Chilling Resistance in Lycopersicon hirsutum Humb. & Bonpl., A Wild Tomato With a Wild Altitudinal Distribution

Abstract

Chilling resistance and other adaptations to low temperature were investigated in the wild tomato, Lycopersicon hirsutum, and the domestic tomato L. esculentum. Chilling resistance was assessed by the ability of seedlings to survive and grow after being exposed to 0°C for several days. For geogra- phical populations of L. hirsutum, chilling resistance was greatest in those derived from the higher altitudes. Other characteristics that correlated with the altitude of origin of the different populations were the rate at which the seeds germinated at low temperatures and chlorophyll development at low temperatures. L. esculentum cv. Rutgers did not tolerate chilling well and, in this respect, resembled low-altitude populations of L. hirsutum. L. hirsutum is a suitable species for physiological studies of chilling resistance, and its altitudinal variants are potential sources of genes 'tailored' to different temperature environments. Methods based on the above-mentioned responses to chilling may enable selection of chilling-resistant seedlings from hybrids of L. esculentum and L. hirsutum.