Abstract

STERLING CUELLAR, Armando  and  MELGAREJO, Luz Marina. Temporal variation to Microcyclus ulei in rubber tree clones FX 3864 and FX 4098 under controlled conditions. Rev. colomb. biotecnol [online]. 2014, vol.16, n.2, pp.158-168. ISSN 0123-3475.  https://doi.org/10.15446/rev.colomb.biote.v16n2.47249.

This study aimed to evaluate the effect of temporal variation on the main physiological components associated with the reaction to Microcyclus ulei of two rubber tree clones of Hevea brasiliensis under controlled conditions. Inoculations were performed in a moist chamber at 23 °C, a relative humidity higher than 90% and a photoperiod of 12 h. The variables severity of attack (SA), conidial sporulation intensity (IE), lesion size (TL) and infection frequency (IF) were analyzed with a repeated over time measurements model and also with correlations. M. ulei produced symptoms (SA, TL, FI) in both rubber tree clones 4 days after inoculation. Signs of the disease (IE = 3) appeared in the FX 3864 at day 8th and in the FX 4098 at day 12th. FX 3864 presented higher susceptibility to M. ulei (greater severity and high sporulation, with IE = 4). In general, the time influenced the reaction of each clone, especially in the variables SA, IE and TL. High significant correlations were found between SA and the variables IE, TL and FI, except on day 12 for IE. It was concluded that intensity and frequency of symptoms and the degree of sporulation produced by M. ulei change significantly over time under controlled conditions and this variation is influenced also by the level of susceptibility to M. ulei showed by each clone of H. brasiliensis.

Keywords : Hevea brasiliensis; South American leaf blight; severity; sporulation.

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