Monitoring the Gene Pool of Sea-Buckthorn Cultivars ( Hippophae Rhamnoides L.) for Breeding in the Conditions of the Nonchernozem Zone of Russia

. The research materials of Hippophaerhamnoides L. cultivars in the Nonchernozem zone of Russia are presented in this paper. The issues of phenology, productivity and resistance to ecological factors of the environment are considered. It was found that the phenophases of the beginning of vegetation, ripening of berries, leaf fall, duration of fruiting and vegetation have a slight variation, i.e., the cultivars slightly differ in the calendar phenophase onset dates. At the beginning of the growing season, this phenophase can be divided into 3 groups: early (18-22 days – Botanicheskaya Aromatnaya, Botanicheskaya and Perchik), medium (23-26 Moskovskaya Ananasnaya, Botanicheskaya Lyubitelskaya, Gibrid Perchika and Lomonosov) and later (27-30 – Podarok Sadu and Vorobyovskaya) bud breaks. There are 3 groups of cultivars according to the duration of vegetation: short (171-174 days – Podarok Sadu, Moskovskaya Ananasnaya and Botanicheskaya), medium (175-178 – Botanicheskaya Lyubitelskaya, Gibrid Perchika, Vorobyevskaya, Otradnaya and Lomonosovskaya) and long (179-182 – Botanicheskaya Aromatnaya). The analysis of the sea-buckthorn


Introduction
Sea-buckthorn Hippophaerhamnoides L. belongs to the family of Elaeagnaceae. It is a large shrub or a small tree up to 9 m tall with a top-level root system and a strongly branched trunk and branches. Its shoots are initially silvery, then rusty-brown, ending in thorns. The leaves are alternate, short-stemmed, linear or linear-lanceolate, up to 8 cm long and 0.8 cm wide. The flowers are unisexual, and the plant is dioecious. Male flowers are collected in short spikes up to 8 mm long, female ones -in the axils of twigs on pedicels up to 0.5 mm long with a tubular brown perianth covered with rare white scales on the outside. The fruits are juicy, shiny drupes, red or yellow in colour, up to 1 cm long and up to 0.8 cm wide. The seeds are dark brown, shiny, ovate-oblong with a longitudinal groove. Sea buck-thorn blooms in April-May; fruits ripen in July-August, sometimes at the end of June, remaining until the spring of the following year. The flowering duration is only 10-12 days [1,2].
Due to the enormous value of sea-buckthorn cultivars, they are studied everywhere, and the phenomenon of the most adaptive ones to local conditions, which was the subject of our research, is revealed.

Results and Discussion
Analysing the average dates of the phenophase onset, it was noted that the be-ginning of bud break occurs on the 24th (± 2 days) day from the average date of the air temperature transition through 0 ° C (April 1), the beginning of berry ripeningon the 124th (± 4) day, the end of berry ripening -on the 146th (± 1) day and leaf-fall on the 200th (± 2) day. Thus, the berries ripening duration, on the average, is 22 (± 1) days, and the vegetation lasts 176 (± 2) days on the average (Fig. 1).
The obtained variation coefficients show that the phenophases of berry-ripening, leaf fall, duration of fruiting and vegetation have a weak variation, i.e., the cultivars differ slightly according to the calendar phenophase onset dates. On the contrary, the beginning of bud break is marked by a large variation. Thus, the cultivars, according to the calendar time of this phenophase onset, can be divided into 3 groups: early (18-22   The analysis of the yield of Hippophaerhamnoides L. cultivars for 2014-2018 showed that the average yield of the species on the total of the studied cvs was 85 ± 21 c/ha. The cultivars variation is also high and it amounted to 88% (Table 1, Fig. 1). The average yield varies greatly over the years. The lowest yield (19±4 c/ha) was recorded in 2014, the highestin 2015 (154±35) and 2018 (154±54). The yield variation of all cultivars over the years is average and high. The average variation was noticed in 2014 and amounted to 33%. In 2015, the variation also turned out to be average (36%). This indicates that, in these years the difference in yield, due to the belonging of a cultivar, is average. In 2016-2018, the variation was strong (2016 -69%, 2017 -49%, 2018 -57%), and this indicates a significant difference in the yield of cultivars in the years under consideration.    The productivity varies greatly among the cultivars (Table 1, Fig. 4). The variation coefficient was 53%, which indicates significant differences in the cultivars productivity. The average cultivars productivity was 13±4 kg/tree. The lowest productivity was noticed in cvs Podarok Sadu (4.2±0.4 kg/tree and Otradnaya (5.9±0.5). The most productive cultivars were Botanicheskaya Aromatnaya (25.2±0.8 kg/tree), Botanicheskaya (18.8±0.7) and Botanicheskaya Lyubitelskaya (17.3±0.7). The berry mass analysis of Hippophaerhamnoides L. cultivars for 2014-2018 showed that the average fruit weight of the species on the total of the studied cultivars was 0.67 ± 0.04 g (Table 1, Fig. 5). The cultivars variation was not high (21%).
The berry mass analysis of Hippophaerhamnoides L. cultivars for 2014-2018 showed that the average fruit weight of the species, on the total of the studied cultivars, was 0.67±0.04 g (Table 1, Fig.5). The cultivars variation was not high (21%).  The average weight of fruits slightly varies over the years. The lowest fruit weight (0.54±0.04 g) was noticed in 2014, and the highest (0.72±0.06)in 2015 (Table 1, Fig.5). The fruit weight variation of all cultivars over years is weak and average. Weak variations were noticed in 2014 (13%) and 2015 (14%). In 2016 (22%), 2017 (22%) and in 2018 (19%), the variation turned out to be average. The data obtained indicate the berry mass stability in different years.
Due to its rich biochemical composition of fruits, high productivity, early ripening, winter hardiness, and ecological plasticity, sea-buckthorn is one of the leading industrial crops at present, especially in the gardens of Siberia. Sea-buckthorn fruits are widely used in food and pharmacological industries, cosmetology, forestry, and land reclamation. The main reason that hinders the broader introduction of this crop into industrial horticulture is the use of cvs with low ecological plasticity, particularly those affected by diseases, in particular, by mycotic drying out, which leads to a significant thinning of sea-buckthorn