Adaptive Potential of Seed Crops on the Example of Apple Tree Varieties and Quince Seedlings

Apple is the main fruit crop in the European part of Russia. Quince is a promising crop as a valuable low-growing rootstock for pears. The most favorable conditions for growing pome crops (apple and common quince) are in the Central and Central Black Earth regions (Voronezh, Tula, Lipetsk, Kursk, Belgorod, Oryol, Ryazan and Tambov regions). Currently, there is a wide variety of varieties and rootstocks (of various selections) for apple and pear trees, but choosing more adaptive ones for each ecological-geographical zone in intensive gardening is considered relevant. The studies were carried out on the basis of VNIISPK in 2018–2023. Apple cultivars of VNIISPK breeding and foreign cultivars grafted on rootstock 54-118 as well as common quince of VNIISPK breeding selected according to a complex of valuable economically useful characteristics were used as objects of study. The research of the presented work was carried out on the basis of the methodological recommendations “Programs and methods for the variety study of fruit, berry and nut crops” and “Methods for the accelerated assessment of winter hardiness of fruit and berry plants”. Severe frosts occur in the Central region of Russia (Orel region) in winter (January-February). Over the past five years, the lowest air temperature was recorded in the winter of 2020/2021, when in February it dropped to minus 30°C. In the field, the studied apple cultivars on the clone rootstock 54-118 showed sufficient winter hardiness. As a result of freezing of annual branches in laboratory conditions, it was revealed that Ligol (the Polish cultivar) and the VNIISPK cultivars Orlovsky Partizan, Vyatich, Orlovskoe Polesie and Pamyat Semakinu had bud and wood damage according to all I, II, III components of winter hardiness. The most winter-hardy cultivar Rozhdestvenskoe of VNIISPK breeding stood out. In VNIISPK, seedlings of common quince with high winter hardiness of the aboveground and root systems adapted to the climatic conditions of the central part of Russia and possessing restrained growth have been identified. Studies have shown that these quince seedlings being in deep dormancy can withstand frosts up to -36°C and are able to tolerate a decrease in temperature in the zone of the root layer up to -10°C without significant damage.