Abstract

MACHADO, Maylen et al. Intraspecific variability of Phytophthora palmivora Butler (Butler) strains isolated from avocado (Persea americana Mill.) orchards on Cuba. Rev. Protección Veg. [online]. 2013, vol.28, n.3, pp. 178-184. ISSN 1010-2752.

The colony patterns were described for eight P. palmivora strains isolated from avocado orchards located in the western Cuban region, that were grown on potato dextrose agar (PDA), malt extract agar (AM), V8 agar (AV8) and carrot agar (AZ). The sporangia shapes observed in the P. palmivora strains were also described. The intraspecific variability was evaluated based on the size of sporangia and papillae. The strains showed a uniform colony pattern on each of the culture media used, arachnoid on PDA and AM media and stellate on AV8 and AZ media. A wide diversity of types of sporangia was observed, mostly ovoid-ellipsoid, obpyriform, spherical and distorted with short pedicels (2-5 µm). Sporangia shape ranged between 25 µm and 80 µm long (average 48,8 µm ± 9,1 µm) and 17,5 µm to 52,5 µm in breadth (average 31,8 µm ± 5,5 µm) with prominent papillae ranging from 2,5 µm to 10 µm long (average 5,7 µm ± 1,7 µm) and between 2 µm to 10 µm in breadth (average 6,5 ± 1,6 µm). The Principal Component Analysis showed a great variability considering both the sporangia and papillae sizes with the length and breadth of the sporangia and their ratio, the width and the length/breadth ratio of the papillae as the most variable characters.

Keywords : Phytophthora; sporangia; papillae.

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