Ryegrass populations from intensively managed leys:I. Seedling and spaced plant characters

Abstract

SUMMARYSeed of Lolium perenne L. was grown from material collected from three S.23 leys and one S.24 ley that had been subjected to high rates of stocking and nitrogen application. Comparisons were made between plants grown from seed derived from the leys and from breeders' seed of S.23 and S.24.Seedling characters indicated that the populations derived from leys differed from each other and from the plants grown from breeders' seed. In S.23 populations the main change occurring in intensively grazed leys was towards higher tillering prostrate seedlings. This did not occur in the S.24, but here the survivor population had a slightly shorter fifth leaf and a lower number of leaves on the main tiller of the seedlings.As spaced plants, the population derived from the S.23 ley, with the highest percentage ryegrass and the reputation for the highest yields on the farm, gave a higher yield, recorded in three cuts in the first year and in four cuts in the second year, than any other populations. Small differences between S.23 populations in aftermath heading, reaction to rust, and mean date of panicle emergence were recorded. Variance of spaced plant yield decreased in ryegrass derived from older S.23 leys. The S.24 ‘survivor’ population was much later in mean date of panicle emergence than S.24 grown from breeders' seed.