Yield and Regeneration Studies in Tetraploid Berseem

Five tetraploid strains (T-708, T-709A, T-709B, T-724 and T-780B) were evaluated under field conditions, in comparison with the diploid strain C-10, in respect of fodder yield, forage quality, seed yield and regeneration. In forage yield, the tetraploids were much superior to the diploid at the time of the first cutting, came down to the level of the diploid during the second cutting and were inferior to the diploid when the third cutting was taken, indicating thereby that the tetraploids have a low regeneration capacity. In total yield, however, tetraploid strains, T-709B, T-724 and T-708, gave higher yields than the diploid did, though the difference was not significant. The tetraploids, however, gave a more uniform yield of green matter throughout the season as compared to the diploid. The dry matter content of the tetraploid was almost as good as that of the diploid. The tetraploids had more leafage per unit weight of the stem in all the cuttings. Some tetraploid strains showed equal or even higher seed yield per plant when compared to that of the diploid but seed yield per hectare was more in the diploid after second as well as the third cutting. The low regeneration of the tetraploids presents a serious problem though they show considerable variation among themselves. This problem needs to be tackled through judicious breeding so as to enable tetraploid berseem to be better suited for large-scale cultivation in comparison with the diploid berseem Trifolium alexandrinum.