Resumo

ALCANTARA-MENDOZA, Susana et al. Characterization of Citrus exocortis viroid in different conditions of indexing. Rev. mex. fitopatol [online]. 2017, vol.35, n.2, pp.284-303. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1701-3.

Citrus exocortis viroid (CEVd) is a regulated pathogen in Mexican citriculture. The diagnosis by indexing to detect the presence and transmission of CEVd in propagative material of germplasm banks is of official application. The aim of this study was characterizing to CEVd by in vitro and in vivo indexing to analyzing the efficiency of the transmission and the speed with which the symptoms are generated to establish their application in the biological diagnosis. The height, incidence, area under the disease progress curve (ABCP) and transmission efficiency were evaluated in etrog citron indicator plants, cultivated in vivo inoculated by grafting and in buds cultivated in vitro inoculated with callus. The mean height of buds and infected plants was 7.5 mm and 56.3 mm less than the control, incidence, ABC and regression model were 81.2%, 10.7, y= 0.0009x2+ 0.0693x- 0.0057, R2= 0.99 in vitro y 70.8%, 9.84, y= 0.0004x2- 0.0048x- 0.0061, R2= 0.94 in vivo, respectively. The efficiency of both indexing methods was 99 % with initial symptoms tenth days after the in vitro inoculation and 40 in vivo. The in vitro conditions generate a rapid expression of symptoms in the diagnosis by indexing contributing to the opportune detection of CEVd to avoid its dispersion.

Palavras-chave : tissue culture; callus; pospoviroid; graft; inoculation.