Mesquite rhizobia isolated from the Sonoran Desert: Competitiveness and survival in soil

Nastaran H. Shoushtari, Ian L. Pepper

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The competitiveness of a mesquite Rhizobium (AZ-M1) and its ability to survive in desert soils was compared to a selected commercial strain (31A5). In a greenhouse study, the native isolate out-competed strain 31A5 in nodule occupancy, when applied as a mixed inoculant to seed germinated and grown in sand culture, and irrigated with N-free nutrients. A high incidence of nodule double occupancy was found when double strain inoculants were used. The survival rate of the two strains was tested in three desert soils in a controlled laboratory study. The desert strain AZ-M1 grew and survived in all the soils for 1 month. The commercial strain 31A5, did not grow, and the population decreased in 14 days from 108 cells g-1 dry soil to below 104 cells g-1. Both strains survived to a lesser extent in a saline-sodic soil. A significant morphological change from a rod to a coccus was observed 2 days after strain 31A5 had been introduced into the desert soils.

Original languageEnglish (US)
Pages (from-to)803-806
Number of pages4
JournalSoil Biology and Biochemistry
Issue number6
StatePublished - 1985


ASJC Scopus subject areas

  • Microbiology
  • Soil Science

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