An attempt to protect winter wheat against Gaeumannomyces graminis var. tritici by the use of rhizobacteria Pseudomonas fluorescens and Bacillus mycoides.
Pseudomonas fluorescens strains III107 and II21 and Bacillus mycoides strains JC192 and K184, stimulating growth of winter wheat, were chosen for the studies. The bacterial strains inhibited on agar nutrient medium the growth of Gaeumannomyces graminis var. tritici (Ggt)--the pathogenic fungus causing take-all on wheat. Both strains of pseudomonads synthesized relatively high amounts of Fe3+ chelators. The strains of bacilli were characterized by the very fast spreading on agar media. Furthermore, strain II21 was highly cyanogenic, and strain JC192 highly chitinolytic. Bacterization of winter wheat seeds (especially with strains III107 and JC192) significantly reduced the percentage of the plants infested with the pathogen in the 28 day glasshouse pot experiment. In the plot experiment, the winter wheat seeds were inoculated with a mixture of strains III107, II21 and JC192. Due to the bacterization the yield of wheat grain and straw was higher in comparison to the series with Ggt alone by 122% and 75%, respectively, but it amounted only to 45% and 43% of the control series not contaminated with Ggt. The decrease of percentage of wheat ears with weight less than 500 mg from 61% in Ggt-series to 25% in Ggt-bacterized-series, and especially the decrease of percentage of wheat ears with weight less than 200 mg from 43% to 14% additionally indicate the partial protection of the winter wheat against Ggt by the rhizobacteria. In the experimental series not contaminated with Ggt the percentage of these wheat ears fractions did not exceed 3% and 0.5%, respectively.