Genetic analysis of feed quality and seed weight of sorghum inbred lines and hybrids using analytical methods and NIRS

Eight lines of grain sorghum and their F1hybrids were evaluated for contents of crude protein (CP), fat (FAT), and starch(STA); protein digestibility (PD); and in vitro dry matter disappearance (IVDMD).The effect of seed weight (SW) on these traits and the potential use of near infrared reflectance spectroscopy (NIRS) to predict them also were investigated. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two large-seeded lines (PL-1 and Eastin1). The female lines included common U.S. seed parent lines (Wheatland, Redlan, andSA3042). The lines and their hybrids were grown under dry land conditions at Kansas State University experiment fields in Ashland and Belleville, Kansas, in 1999.The experiments were conducted using a randomized complete block design with four replications at each location. The effect of genotype was significant for all measured traits. The male parent lines were highly variable and expressed high levels of genetic variation in combining ability for CP, PD, STA, and SW. The female parents were genetically more uniform; however, significant general combining ability effects were noted for PD and SW. Significant negative correlations were noted between CP and STA and between SW and STA. Significant positive correlations were found between CP and SW and between FAT and IVDMD. Crude protein content was predicted accurately by NIRS. Fat content and IVDMD could not be predicted by NIRS. The NIRS equations based on ground samples were more accurate than those based on whole-seed samples.[PUBLICATION ABSTRACT]