Crescimento, trocas gasosas e produtividade de genótipos de feijão-caupi sob lâminas de irrigação.

Abstract

Proper irrigation management takes unto account the depth of the water is the most suitable for the water supply, avoiding reduce plant growth and, consequently, yield components, quality and grain yield. This study aimed to evaluate the growth, gas exchange and productivity of cowpea genotypes under the application of difTerent irrigation. The experiment was conducted under field conditions in the Agrifood Center of the Federal University of Campina Grande, Pombal Science and Technology - PB. The experimental design was a randomized block in a factorial 4 x 5, with tour replications. The fírst factor was formed by tour cowpea genotypes (Rib of Cow, Golden Pingo, Paulistinha and BRS Marataoã) and the second factor of ave leveis of irrigation (40, 60, 80, 100 and 120% of actual evapotranspíration). The experimental unit consisted of tour working planta in the plot. The variables related to plant growth were analyzed atem diameter at 15 and 30 days after sowing (DAS), number of leaves per plant at 1 5 and 30 DAS, the absolute growth rate and relative diameter and number leaves the biomass in the different plana organs such as leaves, petioles, stems, roots and nodules. Rate in relation to the variables related to gas exchange in the plant were evaluated photosynthesis (A), transpiration (E), stomatal conductance (gs), intemal carbon concentration (Ci), intrinsic efl:iciency of water use ( USA) and the intrínsic efficiency carboxylation (EiCI) and eventually crop yield. The cowpea bean leaves is the most sensitive variable to water stress. The blade 120% ETR proposed a greater increase in mass and number of sheets forming independent genotypes. The Cow Rib genotype best expressed in CO2 assimilation rate. The Paulistinha had the highest productivity among genotypes.