Evaluation Of Nitrogen Efficiency Of Different Potato Varieties And Study On Recommended Nitrogen Application Rate Of Nitrogen Efficient Varieties

Potato(Solanum tuberosum L.)is widely planted in Hubei Province,both in alpine and plain areas.At present,in order to further enrich germplasm resources,high-quality varieties such as Huashu series and Huaen series are being promoted and planted.There are genotypic differences in potato nitrogen efficiency,which affects the yield of potato.In production practice,farmers often ignore the influence of genotype on yield,and the phenomenon of unscientific application of nitrogen fertilizer is more common.In order to promote the weight loss and efficiency increase of potato industry in Hubei Province and accurately apply nitrogen fertilizer to varieties,this study took six potato varieties mainly planted in Hubei Province:Huashu 1,Huashu 2,Huashu 3,Huashu 6,Huaen 1 and Zhongshu 5 as objects,investigated the differences of nitrogen efficiency of different varieties through field experiments,and gave the best nitrogen application rate of nitrogen efficient varieties;The physiological differences between nitrogen efficient varieties and nitrogen inefficient varieties were explored through pot experiment.The main results of the study are as follows:1.Among the six varieties widely planted in Hubei Province,Huashu 3 has the lowest nitrogen efficiency and Huashu 6 has the highest nitrogen efficiency.Huashu 6 has the highest agronomic efficiency and partial productivity of nitrogen fertilizer,and its physiological efficiency of nitrogen fertilizer is second only to Huashu 1;The agronomic utilization rate,partial productivity and physiological utilization rate of nitrogen fertilizer of Huashu 3 were the lowest among the six varieties,and Huashu 6 was 4.28,1.74 and3.74 times higher than that of it,respectively.The nitrogen use efficiency of Huaen 1 was the highest,while Huashu 1,Huashu 2 and Huashu 3 were lower,and there was no significant difference among the three.After analyzing the yield of each variety,it was found that Huashu 6 could also have higher yield without nitrogen application,and the yield increase effect was also very obvious after nitrogen application.On the whole,Huashu 6 has high agronomic utilization rate of nitrogen fertilizer,partial productivity of nitrogen fertilizer and physiological utilization rate of nitrogen fertilizer.Considering the characteristics of high yield,Huashu 6 can be considered as a nitrogen efficient variety.2.The ability of"source"organs of Huashu 6 to absorb and utilize nutrients is stronger than that of Huashu 3.The root activity of Huashu 6 under N0,N1 and N2treatment was higher than that of Huashu 3,especially under N2 treatment,its root activity was 1.23 times higher than that of Huashu 3,with significant difference.Under the three treatments of N0,N1 and N2,the chlorophyll content of Huashu 6 was 1.45,1.23 and 1.10 times higher than that of Huashu 3,and its photosynthetic indexes were also better than that of Huashu 3.The NR and GS activities in the leaves of Huashu 6were higher than those of Huashu 3,and their NR activities were 1.07,1.26 and 1.38times higher than those of Huashu 3 under N0,N1 and N2 treatments,respectively;The activity of GS was 1.51,2.01 and 2.02 times higher than that of Huashu 3,respectively.Compared with Huashu 3,Huashu 6 has stronger antioxidant enzyme system and higher content of Osmoregulation Substances.Under the three treatments of N0,N1 and N2,the antioxidant enzyme activity of Huashu 6 was higher,especially under the treatment of N0,its SOD activity was 2.29 times higher than that of Huashu 3.The content of proline and soluble sugar in the tuber of Huashu 6 is higher than that of Huashu 3.It has a stronger ability to regulate the internal osmotic potential,which is conducive to the normal physiological and biochemical process.3.The nitrogen efficient variety Huashu 6 can obtain high yield and high quality after applying nitrogen fertilizer.The yield of Huashu 6 and the contents of starch,protein and vitamin C in tubers first increased and then decreased with the increase of nitrogen application,while the content of reducing sugar continued to increase.Under the five nitrogen levels,the yield of Huashu 6 was the highest under N210 treatment,which was34394.7 kg/hm~2,an increase of 43.8%compared with N0.The regression equation showed that when the nitrogen application rate was 235 kg/hm~2,the yield of Huashu 6was the highest,33659.6 kg/hm~2.After comprehensively analyzing the change law of quality indexes,it is found that the contents of various quality indexes are higher under N210 and N315 treatment,and there is no significant difference in the contents of various quality indexes between N210 and N315 treatment.Therefore,the recommended nitrogen application rate for Huashu 6 to obtain high yield and high quality is 235 kg/hm~2.To sum up,Huashu 6 is a nitrogen efficient variety with High Nitrogen Agronomic utilization rate,nitrogen partial productivity and nitrogen physiological utilization rate,while Huashu 3 is a nitrogen inefficient variety.Compared with Huashu 3,Huashu 6 has higher root activity and stronger photosynthesis,and the"source"organs are more developed.The activities of nitrogen metabolism related enzymes of Huashu 6 were higher.Under nitrogen deficiency,Huashu 6 has stronger antioxidant enzyme activity and can secrete more Osmoregulation Substances to maintain normal physiological metabolism in vivo.The yield of nitrogen fertilizer Huashu 6 increased significantly,and the best nitrogen application rate was 235 kg/hm~2.