Endodormancy in six blackcurrant (Ribes nigrum) cultivars

Abstract

The demand for blackcurrant (Ribes nigrum L.) has increased as consumers have become aware of the health effects of blackcurrant berry. New cultivars suitable for both fresh market and processing are needed. As the winter temperatures are increasing, one aim in major blackcurrant breeding programs is low chilling requirement and therefore a short endodormancy in new cultivars. However, in Northern Europe a long and deep endodormancy is required, so that growth does not resume during warm spells in winter, because possibly following hard frosts can damage plants. The aim of our study was to examine the depth of endodormancy and cold hardiness in six blackcurrant cultivars at different times during winter. Single shoots of the Lithuanian cultivars Almiai and Gagatai, Finnish cultivars Mikael and Mortti, and Scottish cultivars Ben Hope and Ben Tron were collected from the field in Southern Finland. The depth of endodormancy was determined as the percentage of buds broken during forcing and as the duration of time to bud break. Cold hardiness (LT 50 ) was measured with controlled freezing tests by exposing the samples to gradually decreasing temperatures in the freezing chamber. The effectiveness of different chilling temperatures on breaking of dormancy was studied in the two Finnish cultivars. The deepest dormancy was observed in the cultivars Almiai and Gagatai, while the shallowest dormancy was found in 'Ben Tron' and 'Mortti'. 'Ben Tron' was also the least cold hardy cultivar in our freezing tests, while 'Almiai' was very cold hardy. The effectiveness of chilling temperatures 0 °C, + 6 °C, + 12 °C and + 18 °C in breaking of endodormancy was studied under controlled conditions in 'Mikael' and 'Mortti' samples. In both cultivars, the most effective chilling temperature was 0 °C.

Creation of new initial forms of black currant (Ribes nigrum L.) in breeding for adaptation

“…It is known that the winter hardiness of currant depends not only on the characteristics of the variety, but also largely on the cultivation conditions [15,16,17]. In the conditions of the Bryansk region, the crop is quite hardy and able to withstand quite low temperatures.…”