Abstract

OCHOA, María Judith; RIVERA-LOPEZ, Luis  and  GOMEZ-LEYVA, Juan Florencio. In vitro selection method in explants of Opuntia sps. with resistance to black spot caused by Pseudocercospora opuntiae. Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo [online]. 2016, vol.48, n.1, pp.21-31. ISSN 1853-8665.

The black spot cactus is caused by Pseudocercospora opuntiae a disease spread among production systems. The process of pathogenesis, comprising an incubation period of 90 d. and the development of symptoms can occur in 25 d.; however, is still limited information pathosystem P. opuntiae in Opuntia sps. This study aimed to evaluate the effect of extracellular products and spores of P. opuntiae on cactus pear under in vitro conditions. Three genotypes from zygotic embryos and two genotypes product of field selection which were characterized as tolerant (T) and resistant (R) to P. opuntiae were evaluated. Opuntia in vitro seedlings were inoculated with the extracellular extract and a suspension of 10⁸ conidia m/l, the damage at 15, 30, 45 and 60 d. post-inoculation (dpi) were evaluated. After 60 dpi symptoms occurred in explants inoculated with pure fungus, while the excretion products of the fungus in liquid medium showed ability to induce symptoms similar to fungal inoculum. These results demonstrate that P. opuntiae infected Opuntia explants under in vitro culture conditions, which could be an important tool in the selection of resistant genotypes to black spot in Opuntia sps.

Keywords : Black spot; Opuntia; In vitro selection; Fungal extract.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )