The reaction of different cacao types to infection with swollen-shoot virus

Autor: J. F. Longworth, J. M. Thresh
Rok vydání: 1963
Předmět:
Zdroj: Annals of Applied Biology. 52:117-124
ISSN: 1744-7348
0003-4746
DOI: 10.1111/j.1744-7348.1963.tb03733.x
Popis: SUMMARY Graft tests were used to investigate the reaction of different cacao types to infection with swollen-shoot virus. Budlings of all the clones in Nigeria were infected with virulent isolates so that the sequence of symptom expression could be followed. All the Amelonado and Morona clones and most of the Trinitarios were affected severely. They showed extensive, conspicuous leaf symptoms and large stem swellings. The Upper Amazon cacaos reacted less uniformly. The Scavina clones developed conspicuous symptoms, whereas those produced in the Nanay and Iquitos types were often slight and sometimes transient. Many Parinari clones and hybrids of Parinari parentage showed an extreme reaction: a veinal necrosis which often caused complete collapse of affected leaves and sometimes extended to the stem and growing point. Tests on progenies derived from crosses of sensitive with tolerant parents suggested that the sensitive reaction was dominant. These results are discussed in relation to the present plant breeding programme and to the possibility of releasing high-yielding hybrid progenies for replanting the extensive and heavily infected areas of Nigeria, within which control measures have been stopped.
Databáze: OpenAIRE
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