PLANTATION CROPS
 
Cocoa

Cocoa, (Theobroma cacao) is a bevarage crop introduced in India in the early 1965s. It is native of Amazon valley of South America. In India, it is cultivated mainly as a mixed crop in coconut and arecanut gardens. Kerala accounts for 79% of the total area and 71% of the total production and Karnataka shares 18% of the total area and 25% of production and the rest by Tamil Nadu. It belongs to the family Sterculiaceae.

Varieties

Commercial cocoa has two major varieties, Criollo and Forestero.

Other types of cocoa include (1) Trinitario from Trinidad which is said to be a hybrid between Criollo and Forestero with highly variable pod characters (2) Amelonado, a Forestero type bean with a melon shaped pod, cultivated in West Africa and (3) Amazon, a relatively new type collected from the Amazon forests which has got vigour and high yield.

CPCRI, Kasargod recommends some selections introduced from Malaya viz., I-21, II-11, II-18, II-67, III-5 and III-101 for commercial cultivation since they are high yielding and have beans weighing more than one gram.

Climate and Soil

Cocoa is a crop of humid tropics requiring well-distributed rainfall. A minimum of 90 to 100mm rainfall per month with an annual precipitation of 1500-2000mm is ideal. However, it can also be grown in other regions by supplementing rainfall with irrigation during dry periods. However, for successful cultivation the dry months should not exceed 3 to 4 months. This limits the distributions of cocoa to within 20⁰ latitude on either side of the equator. Cocoa tolerates a minimum temperature of 15⁰C and a maximum of 40⁰C, but temperature around 25⁰C is considered as optimum. It can be grown in place from sea level upto an elevation.

Cocoa grows on a wide range of soils but losse soils which allow root penetration and movement of air and moisture are ideal. It should retain moisture in the soil during dry season, as cocoa requires regular supply of moisture for proper growth. Though cocoa can be grown in soils with pH range from 4.5-8.0, it thrives better in neutral soil.

Propagation

Cocoa can be propagated from seeds or vegetatively from buds and cuttings. Seed pods may be collected from trees yielding 80 or more pods per year with pod weight 350-400g. Fresh beans from such pods should be used for sowing, as cocoa seeds lose their viability soon after they are taken out of pods. Before sowing, the seeds are rubbed with dry sand or wood ash to remove mucilage. The beans are planted with their pointed end upwards, either in plastic bags (25 x 15cm size) or in raised beds. If sown in beds, young seedlings are usually transplanted into polythene bags after about two weeks of germination. The seedlings are ready for transplantation to the field after about 3 to 4 months or they attain a height of 30 cm.

Cocoa can be also propagated vegetatively through cuttings, soft wood grafting, forkert method of budding etc., but there are limitations at present for adopting vegetative propagation on commercial scale.

Establishment of plantation

Cocoa requires shade when young and also to a lesser extent when grown up. Young cocoa plants grow best with 50% full sunlight. Therefore, it is planted in arecanut and coconut gardens in our country or as a pure plantation in forestlands by thinning and regulating the shade suitably. It is planted at a distance of 2.5-3.0m both between and within rows, either in the beginning of the monsoon, in May-June or at the end of the southwest monsoon in September.

Cocoa under arecanuts and coconuts is the cropping systems, which can be adopted advantageously in Kerala, Karnataka and Tamil Nadu. In arecanut gardens where the spacing is 2.7 x 2.7m cocoa is interplanted in alternate rows at a spacing of 5.4 x 2.7m. in coconut gardens, it can be planted 2.7m apart in a single row. Under the double hedge system, cocoa is planted in two rows adopting a spacing of 2.7 m within the row and 2.5m between rows of coconut planted at a normal spacing of 7.5 x 7.5 and above.

Manures and fertilisers

An annual application of 100g Nitrogen, 40 g Phosphorus and 140g Potash per tree per year in two split doses is recommended. During the first year of planting, the plants may be given one third of the above dose, while in the second and third year and above, two third and full dose of fertilizers may be applied uniformly around the base of the tree upto a radius of 75cm and forked and incorporated into the soil.

Irrigation

Cocoa plants require continuous supply of moisture for optimum growth and yield. During summer, the plants will have to be irrigated at weekly intervals. If adequate water supply is not ensured in summer months, the yield will be reduced and under mixed cropping systems, if there is severe drought, the yield of both the crops may be affected.

