Effects Of Different Nitrogen Application Treatments On Fruit Growth And Related Genes Of ’Kyoho’ Grape

In grape production,fertilizer is an important link to improve yield and quality,and whether or not to provide fertilizer for grape tree in good time is the key factor to improve the effect of fertilizer.The traditional fertilizer method pays more attention to the proportion of fertilizer and the amount of fertilizer,and the grasp of fertilizer period depends more on the judgment of crop phenological period and personal experience.The introduction of gene information into the study of accurate fertilizer application can monitor the real growth and metabolism of plants in real time,grasp the fertilizer demand period more accurately,and effectively improve the fertilizer utilization rate and promote the growth and development of plants.In this experiment,three nitrogen fertilizer levels,low nitrogen,medium nitrogen and high nitrogen,were applied in different periods during the first expansion period of grape.By measuring the physiological indexes of ’Kyoho’grape(fruit longitudinal and transverse diameter,titratable acid content,soluble solid content,fruit single grain weight),The expression level of genes related to grape fruit development was detected by real-time fluorescence quantitative PCR,and the effects of different nitrogen fertilizer levels and different application periods on berry quality were investigated at physiological and molecular levels.In order to provide some guidance for the rational application of expanded fruit fertilizer in grape production.The main results of the experiment are as follows:1 The application of different nitrogen fertilizer levels can promote the external quality and internal quality of fruit to a certain extent.In the comparison of different nitrogen fertilizer levels in the same fertilizing period,both high nitrogen level treatment and medium nitrogen level treatment could significantly increase the longitudinal and transverse diameter of fruit,increase the single grain weight of fruit,and the high nitrogen level was slightly better than that of medium nitrogen level.However,the effect of low nitrogen level on weight gain is slightly worse.In terms of internal quality,the effect of medium nitrogen level was the best,the soluble solid content of fruit was the highest,and the titratable acid content was the lowest.However,the soluble solid content of high nitrogen level was lower than that of medium nitrogen and low nitrogen level,and the titratable acid content was higher.The treatment of low nitrogen level is in the middle level.At the same nitrogen fertilizer level and in different fertilizer periods,the fruit quality of T2 treatment group was the best,T3,T1 treatment group was about the same,second only to T2 treatment group.T5,T5treatment group showed different results at different nitrogen fertilizer levels,and the effect of fertilizer application was poor.Generally speaking,the medium nitrogen level is the best fertilizer concentration for expanded fruit fertilizer,and fertilizer can improve grape yield and fruit quality as much as possible at T2.2 The gene expression of 9 genes(VvCKX5、VvGA20ox1、VvGASA4、VvCesA1、VvCesA6、VvERP、VvAP1、VvAP3、VvFLC)was analyzed at five different stages:T1(7 Days after anthesis),T2(13 Days after anthesis),T3(19 Days after anthesis),T2(25 Days after anthesis)and T1(31 Days after anthesis).The gene expression of 9 genes at different stages was analyzed.The results showed that the response of VvCKX5,VvGA20ox1,VvGASA4,VvCesAl,VvCesA6,VvERP gene to fertilizer treatment was sensitive,which was helpful to evaluate the effect of fertilizer application.