Effects Of Grafting On Growth And Disease Resistance Of Pepper

This paper is concerned with the lower yield of pepper caused by the successive cropping obstacle and serious phytophthora capsici caused by the soil-borne disease,carrying out research on the screening of phytophthora blight resistance types of pepper r ootstocks,effects of different rootstocks and different grafting methods on grafting effect and phytophthora blight resistance of pepper,aiming to provide reference to the prevention and control of phytophthora capsici and the high quality agricultural production.Thus the following conclusions are obtained through the test:(1)The in vitro inoculation method is applied in fast inspection of resistance types of phytophthora capsici,screening out one high disease resistant rootstock and two disease resis tant rootstocks.The disease indexes separately on 3d inoculation of phytophthora capsici "LT1534 strain" by in vitro inoculation method and on 16 d of living inoculation are found in consistent with classification of pepper disease resistance types,thus a sserting that the “Giant Roots” are identified as high disease-resistant rootstocks,“Qingqing No.1” and “Tuolasijia” as disease-resistant rootstocks,“Weizhuangbeier”,“Jinmayelimu”,“Wolfgang” and “Kate188” as medium disease-resistant rootstocks,and “Dingli No.5”,“Giant Root” and “South Korea Youzhuang” as disease-sensitive rootstocks.(2)The activities of pod,PPO and pal,and the contents of lignin,total phenols and flavonoids are helpful to prevent and control the damage of Phytophthora blight to c apsicum.Compared with CK 2,the activities of pod,PPO and pal and the contents of lignin,total phenols and flavonoids in Capsicum increased after inoculation,especially in the process of disease.The results showed that the grafting treatment of capsic um with high disease resistance rootstock and disease resistance rootstock showed that The three enzyme activities(POD,PPO and PAL)and the contents of lignin,total phenols and flavonoids were significantly higher than those of CK 1.The five indexes of high resistance rootstock grafting were kept at a high level.(3)Due to the interaction effect between rootstocks and scion,the grafting can significantly improve the resistance of grafted seedling to the phytophthora capsici,while the disease resistan ce of rootstock will be weakened to some extent during the transfer process from rootstock to scion.After grafting,the disease index of pepper blight is significantly reduced and the disease resistance of grafted seedlings is improved;According to the resistance level classification of rootstocks,“Giant Root” rootstock is a high disease-resistant rootstock,“Qingqing No.1” and “Tuolasijia” are disease-resistant rootstocks.However,for the disease resistance classification of grafted seedlings under the conventional sleeve oblique cutting grafting method with the three rootstocks,the grafted seedlings of “Giant Root” rootstocks show the disease resistance feature,while the grafted seedlings of “Qingqing No.1” and “Tuolasijia” rootstocks show the medium disease resistance feature.(4)When taking the double root-cut grafting technique,the wound healing on the joint between the rootstock and scion are progressing concurrently with the root regeneration of the rootstock.This technique can effectively prevent the excessive growth of pepper grafted seedlings,greatly increase the seedling index,obviously decrease the incidence rate and disease index of phytophthora capsici,thus increasing the yield and improving the quality.After grafting for 15 days,the wound on the joint between the rootstock and scion is gradually healing,the vascular bridge is increasing with most of part have been jointed.At this moment,the test of pepper leaves shows that solferino absorption amount increased a lot.in addition the rootstocks have grown out regenerated roots which are helpful to freely transport the non-structure carbohydrate and the contents are gradually recovered to a normal level.Double root-cut grafting technique significantly increased the single fruit weight and equivalent yield of the fruit,and the "Giant Root" and "Qingqing No.1" which adopts this technique both increased the vitamin C content and soluble sugar content in the fruit.