小麦籽粒淀粉含量的QTL定位及效应分析

QTL Mapping for Kernel Starch Content in Wheat

为深入了解小麦籽粒淀粉含量的遗传特性和QTL效应，选择淀粉含量差异较大的小麦品种M344和武春3号杂交，创制F2：3群体，并利用973对SSR引物对小麦籽粒总淀粉、直链淀粉和抗性淀粉含量进行基于混合线性模型的QTL定位及效应分析。构建了包含有163个标记的遗传连锁图谱，分布于18条染色体，连锁图谱总长度为1622．5cM，标记间平均距离为9．95cM。QTL分析表明，共检测到4个主效QTL和12对上位性QTL，涉及1B、2B、2D、4A、5D、6A和7A等16条染色体。其中，抗性淀粉含量上位性QTL3对，总淀粉含量上位性QTL4对，直链淀粉含量上位性QTL5对，总贡献率分别为8．34％、17．50％和8．13％。总淀粉和直链淀粉含量各检测到1个加性QTL，抗性淀粉含量检测到2个加性QTL，贡献率分别为5．34％、8．49％、11．47％、12．53％。研究发现，2B染色体Xwmc453．3～XcYd44．2标记区间的QTI，位点同时影响抗性淀粉和总淀粉含量，2D染色体Xgwm296～Xgwm455．2标记区间的QTL位点同时影响抗性淀粉和直链淀粉含量，7A染色体Xwmc488．1～Xwmc48＆2标记区间的QTL位点同时影响直链淀粉和总淀粉含量。

The objective of this study is to understand the genetic control of starch content in wheat grains and QTL effect, and provide theoretical basis for wheat starch quality improvement. A wheat cultivar M344 with higher resistant starch content and Wuchun 3 with lower resistant starch content was crossed to obtain F2： 3 lines, which were used to conduct quantitative trait loci （QTL） analysis for resistant starch content, total starch content, and amylose content. A genetic map was constructed based on 163 SSRs distributing in 18 chromosomes or linkage maps by using Joinmap3. 0, which spanned 1 622.5 cM with an average genetic distance of 9.95 cM per marker. Four main-effect QTLs and 12 epistatic QTLs were detected by using QTLMapper 2.0 , and located in chromosomes of 1B, 2B, 2D, 4A, 5D, 6A and 7A. The results showed that one additive QTL was detected for total starch content and amylose content, respectively, two additive QTLs were detected for resistant starch con-tent. The explainedphenotypic variance of those QTLs was 5.34%, 8.49%, 11.47% and 12.53%, respectively. In addition, three epistatic QTLs for resistant starch content, eight epistatic QTLs for total starch content, and five epistatic QTLs for amylose content were detected, the total phenotypic variance explained by those epistatic QTLs was 8. 34%, 17. 5% and 8. 13%, respectively. What＇s more, it was found that a QTL onXwmc458. 8 ~Xcfd44. 2 of chromosome 2B controlling both resist- ant starch content and total starch content, a QTL onXgwm296 ~ Xgwm455. 2 of chromosome 2D controlling both resistant starch content and amylose content,a QTL on Xgmc488. 1 ~Xwmc488. 2 of chromosome 7A controlling both amylose content and total starch content..