Recherche de cultivars resistants a Phytophthora palmivora. Etude comparative des reactions aux infections experimentales effectuees sur cabosses

Starting in 1967, innoculations were made on the following three types of cacao: - locally selected clones of the Trinitario type (SNK series). - Upper Amazon clones (UPA, SCA, MIC). - Clones from Trinidad (ICS). These trials were carried out under different ecological conditions: at Nkolbisson and Nkoemvone using previously prepared culture blocks of Phytophthora palmivora. The innoculations were done in the field on pods still attached to the tree. Each clone was tested several times and the experiments were repeated the following year. The criteria used were the percentage of successful innoculations (susceptibility) and the speed of development of the lesions. At Nkoemvone, the results to date are: With regard to the rate of development of the lesions, no clones are totally resistant but those tested fall into 10 classes, ranging from low susceptibility, (spread less than 1000 mm2/24 hours) to high susceptibility (spread greater than 3000 mm2/24 hours), significant differences were shown between classes. The vulnerability varies from clone to clone ranging from less than 20 percent successful infections to more than 98 percent. Using hybrids, we hope to work out the inheritance of susceptibility. Knowing the reaction of the parent clones, the progenies should be: - mixed, cross between susceptible and resistant clone. - resistant, cross between two resistant clones. - susceptible, cross of two susceptible clones. Further work is continuing

Bibliographic Details

Main Authors:	Jones, Earl 81495, 107834 Quesnel, V.C., 56331 Chalmers, W.S., 68473 Fordham, R., 80036 Iton, E.F. eds., 49192 Blaha, G., 97646 Murray, D.B., 5330 Cocoa Research Institute, St. Augustine (Trinidad y Tobago), 4. International Cocoa Research Conference St. Augustine (Trinidad y Tobago) 8-18 Ene 1972
Format:	biblioteca
Published:	St. Augustine (Trinidad y Tobago) 1972
Subjects:	THEOBROMA CACAO, PHYTOPHTHORA PALMIVORA, PODREDUMBRES, ENFERMEDADES FUNGOSAS, RESISTENCIA A LA ENFERMEDAD, CULTIVARES, CLONES, CLONES TRINITARIOS, CLONES DEL ALTO AMAZONAS, CAMERUN,
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