Evaluation of white clover (Trifolium repens L.) populations for summer moisture stress adaptation in Australia

Agenetic experiment was conducted using 80 full-sib families in irrigated and dryland treatments under the summer moisture stress conditions of the Northern Tablelands of New South Wales, over 3 years. This paper reports on the effects of climatic and soil moisture conditions, the genetic variation for stolon attributes and seasonal herbage yield, and the development of new recombinant genotypes in relation to the association between stolon attributes and herbage yield. Large components of variance were estimated for genotype-by-environment-by-year interactions for the attributes stolon density, number of branches, number of nodes, number of rooted nodes, stolon thickness, root diameter, internode length, and summer herbage yield. The combined analysis of variance across environments and years indicated the presence of genetic variation for the stolon attributes stolon density, number of branches, number of nodes, stolon thickness, internode length, and herbage yield. Crossing of the morphologically contrasting cultivars El Lucero x Tahora x Duron, and Barbian x El Lucero, resulted in generating genotypic recombinants with new associations between herbage yield and stolon density, number of branches, number of nodes, and number of rooted nodes. Evaluation of the full-sib families and check cultivars (cvv. Haifa and Huia) identified 5 full-sib families with relatively higher herbage yield, stolon density, number of branches, number of nodes, and number of rooted nodes than cultivars Haifa and Huia.