Genetic dissection of interaction between wheat protein and starch using three mapping populations

Protein and starch are important factors in determining wheat end-use quality and yield. However, these two traits are negatively correlated. So in order to dissect the genetic relationship between grain protein content (GPC) and grain starch content (GSC) at QTL/gene level, three mapping populations were used at three locations in 2 years. The QTLs for GPC and GSC were analyzed by unconditional and conditional QTL mappings. Thirteen QTLs were detected for GPC by each of the conditional and unconditional methods of QTL analyses. For GSC, seven and nine QTLs, respectively, were detected using unconditional and conditional QTL analyses methods. Of these QTLs, there was only one major QTL detected for GPC using unconditional QTL analysis. For GSC, two major QTLs were detected through each of the conditional and unconditional QTL mapping methods. Seven QTLs with minor effect on GSC were identified for GPC (Qgpc2A-12, Qgpc6D-3, Qgpc1D-15, Qgpc2D-23, Qgpc2D-31, Qgpc5B-19, and Qgpc4B-7). Four QTLs were found for GSC, named Qgsc1D-1, Qgsc4A-9, Qgsc7B-15, and Qgsc7D1-2, which had minor influence on GPC. The major QTL Qgsc7B-15 can directly be used for improving the GSC in molecular marker-assisted breeding. QTLs detected in the present study could possibly be used in simultaneous improvement of grain protein and starch content in wheat.