Periodic Reporting for period 1 - MEICOM (Meiotic Control of Recombination in Crops) Reporting period: 2018-01-01 to 2019-12-31 Summary of the context and overall objectives of the project Genome structure of the parental species is a crucial factor directly influencing crossing success. This project will apply state-of-the-art technologies such as optical mapping (BioNano Genomics) and synthetic reads (10x Chromium, PacBio, Sequel) aiming to disclose crossover frequency within haplotypes, genome structure and structural variation in parental lines and offspring of crops such as tomato, potato, melon, and lettuce and offspring generations. This knowledge is essential for the selection of compatible breeding parents. Sequence features influencing recombination in these various crops will be obtained using state-of-the-art machine learning approaches. The link between structural diversity, genetic diversity and haplotype meiotic crossover frequency with functional characteristics (QTL) for particular agronomic important traits will be assessed. Plant breeding would have to increase crop yield and crop resilience to biotic and abiotic stresses during the next decades to ensure Food Security. Crop improvement by plant breeders in Europe is exceedingly reliant on harnessing the natural genetic variation and recombination that arises during the meiotic process. The formation of genetic crossovers create new combinations of alleles that could confer new phenotypes/traits on the next generations. This genetic variation can be exploited by plant breeders to produce new crop varieties. Nevertheless, in most plant species, remarkably important crops, recombination is limited to some regions of the chromosomes. For instance, in cereals has been estimated that 30-50% of their genes very rarely recombine. This is a serious problem for plant breeders as they are unable to access all the potential genetic variation within the species. MEICOM is designed to achieve an understanding of the factors that influence the transitions from DSB formation to CO product in crops and evaluate the most effective approaches to manipulating this outcome by capitalizing on our expert knowledge of meiotic recombination in plants combined with cutting-edge methodological developments. To achieve this important and ambitious goal we have assembled a network of leading European plant meiosis research groups that possess a wide range of complementary research skills plus an excellent track record of synergistic interactions through collaborative research and training networks such as MEIOSYS, RECBREED and COMREC. The training of ESRs involves the commitment of stakeholder breeding companies who are providing first-hand insight into the major challenges that confront the industry over the next decade, thus ensuring a strong intersectorial component that can be consolidated and further developed. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far MEICOM research training is organized into 3 research workpackages (WPs 1-3) together with a Training WP (WP4) a Dissemination and Outreach WP (WP5) and a Management WP (WP6). Successful delivery of the WPs and the research projects requires close integration of experimental, technical and bioinformatics skills which is ensured through the assembly of our multidisciplinary academic network and associated industrial partners. Each ESR has been recruited to and is primarily based in one of the MEICOM partner institutions, focusing on one of the three research WPs. ESRs have agreed to do several secondments to partner laboratories with complimentary expertise and to one of the non-academic sector partners or beneficiaries, thus ensuring a truly intersectoral and multidisciplinary research network. WPs 1-3 comprises of 12 ESR projects. The progress reports of their achievements up to date is summarized within the uploaded Draft Technical Report Part B Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) MEICOM enhances human resources by bringing together leading experts working across different disciplines in the academic and private sectors to build a multidisciplinary training and research programme for the improvement of plant breeding by studying the control of meiotic recombination in different crops. The research programme encompasses complementary disciplines such as genetics, biochemistry, cytology, bioinformatics, microscopy and plant breeding in a variety of different crops, and provides exposure to the private sector in a highly research-driven environment.