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Studies on resistance and tolerance to cocoa viruses in Ghana
Author(s) -
ATTAFUAH ALEX.,
GLENDINNING D. K.
Publication year - 1965
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1965.tb01229.x
Subject(s) - biology , cutting , infestation , botany
SUMMARY Cuttings from fifty T17 seedling trees derived from an open‐pollinated pod from the Iquitos selection no. 53 were each infested with fifty infective mealybugs ( Planococcus njalensis ) carrying either the severe New Juaben strain of cocoa swollen shoot virus or the Kpeve strain of cocoa mottle leaf virus. All but forty‐seven out of 1000 cuttings treated with CSSV became infected. All Amelonado beans treated at the same time as these cuttings with thirty insects each became infected. There was no evidence of variation in susceptibility to infection with CSSV in the T17 progeny. The infected plants were scored for tolerance; one clone seemed more tolerant and five less tolerant than the remainder. Deposition of mixed pollen in the natural pollination is suggested as the cause of this variation in tolerance in the progeny. There was no evidence of rcsistance and tolerance being associated. Tolerance to CSSV was much higher in the T17 progeny than in Amelonado. Transmission rates of CMLV were much lower than of CSSV both to the T17 cuttings and to the Amelonado beans, Conditions at the time of infestation clearly affected the transmission rates. No evidence of variation in susceptibility to infection with CMLV was found in the T17 progeny. Plants infected with CMLV were scored for tolerance in only one replicate; there was little evidence of variation and none of an association between resistance and tolerance.