EFFECT OF NITROGEN PHOSPHORUS AND POTASSIUM FERTILIZATION LEVELS ON YIELD AND QUALITY OF GRAFTED CANTALOUPE

Abstract

Propagation of cucurbits via grafted seedlings exhibits an increasing trend in vegetable cultivation in Egypt. This is due to the limited cultivated area, intensive cultivation, and the increasing stress which all lead to problems that negatively affect production. Furthermore, the investigations for determining the accurate fertilization amount of the grafted plants are still scarce. Therefore, this field experiment was carried out in Badr city, El-Behera governorate, Egypt, to evaluate the performance of grafted and non-grafted (control) cantaloupe plants (Cucumis melo var. cantaloupenses, cv. Marella F1 hybrid) onto four rootstock cultivars (Cobalt, Ferro, Star, and 6001) then fertilized with nitrogen (N), phosphorus (P), and potassium (K) at rates of 60, 80, 100, 120, and 140% of these nutrients recommendations for cantaloupe fertilization during the two successive growing seasons of 2018 and 2019. The results indicated that grafting cantaloupe plants onto the tested rootstocks had promoted a higher vegetative growth manifested as plant length, leaves and branches numbers, shoot fresh and dry weight, stem diameter, leaf area, and root dry weight, as well as raising the content of leaf mineral content, the greenness index (i.e. chlorophyll readings, SPAD), phenolic, and proline along with boosting the fruit quality, average fruit weight, fruit number, early and total yield than the control when all were fertilized by any of the applied fertilization rates. Worthy, rootstocks of Cobalt and Ferro provided the greatest superiority in all investigated growth and fruit yield characteristics of the cantaloupe plant through fertilizing by the 140% NPK fertilization rate.