Tomato Landraces May Benefit from Protected Production—Evaluation on Phytochemicals

Plant genetic resources (PGRs) serving as a wide genetic pool of tomato germplasm can provide a solid base for recent breeding efforts to increase consumer acceptance towards the taste and the phytonutrient properties of novel tomato varieties. Old varieties and landraces were abandoned by producers due to unfavorable phenotypic characteristics; however, their high adaptability and nutritional properties are inevitably valuable. This study aims to investigate the impact of open-field vs. protected production on various bioactive compound parameters and on the antioxidant status of seven indeterminate-type tomato PGRs in an organic production system for two years (2015–2016). Genotype main effect plus genotype × environment interaction (GGE) biplots were created for visualizing the which-won-where concept of the PGRs investigated. The GGE analysis revealed that the phytonutrient content of certain PGRs is less dependent on location and more influenced by differences in microclimatic conditions. “Balatonboglár”, “Mátrafüred” and “Fadd” PGRs performed better in a polytunnel, while Tarnaméra provided better results in an open field. “Máriapócs” and “San Marzano” showed a relative independence from production location in terms of their measured phytonutrient values. These findings enrich the nutritional datasets of tomato landraces, which support the in situ conservation and utilization of PGRs in breeding programs.