Diversity of hazelnut varieties and changes in plant development during introduction in the semi-arid zone

Abstract

Global climate change provide the emergence of new opportunities for the introduction of new crops into horticultural production in the areas of insufficient precipitation. In addition to the economic aspect, it is also of interest to the biologists of the development of this plant in a qualitatively new environment.The paper considers the variability of the main traits of plant morphometry, yield for four varieties of hazelnuts in order to identify the most promising forms for cultivating in the northern part of the Steppe of Ukraine characterized by an insufficient precipitation and harsh winters. Recent milder winter conditions and a certain balance in summer droughts have made the required horticultural production possible, thereby increasing the production of hazelnuts and addressing the dietary problems of people in terms of supply of necessary vitamins and micronutrient element from hazelnuts. Promising varieties for the production plantations have been specified, the mechanisms for the yield formation have been studied. Key traits of morphometry have been identified that condition the success of a variety under insufficient humidity. These were such traits as crown volume, leaf surface area, shell thickness, average weight of one nut, weight of dry nuts, yield, kernel yield. It has been established that the yield formation on account of large, well-shaped nuts is best in terms of yield. Some aspects of yield formation and the possibility of combining different varieties, especially when more intensive growing methods are applied, are of additional interest. High variability significantly prevents the modeling of traits, for example, such as yield per tree, from being significant in terms of the formation of high yield. Semi-intensive pruning of hazelnut bushes shows its suitability for use in modern garden plantings. Variety Barselonskiy showed extremely high variability for many key parameters, which may indicate insufficient stability of this variety from a genetic point of view and the presence of a fairly significant number of hidden biotypes, which is additionally negative for cultivation in modern semi-intensive and intensive technologies. Climate change makes it possible to continue to significantly expand the area under hazelnuts due to the previously considered unfavourable southern subzones of the Forest-Steppe and the Steppe zone of Ukraine. Such new and previously unnoticed effects have been noted as fruiting in the first year in production crops, the formation of up to 5–6 inflorescences for each nut-bearing branch in the second or third year. For further investigations, it is planned to analyze the nutritional qualities of the obtained products, in terms of the composition by microelements and the presence of biologically-active substances, to trace the dynamics of the accumulation of heavy metals and the potentially associated risks.