Genetic advance estimates for red clover (Trifolium pratense) grown under spaced plant and sward conditions

A spaced plant experiment and a sward experiment were conducted at INIA La Estanzuela, Uruguay in 1996 with six red clover (Trifolium pratense L.) pop ulations, to study the efficacy of selecting genotypes for sward performanc e in a spaced plant nursery. This was examined through: (a) the ranking of the best linear unbiased predictors (BLUP) of populations and (b) the ratio of the correlated genetic advance in swards by selecting under spaced plan t conditions to the direct genetic advance of selecting under sward conditi ons. From the eight characters analysed, only the rankings of BLUPs for lea f size and flowering were significantly the same between populations. The o ther six characters performed differently according to the level of competi tion imposed. Post-grazing leafiness and the difference between pre- and po st-grazing leafiness (the two most important characters to measure preferen tial grazing) achieved greater genetic advance when selection was done as s paced plants: while for pre- and post-grazing height genetic advance was gr eatest by selecting under sward conditions. For other characters, the best conditions to select depended on the selection intensity achievable.