Abstract:

Genetic dissection for grain yield and its components can provide a new strategy for crop breeding, and it play an important role in improving agricultural production. For dissecting the genetic basis of grain yield and its components, a set of recombinant inbred line (RIL) derived from an elite maize hybrid Yuyu 22, which is planted broadly in China, was used to constructed an “immortalized F₂”(IF2) maize (Zea mays L.) populations including 441 single crosses. The frequency of molecular marker loci for the IF2 population was analyzed using 253 different SSR markers, the results demonstrated that the genetic components and gene frequency of the IF2 population was similar to its F₂ population in molecular maker level, theoretically it could replace F₂ population in related genetic analyses. The IF2 population was evaluated in one environment over two years, and the genetic mechanism of grain yield and its components was dissected through QTL analysis using composite interval mapping (CIM) method. These results showed that grain yield had positive significant correlation with its three components at P<0.01 or P<0.05 level, and in the three components, ear length had negative significant correlation with row number and 100-grian weight at P<0.05 level. A total of 8 QTL were detected for grain yield, 8 for ear length, 11 for row number and 5 for 100-grain weight.

Key words: Maize (Zea mays L. ), “immortalized F₂” population, grain yield, QTL analysis