Abstract

JIMENEZ-HERNANDEZ, Yanet et al. Response of bean cultivars to inoculation and natural incidence of halo blight and usefulness of molecular markers for selection. Rev. Mex. Cienc. Agríc [online]. 2023, vol.14, n.8, e3274.  Epub Feb 09, 2024. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v14i8.3274.

In the Bajío, bean halo blight [Pseudomonas syringae pv. phaseolicola (Psph)] causes severe damage to varieties of the Azufrado and Cacahuate Bola types. To identify resistant genotypes, various bean materials were inoculated with two isolates, races 2 and 6. Likewise, readings of the reaction to natural infection by Psph in the field were recorded in two sets of Azufrado-type lines evaluated under rainfed conditions in Celaya, Guanajuato, in 2018, one with 10 and another with 16 lines established in June and July, respectively. In the marker laboratory, primers B10, W13, and T8, associated with genes of resistance against the bacterium in various bean genotypes, were used to determine the association between the presence of the markers and resistance to Psph. The Azufrado-type genotypes established in June were severely damaged (reaction from 5 to 8 on a scale of 1 to 9) by Psph, while those of July were damaged to a lesser degree. In the first trial, environmental conditions favored the attack of the bacterium, conditions that did not occur in the second trial. Most of the genotypes inoculated with race 6 in the greenhouse were susceptible. Genotypes positive for the presence of the three markers used were susceptible to races 2 and 6; that is, the marked resistance factors do not provide resistance to those races. All evaluated genotypes of the Azufrado-type of Nueva Granada race were susceptible to Psph races 2 and 6. Among the inoculation-resistant genotypes are Flor de Mayo M38, San Rafael, Pinto Laguna 80, and Pinto Saltillo.

Keywords : Pseudomonas syringae pv. phaseolicola (Burkh); Phaseolus vulgaris L.; resistance..