Forage yield and quality of Corn cultivars developed in different eras

摘要: Gains in corn (Zea mays L.) grain yield over time are well documented, but corresponding changes forage and stover quality have received less attention. Our objective was to describe of representative cultivars used by farmers the northern Corn Belt. Six open-pollinated prior 1930, 24 representing four 15-yr eras between 1931 1990, six modern cultivars, for a total 36 were divided into early- late-maturity trials. Each trial grown at three locations Wisconsin during 1997 1998. Since dry matter has increased rate 0.128 0.164 Mg ha -1 yr with yields increasing 0.043 0.054 '. Forage crude protein not changed significantly time. neutral detergent fiber concentration decreased 0.825 0.948 g kg ', while vitro digestibility 0.538 0.612 1 . Stover 1930 forage, stover, ear 1.4, 0.7, 2.4% , respectively. This trend will no doubt continue, greater progress might be made if breeding improvement concentrates on stover.