Recent progress in Polish black raspberry breeding at the Niwa Berry Breeding Ltd.
Black raspberry breeding has been conducted at Niwa since 2012. In 2017 the program was expanded and supported by government and EU funds. Every year 70-140 crosses are made and around 15,000 seedlings planted. The stringency of the selection is 1%. The most important element in the evaluation of new clones is determining the degree of self-fertility, which indicates suitability for further use of the clone in the breeding process. In the evaluation process, 14 clones were compared with Niwot and Jewel. The best was the primocane purple raspberry clone R139501 [((R. occidentalis × R. idaeus) × R. idaeus)×op], which had a yield of 1200 g plant‑1, mean fruit weight of 3.1 g and 11.6 °Brix. In open pollination conditions, this clone had 99.3% ovule fertilization. The first observations indicate a high degree of self-fertility, but verification in commercial plantation conditions is needed. In 2018, 20 seedling selections were black fruited. They were derived from the black and purple cultivars Litacz, Jewel, and Glen Coe and purple clones derived from Niwas breeding. Clones were identified in the first round of selection that had canes with 1/3 and to 1/2 primocane fruiting. In addition, selections with mean fruit weights of 5.3-5.6 g were identified. Among these selections, clone R1422505 had the highest sugars at 15.5 °Brix.
Orzeł, A., Król-Dyrek, K., Jagła, J., Lech, W., Bieniasz, M. and Krośniak, M. (2020). Recent progress in Polish black raspberry breeding at the Niwa Berry Breeding Ltd.. Acta Hortic. 1277, 55-64
primocane black raspberry, pollen growth, fruit set