Genetic Diversity Of Basic Germplasm And Their Offsprings Of Upland Cotton In China

The genetic diversity of the basic germplasm of Upland cotton, and the consanguinity and genetic structure of some important derivative varieties of 4 base germplasm in China were analyzed based on their agronomic performance and fiber quality, SSR markers and the coefficients of parentage (r value). The main results were summed up as follows:1 , The main agronomic characters of basic germplasm showed significant or very significant differences, the genetic diversity (H') was 0.88, covered more than 95% cultivars, This suggested that the base germplasm selected possessed a general representative .2. The fiber length, unity and fiber finess of the second and third period of basic germplasm improved much, and their lint percentage also increased, meanwhile with early maturity and high resistance to the disease and drought, Compared with those of the primary basic germplasm. The average genetic diversity index of SSR marker of the first, second and third period basic Upland germplasm were 0.587, 0.630, 0.630, respectively .This implied that the difference among the modern basic lines was gradually decreased on the genome level and this further showed that the diversity of breeding background is becoming weak.3. The phenotype traits of basic germplasm from different cotton growing area were diversity: the general character of the basic germplasm in Huanghe river valley area was better than that of other areas. The yield of the basic germplasm in Changjiang river valley area was higher, and the early maturity of that in the north area was better.Those from the cultivars introduced from America showed the high resistance to Verticillium wilt. The diversity of basic germplasm between Changjiang and Huanghe river area changed obviously on the genome level.4. The fiber quality's variance coefficient of the basic germplasm of the domestic varieties was lower than that of exotic's, and the SSR similar index of domestic variety(0.624) was higher than exotic's. This suggested the genetic diversity in domestic cultivars was hard to exceed that of the exotic.5. Among 4 basic germplasm derivate lines, The derivate varieties from Uganda exhibited excellent general characters; The derivate lines from DPL14 showed quite different on the yield characters, Those from Stoneville2B possessed strong growing trend. DPL15 developed many derivate varieties with obvious distinct characters.6. The similarity of derivate varieties from different growing areas was coherence with that of basic germplasm from corresponding growing areas, the basic germplasm from different areas can represent related cotton growing areas.The diversity of Huanghe river plantation was lower than that of Changjiang river. The exotic variety have more diversity than that of domestic's.7. The domestic variety can seperated into 4 basic groups: DPL type (including Uganda), Stoneville type(including Foster Trice), lower gossypol cotton type (including kk1543 series), and Delfos531 derivation type .Most of later verities related with these four basic groups.8. The correlation analyse among coefficients of parentage (r value),the SSR similarity coefficients...