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境内一种新发且具有重要经济意义的病害。截至目前，尚未鉴定出抗该病害的大豆品种，仅筛选得到耐病品种，其遗传调控机制仍未明确。为解析大豆对CPMMV的耐病遗传机制，本研究开展了两组杂交实验：其一为耐病品种BRS 133与BRSMT Pintado的杂交，其二为感病品种CD 206与耐病品种BRSMT Pintado的杂交，以此获得F2及F2:3分离群体。对温室表型鉴定获取的实验数据进行定量与定性分析后发现，调控大豆对CPMMV耐病性的至少存在两个独立主效基因，分别来源于品种BRS 133与BRSMT Pintado；该耐病性状以加性遗传效应为主，且具有较高的遗传力，可基于早期分离群体开展高效选择育种。