White Clover (Trifolium repens L.) Germplasm Selection for Abiotic Stress Tolerance from Naturalized Populations Collected in the Southern Regions of Chile

Abstract

Nine white clover populations (WCP) naturalized in Chile were evaluated under controlled (greenhouse pot experiments) and field conditions for water and P stress. The objective of this work was to determine dry matter production and water use and P efficiencies to identify which naturalized white clover populations would be most useful for breeding programs. In the field experiments the clover was grown mixed with perennial ryegrass, but in pots the clover was grown alone. The treatments were the factorial combinations of WCP by water and P levels; completely randomized and complete randomized block experimental designs were used for pot and field experiments, respectively. The population WCP 9-1-X was the most efficient for using water under controlled conditions and was among the three with the highest density of stolons under non-irrigated field conditions. The naturalized WCP 8-1-X produced more clover DM at the low P level than at the high P level and reached the same DM yield as cultivar Huia, which surpassed all the naturalized populations. These genetic materials have high potential to be included in white clover breeding programs whose objective is to generate cultivars for water-restricted and/or P-deficient marginal soils.