Controle genético da resistência a Meloidogyne incognita raça 1 em Phaseolus vulgaris L.

Abstract

The use of resistant cultivars is one of the best methods for nematode control and reduction of economic losses caused by these pathogens. Studies of inheritance of nematode resistance in Phaseolus vulgaris L. are nonetheless scarce. The present paper reports on the estimation of genetic parameters associated with resistance to the root nematode Meloidogyne incognita race 1 in beans P. vulgaris L. Two contrasting lines, 'Aporé' (P1 = nematode resistant, dry bean) and 'Macarrão Rasteiro Conquista' (P2 = susceptible, snap bean), and the generations F1 (P1 x P2), F2 (P1 x P2), BC11 (F1 x P1) and BC12 (F1 x P2), were assessed 45 days after nematode inoculation, through a scale related to the number of eggs per gram of root tissue. Dominant genetic effects were inferior in magnitude to additive effects, indicating incomplete dominance of nematode resistance. Dominance was in the direction of increased nematode resistance (i.e., lower number of eggs per g root). The genetic control of resistance to Meloidogyne incognita race 1 in Phaseolus vulgaris L., is controlled by a gene locus with incomplete dominance of resistance allele, with the possible presence of modifier genes.