Overcoming linkage drag in Sorghum bicolor

Sorghum bicolor (L.) Moench has remarkable resilience to heat and drought, traits that are highly relevant to mitigate the effects of climate change and make it a promising future crop for temperate regions. However, sorghum, which originated in Africa, has been and still needs to be adapted to temperate conditions, such as long days or cold temperatures. Adaptation of sorghum to temperate long-day conditions in Europe relies on a narrow pool of trait donors, for example for photoperiod insensitivity or cold tolerance, which promotes linkage drag associated with essential adaptation loci. This project focuses on finding ways to minimise this linkage drag to improve future sorghum breeding efforts.
The first step of the project is to investigate the effect of increasing intrachromosomal recombination rates during meiosis on genetic gain and other factors as breeding progresses. While higher recombination rates can break unfavourable linkage and increase genetic potential, the effects, particularly on genomic predictability, are not fully understood. Using AlphaSimR simulations, we evaluate how increased recombination affects prediction accuracy, genetic gain and marker density requirements to find a balance that maximises breeding success. Building on this, a possible way to increase recombination rates in sorghum plants will be investigated. By applying temperature stress during meiosis, I am assessing whether a natural increase in recombination rates is possible in sorghum. After applying the stress in climate chamber experiments, markers will be used to track recombination events, providing valuable insights into stress-induced genetic variation in sorghum. Finally, the possibility of optimising breeding programmes to minimise linkage drag during trait introgression in the future will be investigated. By simulating different introgression approaches, we are developing resource-efficient breeding strategies tailored to underutilised crops such as sorghum.