Reaction of common bean to Meloidogyne incognita race 1 and Meloidogyne javanica

ABSTRACT Identification of common bean genotypes resistant to the root-knot nematodes may be useful for bean breeding programs. The objective of this study was to evaluate the reaction of bean genotypes to M. incognita race 1 and M. javanica. Two independent trials to assess resistance to both root-knot nematodes were carried out with fifty-eight common bean genotypes and six snap bean genotypes. The experiments were arranged in a randomized block design, with three replications and two plants per plot. A total of 10,000 nematode eggs were inoculated per plant 15 days after germination. At forty-five days after inoculation, the root system of each plant was harvested and the nematode eggs were extracted. The number of eggs per gram of root was counted and the Reproduction Factor and the Reduction of the Reproduction Factor were calculated. The performance of the genotypes differed between the trials, indicating different resistance reactions to the nematode species evaluated. The genotypes VP-25 and BRS Valente were resistant to M. incognita race 1. The genotypes Aporé, Ouro Vermelho, Radiante, and CNFP 10793 showed good resistance to both M. incognita race 1 and M. javanica, with potential as source of resistance in breeding programs. There was a significant correlation between root mass and number of eggs. The correlation between nematode reproduction and shoot mass was null