COMMON BEAN RESPONSE TO HEAT STRESS IN DIFFERENT PHENOLOGICAL STAGES

Abstract

High temperature reduces grain yield of common bean (Phaseolus vulgaris L.) as a consequence of the abortion of reproductive structures. Heat stress was applied in common bean cultivars BRS Pérola and BRS Valente, in different phenological stages to verify grain yield reduction. Plants were grown in pots at 22C/18C day/night, 12/12 hours, without water and nutrients limitations and with preventive insect and disease control. At stages V4, R5, R7, and R8 plants were submitted to temperatures of 37C/25C day/night, 12/12 hours for 72 hours, in growth chamber and then returned to the initial conditions. Pod abortion was evaluated, and, at R9 stage, accumulated dry weight and yield components were evaluated. Heat stress applied at R5, R7 and R8 stage increased the number of pods per plant; however, grains per pod and dry weight per seed decreased. From the data obtained it can be concluded that incidence of high temperatures from R5 until R7 stages reduced grain yield and commercial grain quality of common beans.

KEY-WORDS: Phaseolus vulgaris; pod abortion; biomass yield; temperature.