| Graduate student: Yang lianzhengTutor: Liu Guedao(South China University of Tropical Agriculture, Danzhou, Hainan,China571737)Brachiaria brizantlia cv Reyan No.6 was recently elected from Brachiaria brizantha induced by CATAS in 1963. It has vigorous tillering ability ,and can rapidly sprawled so that the weed be limited. Brachiaria brizantha cv Reyan No.6 which be extended in South China is established pasture as well as holding water and soil.Brachiaria brizantha cv Reyan No.6 may be propagated both from vegetative and seed. Vegetative propagation is simple, but, only in very small-scale fanning. Brachiaria brizantha cv Reyan No.6 was restrictively extended in large-scale because seed yield was low. The test was designed with improving seed production by nitrogenous fertilizer and planting density, in addition germinative test was designed. The main results are showed as follows1 The results of potted test: vegetative tillers and fertile tillers were significantly increased with improving nitrogenous fertilizer. And the best dose of urea was 0.9g/pot with 9 panicles of per pot 2 The results of field test:The best density was 1 .0m x 1 .0m with the most for 1876 panicles /plot, and the lowest was 1465 panicles /plot with 0.5mx0.5m .There are no significant difference among four nitrogenous levels. The most treatment in A2B1 was 2125 panicles /plot, but it was least for 986 panicles /plot.The shriveled seed percentage of Brachiaria brizantha cv Reyan No.6 was effected by nitrogenous fertilizer and planting density. The maximum of theshriveled seed percentage was 74.83% in the density 0.5 mx l.O m . but the minimum was 72.12% in 1.0 mx J.O m. the most shriveled seed percentage was 75.59% with 100kg/hm:, and the lowest percentage was 69.72% with 150kg/hm2. Among 16 treatments, the shriveled rate of AjBs was the lowest for 66.01% , while A4B2 was the most for 79.4%.The seed production of Brachiaria briyintha cv Reyan No.6 was significantly effected by urea and planting density. The most seed yield was respectively 134.64 kg/hm2 by applying urea 150 kg/hm2 and 141.31 kg/hm2 in 1.0m x 1.0m of planting density. The seed yield of AsBs among treatments was the most in 179.78kg/hm2, however that of A4Bi was the least in 55.66kg/hm20There weren't significantly difference about 1000 seed weight, seed/raceme, length/raceme, anthese/raceme of treatments by using urea and planting density.There was highly significance of difference between seed yield and panicles, and significance of difference between seed yield and shriveled seed percentage. There wasn't different between actual seed yield and 1000 seeds weight.In the first year, There were three harvesting periods with high yield, in which respectively 2002-09-10, 2002-12-18, 2003-04-15. There was different about 1000 seed weight being harvested in asynchronous stage. The 1000 seed weight being harvested in 2002-12-18 was maximum , but that in 2002-7-31 was least. The Seed / raceme in September 2002 was two times of that in April 2003. The length /raceme in September 2002 was more two times than that in April 2003. 3 germinative testPercentage of germination was effected by planting density and urea in field. The germinative capacity of AiBj and AjBj was highest among treatments.Seed dormancy occurs in Brachiaria brizantlia cv Reyan No.6 in seed production, it prevents gennination in seed of B. brizaniha. Germination test of seed in different storage periods showed : Gennination percentage of seeds which were harvested inSeptember 2002 (325 days in storage) was highest among all treatments, following that of 366 days and 248 days in storage. Germination rate of seed harvested in January 2003 (186 days) was lowest.Seeds which was harvested in January 2003 (180 days in storage)were respectively dipped in distilled water, Gibberellin ( GA3 ) l000ppm, 0.2% potassium nitrate, 1200ppm shajunbao( fungicide) and 98% sulphuric acid. The result gave that fungicide was better than others.The relation coefficient showed : there was negative correlati... |
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