两种密度条件下玉米穗上节间距QTL分析

为研究高密度胁迫下穗上节间距的遗传机制,以豫82×沈137的重组近交系(RIL)群体为材料,构建一张包含有1 114个位点的SNP标记的遗传连锁图谱,图谱总长度为1 821.79 cM,标记平均间距为1.64 cM。利用复合区间作图法在60 000株/hm~2密度下共检测到11个、120 000株/hm~2密度下检测到12个穗上节间距的QTL,位于第6染色体上的QTLq For ILL6-2/qForILG6在两种密度下同时被检测到,表明该QTL均能稳定表达;位于第9染色体上的qThiILL9/qForILL9-1在60 000株/hm~2的密度下同时被检测到,解释穗上节间距遗传变异的8.67%和10.61%,在120 000株/hm~2密度下未被检测到,表明此QTL在低密度下特异表达调控穗上节间距3、4。在高密度下检测到qSixILG6和qSixILG10分别解释穗上节间距6遗传变异的16.97%和13.66%,说明该QTL在高密度环境下特异表达。

QTL Mapping of Internodes Length above Upmost Ear under Two Planting Densities in Maize

In order to study the genetic basis of internodes length above upmost ear under the high planting density of adversity in maize, a genetic linkage map containing 1114 SNP markers was constructed based on a RIL population from the cross between inbred lines Yu82 and Shen137. The linkage map spaned a total of 1 821.79 cM with an average interval of 1.64 cM. Eleven QTL under 60 000 plants/ha condition and twelve QTL under 120 000 plants/ha condition for internodes length above up most ear were detected using composite interval mapping. QTL qForILL6-2/qForILG6 on chromosome 6 was mapped under two planting densities, showing that the QTL might steadily control forth internodes length above upmost ear in different planting density conditions. QTLs qThiILL9 and qForILL9-1 were detected for third and forth internodes length above upmost ear and explained 8.67% and 10.61% of the phenotypic variation under 60 000 plants/ha condition while could not be detected 120 000 plants/ha condition, which indicated that these QTLs might control third and forth internodes length above upmost ear only under low planting density condition. QTLs qSixILG6 and qSixILG10 for sixth internodes length above upmost ear were located under high planting density condition and explained 16.97% and 13.66% of the phenotypeic variation, respectively. The results showed the QTLs might be two major QTL for sixth internode length above upmost ear under high planting density condition.