THE RELATIONSHIP BETWEEN PROGENY SEED YIELD IN DRILLED PLOTS AND MATERNAL SPACED-PLANT TRAITS IN PERENNIAL RYEGRASS (LOLIUM-PERENNE L)

Seed production in perennial ryegrass, Lolium perenne L., is low. Earl y selection for high seed yield carried out in spaced plants would be valuable for breeders, but only if this potential is also expressed in derived progenies sown later in drilled plots. Therefore, spaced-plan t traits assessed on clonal ramets of 31 genotypes in each of two pere nnial ryegrass varieties in four environments were related to seed pro duction characteristics in drilled plots of open-pollinated progenies of these plants. Significant differences were found among these half-s ib families for seed yield, thousand-grain weight, spring performance and earliness. The number of spikelets per ear in the maternal plants was negatively correlated with the seed yield of the progenies, explai ning 17% of the variation for seed yield in the cv. 'Barenza' and 14% in the cv. 'Wendy'. Multiple regression analyses revealed that no comb inations of plant traits consistently explained a major portion of the variation for seed yield of the progenies. The results indicate that in these varieties, spaced-plant data are of limited value in predicti ng seed production. Direct selection for seed yield in drills of proge nies in later stages of the breeding programme remains the best method for obtaining varieties with sufficient seed production.