Selection of plant growth-promoting bacteria in sweet sorghum (Sorghum bicolor (L.) Moench) under the effects of salinity

Abstract

Background Sorghum, a grassy non-halophyte, it is both drought and salinity tolerant, and is considered a promising crop for semiarid regions. During the last 20 years, its culture has expanded in Brazilian production by 780%, reaching 1,928,970 tons in 2009 [1]. Salinization of the soil and lack of rain are increasing constraints in semiarid regions. They predominate in northeastern Brazil. This has helped limit the production of plant biomass, which is the basis of agricultural activity. The advantages of sorghum in these conditions can be improved still further by using plant growth-promoting bacteria (PGPB) for the biological processes of nitrogen fixation, and hormone production, as well as others [2]. Endophytic bacteria can secrete up to one half of the nitrogen they fix, and plants may then assimilate the nitrogen efficiently [3]. Inoculation with Azotobacter chroococcum has been shown to attenuate stress in maize grown in saline soil [4]. In this study, we evaluated the action of PGPB on a “Wray” saccharine variety with low salinity tolerance.