Abstract：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.
