Genetic Diversity In Upland Cotton Germplasm Accessions Based On SSR

It is konwn that cotton is one of the important fiber crops and oilcrops because of its excellent fibercharacteristics, and has become very important oil crops due to its seed is rich in fat and protein. Theimportance of economic value and economic status is well known. Cotton production requires a goodquality traits of cotton germplasm as a guarantee, which urgently needs more cotton germplasms. Thisstudy was based on cotton germplasms from different ecological zones from home and abroad, meanwhilegenetic diversity of cotton germplasms were studied by phenotypic traits and SSR markers. This study used372SSR primers to analysis genetic diversity of300cotton germplasms, as well as clustering analysis wascarried on, thus genetic relationships of300cotton germplasms were gotten. We also conducted geneticdiversity analysis of300germplasms from phenotypic traits by two years survey of field trials. It provide atheoretical basis for the correct use of cotton germplasm materials to select parents and hybridizing fomboth comprehensive analysis of the two test results. The main findings are as follows.1It is rich on phenotypic traits of selected300upland cotton germplasm resources. The order ofgenetic diversity index from phenotypic was as follows: growth period> lint percentage> plant height>boll weight> bolls> seed cotton yield> lint yield> onset Index.2They all had a very significant difference on growth period, lint, plant height, boll weight, bollnumber, lint yield, seed cotton yield and other traits. Coefficients of variation that more than20%werelarge containing lint yield, seed cotton yield, boll number, the incidence index. The coefficient of variationwas in the order of onset Index> lint yield> bolls> boll weight> plant height> lint percentage> seed cottonyield> growth period.3Phenotypic traits clustering results showed that some varieties of different origins were clusteredtogether, which was probably due to the cross existed between some varieties, and environmental factors.The vast majority of the materials were gathered together nicely that have the same origin and a similargenetic background, and clustering results broadly in line with the evolution of the genetic background ofeach material.4We choosed372SSR primers, from which38primers with good reproducibility and polymorphism,clear gel bands were gotton for SSR analysis in all300varieties by preliminary screening.132DNA fragments were scored among all materials,88polymorphic bands were obtained, accounting for66.7%ofthe total bands. The largest number of DNA fragments (6) were amplified from the primer JESPR291,followed by NAU3888with fragments (5).5The average coefficient of the genetic similarity of SSR markers among source germplasm was0.533, ranging from0.175to0.905from SSR clustering results.47.81%coefficient of the genetic similaritywere small, which indicated that the genetic diversity of selected source germplasms were rich at thegenomic level, and were representative of the diversity of the germplasms.300germplasm materials weredivided into two categories, which was consistent with the results of clustering of phenotypic traits.