relative importance of the two types of gene action suggesting the predominance of additive types of gene action controlling these traits and therefore selection would be effective for improving these traits. Giza 843 (P1) was the best general combiner for all studied traits. Giza 843 (P1), Nubaria 1 (P2) and Cairo 25 (P3) exhibited useful general combining ability effects. Significant positive SCA effects for all studied traits occurred in different combinations Reciprocal-cross differences occurred in specific crosses in different traits. The hybrids showing high heterosis over better parents could be used to develop synthetic varieties in order to exploit heterosis in faba bean breeding.