IDENTIFICATION OF THE MAIN DISEASES OF WALNUT IN THE SOUTHERN FRUIT-GROWING ZONE OF KAZAKHSTAN

Abstract

Industrial cultivation of nut crops in the Republic of Kazakhstan is promoted by favourable soil and climate conditions, especially in the southern region, which makes it possible to obtain high yields of this valuable plant in the future. Significant damage to the yield of nut crops is caused by diseases, protection of plantations from which is one of the main measures aimed at increasing their productivity. The most important issue in cultivation of nut crops is its protection from bacterial and fungal pathogens. In Kazakhstan purposeful researches on studying species diversity of diseases and pests of nut crops have not been carried out. The novelty of the conducted research is in the fact that for the first time in Kazakhstan fungal and bacterial diseases of walnut in the conditions of the southern zone of fruit growing on the basis of microbiological and molecular-genetic methods were identified.
 The results of research showed that the majority of isolated pathogens are fungi, as well as several species of bacteria causing diseases of walnut. In total, 4 genera of fungi were isolated: Alternaria, Fusarium as causative agents of fungal diseases; Aspergillus, Penicillium as secondary infestation; also 2 genera of bacteria: Pantoea, Pseudomonas as causative agents of bacterial diseases. Molecular identification of fungal and bacterial pathogens by PCR based on genomic DNA showed that the studied walnut samples were identified as phytopathogenic fungi: Alternaria alternata, Fusarium solani, as well as phytopathogenic bacteria: Pantoea agglomerans, Pseudomonas syringae, Pseudomonas oryzahabitans. The conducted research results will allow to make up a system of protection of walnut from harmful diseases in order to increase the productivity of plantations.