The effect of compound fertilizer (NPK) and gibberellic acid on the growth of two transplants grape cultivars Zarik and Thompson seedless (Vitis vinifera L.)

Abstract

The experiment has been conducted on grape seedlings (Vitis vinifera L.) in the nursery of College of Agriculture and Forestry, University of Mosul, Mosul, Iraq. During the growing season 2020, to study the effect of fertilization of compound fertilizer (NPK) 20 : 20 : 20 with three levels (0, 200 and 400 mg.l-1), Spraying with two concentrations of Gibberellic acid (0 and100 mg.l-1) on two grape cultivars Zarek and Thompson Seedless, and study the interaction between all factors and its effect on the vegetative growth characters of grape seedlings. A factorial experiment with three replications was carried out by split - plot system in a Randomized Complete Block Design (RCBD). Data obtained were statistically analyzed Duncan's Multiple Range test at 0.05 level. Results showed that Fertilization with (NPK) specially at 400 mg.l-1 level caused a significant increase in stem height, chlorophyll concentration, vegetative and root dry weight of grape seedlings. Foliar spray with Gibberellic acid especially at 100 mg.l-1 concentration caused a significant increase in stem height, vegetative dry weight of grape seedlings. The characters studied were different according the cultivars, Zarek was significantly superior compared with Thompson Seedless cultivar in the height and diameter of main stem. While Thompson Seedless cultivar was significantly superior compared with Zarek grape cultivar in seedling leaves area, vegetative and root dry weight. Results of triple interaction between all factors showed a significantly effect in stem height of grape seedlings in ( 400 mg NPK.l-1 + 100 mg GA3 .l-1 ) for the Zarek grape cultivar. As well as the response of the grape Thompson Seedless cultivar and fertilizer with 400 mg NPK.l-1 + 100 mg GA3 .l-1 in the characteristics of the chlorophyll content, seedling leaves area and vegetative dry weight of grape seedlings.