Studies On The Sprouting Properties Of Axillary Buds Of Hybird Rice

Three experiments were conducted. Three two-line hybrid rice combinations(PeiLiangYou288, PeiLiangYouSOO and PeiAi64S/E32) and three three-line hybrid rice combinations (ShanYou63, WeiYou644, and WeiYou46 ) were used in cultivar-comparising experiment;,Two hybrid rice combinations (PeiLiangYouSOO and ShanYou63) were used in the sowing-date experiments which were sown at 3/31 , 4/11 and 4/19 respectively; A hybrid rice combination (PeiLiangYouSOO) was used in chemical-regulating experiment ,40 mg/kg GA3 and 30mg/kg CTK were sprayed at 25 days after full heading and 3 days after harvest of main crop . The main results are as follows:1 .The differences of average yield of main crop between varieties did not reach significant level in cultivar-comparising experiment : There was significant difference of the axillary bud sprouting in ratooning rice because of the difference of ratooning ability between different combinations. So there were significant differences of grain yield in ratooning rice, the yields of Peiai64S/E32 , Peiliangyou 500 > Weiyou46, Peiliangyou 288 and Weiyou644 were 26.19%, 23.81%, 11.91%, 7.14% and 4.76% higher than that of ShanYou63 respectively. So Peiai64S/E32, Peiliangyou500 and WeiYou46 can be used as ratooning varieties in Hunan.2. The correlation coefficients between the effective tiller number, grains per panicle, seed-setting percentage and 1000-grain weight with yield were significant; The effective tiller number had largest effect on yield, larger than seed-setting, grains per panicle and 1000 grains weight. In order to increase the grain yield of ratooning rice, increasing the effective tiller number and seed-setting percentage was of most important.3.The sowing time had great effects on the axillary bud sprouting, the sprouting of axillary buds under the first sowing time was best, and the grain yieldwas highest; the second sowing time was worse , but it could mature normally; the third sowing time could not reach full heading stage before safety full earing date, so some panicles could not be heading or could not mature normally. In view of the climate and high yield, the suitable sowing time of ratooning rice was in late March to early April in Changsha district, the most suitable sowing date was in late March.4. The correlation coefficient between a single stem weight at maturing stage and grain yield of ratooning rice was significant(0.760**); The activity of SOD and Pox was highest during fully heading stage in main crop, decreased gradually after full heading, was lowest at 15 to 20 days after full heading of main crop, and then increased gradually; Nonstructural carbohydrate decreased gradually after heading stage and increased slightly later; The root activity and the area of root absorption decreased gradually after heading stage, lowest in maturing stage and increased gradually after the harvest of main crop.5.Chemical regulators could increase the grain yield of ratooning rice .GA3 and CTK were sprayed on main crop rice 25 days after full heading and 3 days after harvest of main crop, the grain yield of ratooning rice increased by 4.09%^ 9.67% compared with CK respectively, but no significant difference was found.