Phenotypic variability and genome-wide association studies in potato (Solanum tuberosum L.) for phosphorus efficiency

BACKGROUND: Potatoes require phosphorus (P) for growth, tuber production and starch quality, but their small and shallow root system limits the nutrient acquisition. This results in excessive use of mineral P fertilisers, leading to environmental and economic concerns due to resource depletion. Identifying potato genotypes with high P efficiency and understanding the underlying genes responsible are crucial for molecular breeding and crop improvement. The present study aims at exploring the phenotypic and genotypic variation among potato genotypes from Gross Luesewitz Potato Collections (GLKS) and identifying markers significantly associated with P efficiency. RESULTS: Phenotypic characterisation of a diversity set of 200 potato accessions for their response to P deprivation in a pot experiment showed a significant variance regarding biomass production, root length, plants height and P efficiency between the genotypes, with moderate to high heritability for these traits. Shoot biomass decreased by 66% on average under low P, while the root biomass decreased by 36% on average. The extent of the reduction was genotype specific, with some genotypes exhibiting higher root biomass and longer root length under low P than in control conditions. Outstanding genotypes were identified such as GLKS 11,578 (Kristall) with a dense and shallow root system or GLKS 10,591 (Tiger) with a long and extensive root system. Genome-wide association analysis identified 27 unique significant marker-trait associations including 13 associated with biomass, 3 with plant height and 11 with P efficiency, with a majority of them related to P utilization efficiency (7) and shoot biomass (11). CONCLUSION: Our research is one the firsts to present a genome-wide association study in potatoes for P efficiency. Our study highlighted significant phenotypic variation among the genotypes, while promising targets for improving P efficiency traits in potato through genomic selection and marker-assisted breeding.