Inheritance of resistance to Cercospora canescens Ellis and Martin in mungbean (Vigna radiata (L.) Wilczek var. radiata) and blackgram (Vigna mungo (L.) Hepper) crosses
1992
Lapis, C.B. | Natural, M.P. | Raymundo, A.D. | Hautea, R.A. (Philippines Univ., Los Banos, College, Laguna (Philippines). Inst. of Plant Breeding)
Two resistant genotypes of Vigna mungo (Acc 22 and Acc 25) were crossed as males with the susceptible variety of V. radiata, NCM 53. Backcrosses were made with NCM 53 as the recurrent parent. Disease assessments (at six weeks after germination and one week before the first harvest) on the parentals, F1, F2, and BC1 generations were used in the generation means analyses. Additive gene effects were found to be significant in both NCM 53 x Acc 22 and NCM 53 x Acc 25 crosses. Dominance gene effects towards resistance resulted in skewed distribution of the progenies derived from NCM 53 x Acc 22 cross. Additive and additive x additive gene effects controlled the expression of resistance in NCM 53 x Acc 25 cross. The presence of epistative effects and the fact that the distribution tended to be normal but skewedness was however present, suggested the occurrence of several loci for resistance and that resistance to C. canescens is conditioned by more than a single gene. Alternate backcrossing and selection with intermating of selected lines can be used in breeding for resistance to C. canescens. Since additive gene effects are present, selection before backcrossing would be effective, and the disease reaction of the parental lines would be a fairly reliable indicator of disease reaction of their progenies
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