QTL Analysis For Kernel Related Characteristics In Wheat

In order to explore the genetic basis of wheat kernel related characteristics, QTL for wheat kernel related characteristics was conducted through CIM by SSR molecular markers based on RIL, developed from the cross between Triticum polonicum L.(XN555) and common wheat ‘Zhong 13’, including 99 lines and the F2 and F2:3, developed from the cross between dwarf wheat ‘0911-46’ and high wheat ‘42’. The results were as follows:1. Construction of genetic linkage14 linkage groups including A and B genomes with 241 SSR molecular markers were constructed based on RIL populations. The whole genetic linkage covered the genome of 1338.29 c M and the average distance between markers was 5.56 c M. 7B was the longest linkage with 183.67 c M, while 7A was the shortest one with 37.48 c M. The average markers on each chromosome was 17.21 SSR markers and 7B was the one with most, 25 SSR markers, while 6A was the one with least, 11 SSR markers.21 linkage groups including 176 SSR markers were constructed based on F2:3 lines. The whole genetic linkage covered the genome of 1423.54 c M and the average distance between markers was 8.09 c M. Except for 6A, which only contained one marker, the rest chromosomes contained 8.8 SSR markers evenly.2. QTL analysis for wheat kernel related characteristics12 QTLs for wheat kernel related traits were identified through CIM based on RIL populations grown in two years. Of all, three QTLs for wheat kernel weight, five QTLs for wheat kernel length and four QTLs for wheat kernel width were identified on chromosomes 1A, 2A, 2B, 3A, 3B, 5A and 5B and could explain 9.76%-40.79% phenotypic variance.53 QTL for wheat kernel related characteristics were identified based on F2 and F2:3 grown in two different places in two years. All of these, six QTLs for wheat kernel weight, 27 QTLs for wheat kernel size, and 20 QTLs for wheat kernel shape were identified onchromosomes 1A, 1B, 2A, 2B, 2D, 3A, 3B, 4D, 5A, 5B, 6D, 7B and 7D. Two gene clusters were found in chromosome 1A and chromosome 2D. QTL for wheat kernel weight were mainly distributed on A genome, and QTL for wheat kernel shape were mainly distributed on B genome, while QTL for wheat kernel size were evenly distributed on A, B and D genomes. QTL for wheat kernel weight and kernel shape were mainly distributed on homologous group one and homologous group two, while QTL for kernel size were evenly distributed on the seven homologous groups.3. Dynamic QTL analysis for wheat kernel dry matter accumulationConditional and unconditional QTLs for thousand-kernel weight in the period of slow growth, rapid growth and plateau phase were detected based on the growth curve fitting of Logistic equation. Five conditional QTLs and five unconditional QTLs were identified. There were two unconditional QTLs in the period of slow growth and rapid growth, one unconditional QTL in the period of plateau phase on the chromosomes 2B, 3A, 3B and 7A, which could explain 9.66%-15.18% phenotypic variance. There were one conditional QTL in the period of rapid growth, four conditional QTLs in the period of plateau phase on the chromosomes 1A, 2B, 5B and 7B.