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.

摘要 鉴定抗根结线虫（root-knot nematodes）的菜豆基因型，可为菜豆育种项目提供重要支撑。本研究旨在评估菜豆基因型对南方根结线虫1号小种（M. incognita race 1）和爪哇根结线虫（M. javanica）的抗性反应。本研究采用58份普通菜豆基因型与6份鲜食菜豆（snap bean）基因型，开展两项独立的根结线虫抗性评价试验。试验采用随机区组设计，设置3次重复，每小区种植2株菜豆。菜豆发芽15天后，每株接种10000枚线虫卵。接种45天后，采收每株菜豆的根系并提取其中的线虫卵，统计每克根系的卵粒数，同时计算繁殖系数（Reproduction Factor）与繁殖系数降低率（Reduction of the Reproduction Factor）。不同试验间菜豆基因型的表现存在显著差异，表明其对供试线虫种类的抗性反应各不相同。基因型VP-25与BRS Valente对南方根结线虫1号小种表现出抗性。基因型Aporé、Ouro Vermelho、Radiante及CNFP 10793对南方根结线虫1号小种和爪哇根结线虫均表现出良好抗性，具备作为育种项目抗性种质资源的潜力。根系鲜重与线虫卵粒数之间存在显著相关性，而线虫繁殖量与地上部鲜重之间无相关性。