| In this study, we researched thirty-two xinjiang local cotton and foreign cotton cultivars, reserarched different mechanisms of drought resistance by examining biochemistry and physiology of cotton during the seedling and flowering two stages under water stress in the field, assessing genetic diversity by phenotypic characteristics and molecular markers. Makeing structure F2 mapping population by using hybrid of drought resistance and not drought resistance type materials, identify genetic discipline of drought resistance patterns and carry out the research of molecular markers to find out molecular markers closely linked drought resistance of cotton, so that supply theories, methods and basis on drought resistance of cotton breeding. The conclusions of this research is as following:1. By principal component analysis,7 interrelated single indicator of 32 varieties were integrated into three separate compositive indicators, establish a drought assessment system of D value at the seedling and florescence. The explanation rate for the drought-resistance of 32 cotton cultivars were 34.49%and 67.0 %.2. The value of D at the seedling stage and florescences were cluster analysed, the similar rate of results is 68%, indicating that the drought resistance of cotton are different mechanism at the seedling stage and the florescence.3. The seven drought-resistance related physiological and biochemical have been analysed, and the result showed that:highest accuracy is betaine by measure single indicator to identification the drought resistance at the seeding stage of cotton. But the highest is MDA at the florescence of cotton, which indicated that the most important matter is different at the seedling stage and florescence on the adjust process, and the best time of measuring the index was also different at the two stages.4. Agronomic traits after water stress at the seedling stage and florescence with drought resistance base on D value were comparative analysis, it was a significant negative correlation on drought resistance with the node of the first flower at the seeding stage, but with the node height of the first flower at the florescence. The result is difference by clustering analysis on agronomic traits after water stress at the seedling stage and florescences. But it basically consistent with the corresponding clustering results of D value.5. Genetic diversity of 32 cotton varieties were analysis with SSR markers, and the difference on alien species which is early introduction less than late introduction of species, it indicating that the genetic background of the local self-sterile varieties is narrow source.But the late introduction of species is more complex, so it has a wide genetic variability, this supply better selection of resources for breeding work.6. The results of SSR marker clustering are similar to the D values similar clustering results on seedling and florescence. It indicats that it hasgenetic effect of drought resistance of cotton. Flowering cluster are more similar agronomic traits after stressed compared to the genetic similarity coefficient clustering of agronomic traits. The influence on agronomic traits on flowering by the environment is smaller than the seedling stage.7.30 effective polymorphic locus were screened from F2 genetic population constructed with a high drought resistance variety Kui 85-174 and a high not drought resistance variety ShiYuan 321 by reciprocal-crossing, and acquire 4 linkage group. The average distance of the linkage map was 37.1cM, the full length is 1112.9cM and the cotton genomic coverage is 20%.8. Within two genetic groups, the generalized genetic rate of proline content respectively is 0.554,0.434, the generalized genetic rate of SOD activity respectively is 0.423,0.494, it is mean to hereditary of the proline content and SOD weaker, influences greatly from environmental.
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