The seed weight of tetraploid red clover was significantly greater than that of diploid in all experiments. Tetraploid seedlings had longer petioles and greater leaf area and accumulated more D.M. than diploid seedlings. The diploid in monoculture populations developed more expanded trifoliate leaves than the tetraploid.Two main effects of competition were:-(a) A significantly lower relative shoot growth rate of the diploid in mixed populations which resulted in significantly reduced D.M. production compared with monoculture populations. Conversely D.M. production in the tetraploid increased significantly in the mixed populations.(b) A significantly greater number of expanded leaves formed by the diploid in monoculture populations compared with the tetraploid was reduced to non-significance in mixed populations. Competition had little or no effect on petiole length or leaf area.The results are discussed in relation to the competitive advantage tetraploid seedlings would have over diploid seedlings.
Germination rate, root, and shoot growth of 'Grasslands Roa' S170, and a wild type tall fescue (Festuca arundinacea Schreb.) were compared with perennial ryegrass (Lolium perenne L.) in the glasshouse and field. There was little variation between tall fescues but S170 established slightly better than the others. Under moisture stress, the wild type was superior to the other tall fescues in germination and establishment. Ryegrass was markedly superior to all tall fescues because of much higher germination, root elongation, and tillering rates. Regrowth following defoliation of tall fescue seedlings was also much poorer than ryegrass. The physiological basis of some of these differences is discussed, together with agricultural implications on the potential use, management, and future selection of tall fescue.
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