ARS | Publication request: Effect of sorghum seedlings of different genotypes, and previous crop, on soil microorganism populations

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 21, 2008
Publication Date: June 1, 2008
Citation: Funnell-Harris, D.L., Pedersen, J.F., Marx, D.B. 2008. Effect of sorghum seedlings of different genotypes, and previous crop, on soil microorganism populations. American Phytopathological Society Annual Meeting. Phytopathology 98: S56.

Technical Abstract: Hypotheses that sorghum seedlings of different genotypes will differentially modify soil microorganisms and will affect subsequently planted wheat seedlings were tested. Wheat cultivar Lewjain, and sorghum genotypes Redlan and RTx433 were planted into soils previously planted with wheat or sorghum. Fungal and fluorescent Pseudomonas spp. numbers (cfu) were significantly affected by plant species, sorghum genotype and previous crop. Soils planted with RTx433 or Lewjain had significantly greater numbers of fungal cfu than soils planted with Redlan. When Lewjain seedlings were grown in soil previously planted with RTx433, there were greater numbers of fungal cfu than when Lewjain was planted into Redlan soil. Wheat planted into wheat soil resulted in significantly fewer numbers of fluorescent Pseudomonas spp. than when planted into sorghum soil. Fluorescent pseudomonads were assessed for presence of the 2,4-diacetylphloroglucinol gene (Phl). Percentage of isolates with Phl declined for most treatments but increased when Redlan was planted in Redlan soil. When rifampicin-marked Pseudomonas fluorescens isolates were applied to soils, sorghum seedlings sustained rhizosphere and soil populations similar to those of wheat. There may be differences between sorghum genotypes regarding associations with soil microorganisms, suggesting that sorghum genotypes may differentially affect numbers of soil microorganisms in cropping systems.