Study On The Fertility Variation Of Thermo-sensitive Genic Male Sterile Rice Y58S

The core seed of Y58S which were bred 1-3 generations and the seed of Y58S which were multiplied many generations but not according the core seed production procedures, which were planted into groups respectively. The leaves age were recorded and the young panicle were reviewed, Sampling in groups and treated in cool water with 23℃for 6d and 21.5℃for 12d during fertility Sensitive stage, the Daily average temperature is 25.7℃～32.0℃during fertility Sensitive stage of the plants which remained in the field, the samples above were all examined anthers with microscope in flowering stage and the self-seeding rate were examined.the main results were as follows:1. There is no significant difference in the leaf number of main stem between the group which were multiplied for the first, the second and the third generations by core seed and the group which multiplied for several generations without by core seed production procedures. The leaf number of the main stem of dual-purpose nuclear sterile line Y58S maintain about 14, which were not changed with the generation increased. But with the multiplication generation increased, the amplitude of the main stem leaf numbers of the Y58S plants of each generation has the tendency of increasing gradually.2.Under the condition of the Daily average temperature were 25.7℃～32.0℃during fertility Sensitive stage, the rate of the plants with normal anther was 0 which were in the first and the second generations inbreeded by core seed, the rate of the plants with normal anther of that of the third generation was 1.00%, and the cultivated groups which without core seed production procedures that the rate of the plants with normal anther was 2.67%, and the fertile plants with the same shape were appeared.3.The other type rice plant rate in the first generation group which bred by Y58S core seed was 0, and the rate that of the second generation group was 0.12%, but the rate that of the third generation group was reached 0.25%. The other type rice plant rate in the group which by several generation multiplications without core seed production procedures was reached 0.78%, that the seed purity was only 99.22%.4.Y58S plants were treated under the condition of cool water with 23.0℃for 6 days during fertile sensitive stage, the rice plants rate with the normal anther in the first and the second generation group which were bred by core seed were 0,0.67% respectively,and the rate that of the third generation group and the group which were multiplied several generations without core seed production procedures were 1.33%,3.00%respectively. it can conclude that the fluctuation is small when Y58S were treated under 23.0℃cool water for six days during fertile sensitive stage. The hybrid seed production which used the first and the second generation seeds that multiplied by core seed would not fail as a result of the fertile fluctuation by the reason of the appearance of constant Daily average temperature were 23.0℃for six days during fertile sensitive stage. It can also conclude that with the increasing of the number of the core seed multiplication generation, the fluctuation amplitude of the group fertile would increase gradually5.Y58S plants were treated under the condition of cool water with 21.5℃for 12 days during fertile sensitive stage, the rice plants rate with the normal anther in different generations group were all appeared normal distribution, which concluded that the essence of Sterile is controlled by a major gene, fertility transition temperature drift is the result of minor genes. The first and the second generation groups which were bred by core seed that The number of rice plants which the self-seeding rate were some kinds of the same was large, the group that of the third generation and the group by several generation multiplication without core seed production procedures which the difference of self-seeding rate of each plant in the groups were large, the number of plants with high self-seeding rate was increased, which shows that the fertility transition temperature was increased. The average seeding rate (55.43%,59.01%,62.07%,64.01%) in groups were also increased with the increasing multiplication generation.6. The first and the second generation seeds of Y58Swhich were multiplied by core seeds that it is safe for hybrid seed production, it has some risk for the hybrid seed production by using the third generation seeds of Y58S, and the seeds which by several generations'multiplication without core seed production procedures were not allowed to product hybrid seeds. During the multiplication of TGMS line, removing the plants with the two extremes of high stained pollen rate (self-seed setting rate) and low stained pollen rate (self-seed setting rate), remain the plants with relatively consistent stained pollen rate(self-seed setting rate),which will help to maintain the relative consistency of the TGMS fertility transformation starting temperature.