KITTUR RANI CHANNAMMA COLLEGE OF HORTICULTURE, ARABHAVIPresentation on Crop Improvement in
Introduction:Cocoa (Theobroma cacao L.; family Sterculiaceae) is indigenous toSouth America.The Mayas, Toltecs and Aztecs knew the plant more than 3000 yearsago. Theobroma bicolor was known to Maya (one of the Indian races inAmerica) as there is evidence to show that the Mayas in South Americawere cultivating cocoa which was wild and inferior in quality.Cocoa thus has one of the oldest histories among crops cultivated byman. It was only during seventeenth and eighteenth centuriesthat the cocoa tree was introduced to many other sub-tropicalcountries.
As a perennial tree crop, it is traditionally and still predominantlycultivated beneath a diverse shade cover.The shaded system enhances the soil, protects it from erosion,provides non-cocoa products to the farmer and a refuge to an array ofanimal groups like birds, insects, small mammals, and reptiles as itprovides a fine biodiversity within the system. It was introduced to Southern India during the present century mainlyas an intercrop of coconut and arecanut gardens as it was found that theclimate within the gardens is conducive to cocoa growth.
Cocoa appears to have occupied an important place during sixteenthcentury and it is not known how it spread to Central America from itsoriginal place of origin in Amazon basin.The cultivation later spread to Venezuela, Caribbean Islands andother areas in South America and from Caribbean area to Philippinesand Malaysia. From there it might have come to Sri Lanka and Indiathrough introductions (Ratnam, 1961).The major cocoa producing countries are: Trinidad, Brazil, Costa Rica,Ghana, Nigeria, Malaysia, Indonesia, Colombia, Madagascar, Cuba, FijiIslands, India, China, Mexico, Guyana, Jamaica, Sri Lanka.Almost 90 per cent of the worlds cocoa production comes from smallholdings of 2 ha or less as a lower storey crop under mixed croppingsystems.
Area and Production: Area Production Productivity46.3 `000ha 12.9MT 0.3MT/Hectare
Nutritional composition per 100 g cocoa powder: Carbohydrate 16.5 g Protein 21.5 g Fat 11 g Dietary fiber 34 g Polyphenols 7-18 g Theobromine 2.5 g Caffeine 0.1 g Potassium 2g Calcium 150 mg Magnesium 550 mg 700 mg Phosphorous
Botany: Botanical Name: Theobroma cacao Family: Sterculiaceae Chromosome number: 2n=20 It is a wide-branching evergreen tree, reaching 20-25 feet in height and grows in the shade. It starts producing after 4 or 5 years but yields most between 15 and 25 years of age. Two harvests are made yearly. The plant is ‘ cauliflorous with flowers (and later fruits) protruding directly from the woody branches and trunk. The fruit or pod, reaches to one foot long and 2-4 inches in diameter. There are three main botanical cultivars, namely, ‘Criollo, ‘ Forestero and ‘ Trinitario . The fruit or cocoa pod` is yellow or orange and about 10 inches long, 6 inches wide and weighs about 500 grams. It contains 30to 50 seeds.
• Criollo, the cocoa tree used by the Mayas, is highly prized and rare, less bitter and more aromatic than other beans, from which only 5– 10% of chocolate is made.• Forestero, which include several sub-varieties, are significantly hardier than Criollos trees and produce cheaper cocoa beans, in fact they are used for 80% of world chocolate production. The Arriba variety is considered the best one.• Trinitario, a hybrid of Criollos and Forastero, is used in about 10– 15% of chocolate production.
Sl. No. Character Criollo Forastero1. Cotyledons Plumpy and white when fresh Flat and purple when & turn cinnamon coloured on fresh & turn dark fermentation. chocolate brown on fermentation.2. Pod colour Dark red Yellow3. Other pod characters Rough surface, ridges Smooth ridges, thick prominent, pronounced point walled, melon shaped & thin walled. with rounded end.4. Flavour and aroma Bland flavour Harsh flavour, bitter taste5. Duration of 3 days 6 days fermentation6. Adaptability in India Poor adaptability and less Good adaptability and yield potential & hence high yielding & hence discouraged for commercial recommended for cultivation. commercial cultivation.
