Humidity Restriction, High Night Temperature and their Combination, during Post Flowering on Common Bean (Phaseolus vulgaris L.) Canopy and Pod Senescence

Abstract

Background: Common bean (Phaseolus vulgaris L.) grain filling is vulnerable to drought and heat stress. The objective of the study was to evaluate the effect of humidity restriction, high night temperatures and their combination in common bean.Methods: The plants were grown in pots at maximum field capacity (100% FC) until the grain filling began. Afterwards, maintained until harvest at: 1) 100% FC, 2) 50% FC at ambient day/night temperature (AT), 22.58°C/16.94°C, 3) 100% FC with high night temperature (HNT) 21.47°C and 4) 50% FC with HNT (combined stress). Evaluations included phenotypic assessment using red-green-blue color segmentation in: green (healthy), yellow (senescence) and brown (necrotic). Result: The combined stress in the cv. Rosa Bufa significantly and synchronously accelerated leaves and pods senescence. In contrast, in leaves of cv. OTI, the loss of green color began several days earlier than in pods. The effect of HNT and combined stress depends on common bean cultivar.