Genetic Diversity And Analysis Of Drought Resistance For Wheat Varieties In The Huang-Huai Valley Region

Wheat is an important food crop in the world,and the main food of about 40% of the world’s population,which is also one of the three major food rations in China.In recent years,the drought caused by global climate change is increasingly serious and has now become the main abiotic stress in wheat growth and development,which severely restricts the high yield and stable yield of wheat.In this study,139 wheat varieties released in recent years in Huanghuai wheat area were used to identify the drought resistance under rainfed and irrigated conditions in the field of natural environment.The genetic diversity,correlation analysis,clustering analysis and drought resistance were evaluated according to the data in 2015-2016 and 2016-2017.The main results are as follows.1.The average value of each characters 139 wheat materials under irrigated conditions were higher than that under rainfed conditions.The genetic diversity index of were1.94-2.10,with an average of 2.03,under rainfed conditions.On the other hand,the values were 1.91-2.08,with an average of 2.00,under irrigated conditions.This indicated that there were great difference and abundant genetic diversity in wheat varieties in Huanghuai wheat area.The genetic diversity under rainfed conditions were higher than that under irrigated conditions.2.2.Under both irrigated and rainfed conditions,yield was closely related to the spike number,plant height and rachis internode length,which was significantly positive correlation.However,yield was not significantly correlated with spikelet number of main stem,the area of flag leaf and grains per spike.Some traits showed difference between rainfed and irrigated conditions.Yield showed significantly(P<0.05)and very significantly(P<0.01)positive correlation with tiller number,significantly positive and no significant correlation with flag leaf length and thousand seed weight,and significantly(P<0.05)and very significantly(P<0.01)negative correlation with flag leaf area,respectively,under irrigated and rainfed conditions.3.In this study,cluster analysis was evaluated under different conditions.Wheat materials were divided into three and five groups under irrigated and rainfed conditions,respectively.Wheat materials were divided into three groups under irrigated conditions,of which most of the varieties were classified as theⅡgroup,and few varieties were divided as theⅠgroup of high-yield and high plant height and the Ⅲ group of low-yield dwarf plant.The most varieties under rainfed conditions were low-yield types and focused on theⅠ,Ⅱand Ⅲgroups,which accounted for 87.77% of the total varieties.Both Ⅳ and Ⅴ groups were belonged to the high-stem types,in which the Ⅳ group were high-yield and large-spike types with the most drought-resistant varieties,and the Ⅴ group were muti-spike and high-yield types coming from Shanxi.4.The tested wheat materials were evaluated with comprehensive drought-resistant coefficient and drought-resistance index of plant height,spike number,grains per spike,thousand seed weight and yield.14 varieties with drought-resistant coefficient and droughtresistance index less than 1.00 were selected,respectively were Cunmai 1,Heng5229,Jimai20,Kenxing 1,Luohan 11,Luohan 7,Luohan 9,Qingnong 2,Shannong 12,Shijiazhuang 8,Xingmai 4,Yannong 0428,Yunong 949 and Yunhan 22-33.