Common bean breeding aiming at root-knot nematode resistance

Abstract

The common bean (Phaseolus vulgaris L.) is one of the legumes mostly consumed in Brazil and worldwide. It as a source of food and income in several regions, mainly in developing countries. Phytonematodes, such as Meloidogyne incognita, are very harmful to crops, including the common bean, infecting the roots and resulting in less vigorous and plant susceptibility to various stresses. M. incognita control is very difficult in production fields and, because of this, the search for genotypes resistant to its attack is becoming more and more essential. This proposal is part of a line of research in partnership between the Department of Genetics of ESALQ/USP and the Bean Breeding Program of the IAC, which aims to developing inbred lines from a cross between a moderately resistant and susceptible genotype to root-knot nematode. Herein, we intend to carry out a phenotypic screening for resistance among the inbreed lines, performing competition assays so that the lines would be evaluated under field conditions. We also propose to genotype the inbreed lines, build a linkage map and map QTLs for response to nematodes. The inbred lines development will take place by the SSD method until the F6 generation. Phenotyping for response to nematodes will be done by counting the number of egg masses and calculating the gall index caused by the pathogen. Genotyping will be performed by GBS (Genotyping by Sequencing) with subsequent construction of a linkage map and QTL mapping. At the end of this research, it is expected to generate information on the genetic architecture of common bean response to root-knot nematodes and, at least, one inbred line that has resistance/tolerance and good agronomic performance.