Abstract

ACOSTA-GALLEGOS, Jorge A. et al. The relationship between the reaction to common blight and the yield and seed weight of irrigated and rainfed beans. Rev. Mex. Cienc. Agríc [online]. 2013, vol.4, n.5, pp.673-685. ISSN 2007-0934.

Various diseases damage the bean crops in the central region of Mexico, especially those under rainfed conditions. The aim of this study was to identify bean genotypes tolerant to common blight (Xanthomonas campestris pv. phaseoli), and to determine the association between the reaction to this disease and yield and seed weight in 36 genotypes established under irrigation and rainfed conditions. From 2004 to 2006, an assay was established five times in Celaya, Guanajuato, with 36 genotypes of different origin and type of grain; two were conducted under irrigated conditions in February sowings, and three under rainfed conditions in July sowings. We determined the reaction ofthe genotypes to common blight incidence, their yield and the weight of 100 seeds of them. Overall, common blight incidence was observed in both planting systems at the beginning of the reproductive stage, intensifying, with differences between genotypes (p< 0.05), towards grain filling; the incidence was higher under rainfed irrigation. All genotypes showed, in varying degrees, disease symptoms on the leaves, and a few of them on the pods. No immune genotypes were observed; the ones with the lowest incidence ofthe disease, as shown in the assays, were: Afn, FEB 190, A 321 (reaction 2.3), Flor de Mayo Anita, PT 98001 (2.6), Alteño 2000, A 339, EMP507 and Flor de Mayo M38 (2.7). There was no relationship between the incidence of the disease and yield, but there was a relationship between the disease incidence and the weight of 100 seeds; this due to the susceptibility of the "pinto" and "bayo" genotypes with medium to large size seeds of the Durango race.

Keywords : Phaseolus vulgaris; Xanthomonas campestris pv. phaseoli; disease resistance.