The objective of this study was to evaluate the components of production, productivity and irrigation efficiency of cowpea under irrigation in the 'Cerrado' of Roraima. The experiment was conducted at Experimental Farm 'Agua Boa'-EMBRAPA Roraima in cultivation on straw under irrigation by sprinkler from February to April and from September to November 2012. Five irrigation levels (30, 60, 90, 120 and 150% of the reference evapotranspiration - ETo) and three cowpea cultivars: (Guariba BRS, Novaera BRS and Pajeú BRS) were tested. The depths of irrigation established were based on fractions of the daily ETo (Pan Class A). The experimental design was in randomized blocks with treatments arranged in bands, split-plot, and five replications. The variables evaluated were: number of pods per plant, number of seeds per pod, weight of hundred grains, dry grain yield and efficiency of water use. It was observed that the variables of BRS Pajeú were not affected by treatments. Novaera BRS and BRS Guariba had the highest grain yield, 1275.19 and 1504.98 kg ha-1, respectively, with irrigation depths equivalent to 74.3 and 94.02% of ETo. The maximum irrigation efficiency was obtained with 30% ETo for all three cultivars.
Vigna unguiculata; savana; cultivars
