Forage Quality of Maize Genotypes Selected for Extreme Fiber Concentrations

Abstract

An understanding of the factors and relationships affecting wholeplant digestibility is needed to improve the nutritional quality of maize (Zea mays L.) forage. The objectives of this study were to: (i) determine the ranges among 24 maize genotypes for fiber composition and digestibility of stover and whole‐plant forage, and (ii) determine the relationships between fiber composition and digestibility. Twenty‐four S0.1 families (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 F1 hybrids. A third experimental group was created by self‐pollinating the S0.1 families to form S0.2 families. These germplasms were evaluated in three Wisconsin environments. Ranges in S0.2 family means for fiber and digestibility were: NDF, 439 to 582 g kg−1 for the whole plant and 579 to 654 g kg−1 for the stover; and in vitro true digestibility (IVTD), 714 to 820 g kg‐1 for the whole plant and 689 to 757 g kg−1 for the stover. Narrower ranges were observed among LH74 and FR23 testcrosses. For S0.2 families, correlation coefficients for stover IVTD with stover NDF and lignin were −0.76 and −0.85, respectively. Correlation coefficients for whole‐plant IVTD with stover IVTD and lignin of S0.2 families were 0.44 and −0.49, respectively. The results of this study show that (i) significant variation exists for nutritional quality traits of the stover and whole‐plant forage and (ii) stover quality is an important factor influencing whole‐plant nutritional quality within the germplasm studied.