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III International Meeting of the Portuguese
Society of Genetics
27th and 28th June 2022
Auditorium of the Colégio Espírito Santo, University of Évora
(Draft Version)
Poster 2
Assessment of Downy Mildew Resistance and Genetic Relationships Among Wild
Rocket (Diplotaxis tenuifolia (L.) DC) Accessions
Paula Coelho1, João Reis2, Ana Pereira1, Aliana Vairinhos2, Violeta Lopes3, José Leitão2
1INIAV - Instituto Nacional de Investigação Agrária e Veterinária, Quinta do Marquês, Av. da República, 2784-505 Oeiras, Portugal
2MED - Mediterranean Institute for Agriculture, Environment and Development & CHANGE - Global Change and Sustainability
Institute, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
3BPGV/INIAV - Banco Português de Germoplasma Vegetal, Polo de Inovação de Braga, 4700-859 Braga, Portugal
Email: jleitao@ualg.pt, paula.coelho@iniav.pt, a61179@ualg.pt
Wild rocket (Diplotaxis tenuifolia (L.) DC.) is an herbaceous species produced as baby leaf salad,
which importance is increasing as a response to the growing preference of the consumers over
the “cultivated” rocket (Eruca spp.). Downy mildew (DM) disease, elicited by the oomycete
Hyaloperonospora sp., is one of the main causes of yield losses in wild rocket cultivation. From a
point of view of food safety, environmental concerns, and viability of organic farming production
the identification of resistant genotypes is a priority to this industry. A set of 29 D. tenuifolia
accessions, and 1 Eruca spp. accession, were screened at the seedling stage, for resistance to the
Hyaloperonospora sp. isolate D5, collected on D. tenuifolia infected plants. The plant/pathogen
interaction phenotype (IP) was assessed at the cotyledon and first two leaves stage, and the
accessions were classified as resistant (R), partially resistant (PR), susceptible (S) and highly
susceptible (HS) in both stages. The Eruca spp. accession was resistant at both stages (R/R), while
the Diplotaxis accessions were, respectively, 1 (R/R), 3 (PR/R), 8 (S/PR), 6 (HS/PR), 9 (HS/PR) and 2
(HS/HS). A significant correlation (r=0,865896, P<0.001) was found between the disease index
values exhibited in cotyledons vs. young leaves. No plants R or PR in cotyledons became
susceptible in the first leaves. Molecular analyses were performed using 7 RAPD and 5 ISSR
markers, which have amplified 110 clearly scorable markers. As expected for genotypes from the
same species, the genetic similarity among the Diplotaxis accessions varied from 0,751 to 0,994.
The Eruca accession exhibited very low genetic similarity (0,171) to the wild rocket accessions. Some
of the accessions that exhibited high genetic similarity were provided by the same breeding
company.
This work was funded by the project: PTDC/ASP-PLA/28963/2017- REMIRucula - Resistance characterization to downy mildew in wild
rocket crop.
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