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

HORDEUM VULGARE-BIPOLARIS SOROKINIANA INTERACTIONS ARE MOSTLY QUANTITATIVE.


Fernanda M. Gamba*
Departamento de Protección Vegetal, Facultad de Agronomía, Estación Experimental “Dr. M. A. Cassinoni”, Ruta 3 k 363, CP 60.000, Paysandú, Uruguay

Maria R Finckh
Dept. of Ecological Plant Protection, University of Kassel, Nordbahnhofstr.1a D-37213 Witzenhausen, Germany

Gunter Backes
Dept. of Organic Plant Breeding, University of Kassel, Nordbahnhofstr.1a D-37213 Witzenhausen, Germany


Poster Presentation
Evolution and Population Biology

Atrium, UCD O'Brien centre for Science
Poster 8

View this abstract online by visting isclb2019.com/see/ABS95619

Race specific and race-non-specific interactions with barley have been previously reported for Bipolaris sorokiniana (BS). 322 single - spore isolates of BS collected in Uruguay from 2001 to 2010 were assessed for their interaction with 35 barley genotypes at the two-leaf stage under controlled conditions. The aims of the study were to characterize the Uruguayan population of BS, to determine if there are race-specific interactions, and to identify a manageable set of the most informative barley genotypes to characterize the pathogen. The quantitative interactions were analyzed with Hierarchical Clustering on Principal Components (HCPC), resulting in nine barley genotype clusters and six clusters of BS. Reducing the number of isolates to 147, based on redundant infection responses, resulted in eight barley genotype clusters and seven BS clusters to which none of the utilized barley genotypes tested were resistant. There were several BS clusters to which none of the tested barley genotypes were resistant, pointing to a serious lack of resistance sources in Uruguay. For screening purposes, 12 barley genotypes were selected based on their resistance profiles to identify isolates with differential interactions. These genotypes grouped into 11 clusters that interacted in a specific but quantitatively variable manner with the 147 isolates selected previously. The isolates grouped into eight clusters each representing different aggressiveness profiles. No specific pattern across years and collection locations were observed suggesting no population subdivision. Despite some clear isolate specific interactions, the overall quantitative interactions in this pathosystem make it unlikely that a universal differential set could be used to monitor BS diversity worldwide.