Analysis of Plant Height Heterosis Based on QTL Mapping in Wheat

Abstract

This study aimed at studying the molecular genetic basis of plant height (PH) heterosis in wheat. From a set of doubled haploid (DH) lines derived from Huapei 3 × Yumai 57, an “immortalized F 2” population was constructed with 168 single crosses. The DH lines, IF 2 population, and the parents were evaluated for plant height in 3 environments, i.e., in Tai'an, Shandong Province, China, in 2007 and 2008 cropping seasons and in Jiyuan, Henan Province, China in 2008 cropping season. Based on the genetic map of quantitative trait locus (QTL) constructed in a previous study, the heterosis of PH of wheat was analyzed using the composite interval mapping method. A total of 3 additive QTLs, 2 dominance QTLs, 4 pairs of epistatic QTLs (including additive by additive, additive by dominance, dominance by additive, and dominance by dominance), and 20 heterotic loci were detected for PH in the 3 environments. Two QTLs, QPh2D and QPh4D, were detected on chromosomes 2D and 4D with a minor interaction of additive by environment. In addition, several heterotic loci for PH except QPh2D were also identified on chromosome 2D in close regions with similar marker intervals. Of them, QTLs QPh2D-2 and QPh2D-7 explained the PH variance by 29.77% and 55.77%, respectively. Another QTL associated with PH heterosis, QPh7D-2, was mapped in the marker interval between Xwmc273.2 and Xcfd175 on chromosome 7D in the 3 environments. These results indicated that a few QTLs on chromosomes 2D, 4D, and 7D play an important role in PH heterosis in wheat. These loci have potential use for the improvement of PH in wheat breeding assisted with molecular markers.