WHAT'S GOING ON IN THE WORLD OF RUBUS BREEDING?

Only one more generation” has been the breeder’s cry in the past, the present and will continue in the future. As we look around the world, we are faced with many of the same challenges we have always faced as the industry needs cultivars with excellent quality, higher yield, greater pest resistance and adaptation. We rely on a mixture of strong science, a keen eye and traditional breeding approaches to meet these demands. As we move forward, old issues are resurfacing, new problems are arising, and whole new production systems, business systems, and production areas are being developed and will soon dominate parts of the industry. As breeders, we are asked to meet these demands with new cultivars. INTRODUCTION A recent survey indicated that there are roughly 30 Rubus breeding programmes, predominantly red raspberry, in 19 countries that will be a source of these new cultivars. New germplasm, molecular tools and active, imaginative breeders are helping us to attack old problems in new ways, adapt to the changing production and business systems of the international market, develop whole new crops such as primocane fruiting blackberries, and berries for completely new markets (e.g. nutraceuticals). Private companies with their own breeders and proprietary cultivars or public breeders with some part of their programme privatized are no longer an anomaly and no longer regional. They are driven and effective as they apply their skills far from home but the proprietary nature of the material leads to concern about long term effects on germplasm exchange. While administrators are primarily concerned with the potential monetary returns that patents will bring into a programme and use it as justification to decrease funding to programmes, breeders face the fact that few cultivars generate the amount of return that the administrators envision. While we are still largely using conventional approaches, good science, and a keen eye, the world of Rubus breeding continues to change. THE CURRENT SITUATION A survey was sent out to all known Rubus breeders in early 2001 to assess the state of their breeding programmes. While we know we are underestimating the world picture, the survey indicated that there are at least 30 Rubus breeding programmes in 19, primarily European and North American, countries that will be a source of new cultivars (Table 1). These programmes have produced at least 105 red raspberry and 50 blackberry cultivars in the past 20 years (Table 2). The bulk of these programmes emphasize red raspberry rather than blackberry. Within the red raspberry programmes, there are programmes solely devoted to floricane fruiting types but the emphasis on primocane fruiting types ranges from zero to 100% more compared to floricane types. There are about seven programmes that include black raspberry breeding but none cited black raspberries as their main programme. Of the 15 programmes that are breeding blackberries, only the USDA-ARS in Oregon and the University of Arkansas have large programmes and listed these as their primary Rubus breeding programme. These programmes work with two different blackberry types (erect and trailing) derived from very different species background. Despite budgetary cutbacks, most breeders reported that their programmes were either maintaining their current size or expanding. Breeding programmes vary in their mix of federal, state, commodity and royalty support. The portion of the support coming from the Proc. 8th IS on Rubus and Ribes Eds. R.M. Brennan et al. Acta Hort. 585, ISHS 2002 32 government is generally decreasing, with commodities being asked to pay more and royalties becoming more important. Many programmes feel that, while they have been able to maintain their programmes fairly well to date, more budget cuts will result in significant modification of their programmes. Unsurprisingly, the core primary objectives in raspberry and blackberry breeding programmes have remained consistent and include: high quality fruit, good yields, suitability for shipping if fresh market, machine harvestability and suitability for processing for the processing market, adaptation to the local environment and improved pest and disease resistance. In raspberry, resistance to Phytophthora fragariae var. rubi is a universal goal and with the loss of effectiveness of most root rot fungicides the need is even more acute. In our survey European programmes were very concerned with cane Botrytis, spur blight (Didymella applanata), and cane spot (Elsinoe veneta) on raspberry, but in America resistance to raspberry bushy dwarf virus (RBDV) was of much greater concern particularly in the Pacific Northwest where RBDV has reached epidemic proportions. Now RBDV has been found in ‘Marion’ blackberry and research has shown a substantial drop in yield for these infected plants. It is too early to tell, but we may soon have to begin searching for resistance in blackberry for RBDV. In blackberry, spineless types are essential and there are an increasing number of erect spineless cultivars. While there are only a handful of thornless trailing cultivars, it is expected that within a few years there will be a wider choice. As raspberries are grown in hotter, more humid climates, and blackberries are grown in colder climates, there is an increased effort to develop cultivars adapted to the biotic and abiotic stresses that come with these “new” environments. Molecular genetics, including transgenic technologies, has been cautiously added to the Rubus breeder’s toolbox. The public discourse on this subject has yet to run its course and until it does it will be difficult to embrace this technology fully. Survey responses ranged from strongly negative to actively positive, with RBDV-resistant transformed raspberries being tested in commercial fields. In addition to RBDV-resistant ‘Meeker’ and parthenocarpic ‘Ruby’, attempts have been made to develop other transformed raspberries. While regeneration tends to be easier in blackberry than raspberry, there were no examples of successfully transformed and regenerated blackberry. Transformation for greater cold tolerance has been successful in ‘Marion’, and attempts to regenerate transformed plants are underway. The programmes that were using molecular tools were most commonly looking at marker assisted selection, mapping, and genetic fingerprinting in raspberry. While not a molecular tool, techniques to utilize the power of flow cytometry have been developed and used to estimate ploidy and DNA content in Rubus, better plan crosses, identify truly hybrid progeny in wide crosses, and for taxonomic purposes. Most programmes have some of their program devoted to the evaluation and incorporation of species germplasm. At least 16 species, primarily raspberry types but many from Asia, have been evaluated and used as sources of new traits in Europe. In North America, at least 58 species have been similarly evaluated and the observations presented elsewhere in this Acta. While European efforts, particularly at Horticulture Research International (HRI), are generally further along in utilization of species material, there are examples of red and black raspberry cultivars recently developed in America that have species other than R. idaeus or R. occidentalis in their background. Species material has proven to be an outstanding source of pest and disease resistance and new or novel traits. The tremendous diversity of wild Rubus germplasm suggests that there are many other potential sources of new traits. Since this germplasm pool is so dauntingly large, it serves as an excellent example where cooperation and continued germplasm exchange is essential. No one programme can do it all. As an example, R. innominatus has been identified by at least four N. American programmes as being an outstanding species to work with and yet it does not appear to have been evaluated in Europe. Instead of recreating the wheel, germplasm containing this R. innominatus background should be sent to Europe. European material with the Asiatic species R. cockburnianus, R. crataegifolius and R. lasiostylus in its background was sent to N. America from HRI 20 years ago. 'Kitsilano', which was derived from 'Comox' and an HRI R. crataegifolius selection, was the first cultivar to be released with R.