Assessment and selection of heat- and drought-resistant potato forms for the Northern Caucasus soil and climatic conditions

The purpose of the study is to evaluate and select heat- and drought-resistant potato forms to create new highly productive, adapted varieties for the soil and climatic conditions of the North Caucasus. In 2019-2021 the study of varieties of domestic and foreign breeding for endurance to heat and drought was continued. The assessment of the degree of drought resistance of potato varieties was carried out by laboratory and field methods. The laboratory method is based on measuring the electrical resistance of leaf tissues (ESTL) (Methodology of I.M. Yashin, 2002). In the collection nursery of the Vladikavkaz Scientific Center of the Russian Academy of Sciences, 130 varieties of potatoes of early, mid-early, mid-ripening and mid-late ripeness groups in the foothill and mountain zones were studied. Evaluation of potato breeding samples took into account a set of characteristics, such as heat and drought resistance, productivity, resistance to diseases and pests, its economically valuable parameters, and the biochemical composition of potato tubers. According to the laboratory assessment, the varieties Record, Slavyanka, Babushka, Gala, Oceania, Goluboj Dunaj, Partner, Krona were classified as drought-resistant. Under field conditions, varieties Nevsky, Predgorny, Kurazh showed resistance above average. Therefore, according to a comprehensive assessment, these varieties are classified as resistant, between laboratory and field data on drought resistance there is an average correlation equal to 0.514. The heat resistance of varieties and hybrids was established by a laboratory method based on ESTL. As a result, heat-resistant varieties Nevsky, Kurazh, Predgorny, Vladikavkazsky, Krona, Bogarny, Nakra were identified. Varieties Partner, Babushka, Liga, Gala, Goluboj Dunaj, Ulyanovsky are classified as moderately resistant. It was found that leaf pubescence positively and significantly correlated with field resistance. The correlation coefficient is 0.467-0.525, respectively. The intensity of the green color of the leaf positively correlates with field resistance Ч = 0,367-0,486. Plants with more intense leaf color are more resistant in the field.