GGE analysis and stability of traits in tomato cultivars grown under organic farming conditions: A two-year study

Abstract

The increasing conversion of agricultural land to organic farming requires the development of specifically adapted cultivars. So far, in tomato there is lack of research for selection of germplasm suitable for sustainable agroecosystems. In this study, we investigated the genotypic and environmental factors affecting the variation of plant, fruits, and root traits in 39 tomato genotypes grown under organic farming conditions. Four independent experiments were conducted in Italy and Spain across two consecutive seasons in 2019 and 2020. For all traits, the factorial linear regression model to estimate the main effects of genotype (G), location (L), year of cultivation (Y) and their interactions, revealed highly significant (P < 0.001) variations, with the G factor being largely predominant for most traits. The implementation of the “which-won-where”, “mean performance versus stability” and “discriminative vs representativeness” patterns in the GGE (Genotype plus Genotype by Environment interaction) analysis, allowed the identification of superior cultivars with high stability across the testing environments. Genomic characterization with 30 890 high quality SNPs from ddRADseq genotyping analysis, revealed that a specific cluster of cherry tomato accessions were low performing in terms of yield and fruit weight, on the contrary, showed a high content of soluble solids, which in agreement with GGE analysis. Results of this study provide a framework for the potential use of this locally adapted tomato germplasm to address the needs of more sustainable agriculture.