Cacao Fruits Research Articles

Shade tree management affects fruit abortion, insect pests and pathogens of cacao

The mortality of cacao fruits caused by early fruit abortion or insect and pathogen attacks was investigated in differently managed agroforestry systems in Central Sulawesi, Indonesia. Nine agroforestry systems shaded by three different types of tree stands were selected, which represented a decrease in structural heterogeneity: forest remnants, diverse planted trees and one or two species of planted leguminose trees. After standardized manual cross-pollination, the development of 600 fruits on 54 trees (6 trees per agroforest) was followed during 18 weeks of fruit development. In total, 432 of all fruits were lost before maturity, which seriously undermined yields. The proportion of harvested fruits per tree (overall average: 27 ± 4%) was not affected by canopy type. Although shade cover did not have a significant effect, losses due to fruit abortion were most likely under forest shade, where nitrogen-fixing leguminose shade trees were absent. Fruit losses due to pathogenic infections and insect attacks increased with the homogenization of the agroforests, supporting the hypothesis that agricultural homogenization increases risks of pest outbreaks. In conclusion, shade management may be improved to increase yields from cacao using highly diversified natural shade agroforestry systems.

Biosynthesis, accumulation and degradation of theobromine in developing Theobroma cacao fruits

We have studied the purine alkaloid content and purine metabolism in Theobroma cacao fruits at differing growth stages: Stage A (young small fruit, fresh weight, ca. 2 g); stage B (medium size fruit, fresh weight, ca. 100 g) and stage C (large size, fresh weight, ca. 500 g). The major purine alkaloid in stage A fruits (mainly pericarp) was theobromine (0.7 micromol g(-1) fresh weight), followed by caffeine (0.09 micromol g(-1) fresh weight). The theobromine content of the pericarp decreased sharply with tissue age, and the caffeine content decreased gradually. A large amount of theobromine (22 micromol g(-1) fresh weight) had accumulated in seeds (mainly cotyledons) of stage C fruits. Theobromine was found also in the seed coat and placenta. Tracer experiments with [8-(14)C]adenine show that the major sites of theobromine synthesis are the young pericarp and cotyledons of T. cacao fruits. Limited amounts of purine alkaloids may be transported from the pericarp to seed tissue, but most purine alkaloids that accumulated in seeds appeared to be synthesised in cotyledons. Degradation of [8-(14)C]theobromine and [8-(14)C]caffeine to CO2 via 3-methylxanthine and ureides (allantoin and allantoic acid) was detected only in the pericarp of stage C fruits.

On two fungal rots of cacao

Two new fungal rots, Phomopsis folliculicola and Fusarium decemcellulare, of cacao fruits collected from Kerala (Southern India) are described together with their etiology.

Translocation of phosphorus-32 into wilting and healthy fruits of cacao (Theobroma Cacao)

The uptake of phosphorus into young cacao fruits (cherelles) was studied by applying 1.0 mC of P-32 to tins of soil in which young cacao trees were growing. The radiation from the fruits was measured daily with a shielded end-window G-M tube until the fruit wilted. While the fruit remained healthy accumulation of P-32 was linear and uptake continued for about three days after the fruit stopped growing (the first sign of wilting); uptake of P-32 then ceased. An increase in the count rate as the fruit became flaccid was attributed to reduced self-absorption due to loss of water. The distribution of the radio-active phosphorus in the seeds and pericarp was investigated and comparative analyses of phosphate in wilting and healthy fruits are presented. The results provide additional evidence for the hypothesis that cherelle wilt is analogous to a fruit-thinning mechanism.

Wilt of Cacao Fruits (Theobroma Cacao): V. Seasonal Variation in Potassium, Nitrogen, Phosphorus, and Calcium of the Bark and Wood of the Cacao Tree

Wilt of Cacao Fruits (Theobroma Cacao): V. Seasonal Variation in Potassium, Nitrogen, Phosphorus, and Calcium of the Bark and Wood of the Cacao Tree

Wilt of Cacao Fruits (Theobroma Cacao): IV. Seasonal Variation in the Carbohydrate Reserves of the Bark and Wood of the Cacao Tree

Journal Article Wilt of Cacao Fruits (Theobroma Cacao): IV. Seasonal Variation in the Carbohydrate Reserves of the Bark and Wood of the Cacao Tree Get access E. C. HUMPHRIES E. C. HUMPHRIES 1Imperial College of Tropical AgricultureTrimidad, B.W.I. Search for other works by this author on: Oxford Academic PubMed Google Scholar Annals of Botany, Volume 11, Issue 2, April 1947, Pages 219–244, https://doi.org/10.1093/oxfordjournals.aob.a083155 Published: 01 April 1947

Wilt of Cacao Fruits (Theobroma Cacao)

Journal Article Wilt of Cacao Fruits (Theobroma Cacao): III. Changes in Mineral Content during Development Get access E. C. HUMPHRIES E. C. HUMPHRIES Imperial College of Tropical AgricultureTrinidad, B.W.I. Search for other works by this author on: Oxford Academic PubMed Google Scholar Annals of Botany, Volume 8, Issue 1, January 1944, Page 57, https://doi.org/10.1093/oxfordjournals.aob.a088552 Published: 01 January 1944

Wilt of Cacao Fruits (Theobroma Cacao)

Journal Article Wilt of Cacao Fruits (Theobroma Cacao): III. Changes in Mineral Content during Development Get access E. C. HUMPHRIES E. C. HUMPHRIES Imperial College of Tropical AgricultureTrinidad, B.W.I. Search for other works by this author on: Oxford Academic PubMed Google Scholar Annals of Botany, Volume 8, Issue 1, January 1944, Page 57, https://doi.org/10.1093/oxfordjournals.aob.a088552 Published: 01 January 1944