Researches with caupi bean, Vigna unguiculata (L.) Walp., indicates the possibility to obtain stable genotypes with broad adaptation to climate and soil, on high productivity, especially with the use of irrigation. The aim of this was to evaluate the yield and its components in 20 genotypes of caupi bean. Seventeen lineages and three cultivars of caupi bean were evaluated in a rainfed cultivation and in an irrigated cultivation, in two experiments. At Teresina-Piauí, in the period of April to December in 2006, on the experimental field of the Middle-north Agricultural Research Center (CPAMN) of Embrapa (Brazilian Company of Agricultural Research) in the Middle-north region. It was used the randomized block design with four replications. The evaluated characters were: initial flowering (FI), length of the main branch (CRP), number of nodes in the main branch (NNRP), number of lateral branches (NRL), layering (ACAM) and productivity (PROD). The MNC99-541F-15, TE96290-12G, MNC99-547F-2, MNC99-510F-16 and TE97-304G-12 lineages and, the BRS-Marataoã and BR-17 Gurguéia cultivars showed the largest productivities in rainfed cultivation. From another standpoint, the MNC99-542F-5, TE96-290-12G, TE97-304G-12, MNC99-541F-18, TE97-309G-24, MNC99510F-16, TE97-304G-4, MNC99-547F-2, MNC99-510F-16 lineages and the BRS Paraguaçu cultivar stood out in the irrigated cultivation. The lineages TE96-290-12G, MNC99-510F-16 and TE97-304G-4 showed good productive levels in both cultivation systems.
