QTL mapping for some morphological traits in recombinant inbred lines of bread wheat

In order to identify the QTLs controlling the morphologic traits of bread wheat, 148 recombinant inbred lines of spring wheat derived from American Yecora Rojo (early maturity and dwarf as the male parent) and No.49 genotype from Sistan Baluchestan (late maturity and tall as the female parent) were studied with the parents. The studied traits included peduncle length, spike length, awn length, flag leaf length, the number of spikes, spike weight, and the number of grains in spike. In this study, linkage map was used based on 202 markers (177 SSR markers and 51 Retro transposon Markers). The map length was about 691.36 cM with the average distance of 3.42 cM in every marker pair and covered 21 chromosomes in bread wheat. QTL analysis was done based on composite interval mapping (CIM) method, and additive effects were estimated for the identified QTLs. The results of QTL analysis showed that one QTL was detected on chromosomes 7B, 5A, 3A, 4A, 3A and 3A respectively for plant height, peduncle length, spike length, awn length, flag leaf length, the number of seed per spikes; two QTL was detected on chromosomes 3A and 2D for the number of spike and seed wieght per spike; and three QTLs were detected and mapped on chromosomes 3A, 4A, and 3A for spike weight. Among the detected QTLs, QSNS3A had the highest additive effect. For spike length, spike weight, the number of grains in spike, and seed weight per spike. The negative additive effect of the mapped QTLs indicate the optimal allele inheritance to crosses in this position of No.49 parent. The phenotypic variance explained by these QTLs varied from 4.93 to 13.63. In this study, the number of QTLs found for spike traits was so limited; it can be due to the large number of small-effect QTLs, mutual effects, and environmental effects.