Increasing the resistance of common bean to white mold through recurrent selection

ABSTRACT White mold, caused by Sclerotinea sclerotiorum (Lib.) de Bary is one of the most important diseases of the common bean (Phaseolus vulgaris L.) worldwide. Physiological resistance and traits related to disease avoidance such as architecture contribute to field resistance. The aim of this study was to verify the efficiency of recurrent selection in physiological resistance to white mold, “Carioca” grain type and upright habit in common bean. Thirteen common bean lines with partial resistance to white mold were intercrossed by means of a circulant diallel table, and seven recurrent selection cycles were obtained. Of these cycles, progenies of the S0:1, S0:2 and S0:3 generations of cycles III, IV, V and VI were evaluated. The best (8 to 10) progenies of the seven cycles were also evaluated, in two experiments, one in the greenhouse and one in the field. Lattice and/or randomized block experimental designs were used. The traits evaluated were: resistance to white mold by the straw test method, growth habit and grain type. The most resistant progenies were selected based on the average score of resistance to white mold. Subsequently, they were evaluated with regard to grain type and growth habit. Recurrent selection allowed for genetic progress of about 11 % per year for white mold resistance and about 15 % per year for the plant architecture. There was no gain among cycles for grain type. Progeny selection and recurrent selection were efficient for obtaining progenies with a high level of resistance to white mold with “Carioca” grain type and upright habit.

摘要 由核盘菌（Sclerotinea sclerotiorum (Lib.) de Bary）引起的白霉病是全球范围内普通菜豆（Phaseolus vulgaris L.）最重要的病害之一。生理抗性以及与病害规避相关的性状（如株型）有助于田间抗性的形成。本研究旨在验证轮回选择技术在改良普通菜豆白霉病生理抗性、“Carioca”粒型以及直立株型方面的效率。研究采用循环双列杂交法对13份具有部分白霉病抗性的普通菜豆品系进行杂交，最终获得7个轮回选择周期。针对其中第Ⅲ、Ⅳ、Ⅴ、Ⅵ周期的S0:1、S0:2及S0:3世代的后代材料开展评价。此外，还针对7个周期中筛选出的最优（8~10个）后代材料设置两项试验进行评价，试验分别设于温室与田间。试验采用格子设计和/或随机区组实验设计。调查性状包括：采用秸秆接种法评价的白霉病抗性、株型以及粒型。首先基于白霉病抗性的平均评分筛选出抗性最优的后代，随后对其粒型与株型进行进一步评价。结果显示，轮回选择可使白霉病抗性每年获得约11%的遗传进展，株型性状每年获得约15%的遗传进展。粒型性状在各选择周期中未获得明显遗传增益。后代选择结合轮回选择可有效培育出兼具高白霉病抗性、“Carioca”粒型以及直立株型的普通菜豆后代。