Observe specimens H, l, J, and K carefully. (a) State one method of propagation of each of the specimens (b) State four advantages of staking the crop which...

(a) One method of propagation of each specimen

• Specimen H (cassava): stem cutting.
• Specimen I (yam): seed yam (whole small tubers or yam setts).
• Specimen J (sweet potato): vine or stem cuttings.
• Specimen K (ginger): rhizome (setts).

(b) Four advantages of staking the crop from which specimen I (yam) is obtained

1. The stakes support the climbing vines and hold them off the ground.
2. They expose the leaves for good interception of sunlight and better photosynthesis.
3. They minimise damage to the vines and prevent the transmission of soil-borne pathogens to the leaves through rain splash.
4. They allow good air circulation and give the farmer more room to carry out cultural practices, leading to higher yields.

(c) Toxic substance in specimen H (cassava) and two methods of reducing it

The toxic substance is hydrocyanic acid (prussic acid, from a cyanogenic glycoside). It can be reduced by:

• Fermentation (grating and pressing out the juice).
• Boiling, sun-drying, frying or roasting.

(d) Processing of specimen H (cassava) into garri

Harvest the raw cassava tubers, peel them with a knife and wash the peeled tubers. Grate the peeled tubers with a grater, put the grated mash into sacks and screw-press (or ferment) it for about three days to drain off the juice. Sift the fermented mash to remove fibres and lumps, then fry it in a pan over fire with constant stirring until dry and crisp. Sift the fried garri again into fine or coarse grades and bag it for storage or sale.