Growth capacity in wild tomatoes and relatives correlates with original climate in arid and semi-arid species

Wild tomatoes and relatives (Solanum sect. Lycopersicon, sect. Lycopersicoides and sect. Juglandifolia) constitute a recently derived clade inhabiting a wide range of habitats across latitudinal and altitudinal axes in South America, with important variation in plant morpho-physiological traits. It is not clear to what extent growth capacity and related traits depend on phylogenetic constraints, or are driven by each species’ adaptation to the climate of origin. The use of wild tomatoes to improve the adaptation of the domesticated species to variable environmental conditions requires knowledge on which wild species are most suitable for growth capacity improvement. Under common garden conditions, results show that the relative growth rate (RGR) in the tomatoes is better determined by its physiological (net assimilation rate, NAR) rather than morphological (leaf area ratio, LAR) component. Moreover, RGR is correlated with the climate of origin in arid and semi-arid habitat species, and display different biomass allocation strategies depending on the climate, particularly related to the green and senescent leaf fractions. When grown under the same conditions, the domesticated tomato showed important differences in leaf size and leaf mass per area (LMA) as compared to its wild relatives, suggesting modifications related to the domestication process. Several semi-arid species appear as suitable species to improve the domesticated tomato growth capacity under more arid cultivation conditions, as those predicted by climate change.