Effect Of Grafting Cultivation On Continuous Cropping Obstacle Reduction Of ’Nan Shui No.6’

‘Nan Shui No.6’ fruit cucumber is a new variety selected by horticulture College of Nanjing Agricultural University.It has strong disease resistance,good yield stability,good marketability,high quality and tolerance to transport.It is one of the best cucumber varieties for protected cultivation.But under the condition of protected cultivation,the continuous cropping obstacle is serious,which affects its cultivation.Through grafting and root changing,the absorption capacity of root system can be improved and its growth can be promoted,and different rootstocks have different effects on the grafted seedlings.The specific research are as follows:1.Selection of rootstocks for grafting cultivation of ‘Nan Shui No.6’Through the grafting experiment of ‘Nan Shui No.6’,the rootstock varieties and technical methods matching the grafting cultivation of ‘Nan Shui No.6’ were selected.In this experiment,black seed pumpkin,white seed pumpkin ‘Jin Mama’,’Yong He’ and‘Xiaozi pumpkin’,yellow seed pumpkin ‘Huo Fenghuang’ and Luffa cylindrica were used as rootstocks,and ‘Nan Shui No.6’ was used as scion to graft respectively.The growth,yield and fruit quality of grafted seedlings and seedlings in spring and autumn were compared.The results showed that: in spring,the growth vigor of seedlings was better than that of grafted seedlings,and the chlorophyll value of black seed pumpkin was higher than that of other treatments;in terms of fruit yield,the treatments with ‘JIN Mama’ and ‘Yong He’ as rootstocks had the highest yield in spring,and the plot yield were 85.64 kg and 84.44 kg respectively,while in autumn,the treatment with ‘Xiaozi pumpkin’ as rootstock had the highest yield,which was 86.84kg;In terms of fruit appearance quality,the treatments with ‘Jin Mama’,‘Huo Fenghuang’ and ‘Xiaozi pumpkin’ as rootstocks had no wax powder on the fruit surface,the commercial property is good;In terms of flavor and nutritional quality,the grafted seedlings with pumpkin as rootstock increased the vitamin C content of ‘Nan Shui No.6’,while the soluble protein content of the grafted combination with ‘Jin Mama’ as rootstock in spring and ‘Yong He’ as rootstock in autumn was significantly lower than that of the control;In autumn,the soluble sugar content of grafted seedlings with pumpkin as rootstock was significantly higher than that of seedling,while in spring,the soluble sugar content of grafted combinations with ‘Xiaozi pumpkin’,‘Huo Fenghuang’ and ‘Jin Mama’ as rootstocks was lower than that of control.2.The effect of Grafting Cultivation of ‘Nan Shui No.6’ on overcoming continuouscropping obstaclesIn this experiment,‘Nan Shui No.6’ was grafted in the soil of continuous cropping melons for many years,and compared with the seedling.The results showed that the growth vigor,yield and appearance quality of the grafted seedlings of ‘Nan Shui No.6’were better than those of the seedling;compared with the seedling,the yield of the grafted seedlings increased by 65.30%,and there was no wax powder on the fruit surface.However,the incidence rate of downy mildew and powdery mildew of grafted seedlings was 52.78%and 80.56% respectively,and the disease index of grafted seedlings was 26.11% and 23.33% respectively,higher than those of seedlings of 8.11%,13.51%;2.70% and 4.32%.The content of organic matter in rhizosphere soil increased with the extension of planting time,and the growth rate of grafted seedlings was significantly higher than that of seedling;the content of available nitrogen,available phosphorus and available potassium in rhizosphere soil decreased with the extension of planting time,and the diminution of available nitrogen and available potassium in grafted seedlings was much more than that of seedling;therefore,the absorption capacity of available nutrients in rhizosphere soil was higher than that of seedlings,showing a strong absorption capacity.In the continuous cropping soil for many years,the grafting cultivation method can enhance the plant growth potential,promote the accumulation of photosynthetic products,improve the fruit yield and quality,improve the problem of wax powder on the fruit surface of ‘Nan Shui 6’,and reduce the influence of continuous cropping obstacles to a certain extent.