EFFECT OF SPRAYING SOME SOURCES AND RATES OF ZINC ON VEGETATIVE GROWTH, MINERAL CONTENT AND YIELD OF "WONDERFUL" POMEGRANATE TREES

Abstract

Nanoparticles (NPs) especially from micronutrients are recently advocated for replacing their common organic and inorganic counterparts. To evaluate their comparative efficacy, this study was carried out to investigate the effect of foliar application of zinc through different sources on vegetative growth, flowering, productivity, fruit quality, improve marketable fruit and leaf mineral content of “Wonderful” pomegranate trees. Field experiment was laid out during two seasons (2017 and 2018) on seven years old pomegranate trees “Wonderful” cv., cultivated in private “Hegazi” farm located at 57 km. from Cairo on the road to Alex., Egypt. Four sources of zinc named “zinc sulphate, zinc mannitol complex, bio nano zinc (Bio Zn NPs) and zinc oxide nanoparticle (ZnO NPs) with four rates from each other were sprayed twice (the first before one week from full bloom and the second after month from the first). So the experiment included seventeen treatments in sample experiment spread in a randomized complete block design with five replicates. Results revealed that, vegetative growth was increased by increasing the rate of spraying Zn irrespective the source expect with zinc oxide nanoparticle (ZnO NPs) which gave a contrary trend. In most cases, 4000 ppm Zn mannitol complex enhanced all vegetative growth parameters. The highest significant values of fruit set%, fruit retention % and least values of fruit drop% were recorded by bio nano zinc (Bio Zn NPs) treatments especially 400 ppm bio nano zinc (Bio Zn NPs). Spraying with 3000, 4000 ppm Zn mannitol complex and 300, 400 ppm bio nano zinc (Bio Zn NPs) gave the highest significant values of productivity, improves marketable fruits and fruit quality of “Wonderful”