Performance of selected cocoa (Theobroma cacao L.) clones under arecanut and coconut

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Growth and yield performance of Trinidad cocoa (Theobroma cacao L.) collections in Karnataka

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Evaluation of selective cocoa (Theobroma cacao L.) clones from Central and South America in their initial years of growth

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Assessment of morphological, physiological and molecular characteristics of cocoa accessions from Central and South America in relation to drought tolerance

Eleven cocoa accessions, representing collections from five central and south American countries, were assessed for their morphological, molecular and physiological parameters. Growth characters were observed in three year old plants and initial pod yields were recorded. Photosynthesis, related parameters and chlorophyll indices, measured during two seasons, showed significant differences between non-stress and stress periods as well as among the genotypes. The transpirational water loss was reduced with increased stomatal closure, which is a favourable drought trait in crops. The results indicated that the genotypes showing higher water potential and Fv/Fm ratio can be considered as drought tolerant. The rank sums of these parameters showed that genotypes JA-1/19, POU-16/A and SC-4 were the most drought-tolerant. Microsatellite markers were used to assess the extent of genetic diversity between clones. The amplification of DNA from the 11 accessions using the 15 microsatellite loci revealed a total of 80 consistent and scorable alleles with an average of 5.33 alleles per locus and all the loci were 100 per cent polymorphic, the most polymorphic locus being mTcCIR33 with 8 alleles. The observed heterozygosity ranged from 0.36 to 0.63 with an average of 0.52. The inbreeding co-efficient (f) ranged from -0.22 (mTcCIR8) to 0.58 (mTcCIR40) with an average of 0.32. The microsatellite marker analysis revealed that the genotypes possess a wide genetic diversity. The drought tolerant types identified in this study viz., JA-1/19, POU-16/A and SC-4 could be used for cultivation in areas with moisture deficient stress and in selective cocoa breeding programs for drought tolerance

Early performance of cocoa (Theobroma cacao L.)genotypes in arecanut under Assam condition of North Eastregion of India

Cocoa is an important plantation crop grown in southern parts of India. Though many cocoa varieties have been released for cultivation in different parts of India, there is no variety recommended for cultivation exclusively for India’s North East region, especially Assam, where arecanut is grown as an important cash crop. Therefore the present investigation was undertaken to study the performance of twelve cocoa genotypes for its growth, pod yield and yield attributing traits for subsequent research programmes. The data for growth, pod yield and yield attributing traits were recorded three years after planting for five years (2015 to 2019), and the mean data were used for analysis. Genotype VTLC 11 significantly produced greater plant height (2.70 m), stem circumference (27.73 cm), height at jorquetting (36.16 cm) and canopy area (17.00 m2). Mean average pod yield among the genotypes varied from 20.65 to 48.40 tree-1 year-1. Genotype VTLC 19 produced significantly higher pod yield (48.40), number of fresh beans pod-1 (34.06), fresh bean weight pod-1 (229.65 g), dry bean weight pod-1 (119.32 g), single dry bean weight (1.20 g) and dry bean yield (1.76 kg). Considering the most economic traits of cocoa, VTLC 19 appears to be the most suitable genotype for commercial cultivation in the region

Evaluation and identification of high yielding trees in Nigerian cocoa germplasm

Forty four Nigerian cocoa clones which are being conserved in the field gene banks of Central Plantation Crops Research Institute, Regional Station, Vittal, Karnataka were assessed for their growth and yield performance. Six year old trees were observed for their morphological characters and annual pod yields were compiled over eight years from five to twelve years of age after planting. Pod and bean characteristics were also studied for all the clones. Precocious, potential high yielders were identified from their vigorous growth habit in the introduced environment with sturdy stems and optimal canopy spread. Among the clones, NC-37, NC-23, NC-26, NC-50, NC-20, NC-51, NC-27 and NC-25 were identified as heavy bearers with an average of 61.9, 53.3, 49.4, 48.4, 45.1, 44.2, 43.9 and 43.0 pods per tree per year respectively and with high dry bean yields of more than one kilogram per tree per year. These clones recorded single bean weight of more than 1 gram, 10-15 per cent shelling percentage and more than 50 percent fat which made them suitable for industries as well

Early evaluation of cocoa (Theobroma cacao L.) clones as intercrop in coconut gardens under red river region of Assam State, India

A field experiment was conducted at Horticultural Research Station (AICRP on Palms), Kahikuchi of Assam Agricultural University for three consecutive years (2018-20) to study the initial performance of cocoa clones as intercrop in adult coconut (Cocos nucifera L) garden spaced at 7.5 m × 7.5 m taking sixteen cocoa clones. Data on tree height, stem girth, number of pods, pod weight, number of beans pod-1, dry bean weight tree-1 year-1 and single dry bean weight revealed significant variations among the 16 cocoa clones. Dried beans are the prime economic produce of cocoa, and single dry bean weight ranged from 0.95 to 1.4 g. With respect to dry bean yield tree-1, VTLC-20 recorded a significantly higher dry bean yield of 2.2 kg tree-1 followed by VTLC-18 (1.5 kg tree-1) compared to other cocoa clones, and eight clones yielded more than 1.0 kg dry bean tree-1. Results showed that the number of leaves on the crown, number of inflorescences per palm and nut yield of coconut was not negatively affected; rather, there was an increase in the yield of coconut over a period

Digital phenotyping of coconut and morphological traits associated with eriophyid mite infestation

Observations were recorded on traits associated with mite infestation related at two stages of button on six different coconut cultivars over three years. Highly significant correlation was found between mite damage score with color or weight of tepal. Step-wise multiple regression of the data analysis showed color of inner tepal as major trait associated with infestation by eriophyid mite. Other traits are ratio of tepal weight to tepal area, per cent of buttons with pink discoloration or with resin, tepals of regular aestivation and gap between fruit and tepal. Digital phenotype data of 83 image files were used to calculate color signature and correlated the same to mite damage score over three years. Red spectral values were found to vary from 14 to 251, green values to 12 to 237 and blue to vary from 5 to 183. Spectral values red max, green max, 3* Red + Green max had high significant negative correlation (>-0.4) with mite damage. Color and firmness of fruits and tepals of three coconut varieties were further analyzed where, fruits and tepals of COD variety showed high red/green (a* value of Hunterlab) >12. Firmness of 3 month old tepal and fruit of Benualim (BGRT) tall variety was (penetrometer reading >38) higher than other varieties

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