| Xinjiang,China's important production area of cotton,has rich resources of photo-thermal.However,as global warming,high temperature,even extreme high temperature weather often occurs in the area.High temperature stress affects cotton growth and development,and thus affect the yield and quality.Screening high temperature germplasm resources,definitude different agronomic traits,physiological characteristics and the relations between high temperature resistances,the establishment of high temperature screening indicators,cultivate high temperature resistant varieties,and reduce the influence of high temperature on cotton varieties' stability and adaptability.All of the above is of great significance to the production of cotton in Xinjiang.In this study,60 cotton germplasm resources were used as experimental materials to analyze the physiological characteristics,biological characteristics and response of agronomic traits to high temperature at different ecological points.Use principal component analysis,membership function method,cluster analysis and stepwise regression analysis to carry out the comprehensive evaluation of heat tolerance and identification index of cotton germplasm resources.The results are as follows:1)The photosynthetic characteristics of Pn,Ci,Gs and Tr were significantly changed in different growth stages.Photosynthetic characteristics as a measure of whether cotton can resistance heat,it is appropriate to choose the flowering period and boll period.At the two ecological points,Pn,Tr and Ci reached a significant level in flowering period,while Gi not.At flowering stage,the net photosynthetic rate of cotton in Shihezi was lower than that in Tumushuke,that was caused by non-stomatal factors.This is consistent with the decline of the net photosynthetic rate at the end of the flowering period 2)After high temperature treatment,DIO / CSO significantly increased,and ETO/CSO,TRO/CSO significantly decreased,FO significantly increased.Fm,the maximum photochemical efficiency Fv/Fm and performance index PIABS were significantly reduced,indicating that high temperature lead to PS? donor Side hurt.The performance index PIABS can reflects the impact of adversity on photosynthetic institutions better.3)In the two ecological points,the coefficient of variationcotton of seed cotton yield,lint yield,bell number and infertility seed is the highest.The leaf chlorophyll content and plant height of cotton at Shihezi were significantly increased at the whole growth period.The leaf area and dry weight were significantly higher and then decreased,and the water content of leaves was first lower and then increased.The plant height,chlorophyll and leaf area of the two ecological plants were significant changed,and the leaf water content was significantly changed,dry weight of the leaves did not change significantly.Under 35 ?,40 ?,45 ? high temperature,pollen viability between varieties reached a very significant level.4)Through the principal component analysis,the indexes of Shihezi and Tumushuke were transformed into eight comprehensive indexes.Using the formula to obtain cotton heat evaluation value D,which was divided into six types by cluster analysis: strong resistant of high temperature type,resistant of high temperature type,moderate resistant of high temperature type,moderate sensitive type,sensitive type and very sensitive type.The comprehensive evaluation values D of two ecological points were significantly correlated and had some consistency.Two high temperature resistant cotton varieties(Xinluzao 10,Xinmian 3)and two high temperature sensitive cotton varieties(NF16388,NF16389)were screened by cluster analysis.Also,the indexes of common high temperature resistance were screened by stepwise regression analysis.The 13 indexes were: yield,Ci,pollen vitality at 45? temperature,infertility rate,Pn,the first fruiting branches,leaf area,single bell weight,pollen vitality at 40? temperature,chlorophyll content,Gs and agronomic traits.5)pollen viability,seedling rate,Pn,first fruiting line,leaf area,40 ? pollen viability,boll number per plant,35 ? pollen viability,chlorophyll content,Gs agronomic traits. |
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