Studies On Hybridization And Heterosis Forecast Of Poa

In this paper, life history, flowering habit and productivity of 14 materials of Poa were studied for about 2 years. According to the breeding objective, 4 materials were selected as parents and 7 hybridization groups were made. The female parent was emasculated with hot water, chemical hybridizing agent and artificial method, respectively. The hybrids of artificial emasculation were identified from morphology, chromosome number and isoenzyme and their heterosis was also predicted in this study. The result of life history shows that the life span of Poa pratensis is much longer than other materials. Considered with breeding object, 8 materials were selected for further study. The flowering habit indicates that the panicle of Poa flowers from top to the bottom, the florescence varies from one to two weeks, in which the fifth to eleventh day, from 4 a.m to 10 a.m, is the most prosperous. Productivity shows that fresh yield of 8 material varies remarkably, and has a positive correlation with tillering number, height and growth speed. The result of quality indicates that the ratio of stem weight and leaf weight has a very great difference. Combined with productivity and nutrition, 4 from 8 materials were selected as final parents. The hybridization groups are Monopoly X Wabash, Wabash X Storpy, Storpy X Wabash,Storyp X Poa pratensis var.anceps, Poa pratensis var.anceps X Storyp, Wabash X Poa pratensis var.anceps, Poa pratensis var.anceps X~Vabash. Emasculation with hot water indicates that the best treatment of Poa pratensis is 47C-2min, 4TC-3min and 48扖-lmin for Poapratensis var.anceps. GENESIS was used as a chemical hybridizing agent in the study, the best rate is 1 .5kg/bin2. Compared with former treatments, artificial emasculation is much more reliable, its hybrids were identified from chromosome number and isoenzyme, and its 3 heterosis was predicted by peroxidase isoenzyme, which indicates that different hybridization group has different heterosis. Fl with hybrid isozyme pattern or complementary isozyme pattern are good, such as Monopoly X Wabash, Wabash X Storpy, while that of hybrid with no difference isozyme patterns or delete isozyme patterns are poor, such as Storpy X Wabash. Heterosis is also positively correlated with enzyme active areas. The result of seedling character from hybrids and parents shows that the hybrids are superior to parents in invasion ability, leaf width and leaf length, which indicates the correctness of the method of heterosis forecast and the reliability of its result.