Transferring a major QTL for oil content using marker-assisted backcrossing into an elite hybrid to increase the oil content in maize.

摘要

Maize oil is highly valued as a human vegetable oil and in animal feed. The normal hybrid, Zhengdan958, is one of the most widely distributed varieties in China. To increase its oil content, a favorable allele of a major quantitative trait locus for oil content, qHO6 on chromosome 6 from the high-oil inbred line, By804, was transferred into the two parents of Zhengdan958, Zheng58, and Chang7-2, using marker-assisted backcrossing. Two improved inbred lines, Zheng58- qHO6 and Chang7-2- qHO6, were developed through six generations of backcrosses guided by molecular markers. An approximately 260-kb fragment from the donor parent was transferred into recurrent lines, and over 99% of recurrent genomes were recovered. Both of the improved inbred lines showed increased oil content of roughly 1% without a change in grain weight. Consequently, the oil content in improved Zhengdan958- qHO6, crossed from Zheng58- qHO6 to Chang7-2- qHO6, reached 4.5%, with increases in absolute and relative content of 0.71 and 18%, respectively, compared with the original Zhengdan958. The grain yield of the improved Zhengdan958- qHO6 ranged from 5,928 to 11,826 kg/ha in ten environments, similar to the original Zhengdan958. This study provides a practical example of the feasibility of improving quantitative traits by transferring desirable alleles using marker-assisted backcrossing.