NifH-based studies on azotobacterial diversity in cotton soils of India.

In order to promote the use of Azotobacter inoculants for cotton crop, a complete characterization of soil isolates of Azotobacter, isolated and screened on the basis of physiological properties, from four different cotton-wheat cropping regions of India was carried out, and their genetic diversity determined by RFLP (restriction fragment length polymorphism) analysis of the functional gene nifH. Genetic analysis of these isolates depicted a similarity coefficient of > or = 80% among them, suggesting that though the isolates were obtained from different cotton soils of India, still they have large commonality in the nifH gene and constituted a homogeneous nifH population.