Yield and fruit quality attributes of selected tomato introgression lines subjected to long-term deficit irrigation

Breeding for high-yielding genotypes with enhanced fruit quality under challenging environmental conditions such as reduced water supply will be the next target of tomato breeders in the nearby future. In this study, we assessed yield and a broad set of fruit quality attributes in four Solanum pennellii introgression lines, previously selected according to their drought resistance at seed level (IL 3-5 and IL 10-1, considered drought-resistant, and IL 7-1 and IL 2-5, considered drought-sensitive), under two distinct irrigation regimes, a deficit irrigation (DI) and an optimum irrigation (OI) treatment where plants were kept at 50 and 100% available soil water throughout the whole plant flowering and fruiting stages, respectively. Water deficit decreased plant yield over 66% and mean fruit weight over 53%. Fruit quality, on the other hand, was improved as indicated by the increase in total soluble solids, fruit redness, fruit firmness, and lycopene content. Poor fruit quality in terms of fruit color and taste was observed for IL 10-1 under CH and DI, respectively. IL 3-5, on the opposite, displayed interesting high fruit firmness under DI. Quantitative trait loci (QTLs) for enhanced lycopene content were detected for IL 2-5 and IL 3-5 under CH and IL 2-5, IL 3-5, and IL 7-1 under DI. The presence of QTLs for reduced plant yield under DI in all studied ILs (IL 2-5, IL 3-5, IL 7-1, and IL 10-1) indicates no association between drought resistance at seed germination and initial development and plant productive stages. In sum, our study provides insights into the potential use of IL 2-5, IL 3-5, IL 7-1, and IL 10-1 for tomato improvement under both optimum and deficit irrigation conditions.