Fruit growing
and viticulture of South Russia

Annotation

The walnut (Juglans regia L.), belonging to the Juglandaceae family, is widely cultivated in all moderate and subtropical regions. In recent years, damage to walnuts by bacterial blight has been noted. This disease, known as bacteriosis, is caused by the bacterium Xanthomonas jglandis (Pierce) Dowson. Bacteriosis causes the most severe damage in spring in wet and warm weather, which leads to a decrease in yield and quality of fruits. The purpose of the study is to identify the most resistant genotypes for use in breeding based on a long-term field assessment of resistance to bacteriosis of walnut hybrid forms. The objects of study are 21 promising hybrid forms of walnuts bred at the FSBSI NCFSCHVW. Control variant is variety Rodina. The garden was planted in 2014, the layout was 5 × 4 m. The studies were carried out on a natural agrobackground in a breeding garden in 2019-2021, in the central part of the Kuban horticulture zone of the Krasnodar region, on the basis of ZAO OPH Tsentralnoye of FSBSI NCFSCHVW Krasnodar. R&D was carried out according to generally accepted programs and methods. The degree of damage of walnut hybrid forms by bacteriosis was assessed using a scale from 0 to 5 points. It was revealed that bacteriosis annually damages walnut plants, and the degree of disease damage depends on the prevailing weather conditions. It was found that the most favorable years for the development of infection were 2019-2020. According to long-term data, hybrid forms of walnut resistant to bacteriosis have been identified: 17-2-35, 17-3-10, 17-3-12, 17-3-41, 17-3-44, 17-3-48, 17- 3-24, 17-3-27, 17-3-29, the degree of damage over the years of study of which varied from 1.1 to 2.0 points, the maximum did not exceed 2.0 points. Most of the hybrids isolated for resistance to bacteriosis were obtained from the Dachny family � free pollination of the NCFSCHVW breeding, which has in its origin the Central Asian variety Ideal. The isolated forms of walnut are promising for further breeding for resistance to Xanthomonas jglandis (Pierce) Dowson.

Annotation

Walnut (Juglans regia L.) is one of the ten most valuable plants on the planet. All its parts are economically valuable. Most often, the species is grown for food purposes. Walnut fruits are of great economic interest for the food industry, directly its edible part (kernel). Fresh, natural kernels are eaten mostly as whole nuts or used in various confectionery products. The nut is a nutrient-rich product, mainly due to the content of: fats (from 60-77 %), protein (16.5-34 %) and carbohydrates (2-10 %). The purpose of the study is to evaluate promising varieties of walnuts in terms of fruit quality and to identify varieties with a complex of economically valuable traits. Modern programs and methods of breeding and variety study are used. The paper presents the results of a long-term study (2018-2022) of 16 varieties of walnut growing in the conditions of the North Caucasus region. In the course of the study, large-fruited varieties were established (with a fruit weight 12.1-14.0 g) MP-118, Rus�, Slavyanin, Vodnik, Olympiets, LP-40; high kernel content (from 53.1 to 56.1%): Timur, Rus�, Novinka, Terkin, Sokol, Yakhont, Nakhodka, Stimul, Vodnik, LP-40; high fat content (from 65 to 71 %): Terkin, Novinka, Slavyanin, Vodnik, Stimul, Shchedryi, Zemlyak, Sokol, Rus�, LP-40; fruits with thin-crust shells (0.8-1.2 mm): Shchedryi, Slavyanin, Timur, Novinka, Terkin, Sokol, Yakhont, Nakhodka, Stimul, Vodnik, LP-40, Rus�. All varieties have a high tasting score. The results of the study allowed us to identify three promising varieties: Vodnik, Rus� and LP-40 with a complex of economically valuable traits (fruit weight, kernel yield, kernel extractability, taste and high fat content). All studied variety forms are of interest for breeding and production, and they can also be recommended as sources for obtaining new varieties.