Interspecific grafting of tomato (Solanum lycopersicum) onto wild eggplant (Solanum torvum) for increased environmental tolerances

Abstract

Two tomato scions (`Celebrity' and `CLN3212A') were grafted onto eggplant rootstock to determine the effect of interspecific grafting on flood and drought tolerance of tomatoes. Wild eggplant <italic>Solanum torvum<italic/> was selected as the interspecific rootstock of interest, and was compared against `Maxifort', self-grafted and non-grafted control rootstock in flood stress, drought stress, and optimal soil moisture conditions. Plant height, internode length, and stomatal resistance of all scion/rootstock combinations in each environmental condition were measured for 25 days. No significant differences in plant height, internode length and stomatal resistance among related scion genotypes occured in optimal conditions. In flood conditions, Celebrityx<italic>S.torvum</italic> had significantly shorter height and internode length, and reduced visible symptoms of deoxygenation stress. Drought conditions revealed that plants grafted on all rootstock genotypes except <italic>S. torvum</italic> had permanently wilted by day 22, while no plants grafted onto <italic>S. torvum</italic> wilted for the duration of the experiment. Further research is needed to determine if the observed resistance to flood and drought conditions conferred by <italic>S. torvum</italic> would also effect flower bud initiation, fruit set and yield.