Evaluation and managing wheat seed-borne diseases: Options and suggestions from the case of Tajikistan

Abstract

Wheat seed-borne diseases are among the major constraints reducing crop yield and the quality of seed and grain. In this study we aimed to evaluate the type and prevalence of fungal seed-borne diseases in Tajik wheat seed samples. Particular emphasis was given to common bunt resistance in advanced wheat breeding materials. Furthermore, we aimed to identify options for improving the seed quality. Seed samples collected from two different locations in Tajikistan were tested by conventional seed-health testing methods for presence of seed-borne diseases. Nineteen advanced wheat breeding lines and three varieties collected from the Tajik wheat breeding program were screened using an artificial inoculation test for their response to common bunt. Significant differences were found between the locations and genotypes concerning presence of common bunt and black point. Fourteen fungal species, where most of them are pathogenic for wheat, were identified in the seed samples. Tilletia laevis, T. tritici, Bipolaris sorokiniana, Stemphylium spp., and Drechslera spp. were the major pathogenic fungi observed in collected wheat samples. Common bunt was predominantly represented by T. laevis. No strong resistance was found in the studied Tajik wheat material, although a low percentage of infection was found in one line (SHARK/ F4105W2.1), while the material was evaluated for common bunt resistance. In managing seed-borne diseases, breeding of resistant varieties should be given a priority, while cultural practices such as preventing contamination and monitoring seed health status should also be considered, as a last resort the use of chemical seed treatments are advised