Heat Resistance Evaluation Of ICARDA Spring Wheat Varieties

Wheat is one of the most important crops in the world,it directly affects the production of global food safety Wheat is a cool crop,and the temperature has a great influence on the growth and development of the plant.However,with the intensification of the greenhouse effect and "dry hot wind" and other extreme weather occurs frequently,making wheat in growth development especially reproductive growth stage prone to heat forced maturity phenomenon production.Therefore,the research of heat tolerance in wheat is particularly necessary.At present,the research on the heat resistance of wheat is relatively small,the evaluation and screening of heat resistance is too single,the selection of heat resistant varieties is also very inadequate.237 spring wheat accessions were introduced from ICARDA,and grown for a two years of two sites(in 2014 and 2015 were planted in Xinjiang Altay test station and Shaanxi Sanyuan test station)and a staging sowing experiment(in Shaanxi Sanyuan test station set up two levels of normal sowing period and late sowing in 2015)method(sowing for spring wheat can provides high temperature stress),to evaluate the correlation between heat tolerance and thousand kernel weight,plant height,spike length,spikelet number,grain number per spike,and screening for the thermotolerance lines.The results are as follows.(1)In both normal and high temperature environment,panicle traits showed significant correlation between each other;significant positive correlation between thousand kernel weight and plant height,and the correlation index reached highest(r=0.543)under heat stress,indicated that PH has great influence on thousand kernel weight.(2)The correlation analysis on the variation rate of agronomic traits in the two sowing dates showed that the change rate of thousand kernel weight was significantly positively correlated with that of PH(r=0.179).The change rate of thousand kernel weight is currently an important index for heat tolerance evaluation,which indicates that the change rate of plant height can be used as an index to evaluate heat resistance.(3)Based on the change rate of thousand kernel weight,12 significant heat tolerant lines and 12 significant heat sensitive lines were screened out.(4)The 237 lines were classified into heat tolerant or sensitive lines,with the 100 owned smallest change rate were tolerant while,the highest100 were regarded sensitive.In the selected lines,the frequency of the corresponding parents were calculated and further performed.Chi square test to find out the significance.The results showed that AEGILOPS SQUARROSA,ARREHANE,FLORKWA-4,PASTOR and SOUS-1,were the highest frequent in the heat tolerant lines possibly contain in heat resistant genes.The AEGILOPS SQUARROSA(TAUS)and ZEMAMRA-1,SHUHA-14 and SHUHA-7 were significantly rich heat sensitive parents,particularly the latter two were in extremely heat susceptive lines.