Heritabilities and Genetic Correlations of White Clover Clones Grown in Three Environments

Abstract

White clover (Trifolium repens L.) is commonly grown in a legume and grass mixture, but most selection for elite clones has been as spaced plants in monoculture. This study estimates (i) population parameters important to breeding white clover when grown with two different grasses or in monoculture, and (ii) the potential for improving yield of clover grown in grasses when selection is made in monoculture. Ramets of 47 randomly selected clones from Southern Regional Virus Resistant white clover germplasm were space‐planted and grown for 3 yr in three environments: in monoculture, in Tifton 44 hybrid bermudagrass (Cynodon dactylon (L.) Pens.), and in common bermudagrass. Plant spread, yield, and stolon branching were measured at four harvests. Compared with monoculture, competition with common and hybrid bermudagrass reduced clover yield 60 and 45%, respectively. Environment had variable effect on magnitude of heritability estimates, which were statistically significant for each trait in each environment (H = 58 to 72%) except yield in common bermudagrass. Genetic correlations between environments were significant for clover yield and plant spread. Predicted response to selection in grass was 12 to 31% more effective than selection in monoculture for yield and 71 to 90% more effective for plant spread. The selection for yield in hybrid bermudagrass to improve yield in common bermudagrass was predicted 30% more effective than direct selection. Selection in monoculture should improve performance with grasses, but clover yield will not be maximized until selection is completed in a grass environment.