Inbred line evaluation and breeding for digestibility-related traits in forage maize

Forage maize digestibility is now a major selection criterion in breeding programs, and in hybrid breeding it is useful to select at the inbred level.:This study was conducted to evaluate the possibility of doing preliminary selection at the inbred level for digestibility-related traits in forage:maize (Zea mays L.). Maize hybrids from a factorial mating design among nine and six maize inbred lines, and the 15 parental,inbred lines per se, were evaluated at silage stage at three locations (France) for 2 yr. Whole plant in vitro digestibility of dry matter and of cell walls, and plant biochemical composition traits were investigated by near infra red reflectance spectroscopy (NIRS). Biomass dry matter content and productivity were also collected. In hybrid trials,general combining ability (GCA) of lines was the most important source of variation in all digestibility traits, compared with specific combining ability (SCA), GCA x environment, and SCA x environment Interactions. Some plant biochemical components were associated with the biomass yield, whereas digestibility of cell walls, particularly, Was found independent from biomass productivity. The efficiency of predicting the hybrid performance from midparent value, as well as the good relationship between inbred line per se and GCA values, for digestibility-related traits, and particularly cell wall digestibility, indicated the possibility for maize breeders to improve digestibility of forage maize by selecting inbred lines.