Genetic resources for organic wheat breeding: impact on resistance to common bunt

Abstract

To develop winter wheat varieties suitable for organic farming, it is necessary to collect plant genetic resources resistant to common bunt, because no seed treatment (with synthetic pesticides) is allowed. For this purpose, the breeding lines developed at the Lithuanian Institute of Agriculture and winter wheat varieties registered in Lithuania were investigated during 2001–2004, using artificial inoculation with Tilletia tritici and Tilletia leavis spores. It was found that among advanced breeding lines 0.0–1.7% were very resistant and 0.0–16.2% resistant to common bunt. Among the gene collection varieties tested, 0.0–7.7% were very resistant and 1.6–36.2% resistant to common bunt depending on the year of testing. Most lines and varieties were infected by 10% to 50%. This means that development and collection of plant genetic recourses resistant to common bunt is one of the limitinė factors in organic wheat breeding. Investigations of common bunt resistance of Lithuania-registered winter wheat varieties showed that among 26 varieties two – ‘Begra’, ‘Baltimor’ – were resistant while ‘Korweta’ and ‘Bill’ medium-resistant to common bunt. These varieties can be used in crosses to improve resistance to common bunt. The infection in most varieties reached 16.5–55.3%. The most susceptible varieties were ‘Flair’, ‘Aspirant’ and ‘Pegasos’ (infection 75.9–87.4%). The Lithuanian winter wheat variety ‘Milda’ was medium-susceptible and ‘Ada’, ‘Seda’, ‘Alma’, ‘Širvinta’ susceptible to Tilletia tritici. Keywords: winter wheat, immunoresistance, common bunt