Studies On Production Security And Variety Purity Identification Technology Of Hybrid Rice

In this paper, the author has studied the characteristics of the resistance to abnormal temperature of medium hybrid rice and to abnormal low temperature of late hybrid rice, with eight medium hybrid rice combinations and their restorers and ten late hybrid rice combinations as materials. In the same time, the author uses the above materials to identify variety genuineness and purity with SSR fingerprinting technology and planting identification technology. The major results of the research were as follows:1. The setting rates of medium hybrid rice combinations vary in different ecocites. The setting rates of eight medium hybrid rice combinations is highest in Changsha, while seven of that is lowest in Changde and one in Huaihua, the name of which is "Luliangyou 106". Because of the abnormal low temperature from Aug. 18 to 20, all combinations of the hybrid rice of the 8^th sowing time didn't get good ear in Huaihua, thus the average setting rates of all sowing time are not ideal. The test showed that the setting rates of medium hybrid rice were lowest recorded in Changde because the high temperature lasts for a long time during a day and the temperature difference is not obvious there, while the situation are opposite in Changsha and Huaihua.2. There are significant differences in setting rate among different medium hybrid rice combinations. The average setting rate of"Liangyou peijiu" is the lowest in all three ecosites, which is obvious lower to other samples. That of "Jinyou 725" is lower, but that of "Luliangyou 106" is much better. All of these show that both "Liangyou peijiu" and "Jinyou 725" have lower production security, which is the same as mass planting practice of the reality.3. Even the same medium hybrid rice has different setting rates in different sowing time. We can know from the test that, of the eight combinations of medium hybrid rice, the most suitable time for sowing was about April 30 in all these three cites, and the setting rates dropped when it came to May 15 or later. Though the condition of climate was suitable for rice earing and blooming and pollination, when the rice was planted after May 15, the setting rates still descended as a whole (normally the late rice is planted on about May 20 in Hunan area ). So we can know from the test that if there is no abnormal high temperature and they are planted in normal sowing period, the medium rice will have better setting rates than late rice, which has probably relation with the feature of resistance to high temperature formed during the long regional selection and identification.4. Temperature affects directly the setting rate of medium hybrid rice. In the test, 31 ℃ was recorded only during the late of July and early of August only in Changde and Changsha cites, which didn't have big compact on the setting rates of hybrid rice. Generally speaking, in comfortable temperature conditions, it is not obviously that the there are positive relations, during the earing and flowing time, between the average day temperature and setting rate. But only for "Shanyou 63" in the three cites, "Liangyou peijiu" in Changde and "Siyou 63", "Shanyou Gui99" and "II You 838" in Huaihua, the...