大豆抗倒伏性的评价指标及其QTL分析

倒伏性的鉴定通常采用倒伏程度分级法, 但其表现依赖于田间实时环境, 分级较粗放。育种实践需要一种不依赖于实时环境的倒伏潜势评价方法。本研究利用表型差异大的32个大豆品种和1个重组自交系(RIL)群体NJRIKY, 研究了鲜重力矩(株高×鲜重, PF)、干重力矩(株高×干重, PD)、单位抗折力鲜重力矩(株高×鲜重/抗折力, PFS)和单位抗折力干重力矩(株高×干重/抗折力, PDS)等4种倒伏性评价指标与倒伏程度的关系, 从中遴选出PF与倒伏程度的相关系数高、物理意义明确、测度简便、环境稳定性高, 与倒伏程度共同QTL多, 综合表现最优, 反映了倒伏势。在A2、C2、D2和G连锁群上, 共检测到7个倒伏程度相关的QTL, 分别解释表型变异的6%~12%, 2年未检测到相同的QTL; 在B1、C2和O连锁群共检测到7个倒伏势有关的QTL, 分别解释表型变异的5%~12%, 其中qPFC2-2, 2年均能稳定表达, 贡献值较大; 倒伏程度和倒伏势共有的QTL区间有GMKF059a~satt319和satt286~A63_1T两个; 抗倒伏性等位基因来自亲本科丰1号。

Lodging Resistance Indices and Related QTLs in Soybean

The used lodging resistance index is lodging score, with 0 as most resistant and 4 as most sensitive. In breeding for lodging resistance, an index more precise than lodging score and independent from the cultivation conditions is expected. In the present study, four kinds of lodging resistance indices, i.e. fresh matter moment (plant height × above ground fresh weight, PF), dry matter moment (plant height × above ground dry weight, PD), fresh weight moment per unit of stem broken strength (PFS), and dry weight moment per unit of stem broken strength (PDS), were designed in two experiments, one with 32 diverse cultivars and one with the RIL population NJRIKY including 184 recombinant inbred lines of the cross (Kefeng 1 × Nannong 1138-2) in 2005 and 2006. Among the four indices, fresh weight moment (PF) designated as lodging potential performed with higher correlation with lodging score, more relevant physical meaning, easier operation of measurement, better stability in various environments and more common QTLs with lodging score than those of the other indices, therefore PF was the best candidate of lodging resistance index to replace lodging score. On the basis of the results, QTL analysis was performed for lodging score and lodging potential. Seven QTLs for lodging score on linkage groups A2, C2, D2, and G explaining 6%–12% of phenotypic variation, but no common one between the two years, were detected. There were seven QTLs for lodging potential on linkage groups B1, C2, and O, explaining 5%-12% phenotypic variation, with the same QTL qPFC2-2 in two years. Between lodging score and lodging po-tential, two QTLs were with same flanking markers, i.e. GMKF059a–satt319 and satt286–A63_1T, and the lodging resistance alleles were mainly contributed from Kefeng 1. Between the two loci, qPFC2-2 was of larger contribution, so its flanking markers can be used in marker-assisted selection for lodging resistance in soybean.