Resumen

GONZALEZ-TOLEDO, Angélica de la C.  y  TOLEDO-SAMPEDRO, Verónica. Behavior of accessions of the genus Nicotiana reported as sources of resistance against Cuban isolates of Phytophthora nicotianae Breda de Haan. Rev. Protección Veg. [online]. 2019, vol.34, n.1, e10.  Epub 09-Abr-2019. ISSN 1010-2752.

The objective of this work was to evaluate the accessions of the genus Nicotiana reported as sources of resistance against Cuban isolates of Phytophthora nicotianae Breda de Haan. The tests were performed under semi-controlled conditions in biological isolators, where the infection rate was calculated in 10 accessions of the genus Nicotiana in the presence of 20 Cuban isolates of P. nicotianae with differential aggressiveness. Among the accessions evaluated, there were Nicotiana species and tobacco cultivars internationally identified as sources of resistance to the pathogen. The values ​​of the infection index were used to classify the cultivars according to the level of resistance to the pathogen, in addition to a Hierarchical Grouping Analysis with Euclidean distance and the Ward method. The dendrogram obtained grouped the accessions into three clusters, where the susceptible control KY-14 showed the highest susceptibility and separated from the rest of the cultivars. The cultivars Florida 301 and Florida 513 integrated another group with variable resistance levels, from highly resistant to moderately susceptible. The accessions Nicotiana longiflora Viv., Nicotiana plumbaginifolia Cav., three accessions of Nicotiana rustica L. (3100, 3137, 2834), and the cultivars Beinhart -1000 and Beinhart- 1000-1 clustered into a group, and they behaved as highly resistant to most of the Cuban isolates evaluated.

Palabras clave : black shank disease; sources of resistance; integrated pest management; Nicotiana tabacum.

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