Genetic analysis and QTL mapping of stalk cell wall components and digestibility in maize recombinant inbred lines from B73 × By804

Abstract

The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value. Previous studies of stem quality have focused mostly on common maize germplasm, and few studies have focused on high-oil cultivars with high grain and straw quality. Investigation of the genetic basis of cell wall composition and digestibility of maize stalk using high-oil maize is desirable for improving maize forage quality. In the present study, a high-oil inbred line (By804) was crossed as male parent with the maize inbred line B73 to construct a population of 188 recombinant inbred lines (RILs). The phenotypes of six cell-wall-related traits were recorded, and QTL analysis was performed with a genetic map constructed with SNP markers. All traits were significantly correlated with one another and showed high broad-sense heritability. Of 20 QTLs mapped, the QTL associated with each trait explained 10.0%–41.1% of phenotypic variation. Approximately half of the QTL each explained over 10% of the phenotypic variation. These results provide a theoretical basis for improving maize forage quality by marker-assisted selection. Keywords: Maize, QTL, Cell wall, Digestibility, Recombinant inbred lines