鲜食甜玉米南方锈病抗性QTL定位分析

为挖掘新的抗南方锈病基因资源,本研究以甜玉米组合M5×M114的216个F2单株为遗传作图群体,应用BSA方法从500对SSR引物中筛选出2对在F2代抗病和感病DNA池间具有多态性的引物,分别位于4和9号染色体上;在4和9号染色体上重新设计100对SSR引物,构建了包含33个标记位点总长为241.2cM的连锁遗传图,各个标记间的平均距离为7.53cM。结合F2单株对南方锈病的抗性表现,用复合区间作图法在4和9号染色体上共检测到7个显著的南方锈病抗性QTLs,其中:4个QTLs位于4号染色体上,可解释12.1%、7.8%、18.2%和14.9%表型变异;3个位于9号染色体上,分别解释17.0%、13.3%与19.2%的表型变异。研究结果可为抗南方锈病的精细定位、主效基因克隆和抗南方锈病鲜食甜玉米品种选育提供理论依据。

QTL mapping for Southern rust resistance in fresh sweet corn

To explore new genetic resources to Southern rust in this study, 216 F₂ individuals of sweet corn combination M5×M114 were used as genetic mapping population to scan resistant QTL of maize Southern rust with the method of Bulked Segregant Analysis. The results showed that: Over 500 SSR markers screened, two markers located on chromosomes 4 and 9 showed polymorphic between resistant and susceptible DNA pools. A linkage genetic map containing 33 marker loci with a total length of 241. 2 cM was constructed by redesigning 100 pairs of SSR primers on chromosomes 4 and 9, and the average distance between individual markers was 7. 53 cM. Combined with the resistance index of 216 F₂ families, a total of 7 significant Southern rust resistance QTLs were detected on chromosomes 4 and 9 by composite interval mapping. Four QTLs were located on chromosome 4 and respectively explained 12. 1%, 7. 8%, 18. 2% and 14. 9% of phenotypic variation. And 3 significant QTLs were located on chromosome 9, which explained 17. 0%, 13. 3% and 19. 2% of the phenotypic variation, respectively. This study provided a theoretical basis for QTL fine mapping of Southern rust resistance, cloning of major genes and breeding Southern rust resistant varieties for maize.