Genetic and Environmental Variance of Water Soluble Carbohydrate Concentration, Yield, and Disease in Tall Fescue1

Abstract

Tall rescue (Festuca arundinacea Schreb.), a widely grown forage in southeastern USA, would be more useful as a livestock feed if its energy value, when grown in summer, were increased. The primary purpose of this study was to measure genetic and environmental variance of water soluble carbohydrate (WSC) concentration of summer regrowth forage harvested from a population of tall rescue derived from a world‐wide germ plasm collection. Variances of yield and disease rating were also measured. Forty‐five genotypes from each of 30 accessions (27 foreign collections and three domestic cultivars) were randomly chosen from a source nursery and established in space‐planted nurseries at three locations in West Virginia in 1980. At each location, three blocks contained plants representative of all 30 accessions. Each accession was present in each block and was represented by two clones of five randomly selected genotypes. Variance components of WSC concentration, yield, and disease rating were estimated by equating mean squares to expected mean squares of appropriate analysis of variance models. Genetic variances of WSC concentration, yield, and disease rating were 55, 65, and 75% of the total variances, respectively, and environmental variances were 42, 36, and 29%, respectively. The area ✕ accession components of the genotype ✕ environment (G ✕ E) interaction variance for WSC concentration, yield, and disease rating were 2.1, 1.5, and 3.4% of the total variances, respectively. The block ✕ accession within area components of G ✕ E variances for the three variables were nonsignificant. The high degree of genetic variance within the population indicates that there is potential for genetic improvement in all three variables. Under conditions of this experiment, interactions between genotypes and environments were minor; therefore, a potential for wide adaptability exists within the population.