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

Dissection of resistance components against Septoria tritici blotch in a common wheat line 'Murga'


Xinayo He
International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600 Mexico DF, Mexico

Gustavo Azzimonti
Instituto Nacional de Investigación Agropecuaria (INIA), Ruta 50, Km 11, 39173, Colonia, Uruguay

Mariel del Rosario Sánchez-Vidaña
Colegio de Postgraduados, Montecillo, 56230, Texcoco, México

Carolina Sansaloni
International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600 Mexico DF, Mexico

Ana María Hernández-Anguiano
Colegio de Postgraduados, Montecillo, 56230, Texcoco, México

Pawan Kumar Singh*
International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600 Mexico DF, Mexico


Poster Presentation
Host Genetics and Resistance Breeding

Atrium, UCD O'Brien centre for Science
Poster 47

View this abstract online by visting isclb2019.com/see/ABS73328

Septoria tritici blotch (STB) is a major foliar disease globally, which is notorious in the fast development of fungicide resistance, making host resistance an indispensable component in mitigating STB. CIMMYT wheat line ‘Murga’ is well known for its high, durable and broad-spectrum resistance against STB infection, and the purposes of this study were to investigate its resistance mechanism and identify molecular markers that could be used in marker-assisted selection (MAS). A recombinant inbred line population was derived from a cross between ‘Murga’ and a STB susceptible line ‘Huirivis’, comprising 297 progenies. The population was evaluated for STB resistance in Toluca, Mexico (2017 and 2018), and in INIA Estanzuela, Uruguay (2016 and 2017). STB disease severity (STBds) was visually scored in field trials artificially inoculated with STB isolates. Plant height (PH) and days to heading (DH) were scored in all the experiments. Genotyping was performed using the DArTSeq technology. QTL mapping (the MQM algorithm in MapQTL) indicated a major and stable QTL on chromosome 3DL, explaining a phenotypic variation for STBds of 41-63% in Mexico and 28-30% in Uruguay. This QTL is close to Stb16q, as indicated by the physical positions of its flanking markers in the Chinese Spring reference genome. Eight location-specific QTL with minor effects were identified: two on 2D and 5B only expressed in Mexico, and six on 2B, 2D (two QTL), 3A, 3B and 5B only expressed in Uruguay. ‘Murga’ was the resistant donor for all QTL, except for those on 2B and 3A. When PH and DH were used as covariates, the major QTL on 3DL was not affected, whereas the minor QTL were affected to various degrees. Flanking markers of the 3DL QTL will be transformed into KASPs to evaluate their suitability for MAS.