POTENTIAL OF CONTROLLED HYBRIDIZATION OF CAUCASIAN TEA (СAMELLIA SINENSIS (L.) KUNTZE) CULTIVARS FOR CREATING F1 POPULATIONS

Tea (Camellia sinensis (L.) Kuntze) belongs to valuable agricultural crops and ranks second in the world in terms of consumption among soft drinks. In the Caucasus, tea plants have been cultivated for over 100 years, where they have been perfectly acclimatized, despite the fact that they grow in the northernmost region of industrial tea cultivation in the world. At the same time, there are limiting factors for productive tea cultivation – drought and frost, which lead to a decrease in yield and quality, and in some cases to the death of plantations. Industrial plantations here were planted with seeds of Chinese, Chinese Assam and Japanese tea, and currently represent a great genetic diversity. As a result of the breeding work, many domestic and foreign cultivars were allocated. The biological features of the tea plant associated with a long period of seed maturation, rapid wilting of flowers, softness of the stigma and pistil, high inbred depression, autogamy, allogamy, self–incompatibility, high heterozygosity and heterogeneity - all this makes crosses difficult and leads to low fruit seed-setting rate (2–25 %). The purpose of this study was to assess the potential of controlled hybridization of Caucasian tea genotypes. Pollen collected in September showed low viability (10.5–19.2 %) compared to pollen collected in October (70 %). Storage at 15 o C was better for pollen viability than storage at +4 oC. Six crossing combinations were evaluated with 23-52 % successful fruit setting; at the same time, the genotype significantly influenced the fruit setting rate. It was found that the Adygei population ♀ × ♂ ‘Karatum’ turned out to be the best crossing combination. In this combination, 650 pollinated flowers produced 336 fruits, and 540 full seeds gave rise to 234 successfully germinated plants. Our results will serve as a basis for mapping the germplasm populations of Caucasian tea plants.