Crop Improvement

Crop Improvement
    The cocoa germplasm has been utilized for crop improve¬ment, in some ways. They are:
    • Evaluation and selection of superior clones which are adapted to the locality with desired traits like higher bean yield and resistance/ tolerance to biotic and abiotic stresses, testing their performance in comparative yield trials and large-scale production of clonal materials from elite clones.
    • Production of first-generation hybrids of self-incom¬patible high-yielders, assessment of their performance and selection of superior hybrids. The important-biotic factors considered are resistance to black pod disease and vascular streak die-back and drought tolerance among abiotic stresses.

    Selection criteria in cocoa
    Trees with medium canopy under intercropping system
    • Earliness in bearing
    • Vigor and yielding efficiency
    • Compatibility reaction
    • Trees bearing lot of fruits with 70 – 100 pods/tree/year
    • Medium to large pods of not less than 350g weight, smooth or shallow furrows on the surface without prominent constriction at the neck
    • Pod value (Number of pods required to produce 1 kg beans) to be not more than 12
    • Husk thickness of pods to be more than 1cm
    • Number of beans per pod should be more than 35
    • Bean weight should be more than 1gram
    • Dry bean yield should be more than 1kg/tree/year
    • Shelling percentage- 10 -15%
    • Fat content > 50%
    • Resistance breeding (India) – Black pod disease (Phytophthora), Vascular Streak Die back, Ceratocystis wilt, tea mosquito bug and drought.

    Varieties
    • Several high-yielding varieties/hybrids have been released from India, Indonesia, Trinidad and Costa Rica.

    India
    • Five varieties were released from Cadbury-Cocoa Research Project, Kerala Agricultural University, Thrissur, Kerala, through single plant selection from local populations and exotic collections. All the clones are tolerant to vascular streak die-back.
    • CCRP I: Pods are medium-sized, green which changes to yellow on ripening, constricted at the base, blunt beak and moderately deep ridges and furrows. The trees are self-incompatible. Mature pods weigh 385 g, with 46 beans and 0.8 g oven-dry bean weight. On an average, a tree yields 56 pods /year, with an yield potential of 72 pods.
    • CCRP II: It is a single plant selection from local population. It has spherical pods with obtuse apex. No ridges and furrows in the pods and yields 54 pods /tree /year.
    • CCRP III: It is a selection from open pollinated seedling of T76/1224/1201 (Amazon). It has elliptic pods with moderate ridges and furrows. It yields 68 pods per tree with 42 beans /pod.
    • CCRP IV: Pods large, purple tinged, turning yellow on ripening, beaked with acute tip, basal constriction shallow or absent, pericarp deeply rugose with deep ridges and furrows. The trees are self -incompatible. Mature pods weigh 402 g with 45 beans and 1.1 g oven-dry bean weight. On an average, a tree yields 66 pods/ year with a yield potential of 93 pods.
    • CCRP V: Pods large, elliptical, green when immature turn yellow on ripening, moderately deep ridges and furrows, apex acute. Trees are self-incompatible. Mature pods weigh 425 g with 45 beans and 0.8 g oven-dry bean weight. Average yield is 38 pods/tree/year with a yield potential of 55 pods.
    • CCRP VI: Pods very big, green turning to yellow on ripening, thick rind, elliptical without basal constriction, apex obtuse, pod surface rugose 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 an yield potential of 180 pods.
    • CCRP VII: Pods large, elongated, green, turning to yellow on ripening, beaked with acute apex, slight basal constric¬tion, pod surface rugose, moderately deep ridges arid furrows. The trees are self-incompatible. Mature pods weigh 526 g with 47 beans and 0.9 g oven-dry bean weight. Average yield 78 pods/tree with an yield potential of 95 pods.
    • CCRP 8: Hybrid between CCRP 1 x CCRP 7. Trees are self-incompatible. Pods green, medium sized, turning yellow on ripening, apex attenuate, base intermediate, rugosity intermediate. 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.
    • CCRP 9: Hybrid between CCRP 1 x CCRP 4. Trees are self incompatible. Pods green, medium sized, turning yellow on ripening, apex attenuate, base strong, rugosity intermediate. 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.
    • CCRP 10: Hybrid between CCRP 3x GVI 68. Trees are self incompatible. Pods green, medium sized turning yellow on ripening, apex attenuate, base intermediate, rugosity intermediate. Mature pods weigh 332 g with 41 beans and 1.1 g oven dry bean weight.
    • Average yield is 80 pods/tree giving 8.15 kg wet beans
    • Central Plantation Crops Research Institute, Regional Station, Vittal (Karnataka): Drought tolerant accessions NC 23, NC 29, NC 31, NC 39 and NC 42 have been identified
     

Last modified: Sunday, 1 April 2012, 6:40 PM