Abstract

Rubus breeding, implemented by Mylnefield Research Services Ltd (MRS) at SCRI, is currently focused on red raspberries, although some work also continues on blackberries, blackberry-raspberry hybrids and novel fruits such as yellow/amber raspberries. The objectives of the programme are two-fold: first to enhance the germplasm available to commercially orientated breeding programmes and second to breed commercially acceptable summer-fruiting raspberry cultivars, suitable for mechanical harvesting, for all sectors of the UK and European industry. Under commercial funding from Scottish Soft Fruit Growers Ltd nineteen breeding lines, with various characteristics, were selected as potential new cultivars. After extensive field trialling at SCRI, four selections have been identified as most promising and will be released as cultivars in the near future. A key objective of the breeding programme is to incorporate resistance/tolerance to pest and disease. Of paramount importance is the development of cultivars with resistance to raspberry root rot, caused by the fungus Phytophthora fragariae var. rubi. Approximately 25% of the SCRI programme is dedicated to breeding for resistance or tolerance to Phytophthora, using resistance genes from R. strigosus. Genotypes have been identified with putative resistance and these are undergoing further evaluation to enable the eventual release of a tolerant cultivar with commercial fruit quality. Future breeding plans with respect to Phytophthora resistance are underpinned by the development of molecular markers, mainly SSRs, to improve and accelerate selection efficiencies.