AGGRESSIVENESS ESTIMATES AND INOCULATION METHODS OF PATHOGENIC BACTERIA ON SEEDS AND SEEDS LINGS OF WHEAT ‘SERI M82’

Abstract

In México, the aggressiveness of plant pathogenic bacteria on wheat (Triticum aestivum L.) seedling initial growth has not been evaluated. During the Spring-Summer growing season of 2004 an experiment was conducted in sand beds at Montecillo, State of México, to evaluate three methods of bacterial inoculation on cv. ‘Seri M82’: 1) Inoculation on seedlings by spraying; 2) Seed vacuum-infiltration; and 3) Seedling puncture. Two strains of Pseudomonas syringae pv. syringae (150-3, 151-3), two of P. fuscovaginae (21-5, 169-2), and three of Stenotrophomonas maltophilia (150-2, 150-4, and 200- 8) were used. Seedling length, number of diseased seedlings, and aerial biomass dry weight production at 17 and 34 d after emergence (dae) were used as aggressiveness bacterial indicators. A complete randomized block design in a split plot arrangement of treatments with four replications was used. At 17 dae, the number of diseased seedlings did not have significant differences (P ≤ 0.05) among bacterial strains or inoculation methods. At 34 dae the only aggressiveness indicator that produced differences (P ≤ 0.05) among bacterial strains, inoculation methods and their interaction was the production of aerial biomass dry weight. It is concluded that the aerial production of biomass is the best indicator to evaluate the aggressiveness of bacteria. The spraying inoculation method caused the lowest production of seedling dry matter weight. S. maltophilia (150-4 strain) was the most aggressive strain when it was sprayed, while P. fuscovaginae (169-2 strain) when it was seed vacuumin-filtrated.