QTL Analysis of Spike Traits in an Recombinant Inbred Lines(RILs) Population Derived from the Cross of Triticum polonicum×T. aestivum Line Zhong 13 | 波兰小麦×普通小麦品系中13重组自交系(RIL)群体穗部性状的QTL分析

Chinese. 小麦穗部性状是与籽粒产量关系密切的重要农艺性状。本研究以一个由99个株系组成的来源于波兰小麦(Triticum polonicum L.)和普通小麦(Triticum aestivum L.)品系中13杂交后代的F8重组自交系(recombinant inbred lines, RIL)群体为实验材料，利用微卫星(simple sequence repeat, SSR)标记对穗长、穗粒数和有效小穗数进行数量性状基因座(quantitative trait locus, QTL)定位分析。所构建的A染色体组和B染色体组共14个连锁群的遗传连锁图谱由115个SSR标记位点组成，图谱全长822.9 cM，标记间的平均遗传距离为7.16 cM。采用复合区间作图法在两年的环境中检测到分布在2A、3A、3B、5B和7B染色体上的6个穗长QTL，5个穗粒数QTL和2个有效小穗数QTL，表型变异贡献率分别为9.21%~22.94%，9.18%~19.71%和11.48%~13.01%。两年中都在3A染色体上的Xbarc12~Xbarc310区间内检测到控制穗粒数的主效QTL，说明该QTL较少受环境条件的影响，是一个稳定可靠的穗粒数QTL。该QTL与最近标记的遗传距离为0.01 cM，可用于小麦产量性状的分子标记辅助育种。

English. Ear traits closely related to grain yield are important agronomic characters of wheat. In this study QTLs of traits related spike, spike length, grains per spike and fertile spikelet number, were analyzed using simple sequence repeat (SSR) markers in a population which consisted of 99 F8 recombinant inbred lines (RILs) derived from the cross of Poland wheat (Triticum polonicum L.)×common wheat (T. aestivum L.) line Zhong 13. The analysis of variance showed that there was highly significant difference between Poland wheat and Zhong 13 in spike length and grains per spike in 2010 and 2011, and significant difference was observed between Poland wheat and Zhong 13 in fertile spikelet number in 2010. It was clear that the hereditary basis of two parents about spike length, grains per spike and fertile spikelet number were very different. Highly significant difference among RILs was found in all three traits in two years. Of 355 pairs of polymorphic SSR marker between parents, 115 SSR markers were located to the 14 linkage groups including genome A and B. On average, there were 8.2 marker loci each chromosome. Chromosome 3B, with the most marker loci, had 13 marker loci and there were only 5 marker loci on chromosome 1A, 5B and 6B. The total length of 14 linkage groups was 822.9 cM, and average genetic distance between markers was 7.16 cM. With the method of composite interval mapping, the QTLs of traits related spike were detected using the field data in two environments. 6 QTLs for spike length, 4 located on chromosome 3A and 1 located on chromosomes 2A and 5B, respectively, were found in two years. The single of those QTLs for spike length could explain phenotypic variance from 9.21% to 22.94%. Two QTLs for fertile spikelet number located on chromosome 3B accounted for phenotypic variance 11.48% and 13.01% , respectively. Five QTLs for grains per spike were detected in 2010 and 2011. 4 QTLs were targeted to chromosome 3A and 1 to chromosome 7B. The single of those QTLs for grains per spike could explain phenotypic variance about 9.18%~19.71%. A major QTL for grains per spike was detected in the interval of Xbarc12~Xbarc310 on chromosome 3A in both 2010 and 2011. It indicated that this QTL was a stable and reliable grain per spike,which was less susceptible to environment conditions. This QTL was 0.01cM away from the nearest marker. So it can be used in molecular marker- assisted breeding for the improvement of grains per spike in wheat.