Physiology and Grain Yield of Common Beans under Evapotranspirated Water Reposition Levels

Abstract

The aim of this work was to evaluate gas exchanges, photochemical efficiency and yield of common bean grains (crioula variety) grown under different irrigation levels in the state of Alagoas. The experimental design was a randomized block design with four replications. Treatments were composed of crop evapotranspiration fractions (25, 50, 75, 100, 125 and 150% of crop evapotranspiration). Gas exchanges were determined from measurements of internal CO2 concentration, transpiration, stomata conductance, photosynthetic rate, instantaneous water use efficiency and instantaneous carboxylation efficiency. Chlorophyll a fluorescence evaluations were determined through the potential and effective quantum yield of photosystem II. Chlorophyll content was indirectly measured. The following production components were evaluated: number of pods per plant, number of grains per pods, mass of 1000 grains and grain yield. The water application variation promoted a significant difference for gas exchanges, causing a reduction in the potential and effective photochemical efficiency of common bean. The increase in the application of the irrigation levels directly influenced the SPAD index and the following production components: number of pods per plant and grain yield, obtaining significant values with irrigation level of 125% of ETc.