Effects Of Seed Upgrading With Specific Gravity On The Seed Vigor And Its Population Characteristics Of Rice Male Sterile Lines

Study on the effects of seed grading of male sterile line of rice on seed vigor and characteristics, trying to provide the basis for Mechanized precision planting of female parent seed breeding. The grade of seeds is using gravity separation. The research was carried out in Hunan Agricultural University, April to October,2013. The rice sterile line were T98A, Feng Yuan A, Y58S and Xiang Ling628S. They graded by5FZ-50gravity seeds separation to separate four different grades (Ⅰ,Ⅱ,Ⅲ,Ⅳ), and unrated seed was the contrast check(CK). We determined seed germination characteristics, seedling emergence, seedling quality and seed characteristics of female groups. The main results are as follows:1The germination rate and vigor index are growing with the increasing of specific gravity of seeds. The grade Ⅳ of Y58S and Feng Yuan A have higher germination rate and vigor index than increased grade1,9%,22.6and28.5%,70.38, respectively. The germination rate and vigor index of the grade Ⅲ of Xiang Ling628S and T98A are highest,96.25%,194.98and92.75,165.39, respectively, while the value of CK was between grade Ⅰ to grade Ⅳ.2. Protrusion rate and field germination rate increased with the rise of specific gravity, and the CK value was also in the middle level. The grade I of Xiang Ling628S, Y58S, T98A and Feng Yuan A had the lowest protrusion rate,72.33%,82.33%,76.33%and70.00%, respectively. Statistical analysis showed that protrusion rate had significant differences between grade I and grade IV. The grade IV of Xiang Ling628S, Y58S, T98A and Feng Yuan A had the highest field germination rate, increased by20.97%、19.55%、30.03%and35.12%than grade I, respectively. And the advantages were obvious in higher specific gravity of seed.3. The larger specific gravity of the seed was, the better seedling quality was, and the more conducive to cultivating strong seedling with tiller was. Grade Ⅳ of Feng Yuan A had higher plant height, width and fresh weight than the grade Ⅰ, increased by2.02cm,0.47cm and7.43g, respectively. It proved that the larger specific gravity of the Feng Yuan A seed was, the better its seedling quality was. The seedling quality of mixed CK seeds was between grade Ⅰ and grade Ⅳ.4. The heading and flowering in female parent groups were relatively concentrated after seed grading. The heading duration of grade Ⅱ、Ⅲ and Ⅳ was one day less than grade I and CK in Xiang Ling628S, and grade IV was the most concentrated one, which heading rate achieved90%in three days. The heading duration of grade Ⅱ was one day longer than CK in Y58S, and two days longer than grade Ⅰ、Ⅲ、Ⅳ. Flowering duration of graded seeds was1-2days shorter than CK in Feng Yuan A, grade Ⅳ was4days, flowering rate was86.21%,with relatively concentrated flowering. The results showed flowering duration of graded seeds decreased1-2days than CK in general.5. The total number of spikelets per unit area increased after seed grading. This may affect its production.In conclusion, the seed grading based on specific gravity have influenced the seed vigor and seed characteristics of female parent breeding groups. With the increasing specific gravity of seed, germination rate rised, seed vigor became stronger, field germination rate increased, seedling quality became better, and the heading and flowering in female groups became more concentrated. Seed grading is more conducive to quantify the mechanical precision planting.