Genetic Analysis Of High Temperature Resistance Of 144 Cotton Germplasm Materials

The cotton are one of the main economic crops and important factors of social stability and economic development in Xinjiang.The heat damage tend to occur most frequently during the full-bloom stage and the boll stage,which infects the cotton and decrease its yield and fiber quality.This study was mainly aimed at study on the physiological characteristics of heat resistance,agronomic traits,yield traits,qualitative character and correlation analysis by SSR marker of 144 upland cotton cultivars in Xinjiang.The research contents and results were listed as follows:1.The majority of upland cotton cultivars are middle tolerant and sensitivity.Reasonable clustering analysis of data done by 144 high temperature tolerance upland cotton germplasm resources can be obtained when the strategy of agriculture characters is applied to high temperature tolerance clustering.The Genetic diversity of the 144 cultivars was detected by SSR primers to cluster their heterotic groups based on genetic similarity coefficient(0.49-1.00),which suggested that there was rich genetic diversity among the upland cotton cultivars at the molecular level.2.The results showed that photosynthetic traits and yield traits of 20 varieties decreased compared with CK at flowering and boll setting stage,high temperature resistance of 20 cultivars was significantly different in different varieties,but there were no difference in fiber traits.The boll number per plant and boll weight were positively associated with net photosynthetic rate,transpiration rate and water use efficiency.3.The net photosynthetic rate,transpiration rate,water use efficiency,boll number per plant and boll weight of high temperature tolerance cotton variety resources were highest among all the cultivars through comparative analysis,which illustrates that high temperature tolerance cotton variety resources still maintain better photosynthetic performance,lessen the number of cast buds and bolls and improve the boll setting ration in an arid environment.4.The net photosynthetic rate,transpiration rate,water use efficiency,boll number per plant and boll weight of Zhongmian 35,Xiang mian 11 and EmianlO were highest among all the cultivars through comparative analysis,which could be used for improvement of cotton breeding for anti-high temperature as the medial material and parent selection.5.There were 46 SSR loci associated with cotton agronomic traits,quality traits and disease by resistance association analysis,including 35 SSR loci associated with agronomic traits,11 SSR loci associated with quality traits and 4 SSR loci(explaining 0.21%-4.2%of total phenotypic variation)associated with shedding rates of buds and bolls and pollen viability.