洪涝灾害是大豆生产的主要逆境之一,培育耐涝品种是抗灾保收的重要措施。大豆耐涝性育种方案的设计必须以耐涝性遗传为前提。以苏88-M21(淹水不敏感)×新沂小黑豆(淹水敏感)衍生的175个重组自交系(NJRISX)为材料,在盆栽V2期土壤表层保持5~7cm水层20d的淹水条件下,研究大豆苗期耐淹性的遗传和QTL定位。通过对8个耐淹性有关性状的相关分析和主成份分析,确定以处理前后株高变化量、处理终叶龄和成熟期株高3个性状的平均耐淹指数为评价指标。NJRISX家系间耐淹性差异极显著,存在超亲分离。主基因+多基因分离分析表明该群体的耐淹性为2对连锁主基因+多基因遗传,主基因遗传率为62.83%,多基因的遗传率为8.90%。WinQTLCart2.5复合区间及多区间QTL定位分析均检测到2个QTL,位于连锁群L2上的Satt229~Satt527和Satt527~Sat_286区间,对表型的解释率分别为11.76%~25.20%和10.10%~12.34%。大豆NJRISX群体苗期耐淹性遗传分离分析与QTL定位结果相对一致。
Flooding is a serious problem for soybean production in eastern and southern China. Development of cultivars with tolerance to waterlogging is one of the effective ways to cope with the stress problem. For which,the genetic knowledge of waterlogging tolerance is of essential importance. The present study was aimed at revealing the inheritance and mapping the QTLs for waterlogging tolerance of soybean at seedling stage. The materials used were 175 recombinant inbred lines (RILs) derived from the cross Su88-M21 (tolerant) × Xinyixiaoheidou (highly sensitive),designated as NJRISX. A pot experiment was held under 5–7 cm waterlogging stress for 20 days at V2 stage. Based on the correlation and principal component analysis of eight traits,we calculated the joint waterlogging tolerance index from the average of individual tolerance index of plant height increment,number of leaves at the end of waterlogging and plant height at maturity to evaluate the tolerances of the materials. There existed obvious transgressive segregation and significant differences among the RIL lines. The segregation analysis under major gene plus polygene mixed inheritance model showed that waterlogging tolerance of soybean was controlled by two linked major genes plus polygenes with major gene heritability of 62.83% and polygene heritability of 8.90%. By using composite interval mapping (CIM) and multiple interval mapping (MIM) of WinQTL Cartographer Version 2.5,two QTLs conferring waterlogging tolerance were mapped in the marker regions of Satt229–Satt527 and Satt527–Sat_286 on linkage groups L2,explaining 11.76%–25.20% and 10.10%–12.34% of the total phenotypic variation,respectively. Accordingly,the results from segregation analysis and QTL map-ping are relatively consistent in NJRISX population.