The Potential Resistance to Low Temperatures in Selected Solanum Species

Brief low positive temperatures in spring negatively affect early field tomato harvests. Low-temperature stress inhibits plant growth and negatively affects pollen viability, leading to a decrease in the yield of early tomato fruits. This study applied a comprehensive assessment method to evaluate cold-stress resistance in selected Solanum genotypes. Plant material comprised five wild accessions: Solanum pimpinellifolium (lines spr 1, spr 5), S. cheesmaniae and cultivated S. lycopersicum lines (sc 4, sc 3) and the varieties Sw-7 and Flora. The study aimed to evaluate wild tomato genotypes for cold tolerance using several modes of exposure to low temperatures. Since cold resistance is a polygenic trait, the identification of cold-resistant genotypes during several consecutive treatments with low temperatures and in different variants made it possible to select plants with greater cold resistance and a greater number of genes responsible for cold resistance, which is valuable for the climatic conditions of Ukraine. Authors evaluated “growth after stress” and “pollen viability” because recovery after cold exposure is critical for achieving an early harvest. Seeds and plants were exposed to multiple temperature regimes beginning at germination. Results indicated that spr 5 and sc 3 outperformed other genotypes in multiple cold-tolerance assays across developmental stages and exhibited high to moderate stability of resistance. Although average daily temperatures have risen with climate change in Ukraine, spring cold snaps still occur; therefore, studying cold resistance among tomato genotypes remains relevant for adaptation.