Interação entre genótipos e estirpes de rizóbio em feijão-caupi

Abstract

Cowpea is a crop widely produced in the North and Northeast of Brazil, and quite adapted to adverse environmental conditions. However, the cowpea is still a culture with low productivity, mainly by low technological level employee. In this respect Biological Nitrogen Fixation (BNF) is a viable option for the supply of nitrogen on the cheap alternative, but it is important to select cowpea varieties most efficient and adapted to the FBN process. The objective of this work was to test the ability of strains of rhizobia and semiarid regions, generating gains in the production of cowpea, able to match the fertilized crop and verify the existence of interaction between cowpea and rhizobia. 21 genotypes obtained from the germplasm bank of the UFC and four strains of native rhizobia obtained semiarid from the culture collection of the laboratory of environmental microbiology at UFC were tested. Four experiments were conducted in a randomized block design in a factorial 6X8 being six genotypes of cowpea, eight sources of nitrogen and three replications. The nitrogen sources were composed of four native strains plus two standard strains and fertilized witness over the uninoculated control (without fertilizer and without rhizobia). The CE-930 genotype was repeated for all trials. The experiments were conducted in a greenhouse of the UFC and genotypes was sown in pots such as "Leonard", with sterile and inert substrate composed of sand and vermiculite. After 35-40 days of planting was carried out collect data for analysis. No significant interaction was found between genotypes and strains of rhizobia. There was no response variation for total nitrogen between any of the genotypes in the four experiments, all were statistically equal, but as the other variables there were very different values in some cases. When we analyzed the sources of nitrogen in the four tests all strains except LAMAB-8 generated increased production almost always similar nitrogen witness. The genotypes of cowpea did not influence the responses of strains of rhizobia, not being revealed interaction between them. The LAMAB-40, LAMAB-48 and LAMAB-65 strains expressed ability to fix nitrogen assimilated form already strains recommended for culture and when chemically fertilized.