Comparison For Cold Resistance Of Different Wheat Cultivars In Huang-huai-hai Plain

Low temperature freezing is one of the major natural disasters that restricts production of wheat.We selected 11 wheat varieties grown in the Huang-Huai-Hai region as experimental materials,studied the effects of wheat leaf biochemical indexs and yield traits under natural low temperature during wintering and artificial low temperature stress duringspring,in order to explore the physiological and biochemical mechanism of wheat under low temperature stress.The aim of the experiment was to compare the low temperature resistance of different wheat varieties.The experiment of wheat under natural low temperature stress during wintering conducted in the experimental field inHenanNormalUniversity,and the other experiment of wheat under artificial low temperature stress during spring conducted in a temperature and moisture controlled artificial greenhouse in HenanNormal University in 2015-2016.The main conclusions were as follows:1.According to the changes of soluble sugar content,soluble protein content,SOD activity,CAT activity and MDA content of leaves at low temperature,the cold resistance at floret differentiation stage was the strongest,and the stamen and pistil differentiation stage was the second,anther connective stage was the worst.From the changes of the number of spikelets,the number of sterile spikelets,the number of grains per panicle and the quality of single panicle of wheats,there were no differences in cold hardiness between the three spike differentiation stages.2.The soluble sugar content,soluble protein content and MDAcontent of leaves were suitable to be used as the winter and spring common indexes of cold resistance.The activity of SOD and CATof leaves were suitable to be used for winter cold resistance identification.3.Under natural low temperature stress in the over-wintering stage,the yield components of different varieties were different.However,there was no significant difference in grain yield between the cultivars,and the grain yield of Shi Mai 22 was the highest.The yield components under low temperature treatments in the spring all showed that the spike number,grain number per spike and kernel weight per plant were significantly decreased.The infertility spikelet number was significantly increased under cold stress,while the effect on the spike length was less significant under the low temperature.The low temperature stress in spring mainly resulted in the decrease of effective panicle number and grain number per spike in wheat,which resulted in the decrease of single ear quality.4.The average subordinate function values and comprehensive scores of varieties were calculated under low temperature treatments.Based on the average subordinate function values and comprehensive scores,the 11 wheat varieties were clustered into three groups under different treatments respectively.Shannong 20 and Huaimai 33 belonged to higher cold resistance group,and Zhoumai 18,Liangxing 99,Aikang 58 and Shimai 19 were of lower cold resistance group in over-wintering stage.Liangxing 99,Jimai 22,Aikang 58,Zhengmai 7698 and Annong 0711 were of the lower cold resistance group,Zhoumai 22,Shimai 22 and Huaimai 33 were of the higher cold resistance group at floret differentiation stage.Shimai 22 and Huaimai 33 were of lower cold resistance group,Zhoumai 18,Jimai 22,Aikang 58 and Shimai 19 were of the higher cold resistance group at stamen and pistil differentiation stage.Zhoumai 22 and Shannong 20 belonged to lower cold resistance group,and Huaimai 33 of cold resistance was strongest at anther connective stage.The lower cold resistance group contained cultivars Liangxing 99,Jimai 22,Zhengmai 7698 and Zhoumai 22,the higher cold resistance group contained cultivars Annong 0711 and Shimai 22 under twice low temperature treatments at floret differentiation stage and stamen and pistil differentiation stage.The lower cold resistance group contained cultivars Zhoumai 18,Liangxing 99,Zhoumai 22 and Huaimai 33,the higher cold resistance group contained cultivars Aikang 58,Annong 0711 and Shimai 22 under twice low temperature treatments at stamen and pistil differentiation stage and anther connective stage.The lower cold resistance group contained cultivars Zhoumai 22,Shannong 20,Annong 0711,Shimai 22 and Huaimai 33,the higher cold resistance group contained cultivar Jimai 22 under thrice low temperature treatments in the spring.Taking the percentage of decreased the quality of single spike under low temperature stress as the assessment criterion,cultivars Shannong 20,Shimai 22 and Huaimai 33 showed stronger cold hardiness,cultivars Zhoumai 18 and Liangxing 99 and Jimai 22 Aikang 58 and Zhengmai 7698 showed lower cold hardiness.The two evaluation methods both showed that the cold hardiness of cultivars Huaimai 33 and Shimai 22 were stronger,Liangxing 99 showed lower.