The influence of genetic similarity, peroxidase activity and ascorbic acid content in the components of pumpkin crop grafts on their survival rate

Grafting of vegetable crops is widely used in industrial vegetable growing in Asia and Western Europe. However, the influence of the genetic relationship of the scion and rootstock, the activity of peroxidase and the content of ascorbic acid in the components of the graft during inosculation period on graft survival has been poorly studied. The objects of the research are nine species of the pumpkin family (Cucurbitaceae). The polymorphism of 11 taxa was studied based on ISSR-PCR of genomic DNA. The record of survival rate of scion-rootstock combinations was conducted on the 10-th day. The activity of peroxidase was determined by the spectrophotometric method, the content of ascorbic acid was determined by Murri. Significant differences in survival rate were noted when grafting momordica into pumpkin rootstock variants: large-fruited (94.6 %) and nutmeg (67.1 %). In experiments with watermelon, melon and trichosanthes, the influence of the type of rootstock on the viability of the graft was not revealed. According to the ISSR spectra, the taxa were divided into two clusters; interspecific groupings of each clade were supported by average bootstrap values (from 26 to 100 %). A medium effect (r = 0.36) of the degree of genetic similarity of the scion with the rootstock on the survival rate of watermelon and a weak effect on the survival rate of melon, momordica and trichosanthes were revealed. The activity of peroxidase and the content of ascorbic acid in the grafting components in different scionrootstock combinations had a weak and moderate effect on plant survival, respectively. The survival rate of trichosanthes on various types of rootstocks strongly depended on the content of ascorbic acid (r = 0.7). Genetic relatedness, peroxidase activity, and ascorbic acid content had a weak or moderate effect on the survival rate of plants in scion-rootstock combinations.