Growth traits comparison among M1 of 28 introduced varieties of Lolium

Seeds of twentyeight perennial ryegrass varieties introduced from Germany were irradiated by 60Co with 400 Gy, 500 Gy. The effects of radiation treatments on the germination potential, number of tillers, plant height, fresh weight and heading date were observed and analyzed in the field. The results showed that the low dose caused death of Gordo, Ligrande and Barmultra, while the high dose caused death of Remy and Bartissimo. Furthermore, gamma beam causes changes of the perennial ryegrass minute tiller number, height, growth characters, fresh weight and earing period. The tiller numbers of Zarastro, Barfort, Tosca and Orlando mutagenesis material increased signficantly after radiation, The height and the fresh weight of Lolita mutagenesis material increased by 20%. These results indicated that radiation is a good and fast way to improve the quality of forage, which could be used in further breedings.