Plant breeding for increased seed yield in red clover

Access to high-quality forage with good protein content, to which red clover makes an important contribution, is crucial for the production of meat and milk in agriculture. Forage cultivation depends on the availability of seeds. Since forage crops are the most widely grown crops in Sweden, this involves large volumes. Crops with high and consistent yields are fundamental to a sustainable and circular food production system. A reliable supply of seed ensures a competitive food value chain and is one of the cornerstones of the profitability of Swedish farms. Forage is also a perennial crop that contributes to carbon sequestration in the soil, as it does not require annual tillage.

In red clover, seed yield is influenced by many factors, including the availability of pollinators, cultivation practices, and varietal differences (such as ploidy level). The goal of the project is to identify stable associations between seed yield and genomic data that can be used in future breeding programmes based on genomic selection. The project consists of three components that together will generate knowledge to improve the efficiency of red clover selection in plant breeding programmes.

• Large-scale field trials will be established at three locations in southern and central Sweden to evaluate seed yield across different red clover varieties. These trials will also include the development of methods for measuring flower density using drones.
• Smaller field trials and greenhouse experiments will be conducted to study in detail how the genetic traits of individual plants relate to physical characteristics such as floral scent and nectar production.
• Genetic analyses based on genomic data generated in the adjacent project Genomic selection in red clover will enable the identification of genes and genetic markers associated with desirable traits that contribute to increased seed set.

The project will also connect with other initiatives, such as Resistance breeding for healthy crops, which for red clover focuses on resistance to root rot and clover rot, and Faba bean for future food and feed, as faba beans also depend on pollination.

The project includes participants from both SLU Alnarp and SLU Umeå, as well as from Lantmännen and Sveriges Frö- och Oljeväxtodlare. The project will also contribute to competence development in plant breeding by involving students at various levels, alongside senior professionals from both academia and industry.