Effects of Low Temperature on Physiology and Yield of Different Genotype of Wheat Varieties at Jointing Stage

Using multi-spike wheat varieties(Jimai22,Han6172) and large-spike wheat varieties(Linmai4,Weimai8) as experimental materials,the dynamic variation of the content of soluble sugar,soluble protein,proline,SOD,POD,MDA at different days(0,3,6) and the yields were investigated after different temperature(normal,-1 ℃,-3 ℃) treatments.The results indicated that,compared to the control,the content of soluble sugar,soluble protein and proline increased in different degrees;the activity of SOD and POD was varied with different varieties,the activity decreased except Linmai4,Jimai22;the content of MDA significantly decreased at-1 ℃,but it decreased a little at-3 ℃ except Weimai8.The contents of soluble sugar and proline increased apparantly,the content of soluble protoin increased a little except Weimai8,the activities of SOD in Han6172,Linmai4 increased significantly,the activity of POD except Linmai4 increased,the content of MDA in each variety decreased.On the 3rd day and the 6th day after treatment,the differences of the contents of soluble sugar,proline,and POD between different treatments were still significant.The yield results showed that,the large-spike wheat varieties had lower yield than the multi-spike wheat varieties after spring low temperature of-1 ℃,-3 ℃.Further analysis revealed that,the dropping degree of 1 000-grain mass in multi-spike wheat varieties was more obvious than that of largespike wheat varieties,but the dropping degree of ear number per spike and grain number per spike was lower than that of the large-spike wheat varieties.