ALBIZIA ZYGIA (DC) MACBRIDE, A SHADE TREE FOR COCOA. THE EFFECTS OF DURATION OF ACID SCARIFICATION AND SUBSTRATE ACIDITY ON THE GERMINATION OF SEEDS

ABSTRACT The Cocoa Research Institute of Ghana has embarked on studies to support the re-establishment of cocoa in degraded forest areas. Albizia zygia (DC) Macbride is an indigenous West African tree species used to provide shade for cocoa. Its potential for the amelioration of degraded cocoa soils is being studied. The effects of the duration of soaking seeds in 98% concentrated sulphuric acid and of substrate acidity on its germination and early root growth are presented. Scarifying seeds for five minutes, the shortest duration trial, in acid elicited maximum germination response—99% germination compared to 7% without acid scarification. Seeds germinated at all the pH levels tested (pH 3.5 to 6.5), with no significant differences in percent germination among treatments in the pH range of 4.5 to 6.0. Radicle length was also not affected by pH in the range of pH 4.0 to 6.0. The results indicate that germination and early root growth in A. zygia are relatively tolerant of low pH soils. These results suppo...