Control of Common Bunt in Organic Wheat

Abstract

Common bunt, caused by the seedborne and soilborne pathogens Tilletia caries and T. laevis, has re-emerged as a major disease in organic wheat. In conventional agriculture, common bunt is routinely managed with the use of synthetic chemical seed treatments. For this reason, common bunt is a relatively unimportant disease in conventional agriculture. However, since synthetic chemical inputs are prohibited in organic agriculture, common bunt is a major threat once more in organic wheat and seed production. The challenge today is to manage the disease without the use of chemical seed treatments. This review reports on the management of common bunt under organic farming systems, mainly through host resistance and organic seed treatments. We report the history of screening wheat germplasm for bunt resistance, the search for new sources of resistance, and identification and mapping of bunt resistance genes. Since the pathogen has a gene-for-gene relationship with the host, this review also includes a summary of work on pathogen race identification and virulence patterns of field isolates. Also included are studies on the physiological and molecular basis of host resistance. Alternative seed treatments are discussed, including physical seed treatments, and microbial-based and plant-based treatments acceptable in organic systems. The article concludes with a brief discussion on the current gaps in research on the management of common bunt in organic wheat.

Characterization of two wheat doubled haploid populations for resistance to common bunt and its association with agronomic traits

“…Thus, they are not suitable for direct use in wheat production but can serve as donors of resistance genes in breeding programs (Ruzgas and Liatukas 2009;Matanguihan et al 2011). In compliance with this observation, the present study showed that bunt incidence was positively correlated with yield components (spike length, spikelet number and grain number in the main spike) in the progeny of 'Svilena' × A-38b cross.…”

“…T. laevis JG Kühn). T. caries is more prevalent in North-Western Europe, while T. foetida is more common to Eastern Europe (Matanguihan et al 2011), including Bulgaria (Atanassov 1929;Dodov and Todorova 1974).…”

“…This is one of the factors explaining the low number of commercial varieties of high bunt resistance Bonman et al 2006;Ciuca and Saulescu 2008;Dumalasová and Bartoš 2013). The disease has recently re-emerged in bio-controlled farming systems in Europe where chemical disease management is restricted or not allowed (Matanguihan et al 2011). Bunt resistant varieties could be a good alternative in low-input and organic wheat production.…”

“…There are 15 known major genes (Bt genes) for race-specific bunt resistance (reviewed in Matanguihan et al 2011), but quantitative mode of inheritance associated with field non-race specific resistance was also reported (Fofana et al 2008;. The latter type is considered valuable in providing durable resistance against the dynamic pathogen population and is a highly desirable trait for environmentally safe wheat production.…”

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

“…In managing seed-borne diseases, resistant varieties play a crucial role, and therefore efforts have been made to identify sources of disease resistance against, e.g. common bunt (Dumalasová and Bartoš 2006;Gaudet et al 2007;Matanguihan et al 2011) and black point (Conner and Davidson 1988;Christopher et al 2007) in wheat. Wheat material originating from CIMMYT has been evaluated in Canada and limited resistance was found (Gaudet et al 1995).…”