Agronomic Evaluations of Maize Genotypes Selected for Extreme Fiber Concentrations

Maize (Zea maysL.) hybrids with good yields of grain and wholeplant dry matter are recommended for silage production. The stover can comprise more than 50% of the whole‐plant dry matter and, therefore, can influence dry matter yield and nutritive value of the whole plant. The objective of this study was to determine relationships between agronomic characteristics (stover and whole‐plant forage yield and moisture, grain yield and moisture, lodging, maturity, and ear percentage) and nutritional quality of maize forage in three populations. Twenty‐four S0.1families (S0‐derived families in S1) exhibiting a range in neutral detergent fiber (NDF) and lignin at mid‐flower, were testcrossed to two commercial inbred lines (FR23 and LH74) to form two groups of F1hybrids. A third experimental group was created by self‐pollinating the S0.1families to form S0.2families. This germplasm was evaluated at three environments in Wisconsin. for FR23 testcrosses, grain yield had a correlation coefficient of 0.53 with stover dry matter yield, 0.65 with whole‐plant dry matter yield, and −0.03 with whole‐plant in vitro true digestibility. For LH74 testcrosses, the similar correlation coefficients were 0.46, 0.54, and −0.02, respectively. Also for FR23 testcrosses correlation coefficients of stover yield with whole‐plant yield, NDF, and in vitro true digestibility were 0.89, 0.53, and −0.28, respectively. For LH74 testcrosses the coefficients were, 0.85, 0.40, and −0.48, respectively. The results of this study demonstrate that stover yield and nutritional quality are important factors influencing whole‐plant yield and nutritional quality of maize forage.