Study On The Outcrossing Characteristics Of Seven PTGMS Rice Lines

To explore the outcrossing chatacteristics of photo-thermo-sensitive genic male sterile rice (PTGMS) and the influence to the hybrid seed production, seven PTGMS rice lines,long S、 Chuang 5S、 Yun 9S、 Pei ai 64S. Guang zhan 63-2S、 P88S. Y58S were used as experimental materials to compare their heading characteristics, blossom habit and stigma features etc. At the same time, their stigma vitality and outcrossing rate were investigated by using R608 as the male parent.The main results were as follows:1. Four PTGMS rice lines, Peiai 64S, chuang 5S, Yun 9S and Y58S began flowering at 7:30 to 8:30, earlier than others. The heading duration of the tested seven rice PTGMS lines waried from 4 to 10 days. The longest heading duration was Y58S, while Long S was the shortest.2. Correlation analysis showed that the open angle of spikelets was a significantly negative correlation to the temperature during the flowering day (r=-0.387**), and a significantly positive correlation to the humidity (r=0.377).Otherwise, the stigma exsertion rate was a positive correlation with the stigma length(r= 0.912*),and a significantly positive correlation with stigma width(r=0.968**).3. The best feature stigma of seven PTGMS rice lines was P88S, such as stigma length, stigma width, stigma area, stigma volume, stigma vitality and stigma exsertion rate etc.4. In the seven rice PTGMS lines, the card neck grains rate of Guangzhan 63-2S and P88S are the highest and no significant differences, the rate were 5.66% and 5.25%; the Chuang 5S was the lowest, only 3.08%;Yun 9S and Y58S almost the same, were 2.38% and 3.01%.The ear neck to seed space of Guangzhan 63-2S was up to 3.37cm which was the highest among them.5. The stigma exsertion rate had greatest impact in outcrossing rate,and a significant positive correlation between them (r=0.977**); At the same time, it can also affected by the spikelet angle, stigma length, stigma width, there were significantly positive correlation between them, the correlation coefficients were 0.903*,0.934* and 0.934* respectively. Therefore, the outcrossing seed rate of PTGMS rice lines was influenced by many factors, not single.6. According to outcrossing characteristic of PTGMS, taking appropriate measures such as protecting the flower and assistant pollinating is expected to reduce the cost of production, and to increase the yield of rice seed production.