Efeitos da intensidade luminosa e do genótipo sobre o crescimento em altura do fuste do cacaueiro
Elongation of the orthotropic axis of cacao (Theobroma cacao L.), which is restricted when the apical bud interrupts meristematic growth and allows for the formation of plagiotropic branches, is affected by genetic and ecological factors. This study contains some assays that intended to investigate the effects of the genotype and light on the rate of stem elongation of cacao seedlings during the period that precedes "branching" of "crowing". With few exceptions, no significant differences were detected within the genotypes tested, indicating that the genotype is not the most important cause of the observed variation on stem length of cacao and remarking the importance of external factors. In one experiment, the hybrid SCA-6 x Catongo was superior than the other genotypes tested. The "Comum da Amazonia" showed higher elongation rate, in other study, than various hybrids observed. Assays in which spacing among cacao trees varied showed that planting density, within the range studied, did not affect stem elongation. Greenhouse studies in which cacao plants were maintained for 19 months under four light intensities showed that the light requirements of a new plantation are under 60 per cent and over 30 per cent direct sunlight. Elongation of the stem is reduced when the seedlings are cultivated at 60 per cent direct sunlight. It was observed than under this treatment cacao plants branch earlier, three months before plants maintained under lower light intensities. Of the levels of light studied, the 36 per cent direct sunlight was better for seedling growth. At lower light intensities stem elongation is normal but dry matter accumulation is reduced in about 25 per cent under the experimental conditions employed. The results of an assay designed to investigate the effects of the species utilized for over-head shade of cacao suggested that higher stem elongation is obtained under the shade of legume trees and allowed to select erythrina (Erythrina glauca) as the best of the species observed
| Main Authors: | , |
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| Format: | biblioteca |
| Language: | por |
| Published: |
Ilhéus (Brasil): CEPLAC,
1981
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| Subjects: | THEOBROMA CACAO, GENOTIPOS, LUZ DEL DIA, ALTURA, TALLOS, RAMAS, SOMBRA, ETAPAS DE DESARROLLO DE LA PLANTA, |
| Online Access: | https://www.gov.br/agricultura/pt-br/assuntos/ceplac/publicacoes/revista-theobroma/theobroma-1981v11n1.pdf/view |
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