CHARACTERIZATION OF ISOLATED RHIZOBIA OF PACHYRHYZUS EROSUS CULTIVATED IN SALINE SOIL Of THE STATE OF PERNAMBUCO, BRAZILInvestigation on microbiological biodiversity in the saline soils involves searching for tolerant genotypes to this type of emvironmental stress. Genotypic data associated to morphologic, physiological and biochemical characteristics of bacteria provide important information regarding its identification and clusters. The objective of this work was to characterize indigenous rhizobial strains of saline soils in the Wasteland and Hinterland of Pernambuco State, using yam bean (Pachyrhizus erosus L. Urban) as plant-tramp. Assays had been performed in YMA media and the observed cultivation characteristics of twenty-four isolates had been: change of pH, time of growth, transparency, form, edge, production of exopolysaccharides of the colonies and resistance to salinity. DNA amplification by the PCR technique of the repetitive sequence BOX indicated a high level of genetic and fenotipic diversity between the thirteen indigenous isolates. Comparing cultivation and genetic characteristics of these isolates with

RESUMOA combinação eficiente entre variedades e estirpes de rizóbio é importante para aumentar a produtividade do feijão macassar; entretanto, estirpes selecionadas não foram testadas com a maioria das variedades cultivadas na região semiárida do Nordeste do Brasil. Com o objetivo de avaliar a eficiência de quatro estirpes recomendadas de rizóbio em seis variedades de feijão macassar cultivadas no Agreste da Paraíba, conduziu-se um experimento fatorial em blocos casualizados com três repetições, em vasos de Leonard contendo substrato estéril. As variedades IPA 206, Sedinha, Corujinha, Canapu, Sempre Verde e Azul, receberam inoculação com as estirpes BR 3267, BR 2001, EI 6 e NFB 700, além dos tratamentos com e sem fertilização nitrogenada. As plantas foram colhidas 40 dias após o plantio. As estirpes BR 3267 e BR 2001 produziram os melhores resultados quanto a biomassa, teores e conteúdos de N na planta e número de nódulos. A inoculação com a EI 6 resultou em um desempenho fraco, especialmente com a variedade IPA 206. O desempenho da estirpe NFB 700 foi um pouco melhor que o da EI 6. Sedinha e Sempre Verde foram as melhores variedades em produtividade de biomassa, conteúdo de N e número de nódulos. Inoculation of local cowpea varieties with selected rhizobia strains Palavras ABSTRACTThe efficient combination of cowpea variety and rhizobia strain is important to raise crop productivity. However, selected strains have not been tested with most of the varieties cultivated in the semiarid area of Northeast Brazil. To evaluate the efficiency of four recommended strains with six cowpea varieties cultivated in the Agreste region of Paraíba, a completely randomized factorial experiment, with three replications, was conducted in Leonard pots filled with sterilized substrate. Varieties "IPA 206", "Sedinha", "Corujinha", "Canapu", "Sempre Verde" and "Azul" were inoculated with BR 3267, BR 2001, EI 6 and NFB 700 strains, plus two treatments with, and without, N fertilizer. Plants were harvested 40 days after sowing. BR 3267 and BR 2001 strains produced the highest biomass, N concentrations and contents and nodule numbers. Inoculation with EI 6 resulted in poor plant performance, especially with variety IPA 206. Performance with NFB 700 was slightly better than with EI 6. Sedinha and Sempre Verde were the best varieties regarding biomass, N content and nodule numbers.