| Cucumis melo is one of the most popular cash crops of Cucurbitaceae in China.However,in South China,the soil-borne disease,especially the blight and meloidogyne incongnita of cucumis melo are becoming increasingly more serious,and the breeding of disease resistant stock is extremely urgent.China's disease-resistant breeding of Cucurbitaceae stock started late.There are little work of cucumis melo disease resistant stock screening,especially disease resistant stock breeding for two kinds of soil-borne diseases which have serious damage.This study takes the germplasm resources of stock cucumis melo and stock pumpkin collected by the research group and preserved for many years through selfing as the object of study,and makes analysis of the characters at seedling stage to see if it is suitable for grafting stock.It adopts seedling stage artificial indoor inoculation method to appraise its disease resistance to the blight and meloidogyne incongnita of cucumis melo,and screens out good stock,and takes the thin-skin cucumis melo cultispecies as the scion for grafting research.The results clarified the disease resistance differences of germplasm resources of tested stock and the grafting performance,which provides breeding materials and reference for the breeding of cucumis melo disease resistant stock.The main research results include:1.Through analysis of the quantitative characters of 11 shares of tested stock thick-skinned cucumis melo germplasm resources at seedling stage,the results showed that the fresh weight of the underground of seedling had the maximum variation coefficient,and the seedling cotyledon expansion had the minimum variation coefficient,and the variation coefficient of other seedling characters was between 2.5%and 33.34%.The variation coefficient of the quantitative characters of seedling was less than 36.40%on the whole.The coefficient of variation of character of the hypocotyl thickness,cotyledon expansion and hypocotyl medullary cavity diameter were less than the mean value and showed genetic stability.2.It appraised the resistance to blight of 37 shares of germplasm resources of cucumis melo stock,and used "Guangmi No.1" thin-skin cucumis melo cultispecies as the contrast.The results showed that among the tested materials,there were 23 shares that showed high resistance to blight,accounting for 62.12%of the total amount,the incidence and disease index of T02 stock were the lowest,which were respectively 2.82%and 2.46%.There were 9 shares which showed moderate resistance to melon blight,accounting for 24.32%of the total amount.There were 5 shares of germplasm resources of cucumis melo stock which showed mild resistance to blight,accounting for 13.51%of the total amount.3.It made appraisal of the meloidogyne incongnita resistance of 9 shares of stock cucumis melo germplasm resources.Through calculating the subordinative function values of indexes which had larger variation coefficient after tested stock inoculation,such as plant height,dry weight of the underground,root knots index,ovum index and propagation coefficient.Combined with counting root knots method,it calculated the disease index of tested stock.The resistance to meloidogyne incongnita of tested stock under comprehensive evaluation was as follows in descending order:T05,TKH1,T06,T03,T07T,T02,T04,T03T,T07.4.It selected 19 shares of different stocks for grafting experiment.the grafting survival rate of cucumis melo seedling grafted with cucumis melo stock reached above 90%,which was higher than the cucumis melo seedling grafted with pumpkin stock,and the scion leaf area,fresh weight and dry weight of the grafted seedling were significantly higher than the cucumis melo seedling grafted with pumpkin stock.The survival rate of T06 stock grafted seedlings was the highest,which reached 95.32%,and the survival rate of T02,T07 stock grafted seedlings also reached more than 95%.The survival rate of the cucumis melo seedling grafted with pumpkin stock was lower than cucumis melo seedling grafted with cucumis melo stock.Besides the two shares of cross-fertilized pumpkin stock grafted seedling which had survival rate of more than 87%,the survival rate of the cucumis melo seedling grafted with pumpkin stock was less than 76%.The results of blight resistant appraisal of different stock cucumis melo grafted seedlings showed that the disease index and incidence rate of grafted seedlings of T02 were the lowest among the 9 shares of cucumis melo seedlings grafted with cucumis melo stock,which were 5.73 and 6.25%respectively,and the disease prevention effect reached 94.17%.Among the 9 shares of cucumis melo seedlings grafted with pumpkin stock,the incidence of N1001 stock grafted seedling was the lowest(10.00%).The disease index of N01 stock grafted seedling was the lowest(7.35),and the disease prevention effect was the best,which was 92.52%.6 shares of grafted seedlings showed mild resistance.The results of grafting seedling inoculation were different from those of stock inoculated blight pathogenic bacteria alone.Under comprehensive assessment of the stock grafted cucumis melo seedling's resistance to the blight,the resistance was as follows in descending order:T02>T06>T03>NC02>N1001>NC06>N10>TKH1>N0110>T04>T07>T07T>N01.In conclusion,cucumis melo stock T02,T03,T06 had certain resistance to blight and meloidogyne incongnita.And the graft compatibility was good,which could be used as breeding parents of disease resistant stock which had comprehensive resistence.The pumpkin stock NC02,NC06 and cross-fertilized stock N1001 had certain resistance to the blight,but the graft compatibility of tested thin-skin cucumis melo scion is waiting to be improved further. |
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