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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #370893
Research Project: Biology, Ecology, and Genomics of Pathogenic and Beneficial Microorganisms of Wheat, Barley, and Biofuel Brassicas

Location: Wheat Health, Genetics, and Quality Research

Title: Survey of take-all (Gaeumannomyces tritici) on cereals in Tunisia and impact of crop sequences

Author
item GARGOURI, S - University Of Carthage, Tunisia
item KHEMIR, E - University Of Carthage, Tunisia
item SOUISSI, A - University Of Carthage, Tunisia
item MURRAY, T - Washington State University
item FAKHFAKH, M - University Of Carthage, Tunisia
item ACHOUR, I - University Of Carthage, Tunisia
item CHEKALI, S - University Of Carthage, Tunisia
item MLIKI, M - University Of Carthage, Tunisia
item Paulitz, Timothy

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2020
Publication Date: 4/28/2020
Citation: Gargouri, S., Khemir, E., Souissi, A., Murray, T., Fakhfakh, M., Achour, I., Chekali, S., Mliki, M., Paulitz, T.C. 2020. Survey of take-all (Gaeumannomyces tritici) on cereals in Tunisia and impact of crop sequences. Crop Protection. 13. Article 10589. https://doi.org/10.1016/j.cropro.2020.105189.
DOI: https://doi.org/10.1016/j.cropro.2020.105189

Interpretive Summary: A survey was conducted for take-all disease in Tunisia. Disease was more severe in wetter areas of the country. A one-year break crop of a non-host such as a legume could reduce disease and the amount of inoculum in the soil, as measured by quantitative PCR.

Technical Abstract: Abstract: Cereal cultivation constitutes a priority in the Tunisian agriculture. Take-all of cereals caused by the soilborne ascomycete Gaeumannomyces graminis var. tritici and G. graminis. var. avenae is a common disease worldwide. The aim of the present study was to evaluate the incidence and distribution of the disease across the cereal growing areas in different climatic regions in Tunisia and to investigate the impact of crop sequences on the inoculum density in soil and disease development. During the cropping seasons of 2009/2010, 2010/2011, 2012/2013, and 2013/2014, the percentage of fields infested varied from 8.1 in 2011 to 39.6% in 2013 and the incidence of take-all varied from 0 and 60% in the 298 fields surveyed. Disease incidence was significantly higher in wetter climatic regions than in semi-arid regions and the disease was not detected in the driest area. No significant differences were observed in the incidence of take-all among durum wheat, bread wheat, barley, and oat. However, the greatest incidence was recorded in durum wheat fields and none of the oat fields were infested. All findings in this study including surveys, molecular identification of isolated fungi, and determination of DNA concentration in soil points to the dominance of G. graminis var. tritici and scarcity G. gramins var. avenae in Tunisian soils. Rotation trials conducted over four cropping seasons on the experimental station showed that a one year break crop could reduce significantly the incidence and severity of take-all on durum wheat. In addition, inoculums density of Ggt/Gga in soil estimated by quantitative PCR was significantly reduced after a legume crop compared to monoculture of durum wheat, and consequently there was a significant decrease in the incidence and severity of the disease in the following year. This study highlights the influence of climatic conditions on the distribution of take-all in the cereal growing areas of Tunisia and the importance of rotation in reducing incidence and severity of take-all.