International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

Variety mixtures: a promising strategy to improve STB disease management


Sarrah Ben M'Barek
Regional Field Crops Research Center of Beja (CRRGC) BP 350, 9000 Beja, Tunisia
CRP Wheat Septoria Phenotyping Platform, Tunisia

Petteri Karisto*
Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland

Moez Fakhfakh
Comptoir Multiservices Agricoles, 82, Avenue Louis Brailles, Tunis Belvédère, Tunis, Tunisia

Hajer Kouki
CRP Wheat Septoria Phenotyping Platform, Tunisia

Alexey Mikaberidze
Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland

Amor Hassine Yahyaoui
International Maize and Wheat Improvement Center (CIMMYT) km. 45 Carretera México-Veracruz El Batan, Texcoco, Estado de México, CP 56130
CRP Wheat Septoria Phenotyping Platform, Tunisia


Oral Presentation
Cultural Management, Fungicide Resistance and Epidemiology

Moore Auditorium, UCD O'Brien centre for Science
22 May 2019, 15:20

View this abstract online by visting isclb2019.com/see/ABS98424

Septoria tritici blotch (STB) caused by Zymoseptoria tritici is the most important foliar disease of durum wheat in Tunisia. Popular old variety Karim occupying 60% of cultivated area, is highly susceptible to STB and yield losses easily reach up to 40%. Disease management mainly relies on the use of fungicides and resistant varieties. Nevertheless, variety mixtures may provide more sustainable disease management.

The objective of this study was to test the effect of added resistant variety in mixtures with Karim for their capacity to cope with disease and to improve yield. Two resistant durum wheat varieties, Salim and Monastir, and the susceptible variety Karim, were assessed in pure stands and different mixtures at the CRP Wheat Septoria Phenotyping Platform at Kodia station (Tunisia). STB levels were measured twice: on F-1 leaves and a month later on Flag leaves. Leaves were collected at random, incidence was assessed visually on the collected leaves, and diseased leaves were analyzed using automated image analysis. Severity was measured as the percentage of leaf area covered by lesions and the density of pycnidia within lesions. Yield performance of these mixtures was measured by calculating thousand kernel weight (TKW) and grain yield (kg/ha).

Results suggest that STB is efficiently controlled by adding a proportion of resistant variety to a susceptible variety. Karim showed the highest disease levels, but adding only 25% of resistant cultivar resulted in significant decrease of the disease to a level comparable to pure stands of the resistant varieties. Moreover, treatments with 25% resistance had also significantly higher TKW and grain yield than what expected from linear relationship.

The analysis confirms that adding 25% of resistant component into mixture with susceptible variety suppresses the epidemics and increases yield. Hence, variety mixtures are a promising and efficient strategy to improve the disease management.

Keywords: variety mixtures, Zymoseptoria tritici, durum wheat, sustainable disease management