Analysis On The Male Sterility, Thermo-photosensitive And Genetic Character Of New Male-sterile Line BNS In Wheat

In order to evaluate the heterosis utilization of BNS in wheat, the fertile performance, restoring chatacter, thermo-photosensitive characteristics, genetic character and the fertile conversion were studied with BNS and Bainongaikang 58 in present work. The method of time sowing was conducted in autumn as well as the sowing in spring. The temperature and light length were also recorded to study the fertility, dynamics of average daily temperature and light length, to study the thermo-photosensitive effect of BNS. In the other hand, the experiment also used 32 male parent materials, liked Bainongaikang 58 and so on, to carry on cross, in order to study the problem of BNS's restoring ability. And then the experiment used the best F1 hybrid to perpare reciprocal cross F1 hybrid, F2 hybrid and backcross (BC1) population, for purpose of studying the genic character of male-sterile gene in BNS and determining its genetic mechanism. The results showed that:1. The spikes of BNS were light, shag and expanding. The anthers were slim and thin. A little present pollen was lack of activity, and the sterile type of spherical abortion was identified by iodine-treatment. The male-sterile lines exhibited high and stable sterility. The national and international seed setting rate of artificial saturation pollination ranged from 79.64% to 87.22 % and 89.89% to 102.10 %, respectively, indicating that the pistil was normal. During the transforming stage of fertility, the sites of seed setting were mainly on basal and middle spikelets but top ones. Compared with caulis spikes, the male sterility of whereabout spikes was lower.2. The pollen of BNS with different sowing dates after iodine-treatment indicated that: The pollens were completely sterile between sowing date October 1st and October 9th. And the pollens were normal after iodine-treatment on sowing dates of October 17th and 25th, but their seeds rates were not high, range of 1.11%~7.97% (National) and 3.96%~13.46% (International). Then the pollen and fertility were all normal after October 25th. There were three types in F1 hybrids: typical abortion type, stained abortion type, and normal type. And as the restoring degree increasing, the colour of pollens after iodine-treatment was deepened, and the fertility became normal.3. The thermo-sensitive stage of BNS with high sterility (97.57%~100%) was from the differentiating period of floret primordium to pistil and stamen primordium, when the sowing date was earlier than October 17, and the temperature ranged from 7.4℃to 11.4℃in this period. The transformation of fertility was detected, with a range of self-seeds rate from 7.71% to 70.15% (National) and 9.41% to 102.50% (International), when the temperature was higher than 11.4℃in the following sowing dates. Correlation analysis was performed to detect the relationship between sterile degree and temperature. The correlation coefficients (r) ranged from -0.578 to -0.866 (r0.05/0.01=0.532/0.661), which indicated that correlation was significant or extremely significant between sterile degree and temperature. Similar to referenced material Bainongaikang 58, BNS sowed in spring was fertile with the temperature up to 15.9℃during the differentiating stage of floret primordium to pistil and stamen primordium. There were differences between transformation of fertility and light length with different sowing dates and stages before heading, but no obvious regularity was found.4. The fertility could be restored. In 32 combinations of F1 hybrids, self-seeds rates of three F1 hybrids were below 5% and their pollen sterility rates were up to 96%, the others were from 6.28% to 156.57%, and fertility restoring degree of SN055525 was the best with its F1 hybrid self-seeds rate of 95.85% (National) and 156.57% (International) and pollen sterility rate of 2.02%. And BNS/SN055525 behaved transgressive heterosis in plant height and yield per plant, the heterosis were 11.12%, 162.26%, respectively. But it was nagitive heterosis on 1000-grain weight, the heterosis was -0.47%.5. Genetic analysis showed that, the male sterility was controlled by three recessive genes. And there was certain of cytoplasmic effect of BNS, which could significantly affect the seeds rate of some restorer lines.