Genetic Variation among Canada Wildrye Accessions from Midwest USA Remnant Prairies for Biomass Yield and other Traits

Abstract

Canada wildrye (Elymus canadensis L.) and Virginia wildrye (Elymus virginicus L.), which are native to the USA, were collected from remnant Midwest prairies. The objectives of this study were to determine the genetic variability among the collected accessions for biomass yield and other traits, determine the extent of genotype × environment interactions for these traits across Midwest environments, and to determine the relationship between the geographical location of the collection site and evaluation sites for these accessions for plant biomass yield which can be used as a measure of adaptation. Seed collected from six Midwest states was bulked by collection site to form individual accessions. Space transplanted evaluation nurseries were established at Mead, NE, Ames, IA, and West Lafayette, IN, and accessions were evaluated on a plot basis for 2 yr. There was significant genetic variation among accessions for post‐heading forage yield, heading date, height, pre‐heading in vitro dry matter digestibility (IVDMD) and crude protein (CP) concentration, and post‐heading CP concentration. Strain × location (S × L) interaction effects were only significant for post‐heading IVDMD and height indicating that for the other traits, the relative ranking of the strains was similar at all three locations over the two evaluation years. Regression analyses of the effect of distance of the collection site from the evaluation site (direct, east or west, and north or south) on biomass yield were largely nonsignificant or had very low R2 values. These regression results along with the nonsignificant S × L effects from the analysis of variance indicate that longitudinal or latitudinal adaptation gradients for plant biomass yield are lacking for Canada wildrye accessions from Midwest prairies. All but five of the Canada wildrye accessions had higher biomass yield than the only released cultivar, Mandan, indicating that this germplasm can be used to develop improved cultivars that should be adapted to the region represented by the collection and evaluation sites.