Inheritance of tolerance to Cowpea Mild Mottle Virus in soybean

Soybean stem necrosis is caused by Cowpea mild mottle virus (CPMMV) and it has been recognized as an emerging and economically important disease in Brazil. No resistant, but only tolerant cultivars have been identified so far, and their genetic control is still unknown. To investigate the inheritance of soybean tolerance to CPMMV, two crosses between tolerant cultivars (BRS 133 x BRSMT Pintado), and between a susceptible (CD 206) and a tolerant cultivar (BRSMT Pintado) were carried out to obtain F2 and F2:3generations. Quantitative and qualitative analyses applied to the data from greenhouse evaluations showed that there are at least two distinct major genes determining tolerance to CPMMV, one in the soybean cultivar BRS 133 and another in the cultivar BRSMT Pintado, with predominance of additive genetic effects and heritability levels that allow for efficient selection based on early generation means.

大豆茎坏死病由豇豆轻斑驳病毒（Cowpea mild mottle virus，CPMMV）引发，目前已被认定为巴西地区一种新兴且经济意义重大的病害。截至目前，尚未鉴定出抗该病害的大豆品种，仅筛选到耐病品种，且其遗传调控机制仍未明确。为解析大豆对CPMMV的耐病性遗传机制，本研究开展了两组杂交组合：其一为耐病品种BRS 133与BRSMT Pintado杂交，其二为感病品种CD 206与耐病品种BRSMT Pintado杂交，以此获得F₂代与F₂:₃代群体。通过对温室接种鉴定所得数据开展数量与质量性状分析，结果表明：至少存在两个独立的主效基因调控大豆对CPMMV的耐病性，分别来自品种BRS 133与BRSMT Pintado；该调控机制以加性遗传效应为主，且遗传力水平较高，可基于早期世代群体开展高效选择。