Pruning

The cocoa trees should be pruned regularly to develop a good shape. Cocoa grows in a series of storeys. The chupon or vertical growth of the seedlings terminates at the jorquette, where four or five fan branches develop. Further chupon develops just below the jorquette and continues its vertical growth till another jorquette forms and so on. When the first jorquette develops at a height of about 1.5m, the canopy will form at a height convenient for harvesting and other operations. Hence, all the fan branches arising from the main step are nipped off up to a height of about 1.0 to 1.5m or cut in the initial years of their growth. It is desirable to limit the height of the tree at that level by periodical removal of chupon growth. A second jorquette may be allowed to develop, if the first one formed was very close to the ground. Generally 3 to 5 fan branches are developed at each jorquette. When more fan branches develop, one or two weaker ones may be removed. The branches badly affected by pests and diseases also should be removed.

Harvesting

Cocoa flowers from the second year of planting and the pods take about 140 to 160 days to mature and ripen. Each pod will have 25 to 45 beans embedded in white pulp (mucilage). Generally cocoa gives two main crops in a year i.e., September-January and April-June, off season crops may be seen almost all through the year, especially under irrigated condition.

Only ripe pods have to be harvested without damaging the flower cushion, at regular intervals of 10 to 15 days. The pods are harvested by cutting the stalk with the help of a knife. The harvested pods should be kept for a minimum period of two to three days before opening for fermentation. For breaking the pods crosswise, wooden billet may be used and the placenta should be removed together with husk and the beans and collected for fermentation. A pod will have about 30 to 45 seeds covered with pulp or mucilage.

Processing

Fermentation: The beans should be fermented to develop chocolate flavour, reduce bitterness, loose its viability, remove the mucilage coating and enable the cotyledons to expend. Fermentation is done immediately after collecting the beans from the pods. There are two popular methods of fermentation using either trays or boxes.

Box method: In this traditional method, boxes of various shapes and sizes are used. The smallest one has the measurements of 60cm x 60cm and will hold about 150kg wet beans. The bottom of the box has a number of holes of 1cm diameter spaced at about 10cm apart. Three such boxes are arranged in a row so those beans can be transferred from one box to the other. The beans are placed in the top most and covered with banana leaves or gunny bags. After 2 days, the bean should be uncovered and transferred into the second box and then to the third box after another 2 days. On the sixth day, fermentation is completed and beans can be taken out for drying.

Tray method: This method is used only for fermenting forestero cocoa beans. The normal size of the tray is 90 x 60 x 12cm with a capacity to hold about 40 kg wet beans. The bottom of the tray is either slotted or drilled to make 1cm holes on a 4cm sq. pattern. A minimum of 4 trays is needed for successful fermentation. All the trays are filled with beans. The top-most tray is covered with banana leaves or sacks. The fermentation is faster here and is completed in about 4 to 5 days. This method is more convenient for large growers as the trays can be easily handled and no mixing is required and the period of fermentation is less.

Basket method: Bamboo or cane basket of suitable size having one or two layers of banana leaves at bottom to drain the sweating is filled with the beans and the surface is covered with banana leaves. After one day the basket is covered with thick gunnysacks. The beans are mixed thoroughly on the third and fifth days and covered with gunnysacks. The fermentation will be completed at the end of the sixth day and the beans are withdrawn for drying.

Drying

After the fermentation, the beans can be dried by sun drying or artificial drying as the fermented cocoa beans have considerable moisture (55%). Sun drying is good as it gives superior quality produce when compared to artificial drying. The fermented beans are spread in a thin layer over a bamboo mat or cement floor and dried beans is around 6 to 7 percent.

During the monsoon period, artificial drying has to be adopted. Electric ovens or conventional Samoan type drier could be used. The duration of artificial drying varies from 48 to 72 hours at 60 to 70⁰C. The drying of beans at high temperature should be avoided as it results in low quality end product. Slow drying in the initial stage has given better quality beans. Well-dried beans when shaken should give a metallic sound.

Grading and Storage

The flat, slaty, shrivelled, broken and other extraneous materials are removed. The cleaned beans are packed in fresh polythene-lined (150-200 gauge) gunny bags. The bags are kept on a raised platform of wooden planks. The beans should not be stored in rooms where spices, pesticides are fertilizers are stored as they may absorb the odour from these materials.

The roasted product of the dried beans is called as Cocoa, which are used for the manufacture of various products. When cacaonibs are ground, the resulting product is called Chocolate liquor or mass. The fat that is pressed from chocolate liquor is termed as cocoabutter. It is mainly used for the manufacture of chocolates, in pharmaceutical preparations and soap making.

Plant protection

Many pests and diseases are known to infect cocoa and cause economic losses.

Cherelle wilt: The shrivelling and mummifying of some young fruits is a common phenomenon in all coca gardens. In the early stages, the fruits lose their lusture and in four to seven days, the fruits shrivel. The fruits may wilt but do not abscise. Many factors are involved in the causation of this malady. The most important factors are insects, fungi, nutrient competition, over production etc. Hence, the remedial measures will depend upon the nature of the causative factors involved.

Ag.
Technologies
(Horticulture)