Cold Stress During Common Bean (Phaseolus vulgaris) Reproductive Stage: Effects in Physiological and Agronomic Parameters

Common beans have great nutritional importance, but because it is a cold-sensitive species, its production could be limited by low temperatures. As far as the authors know, there are no studies on the effect of cold stress on common beans during reproductive stage and how this stress affects grain productivity. Given this, the objective of this study was to evaluate physiological and agronomic responses of common bean cultivars exposed to cold stress during the reproductive phase. Two experiments were conducted with six common beans cultivars. One experiment was conducted in the field, with two sowing dates: one at the recommended time, and the other outside of this period. The second experiment was carried out in a greenhouse. The sowing was performed at the recommended date, in pots. When the plants reached the flowering stage, half of the pots were transferred to cold conditions for three days. In the second experiment, on the last day of stress, plant material was collected to measure soluble sugars, proline, catalase, superoxide dismutase and peroxidase content. In both experiments, yield components were analyzed at physiological maturity. Cold stress extended the common bean cultivars' growth cycle in the field. In both experiments, low temperature negatively affected grain yield components, reducing productivity. Furthermore, the results demonstrate that a lower superoxide dismutase enzyme activity when cultivars are exposed to cold stress is associated with a better performance of the cultivars in the cold group.