Preliminary Results of a Comparison between Tetraploid and Diploid Ryegrass

Abstract

MUCH interest has been aroused by the introduction from Holland of bred varieties of tetraploid ryegrasses. Herbage production experiments1 have not shown any remarkable differences in dry matter yield between these tetraploid and good diploid varieties; it was noted, however, that during the winter the tetraploids were singled out by hares for very hard grazing. The moisture content of the tetraploids is higher and in experiments at the West of Scotland Agricultural College2 Italian tetraploid outyielded S.22 on a green weight basis. Dent and Aldrich3 found that the soluble carbohydrate content of both perennial and Italian tetraploids was higher than that of comparable diploid varieties throughout the summer. In view of these findings, diploid and tetraploid varieties of both Italian and perennial ryegrass were sown in an animal production experiment in 1963; further sowings will be made in 1964. The preliminary results are presented here.