PERFORMANCE AND GENE ACTION FOR EARLINESS, YIELD AND CHOCOLATE SPOT DISEASE OF FABA BEAN

Abstract

In order to determine performance, gene action and heritability for earliness, yield and chocolate spot disease of faba bean, a half diallel crosses among six parental genotypes were evaluated under control and artificial infection by chocolate spot disease (Botrytis fabae sard). The results indicated highly significant differences among faba bean genotypes for all the studied characters under these conditions. All faba bean genotypes under study appeared to be high resistant or resistant for chocolate spot disease with a few exception under different conditions. Whereas, genotypes Misr 3, Wadi 1, Sakha 4 x Misr 3, Sakha 4 x Nubaria 1, and Misr 3 x Wadi 1 under the natural infection conditions. However, Sakha 4, Nubaria 1, NA 112, Sakha 4 x Misr 3, Sakha 4 x NA 112, Misr 3 x Wadi 1, Nubaria 1 x T.W, Wadi 1 x NA 112 and T.W x NA 112 under the artificial infection were less resistant or susceptible to chocolate spot disease. The results revealed that additive (D) and dominance (H1 and H2) appeared to be significant for days to flowering and maturity, chlorophyll content (SPAD), seed weight/plant and resistance to chocolate spot under both conditions. The additive genetic component was higher in its magnitude as compared to the dominance ones for resistance to chocolate spot under the natural infection condition, resulting in average degree of dominance (H1/D)0.5 less than the unity. Whereas, dominance component (H1 and H2) made up the most part of the total genetic variation as it was larger in its magnitude than the corresponding additive one for earliness characters, chlorophyll content and seed weight/plant under both conditions and resistance to chocolate spot under the artificial infection only. Thus, the average degree (H1/D) 0.5 was more than the unity for these characters. Narrow sense heritability (h2n) was moderate (39.1%) to low (20.4%) for seed weight/plant and high (65.1%) to moderate (45.0%) for chocolate spot disease under control, natural infection and artificial infection of chocolate spot disease, respectively.