Evaluation of the main biological and production traits of Latvian apple cultivars in the conditions of Central Russia

Apple selections of Latvian breeding were evaluated in the Central zone of Russia since 1980, in total 32 cultivars and hybrids. After long-term evaluation, the following can be recommended for use in breeding of scab resistant cultivars with high quality fruits - ‘Dace’ (gene Rvi6), ‘Arona’, and good storage - ‘Edite’ (Rvi6), ‘Forele’, ‘Olga’, ‘Маdоna’, for breeding of early cultivars - ‘Roberts’ and DI-93-4-8, both resistant to scab (gene Rvi6) and fruit rots. Cultivars and hybrids with the best cold resistance of vital tissues were selected by artificially modelling winter-hardiness components − early colds (1st component) and mid-winter colds up to -38 °C (2nd component), showing reversible damages not exceeding 2.0 points: ‘Daina’, ‘Ella’, ‘Atmoda’, ‘Gita’, ‘Saiva’, of which the last 3 maintained high hardiness of bark, cambium and xylem with slight increase of bud damages also at -40 °C. Cultivars ‘Daina’ and ‘Ella’ showed resistance of buds and vital tissues on the level of ‘Antonovka’ after modelling a thaw with following freezing to -25 °С (3rd component), which suggests tolerance to fluctuating winter temperatures. These cultivars demonstrated good adaptation to different environment conditions and may be considered in breeding of new adaptive apple cultivars with high fruit quality