小麦重要农艺性状QTL近等基因导入系的选育

Development of Near Isogenic Introgression Lines (NIILs) of Agronomic Important Traits in Wheat

为了给小麦重要农艺性状的QTL精细定位及克隆奠定基础，对14个从Am3／莱州953（轮回亲本）BC4F4代选出的性状表现与莱州953有明显差异的导入系的8个农艺性状进行了分析，结果表明，每个导入系有2～7个性状与莱州953差异显著，在每一个性状上都有对农艺性状具有正向效应的位点。利用143对在亲本之间具有多态性的SSR标记对导入系舍有的供体片段进行了检测，其中54对引物在14个导入系中检测到了供体片段，每一个导入系中检测到3～15个纯合供体片段及0～4个杂合片段，占受体基因组的1．7％～14．2％，平均为7．48％。利用其中10个导入系与轮回亲本莱州953杂交的F2群体进行了单片段代换系的选择，从10个导入系的F2中检测到40个供体片段，并从F2群体中选出了22个单片段代换系。这些导入系及其单片段代换系可用于有益的QTL的发掘、QTL精细定位与作图等研究。

Introgression lines （ILs） are useful tools for fine mapping of quantitative trait loci （QTLs）, which were often obtained through continuous backcross and selfing with marker assistant selection （MAS）. Fourteen introgression lines were generated from the BC4F4 generation of Laizhou 953/Am3 and common wheat genotype Laizhou 953 was used as the recurrent parent, while wheat genotype Am3 synthesized by＇crossing Triticum carthlicum （AABB）with Aegilops tauschii （DD） was used as the donor parent. The t- test result of 8 agronomic important traits between each introgression line and Laizhou 953 showed that each introgression line had 2 ~ 7 traits showing significant difference from Laizhou 953. For every trait, there are positive effect loci from Am3. Five hundred pairs of wheat SSR （Simple sequence repeat） markers were used to detected polymorphism between Laizhou 953 and Am3 and 143 pairs showed polymorphism between the two parents. Among them, 112 pairs mapped in the wheat SSR consensus linkage map were used to detect the introgressed segment from Am3 in the 14 introgression lines and 3～15 homozygous introgressed segments and 0～4 heterozygous introgressed segments with average of 7.21 homozygous and 0.93 heterozygous segments were detected in each introgression line. The ratio of the introgressed donor segment ranged from 1. 7% to 14.2% and averaged 7.48% in the 14 ILs. Ten F2 populations using 10 of the 14 introgression lines to cross with Laizhou 953 furthermore were used to develop single segment substitution lines （SSSLs）,40 Am3 segments were detected from the ten populations and 53 lines containing the donor segments were selected. Among them, 22 single segment substitution lines （SSSLs） contained only one homozygous or heterozygous donor segment, the remained 31 lines contained 2 or more donor segments and can be used to develop single segment substitution lines. The introgression lines and the single segment substation lines are useful in the detection and fine mapping of agronomic important QTLs.