Effects Of Different Topping Methods On Plant Growth And Fruit Development Of ’Crimson Seedless’ Grapes

【Objective】In this study,the‘Crimson Seedless’grapes planted in 223 Regiment of 2nd Division of Xinjiang were used as materials to explore effects of different topping methods on grape plant growth and fruit development to provide a reference for the high-quality standardized production of‘Crimson Seedless’grapes in Xinjiang.【Method】In this experiment,One-way completely ranomized block design was adopted.The grape plants were treated with T1,T2,T5 and T3,T4 one week before and after anthesis,respectively,and no-topping treatment was considered as CK.The grape phenological stage,branches and leaves growth and development,photosynthetic physiology,fruit growth and development,and pests were measured,and the results were as follows:【Results】（1）Different topping methods changed the fruit development of‘Crimson Seedless’grapes.Compared with other treatments,plants under T1 and T2 treatments completed flowering and fruit setting 2days earlier,and entered the fruit expansion stage.And T1and T2 treatments were 3 days earlier than T5treatment,and 7 days earlier than T3 and T4 treatments in fruit ripening stage.（2）In different stage of grape plant growth and development,leaf curtain thickness of T2,T3 and T4treatments was significantly lower than that of CK treatment.And the order of leaf curtain width of each treatment at fruit ripening stage was as follows:CK>T5>T1>T2>T3>T4.Among the treatments,CK and T4 had the fastest shoot growth,and shoot length of CK treatment was significantly higher than that of other treatments,showing that new shoots were prosperous.Finally,the dry matter content of grape leaves treated by five topping methods was higher than that of CK treatment.（3）Compared with the CK treatment,chlorophyll content of leaves treated by five topping methods was significantly increased.The diurnal variation trend of net photosynthetic rate of grape leaves treated with different topping methods showed a‘double peak curve’.Among these treatments,T2 treatment showed highest net photosynthetic rate daily average value,showing strong photosynthetic capacity.The diurnal variation trend of transpiration rate was consistent with stomatal conductance,and both had obvious‘double-peak’curve,and intercellular CO₂concentration showed a‘W-shaped’diurnal variation trend.In terms of water use efficiency,all treatments showed a trend of first decreasing and then increasing.And the relatively high treatment groups were T1 and T2 treatments.（4）The vertical and horizontal diameters of grapes treated with different topping methods showed a double‘S’curve and T1,T2 and T3 behaved better than other treatments.In terms of setting rate of grapes,except for T4 treatment,the fruit setting rates of the other four topping methods were improved compared with CK treatment,and T2 treatment was most obvious,which was 10.33%higher than CK treatment,and 11.44%higher than T4 treatment obviously.（5）In terms of fruit color,color index（CIRG）treated with T2 was the largest,which was 4.13,and was significantly improved by 22.19%compared with CK treatment,with the best coloring effect.Appearance indicators such as fruit ear horizontal diameter,fruit weight,fruit vertical and horizontal diameters treated with different topping methods were significantly improved compared with CK treatment and T1 and T2treatments behaved the best.Soluble sugar,sugar-acid ratio,soluble solids and Vc contents of the other four treatments were higher than CK treatment,and titratable acid contents were lower than CK group except for T4 treatment,and among these treatments T2 treatment performed the best.According to principal component analysis,the comprehensive evaluation of effect with different topping methods on grape fruit quality was ranked from high to low:T2>T1>T3>T4>T5>CK.The grape yield treated with different topping methods was improved compared with CK treatment,and yield improvement ranged from 23.1%to 54.07%.Among them,T2 treatment was the best,which was significantly improved by 54.07%compared with CK treatment.（6）In terms of pests and diseases,the frequency and damage of grape plants treated with T1,T5 and CK were greater than other treatments.【Conclusion】Comprehensive analysis of effects of different topping methods on grape phenology,growth and development of branches and leaves,photosynthetic physiology,fruit growth and development,pests and diseases,etc.,T2 treatment can accelerate fruit ripening of‘Crimson Seedless’grape,improve net photosynthetic rate of leaves,degree of stomata,water use efficiency,fruit setting rate,ear shape and peel color,ear quality,increase sugar and reduce acid,increase Vc content,yield and reduce pests and diseases to improve plant growth and fruit development of‘Crimson Seedless’grapes.Therefore,for‘Crimson Seedless’grapes planting and production in Xinjiang,6-leaf topping before flowering,3-4 leaves topping on top auxiliary shoots,top secondary auxiliary shoots growing,and remaining auxiliary shoots with single leaves were recommended.