Institut für Züchtungsforschung an Obst
The cultivated apple Malus domestica Borkh. is the Germans' favorite native fruit and is one of the most economically important fruit species worldwide. However, German apple production faces a variety of challenges. Sustainable production, eco-logization of agriculture and resilience to the effects of climate change are just some of the demands that producers have to face, in addition to growing international competition in the market. To meet these demands, an alliance of institutional apple growers and many of the currently existing private breeding initiatives, the Fachgruppe Obstbau im Bundesausschuss Obst und Gemüse and the Fördergemeinschaft Ökologischer Obstbau e.V. (FOEKO) is aspired, which wants to face the challenges together. In first online meetings, the framework of such a growers' association has already been agreed upon. The aim of this association is to promote the targeted and systematic breeding of site-adapted varieties in all breeding initiatives in Germany through the exchange of breeding material, knowledge and know-how. The aim is to enable German fruit-growing to make the transition to environmentally and climate-friendly cultivation systems in order to make it enhance internationalcompetitivity by providing high-performance varieties. The first common goal of this assciation is to breed apple varieties with resistance to apple powdery mildew (Podospheara leucotricha) and apple scab (Venturia in-aequalis). Control of these pests requires up to 20 pesticide treatments per season in commercial orchards, corresponding to a treatment index of 26 (Roßberg and Harzer 2015). This is expected to increase due to climate change. Due to the fact that many known resistances are already broken and modern apple cultivars have a limited genetic variability, there is a need to discover new, unknown resistances in the genetic resources and to make them, as well as already known resistance genes, available to all partners for targeted breeding. To discover new resistance capabilities, infestations must be phenotyped in cultivar collections that have not been treated with fungicides for several years. The use of columnar apple cultivars also allows for increased resilience to drought stress and, in combination with resistance to the two pests, is seen as another way to address the above challenges. However, accumulating resistance genes in varieties requires the use of marker assisted selection (MAS). However, this is a major obstacle, especially for private breeding initiatives, as the necessary laboratory capacities are lacking and commissioning service providers is too expensive. Therefore, cost-effective and easy-to-use KASP (Competitive Allele-Specific PCR) assays are to be developed, which can be combined by all partners independently, depending on the breeding strategy. The implementation of the analyses can then be commissioned from independent suppliers. From this network, ApRésKlimaStress is a project initiated with the following objectives: 1. broadening the genetic base for fungal resistance in new German breeding by providing resistant breeding material from government breeding for private breeding programs, 2. development of new fungal resistances from the available genetic resources of M. domestica and the apple wild species M. orientalis, 3. testing the possibility of transferring promising non-host resistance (NWR) to apple scab from pear to apple using existing apple-pear hybrids; and 4. establishing and providing KASP assays for targeted and cost-effective selection of genotypes with multiple (partly pyramidized) resistances that can be used by all breeders.
Federal Ministry of Food and Agriculture
