Cultivation prospects of selected plum varieties in dense planting areas of the North Caucasus region of Russia

Abstract

The intensification of Russian horticulture in modern conditions is impossible without a comprehensive assessment of fruit crop varieties, including already introduced ones, to identify the most ecologically adaptive and productive genotypes for cultivation. The purpose of this study was a comprehensive assessment of the biological potential of newly-introduced plum varieties and the peculiarities of their implementation under the conditions of the North Caucasian horticultural region, intending to select the best ones to expand the regional assortment. The research focus was the plum varieties of Italian breeds: Big Stanley (Prunus domestica L.), Blue Moon (Prunus domestica L.), August Delight (Prunus domestica L.), Dark Sunlight (Prunus domestica L.), Crimson Glo (Prunus cerasifera L.) of differentecological and geographical origin. The August Delight, Blue Moon, Crimson Glo and Dark Sunlight varieties are earlymaturing and start bearing fruits in 3 years and Big Stanley in 4 years. These varieties have a restrained spread, respond positively to alternative methods of crown formation and are technologically advanced. According to the ripening time of the fruits, the varieties can be divided into distinct groups: August Delight and Blue Moon are middle-late, while Big Stanley, Crimson Glo and Dark Sunlight are late. Under the research conditions, the August Delight, Blue Moon and Big Stanley varieties developed large fruits of 44.6-52.4 g, while very large fruits, between 75.5 and 78.9 g, were found in the Crimson Glo and Dark Sunlight varieties, respectively. Under extreme weather conditions, Crimson Glo (19.5 t/ha) and Dark Sunlight (22.3 t/ha) varieties were characterised by higher yields, while for the Big Stanley, Blue Moon, August Delight varieties, the yield was at the level of the control group (15.0-16.2 t/ha). Newly-introduced varieties have several agronomic characters, allowing them to be recommended for expanding the regional assortment and plum supply of late varieties. This strategy can provide an increase in the arrival duration of fresh fruits by 26-30 days.