Further cytological studies on the L and S types of Phytophthora from cocoa
There are two chromosome types among isolates attributed to Phytophthora palmivora on cocoa in West Africa. An L-type with larger chromosomes forming three bivalents and an association of four (n = 5); and S-type with n = 9-12 much smaller chromosomes in which an association of four was observed in some isolates of both mating types. The L-type has been redesignated P. megakarya and the S-type retained as P. palmivora (Brasier & Griffin, 1979). The L-type is particularly favourable for the study of meiosis and fertilisation. Differential staining of the oogonial walls of the two types, together with the differences in the nuclei, permitted a study of gametangial combinations in L X S pairings. Hybrid combinations were most frequent but selfed combinations of both parental types occurred in up to 25 per cent of cases. The significance of selfing for survival of these fungi in nature is discussed
| Main Authors: | , , |
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| Format: | biblioteca |
| Published: |
1979
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| Subjects: | THEOBROMA CACAO, PHYTOPHTHORA PALMIVORA, PHYTOPHTHORA MEGAKARYA, ENFERMEDADES FUNGOSAS, AISLAMIENTOS, TIPOS COMPATIBLES, AFRICA OCCIDENTAL, |
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