Effects Of Nitrogen And Selenium On Yield And Nutrient Quality Of Different Varieties Of Sweet Potato

Sweet potato is one of the important carriers of supply selenium by food,study on the effects of nitrogen fertilizer and selenium treatment on yield and nutrient quality of different varieties of sweet potato are important basis for increasing yield of sweet potato and making use of sweet potato to supply selenium.With five varieties of fresh edible sweet potato（Qinshu8,Pushu32,Manshu010,Xvyu34 and Taizhong14）as the experimental subjects,four treatments of CK,N,Se and NSe by combination with field experiment and lab analysis.The main results were as follows:1 Nitrogen treatment could increase yield of sweet potato,effect of increasing in yield was significant genotype difference.Increasing effect of yield on five varieties of sweet potato under different treatment:N treatment>NSe treatment>Se treatment,the average of yield under N treatment was 736.36kg·hm^-2,It’s 23.32%more than CK.In different treatment,the range of increasing in yield of five cultivars was:Taizhong14>Xvyu34>Pushu32>Qinshu8>Manshu010.The range of increasing in yield of Xvyu34 and Taizhong14 were the biggest in N treatment,they’re 31.37%and 37.41%.Taizhong14 was the least sensitivity to Se treatment,and the range of increasing in yield was only 2.36%,the range of increasing in yield of it was 35.85%by NSe treatment.2 The significantly effect of weight per plant,weight per lump and root number per plant of different varieties of sweet potato by applying nitrogen and selenium,but there were differences between different varieties.Generally speaking,consistent with what the range of increasing in weight per plant and yield of sweet potato,effect of yield of sweet potato mainly came from the increase of weight per plant,followed by weight per lump and root number per plant.In N and Se treatment,the root number per plant of Manshu010 and Taizhong14 were significant higher than CK,the weight per lump of Xvyu34,but Manshu010s’was lower than CK,significantly.3 Nitrogen and selenium could increase average of dry material accumulation per plant of different varieties of sweet potato,different effect of different varieties in different treatment.In N,Se and NSe treatment,Root dry material accumulation per plant of five varieties of sweet potato were higher than CK.In NSe treatment,root dry material accumulation per plant of Taizhong14 was maximized,it was 331.58 g·plant^-1,but Nanshu010was minimized,it was 98.29 g·plant^-1.Stem leaf dry material accumulation per plant of five varieties of sweet potato by NSe treatment were higher than N and Se treatment,and Nanshu010,Xvyu34 and Taizhong14 were higher than CK by NSe treatment,Qinshu8 and Pushu32 were significant higher than CK by N,Se and NSe treatment.4 The significantly effect of the T/R value of different varieties of sweet potato by applying nitrogen and selenium,but genotype difference are significantly.The vast majority of T/R value of different varieties of sweet potato were less than 1.00.The T/R value of Nanshu010 up to 1.12 in NSe treatment,Xvyu34 and Taizhong14s’were lesser by N treatment,they were 0.36 and 0.41,respectively.5 The significantly impact of nutritional quality of different varieties of sweet potato by applying nitrogen and selenium,but cultivar difference are differently.N,Se and NSe treatment could increase starch and soluble sugar content of sweet potato root,the significant difference of flavone and anthocyanin content of different varieties root on the same processe conditions.Comparing with the CK,the range of increasing in starch content of Pushu32 was the biggest by N treatment,it was 42.11%,the range of increasing was the lowest by NSe treatment,it was 1.66%.Soluble sugar content of Nanshu010 was the biggest in NSe treatment,it was 6.47%,and 37.05%more than CK.Flavone content of Pushu32,Nanshu010,Xvyu34 and Taizhong14 were much higher than CK in NSe treatment,but Xvyu34 and Taizhong14 were much lower than CK in N and NSe treatment,the decrease range of them were 8.65%and 6.92%,respectively.Anthocyanin content of Qinshu8 and Pushu32 were much lower than CK in N treatment,respectively.Qinshu8,Pushu32 and Nanshu010 were much lower than CK in Se treatment,the decrease the range of them were9.85%,11.97%and19.45%,respectively.6 Nitrogen and selenium could increase P,K,Mg,Ca,Zn and Se element content of different varieties of sweet potato root,and there were genotype difference among different varieties.In N,Se and NSe treatment,P and K element content of Nanshu010 was the highest;Se element content of Qinshu8 was the highest,but P and Zn element content was the lowest;Mg element content of Pushu32 was the highest,but Ca and Se element content was the lowest;Mg element content of Xvyu34 was the lowest,but Ca element content was the highest;Zn element content of Taizhong14 was the highest,but K element content was the lowest.7 Apply selenium could increase selenium content of different varieties of sweet potato root,selenium content and accumulation were 4-7 times and 5-9 times that of CK,respectively.There were different content and accumulation of Se among different varieties.Se content of Qinshu8 was higher than other four cultivars in Se and NSe treatment,the highest by NSe treatment was 483.43μg·kg^-1,and it was 5.09 times that of CK.Se accumulation of Taizhong14 was higher than other four cultivars in Se and NSe treatment,the highest by NSe treatment was 145.65μg·plant^-1,and it was 8.46 times that of CK.The selenium-rich effect of Qinshu8 and Taizhong14 were better in NSe treatment.