Consistent Progress From Four Cycles of RRPS for Winter Productivity in Annual Ryegrass.

Availability of standing forage for grazing in the southeastern USA is limited during the cooler months and animals feed on stored forages, which in turn increases management costs. Therefore, improved winter growth would be a great benefit to cattle producers. The objectives of this study are to 1) evaluate the progress from selection for increased dry matter winter production in annual ryegrass (Lolium multiflorum Lam.) resulting from four cycles of phenotypic recurrent selection. Intermating 50 plants from the six top performers in Alabama Annual Ryegrass Trials formed the base population for the selection experiment. Bulk-harvested seed from the 1st synthetic generation was intermated again to create a random mating population (C₀) for the selection experiment. A 1200-plant nursery was established in late October of each year with plants spaced 90 cm in all directions. The nursery is subdivided into 48 blocks of 25 plants each (5 x 5 arrangement). Plants were harvested and evaluated for dry matter yield 750 growing degree days (GDD) after transplanting, the best entries selected from each block were then intermated in isolation and bulk-harvested seed used for the next cycle. Replicated small-plot trials were established at five locations in Alabama during the 2008/9 and 2009/10 growing seasons. At three out of five locations, first cut yields increased with every cycle. One location did not show any yield increase for first cut yield because the winters were too cold. The Gulf Coast location did not show any yield increase during the first evaluation year because the average temperature never dropped below 10 C during the first growth period. Total seasonal yield was not significantly different from the long-term check cultivar Marshall. We conclude that the breeding approach to increasing winter productivity was successful.