Peppers are an essential ingredient for many cuisines and contribute flavor and spice to our dishes. Peppers are a biodiverse crop, and thousands of accessions belonging to five major cultivated species are conserved in genebanks all over the world. WorldVeg contributed more than 4,000 pepper accessions to the Horizon2020 project G2P_SOL (Linking genetics resources, genomes and phenotypes of solanaceous crops), that investigated the diversity of pepper (as well as of tomato, potato and eggplant) to find genetic diversity that will help researchers and plant breeders to find traits that will allow new varieties of these crops to be better adapted to changing environments, emerging pests and new markets. The G2P-SOL research team looked into the genetic architecture of important agronomic traits to understand the variation of fruit flavor, color, size and shape, and the genomic functions contributing to plant productivity, vigor and precocity.

The results were published in the December edition of the Plant Journal (https://doi.org/10.1111/tpj.16425), and a small sample of the diversity of fruit shape and the genetic base of this variation can be seen on the the journal cover.

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SUMMARY

Investigating crop diversity through genome-wide association studies (GWAS) on core collections helps in deciphering the genetic determinants of complex quantitative traits. Using the G2P-SOL project world collection of 10 038 wild and cultivated Capsicum accessions from 10 major genebanks, we assembled a core collection of 423 accessions representing the known genetic diversity. Since complex traits are often highly dependent upon environmental variables and genotype-by-environment (G × E) interactions, multienvironment GWAS with a 10 195-marker genotypic matrix were conducted on a highly diverse subset of 350 Capsicum annuum accessions, extensively phenotyped in up to six independent trials from five climatically differing countries. Environment-specific and multi-environment quantitative trait loci (QTLs) were detected for 23 diverse agronomic traits. We identified 97 candidate genes potentially implicated in 53 of the most robust and high-confidence QTLs for fruit flavor, color, size, and shape traits, and for plant productivity, vigor, and earliness traits. Investigating the genetic architecture of agronomic traits in this way will assist the development of genetic markers and pave the way for marker-assisted selection. The G2P-SOL pepper core collection will be available upon request as a unique and universal resource for further exploitation in future gene discovery and marker-assisted breeding efforts by the pepper community.

McLeod L, Barchi L, Tumino G, Tripodi P, Salinier J, Gros C, Boyaci H, Ozalp R, Borovsky Y, Schafleitner R, Barchenger D, Finkers R, Brouwer M, Stein N, Rabanus-Wallace M, Giuliano G, Voorrips R, Paran I, Lefebvre V. 2023. Multi-environment association study highlights candidate genes for robust agronomic QTLs in a novel worldwide Capsicum core collection. Plant Journal, 1-21. https://doi.org/10.1111/tpj.16425