鲜食甜玉米籽粒蛋白质含量的QTL定位

QTL mapping for grain protein content in fresh sweet corn

【目的】研究鲜食甜玉米籽粒蛋白质含量的QTL定位,为加快高蛋白质含量甜玉米的育种进程及实现分子标记辅助选择提供理论依据。【方法】以籽粒蛋白质含量有极显著差异的超甜玉米自交系T8和T48为亲本配制杂交组合,以232个F2单株为作图群体,构建了包含245个SSR标记位点、全长1 527.76cM的玉米遗传连锁图谱,标记间的平均距离为6.23cM,用复合区间作图法在F2和F2:3家系中检测籽粒蛋白含量相关QTL。【结果】在F2群体和F2:3家系中共检测到10个鲜食甜玉米籽粒蛋白含量QTL,分别位于第2、4、5、6和9号染色体上,其中F2群体、F2:3家系分别定位到4和6个籽粒蛋白含量QTL,单个QTL可解释5.97%～16.52%的表型变异。【结论】有2个主效QTL在F2群体和F2:3家系中均可被检测到,分别位于2号染色体的bnlg1017-umc1823区间和9号染色体上的umc2119两侧,1个主效QTL在F2:3家系的2个重复中均可检测到,位于第4号染色体的umc1808-umc1871区间。这些QTL可以作为利用分子标记辅助育种途径进行玉米遗传改良的依据。

【Objective】 The aim was to study the QTL mapping of grain protein content in fresh sweet corn to improve the procedure of high protein sweet corn breeding and molecular marker-assisted selection（MAS）.【Method】 A genetic linkage map of 1 527.76 cM length was constructed with 245 SSR markers based on a sweet corn population consisting of 232 F2 individuals from the cross T8×T48,with an average interval length of 6.23 cM.【Result】 10 QTLs for GPC were detected with the method of composite interval mapping（CIM） on chromosome 2,4,5,6 and 9,among which 4 were identified in F2 population and 6 in F2：3 families and the phenotypic variances explained by each QTL ranged from 5.97% to 16.52%.Moreover,2 QTLs were detected in both F2 and F2：3 families located on bnlg1017-umc1823 interval of chromosome 2 and both sides of umc2119 of chromosome 9,respectively.1 QTL was detected in F2：3 families twice on umc1808-umc1871 interval of chromosome 4.【Conclusion】 These QTLs were detected in both F2 and F2：3 families suggested that these QTLs would provide useful information for molecular assistant selection（MAS） in maize genetic improvement.