Combined and genetic analysis for multiple-disease resistance to chocolate spot and rust on faba bean yield
Abstract: This study showed that fungal foliar diseases i.e., chocolate spot (Botrytis fabae Sard.) and rust (Uromyces viciae fabae (Pers.) Schroet.) caused considerable yield losses in Egypt ranged from 6.54 to 26.45 %. Therefore, the genetic parameters for seed yield and resistance to leaf spot diseases (multiple-disease resistance) were assessed in half diallel crosses between five parents of faba bean and their offspring F1's and F2's, to improve the productivity. Highly significant differences among the studied genotypes were detected, pointing to a wide genetic variability for seed yield and two foliar diseases resistant. Nubaria 1 was recorded as good combiner. The general to specific combining ability (GCA/SCA) ratio revealed great additive effects for the two foliar diseases resistant, on the contrary seed yield. Some crosses had useful or true heterosis above mid-parent and/or better parent for resistance to chocolate spot disease and/or seed yield, indicating to high role of non-additive gene action. Then, Giza 40 × Giza 429 and Sakha 1 × Giza 429 crosses had best level of resistance to chocolate spot disease with potential yield. The results of genetic variance components revealed that additive component of genetic variability "D" estimates were greater than dominance effect "H1", suggesting that additive genetic variance is important than non-additive one. Meanwhile, "F" and KD/KR confirm that dominant alleles were more the recessive ones, but (H1/ D)1/2 indicated that dominance for resistance was almost partial. As well as the correlation between parental performance (Yr) and parental order of dominance (Wr+Vr) indicated that the faba bean parents possessed mostly negative genes in dominance form for resistance, but possessed positive genes in for seed yield. Simple correlation coefficients between two diseases in both generations (-0.95** and -0.94**) revealed that selection for either chocolate spot resistance would be accompanied by resistance to rust disease (multiple-disease resistance) and would be effective for the improvement of seed yield per plant in faba bean.
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Publication year 2014
Pages 181-193
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Author(s) from ARC
Publication Type Journal
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