甜玉米茎秆强度相关性状的数量性状基因座定位

为选育抗倒伏玉米品种，挖掘甜玉米茎秆强度相关性状的数量性状基因座（quantitative trait locus，QTL），应用复合区间作图法以甜玉米组合T49×T56的F₂为作图群体，通过测定F_2：3家系的茎秆穿刺强度、茎秆抗压强度和茎秆弯折性能3个性状进行相关性状的QTL定位。结果表明，遗传连锁图谱包含153个SSR标记位点，覆盖玉米基因组1 199.1 cM，平均图距7.83 cM。3个性状共检测到10个QTL，其中与茎秆穿刺强度相关的2个QTL位于第3、7染色体上，解释11.81%和22.15%的表型变异，与茎秆抗压强度相关的4个QTL位于第1、3、7染色体上，单个QTL可解释3.68%~33.26%的表型变异，与茎秆弯折性能相关的4个QTL位于第3、6、8染色体上，单个QTL可解释3.55%~18.58%的表型变异。第7染色体检测到1个同时控制茎秆穿刺强度和茎秆抗压强度2个性状的QTL，位于umc1015~umc1987标记区间，分别可解释11.81%和33.26%的表型变异，第3染色体检测到1个同时控制茎秆穿刺强度、茎秆抗压强度、茎秆弯折性能3个性状的QTL，位于umc1400~dupssr23标记区间，分别可解释22.15%、13.27%和18.58%的表型变异。3个茎秆强度性状共同检测到的主效QTL，可在育种实践中用于分子标记辅助选择和抗倒伏玉米品种的选育。

QTL mapping of stem strength related traits in sweet corn

In order to select lodging-resistant varieties and develop quantitative trait locus(QTL) for stem strength-related traits in sweet corn, the penetration strength, crushing strength and bending strength of F_2:3 family from F₂ generation of the T49×T56 cross were measured and QTLs for related traits were mapped by composite interval mapping method. The results showed that the linkage map contained 153 SSR markers, covering the maize genome of 1 199.1 cM with an average distance of 7.83 cM. A total of ten QTLs were detected for three traits, of which two QTLs related to penetration strength were located on chromosomes 3 and 7, explaining 11.81% and 22.15% of phenotypic variation; four QTLs related to crushing strength were located on chromosomes 1, 3 and 7, and a single QTL could explain 3.68%-33.26% of phenotypic variation. Four QTLs related to bending strength were located on chromosomes 3, 6 and 8, a single QTL could explain 3.55%-18.58% of phenotypic variation. It was found that a QTL controlling both puncture strength and crushing strength of stem was located in the marker region of umc1015-umc1987 on chromosome 7, which could explain 11.81% and 33.26% of phenotypic variation respectively. A QTL controlling penetration strength, crushing strength and bending strength was located in the umc1400-dupssr23 marker region in Chromosome 3, which could explain 22.15%, 13.27% and 18.58% phenotypic variation, respectively. The results suggested that common QTLs were detected for the three traits, which could be used in marker-assisted selection and lodging resistant maize breeding.