Genetic and phenotypic evaluation of european maize landraces as a tool for conservation and valorization of agrobiodiversity

The ECPGR European Evaluation Network (EVA) for Maize involves genebanks, research institutions, and private breeding companies from nine countries focusing on the valorization of maize genetic resources across Europe. This study describes a diverse collection of 626 local landraces and traditional varieties of maize (Zea mays L.) from nine European genebanks, including criteria for selection of the collection and its genetic and phenotypic diversity. High-throughput pool genotyping grouped the landraces into nine genetic groups with a threshold of 0.6 admixture, while 277 accessions were designated admixed and likely to have resulted from previous breeding activities. The grouping correlated well with the geographic origins of the collection, also reflecting the various pathways of introduction of maize to Europe. Phenotypic evaluations of 588 accessions for flowering time and plant architecture in multilocation trials over three years confirmed the great diversity within the collection, although phenotypic clusters only partially correlated with the genetic grouping. The EVA approach promotes conservation of genetic resources and opens an opportunity to increase genetic variability for developing improved varieties and populations for farmers, with better adaptation to specific environments and greater tolerance to various stresses. As such, the EVA maize collection provides valuable sources of diversity for facing climate change due to the varieties’ local adaptation

Genome-wide association studies on DNA pools identifies promising maize landraces and genomic regions to develop next generation varieties

International audienceLandraces have a large diversity that could help to cope with climatic change and low input agriculture. To identify promising maize landraces and genomic regions to enlarge the genetic diversity of modern varieties, the DNA pools of 156 American and European landraces as well as 264 French landraces were genotyped with a SNP array. French landraces were evaluated for different agronomic traits. They were compared to elite cultivars produced across 20th century, represented by 327 inbred lines. We identified several genomic regions involved in agronomic traits, environmental adaptation, tolerance to abiotic stresses by detecting selective footprints and studying association with both environmental variables and agronomic traits. Promising landraces were identified by estimating their genomic contribution to inbred lines and by genomic selection. Most landraces do not have closely related lines while 10 landraces have a lot and cumulated half of the total contribution to inbred lines

Genomic prediction and landscape genomics in a large maize landraces collection using high-throughput pool genotyping identifies promising sources of diversity for prebreeding

Maize landraces are a valuable source of genetic diversity for facing climate change due to their local adaptation. High-throughput pool genotyping (HPG) is a cost-effective approach to genotype maize landraces and identify promising sources of alleles for tolerance to abiotic stress. We applied this approach on a large world-wide collection of maize landraces to i) characterize its genetic structuration; ii) identify genomic regions involved in adaptation through environmental association studies; iii) perform genomic prediction (GP) of both adaptive and agronomic traits. Landraces were structured according to their history and environmental conditions. GP yielded high accuracy, allowing to identify promising landraces. We identified genomic regions associated with bioclimatic variables that could be putatively involved in adaptation to abiotic stress. Combining eco-genetic and genomic prediction opens an avenue for using these genetic resources for prebreeding