Other species of Cocoa:• Theobroma angustifolium• T. bicolor• T. chocoense• T. gileri• T. grandiflorum• T. mammosum• T. microcarpum• T. obovatum• T. speciosum• T. sylvestre• T. velutinum
Pollination and Thinning:• Cocoa flowers are Self-incompatible.• Flowers open in the early morning and hand pollination accomplished by using a small artists paint brush that is first placed in contact with the anthers of an open flower and then placed in contact with the stigma of another flower.• Cocoa plants may set a large number of fruit, which may lead to plant decline. In general, only 1 to 2 pods should be allowed to develop at any one flowering cushion on a limb.• The vector of pollination are small midges of Dipteran familiesCeratopogonidae and Cecidomyiidae
Genetics and breeding: Breeding objectives:• High yield• Resistant to disease (CSSV and black pod)• Flavour• Adoption to local climate• Early and sustainable bearing Constraints in breeding• Genetic base of cocoa is very narrow• Environment problem• Alternate bearing• Cross incompatibility• Limitation of space
Germplasm collection:• 159 Exotic cultivars are maintained in CPCRI, Kasaragod.• In India, the crop improvement work started during 1980s at Vittal and Vellanikara. This involved selection of parental material, evaluation and production of hybrids.• At Vittal four progeny trials with 57 combinations have been field evaluated (Bhat, 1999).• At KAU, Vellanikara a total of 119 crosses were made and some of these have been assessed (Nair et aI, 1994). Breeding for drought tolerance has also been done in CPCRI, Vittal (Balasimha et al., 1988; Balasimha et al., 1999).
• Nine accessions were evaluated for yield and related characters at Bangalore in 1986-87 (Nair et aI, 1990).• ICS-l and ICS-6 performed best for number of pods/plant (71.3 and 69, respectively) and bean yield (3.5 and 2.2 kg/plant), and had good plant heights and canopy spreads.• Single-bean weight was greatest in IMC-67(2 g) and this accession had the best pod value.
In India ten varieties were released from Cadbury Cocoa Research Project, Kerala Agricultural University, Thrissur, Kerala. CCRP 1 to 7 are improved clones of Forestero type developed through single plant selections from local populations and exotic collections. CCRP 8 to 10 are hybrids. All varieties are tolerant to vascular streak die back.
1) CCRP 1:• Pods medium sized, green which changes to yellow on ripening, constricted at base, blunt beak and moderately deep ridges and furrows. Trees are self incompatible. Mature pods weigh 385 g, with 46 beans and 0.8 g oven dry bean weight.• Average yield 56 pods / tree / year with a potential yield of 72 pods.2) CCRP 2:• Pods large, green in colour changing to yellow on ripening.• The rind is smooth with thin pericarp. Trees are self incompatible.• Mature pods weigh 311.3g with 45.5 beans and 0.9g oven dry bean weight. On an average a tree yields 54 pods/plant /year.
3) CCRP 3:• Pods medium sized, large in number, green in colour changing to yellow on ripening.• Trees are self incompatible.• Mature pods weigh 240.6g with 42.3 beans and 1.0g oven dry bean weight. On an average a tree yields 68 pods/plant /year.4) CCRP 4:• Pods large, purple tinged turning yellow on ripening.• Trees are self incompatible.• Mature pods weigh 402 g with 45beans and 1.1 g oven dry bean weight.• Average yield is 66 pods l tree/year with a potential yield of 93 pods.
5) CCRP 5:• Pods large, elliptical, green when immature turns yellow on ripening,• Trees are self incompatible.• Mature pods weigh 425 g with 42 beans and 0.8 g oven dry bean weight.• Average yield is 38 pods/tree/year with a potential yield of 55 pods.6) CCRP 6:• Pods are very big, green turning to yellow on ripening.• Rind thick, elliptical without basal constriction, with shallow ridges and furrows.• Trees are self incompatible.• Mature pods weigh 895 g with 48 beans and 1.9 g oven dry bean weight.• Average yield is 50 pods/ tree/year with a potential yield of 180 pods.
7) CCRP 7:• Pods large, elongated, green turning to yellow on ripening, pod surface rugose, moderately deep ridges and furrows.• Trees are self incompatible.• Mature pods weigh 526 g with 47 beans and 0.9 g oven dry bean weight.• Average yield is 78 pods / tree with a potential yield of 95 pods.8) CCRP 8:• Hybrid between CCRP 1 x CCRP 7.• Trees are self-incompatible.• Pods green, medium sized, turning yellow on ripening.• Mature pods weigh 389 g with 49 beans and 0.88 g oven dry bean weight.• Average yield 90 pods/tree giving 11.40 kg wet beans.
9) CCRP 9:• Hybrid between CCRP 1 x CCRP 4.• Trees are self incompatible.• Pods green, medium sized, turning yellow on ripening.• Mature pods weigh 370 g with 37 beans and 0.8 g oven dry bean weight.• Average yield 106 pods/tree giving 8.97 kg wet beans.10) CCRP 10:• Hybrid between CCRP 3xGVI 68.• Trees are self incompatible.• Pods green, medium sized turning yellow on ripening.• Mature pods weigh 332 g with 41 beans and 1.1 g oven dry bean weight.• Average yield is 80 pods/ tree giving 8.15kg wet beans.
Web links:• CPCRI, Kasaragod.• http://www.skillsspace.co.uk/images/flash_processing.gif Dt 15/10/2011• http://www.food-info.net/images/chocolateflowsheet.jpg