Journal of Taiwan Agricultural Research

Author:Pao-Jen Ann*, Jyh-Nong Tsai, and Ien-Tien Wang

Abstract:

      From 1977 to 2011, a total of 278 Phytophthora isolates were obtained from papaya diseased tissues, including fruit, roots, and young seedlings, which were collected from 106 papaya orchards located at 39 sites (districts, townships or cities) of 13 counties/cities. All isolates were identified as Phytophthora palmivora (Butler) Butler, of which 262 isolates were A¹ mating type and only 16 isolates were A² mating type. Isolates from 101 of 106 orchards were all of the A¹ mating type, while isolates from 2 orchards were all A² mating type. Isolates from the other three orchards contained both A¹ and A² mating types, but A¹ was dominant. Only one A² was found in each of the 3 orchards. All 13 isolates obtained before 1980 were A² mating type. Of the 164 isolates obtained during the periods from 1988 to 2000, 161 were A¹ mating type and only 3 were A² mating type. The 101 isolates obtained after 2000 (2001–2011) were all A¹ mating type. These results indicate that A¹ mating type of P. palmivora is currently the dominant Phytophthora pathogen in papaya orchards in Taiwan.

Key words:Papaya, Phytophthora palmivora, Mating type

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