Parâmetros fisiológicos e componentes de produção de feijão-caupi cultivado sob deficiência hídrica

Abstract

The objective of this study was to evaluate gas exchange and this yield components of cowpea cultivars under different levels of water stress in the semiarid Paraiba. The experimental design was randomized blocks factorial 3 × 4, with three replications. In the factor A allocated to the three varieties of cowpea BRS Guariba, BR17 Gurguéia and BRS Marataoã and the B four irrigation levels established in terms of fractions of the reference evapotranspiration (40, 60, 80 and 100% of ETo) and three replicates. Gas exchanges were determined from measurements of internal CO2 concentration, transpiration, stomatal conductance, photosynthetic rate, instantaneous efficiency of water use and instantaneous carboxylation efficiency. As for yield components was evaluated mass of pods, number of seeds per pod, weight of 100 grains and grain yield. The cowpea cultivar 'BRS Guariba', regardless of irrigation, has better performance of gas exchange with a positive impact on production components. The highest rates of physiological cultivars 'BRS Guariba' and 'BRS Marataoã' blades were found with 40% of ETo, which may reflect more tolerance to drought.