Radiomutagenesis and an in vitro conductimetric bioassay: it's application to avocado improvement for Phytophthora spp. resistance
2009
Álvarez, A., Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, Ciudad de La Habana (Cuba) | Santiago, L., Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, Ciudad de La Habana (Cuba) | Coto, O., Instituto de Investigaciones de Fruticultura Tropical, Ciudad de La Habana (Cuba) | Machado, M., Instituto de Investigaciones de Fruticultura Tropical, Ciudad de La Habana (Cuba) | Ramos, M., Facultad de Biología, Universidad de La Habana (Cuba)
Avocado root-rot, caused by Phytophtora cinnamomi is among the main biotic stresses causing important economic losses to the crop. Therefore, development and identification of new genotypes resistant to the pathogen is important for an integrated disease management. However, limitations to avocado breeding and production are also related to the long juvenile period, large cultivation areas and extensive natural cross-pollination. In this sense, radiomutagenesis has proven to be a valuable tool to improve disease resistance in fruit trees. For this, the determination of mutagenic doses, combined with in vitro selection and conductimetric bioassays are necessary to accelerate the mutation breeding schemes. In avocado, the measurement of electrical conductivity, based on the release of microelectrolytes to the medium due to cell permeability damage, has been performed on inoculated roots and leaves. In the present work is showed a report of mutagenic doses against gamma rays (LD50 and LD20) determined for in vitro propagated zygotic embryos of three avocado cultivars. Additionally, electric conductivity was measured in leaf discs and root segments from zygotic embryos of Catalina cv. challenged with culture filtrates of isolates from different regions of the country. The results indicated a differential response of the genotype depending on the strain used. Also, differential response was observed, depending on tissue type.
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