| In the process of plant breeding, germplasm resources are the basis of all the breeding work. The cultivation of seedlings is a critical means of cross-breeding. By means of sexual hybridization and seed multiplication can achieve genetic recombination, and change the gene and genotype frequencies in the groups, which will be separated and developed to more new kinds of variability. But at present seed germination characteristics of Loropetalum chinense var. rubrum and Loropetalum chinense are few known by us. This research is using Loropetalum chinense and several typical varieties and strains of Loropetalum chinense var. rubrum as materials, investigated the influence of pretreatment means before sowing like different harvest time, varieties and strains, store ways, sowing time on the seed germination through determination of biological characteristics of all the tested materials and germination tes. At the same time has revealed the genetic diversity in propagate of Loropetalum chinense and Loropetalum chinense var. rubrum from molecular level, by inspect and analyze the seedling in early times on SRAP-based moledulr. This paper is expecting to provide reference for genetic improvement and creation through sexual hybridization and seedlings selection means. The main results are as follows:(1) Seeds of Loropetalum chinense and the typical varieties and strains of Loropetalum chinense var. rubrum are significantly different in the seed length, width, thickness, single grain weight, and grain weight. Each number could be identification of quality and varieties at some degree. Among the numbers, the value of Loropetalum chinense var. rubrum ’Yuangyeqing’ are all the biggest:Length7.10mm,Width3.74mm, Thickness3.15mm, Grain Weight40.423g. The length and grain weight of Loropetalum chinense are the smallest:5.48mm,17.813g; the width and thick is a bit little:2.98mm,2.51mm.(2) Seeds of Loropetalum chinense and Loropetalum chinense var. rubrum possess afterripening, they will only germinated well stay through biological dormancy in cold sands(stratification treatment) for around100days(gemination reaches70%-80%while indoor)(3) The determination of proper harvest period. In order to harvest better seeds before capsule crazing, the middle decade of September to the first decade of October was the optimum harvest period in Changsha.(4) The germination percentage sowing outdoor in autumn is much higher than the ones sowing outdoor in spring. And the separation traits of seedling are different according to different varieties of seed sources, seedlings from’Touguhong’,’ Shuangmianhong’, Loropetalum chinense are relatively stable, few separation, while seedlings from’Yuanyeqing’’Changyeqing’,’Huaye’have high degree of separation, which indicates that the first three’s genotype are homozygous while the after three have high heterozygosity.(5) Though6pairs of primers, conducted SRAP analysis on ’Yuanyeqing’20activists on behalf of’Yuanyeqing’’Touguhong’and Loropetalum chinense, and1566of the total1980amplified fragments were distinctive,and149of the total167stable polymorphic site were distinctive. The tested materials’ genetic similarity coefficient ranges between0.4671-0.8545, with an average similarity coefficient of0.7265. The genetic differences of’Yuanyeqing’’Touguhong’and Loropetalum chinense are small; there are big difference in genetic information of sexual reproduction, female parent and offspring of Loropetalum chinense.(6)Based on the observation of characteristics table, selected the high grade single that grows fresh red and yellow leaves and branch grow prone on ground, horizontal or down from the seedlings with high separation. Through SRAP-based genetic diversity analyses, a genetic information-rich strains (20) and two phenotypic traits and genetic information has a certain particularity of lines (2and8) had selected from sexual reproduction. |
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