Grain yield, forage yield, and forage quality of different sorghum types under irrigated and dryland conditions

Sorghum (Sorghum bicolor (L.) is generally grown where water may be severally limited. It is grown in some areas as a dual purpose crop, with the grain for humans and the fodder for animals. Little has been done to date to select improved types of sorghum for both purposes. We evaluated response of 54 diverse cultivars of grain, dual, and forage sorghums to irrigated and dryland conditions in 1986 and 87, using a randomized complete block design. There is a lack of agreement regarding which type of sorghums should be grown for superior forage yield and forage quality. We questioned whether there were differences in grain and forage yields and forage quality among these various types. The three types of sorghum differed significantly in grain yield, forage yield, stover yield, acid detergent fiber, crude protein, harvest index, seed weight and bloom date. The environment significantly affected the traits studied.;It was found that grain type sorghum cultivars produced maximum grain yield and better quality forage than both dual and forage type sorghum cultivars. Both grain and dual type sorghums produced two times more grain yield than forage type sorghums. Dual type sorghums produced maximum but medium quality forage. The optimum environment (Garden City irrigated) produced maximum forage yield, grain yield and acid detergent fiber while maximum crude protein contents were produced at Hays.;Phenotypic correlations and principal component analysis indicated that environment influenced all traits of interest.;Favorable, positive associations between maximum forage yield and superior quality as defined by higher crude protein contents and lower acid detergent fiber were observed in optimum environment (Garden City irrigated) and these associations changed with a change in environment (Garden City dry). It is believed that forage yield and forage quality are negatively correlated. This association was occassionally observed in this study, but favorable, positive associations between maximum forage yield and superior quality, as defined by high crude protein content and lower acid detergent fiber were also observed.;The results of this study suggest that cultivation of dual and grain type cultivars is a best compromise between forage yield, grain yield and forage quality. A majority of dual type cultivars were superior in forage yield and moderate in forage quality but were unstable across diverse environments. Grain type cultivars produced moderate forage yields, highest grain yield, excellent forage quality, and were stable across diverse environments.