Cowpea cv BR17 Gurguéia yield inoculated with symbiotic diazotrophic bacteria in Piauí

Abstract

Cowpea bean is an important culture for the North and Northeast regions in Brazil for its adaptability to soilclimatic changes and for being one of the  main protein sources for these regions population. Therefore, this work aimed to select symbiotic diazotrophic bacteria strains to be used as inoculants for Cowpea bean (Vigna unguiculata (L.) Walp) cultivation, in the Middle North region of the Piauí State, Brazil. The experiment was installed into Middle North EMBRAPA Experimental Station, located in the municipality of Teresina, PI, Brazil. Treatments consisted of four strains inoculations recommended by the Ministry of Agriculture, Livestock and Food Supply (MAPA) for cultivation of the cowpea bean INPA 03-11b (BR 3301), UFLA 03-84 (BR 3302), BR 3267 and BR 3262, and also the strain BR 3299 to be tested, two witness with nitrogen fertilization addition (50 kg ha^-1 during plantation and; 80 kg ha^-1, 40 kg during plantation and 40 kg in covering layer 30 days after plantation) and one witness without nitrogen adubation and without inoculation. Recommended strains INPA 03-11b (BR 3301), BR 3267, BR 3262 and BR 3267 and the tested strain BR 3299 responded satisfactorily to agronomic efficiency tests and presented high potential for use as inoculants for cowpea bean in the Middle North region of Piauí.