The objective of the present study was to evaluate the productive characteristics of three castor bean cultivars under different levels of drip irrigation. This work was carried out at the Experimental Farm Vale do Curu, Pentecoste (CE). The experiment was conducted in randomized block design in split plots, with factorial scheme consisting of 5 irrigation levels and 3 cultivars. The levels of irrigation were based on evaporation of the Tank Class "A" - ECA (T1 = 0.25 ECA; T2 = 0.50 ECA; T3 = 0.75 ECA; T4 = 1.00 ECA; T5 = 1.25 ECA). The variables length and number of fruits per racemes were higher for the IAC Guarani, while the content of oil and number of racemes per plant were higher for the Mirante 10. However the Paraguaçu BRS stood out in comparison to other cultivars as for the mass of one hundred seeds and productive potential. The irrigation levels influenced in increasing the variables of production. The best water use efficiency was obtained in the treatment T5 (913.4 mm) in the BRS Paraguaçu, resulting in productivity of 2,872.42 kg ha-1. The secondary racemes were the ones that most contributed to the total productivity.
Ricinus communis L.; semi-arid; tank class "A"
