Construction of a high‐density genetic linkage map and identification of QTLs for main agronomic traits of tetraploid hybrid crested wheatgrass

Abstract

AbstractThe composition and structure of the crested wheatgrass genome are still poorly understood. In the present study, using 347 F2 individuals from the chromosome doubling of intra‐specific hybrids F1 plants by a cross of diploid Agropyron mongplicum × Agropyron cristatum as mapping population, an effort was made to construct a high‐density genetic linkage map based on amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers and identify quantitative trait locus (QTLs) for main agronomic traits of tetraploid hybrid crested wheatgrass. The map contained 766 markers, which were ordered in 14 linkage groups, and covered a total of 2,574.3 cM with an average distance of 3.82 cM between adjacent markers. It is the genetic linkage map with the largest number of molecular markers of the crested wheatgrass and the first map for tetraploid crested wheatgrass. A total of 136 QTLs were identified for 11 traits, of which 45 were major QTLs. A total of 23 QTLs co‐localized with 14 AFLP markers and nine SSR markers, respectively, and showed a great potential for marker‐assisted selection in improving these traits. A total of 30 QTLs showed pleiotropism, and the consensus QTLs were further integrated into seven pleiotropic unique QTLs. The significant co‐localization of QTLs was consistent with the significant phenotypic correlations among these traits. The results lay a foundation for map‐based cloning, functional analysis and designing molecular breeding of favorable genes in crested wheatgrass of further study.