Análise de diversidade genética e ecofisiologia de germinação de Theobroma cacao L.
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Data
2018-02-22
Autores
Lavanhole, Daniele Freisleben
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Editor
Universidade Federal do Espírito Santo
Resumo
The great variability of fruits and seeds makes it difficult to distinguish existing groups
of cocoa. The analysis of genetic diversity has been an important tool to subsidize
the identification of promising materials for commercial use. Another factor is the
variability between the different cacao genotypes at temperature, highlighting the
need and the opportunities for the adequate correlation of the planting material with
the local environments. This work is divided into two chapters, the first chapter
entitled "Analysis of genetic diversity of Theobroma cacao L.", aiming to analyze
genetic diversity using biometric characteristics of fruits and seeds of cacao
genotypes, aiming to identify promising materials for commercial use. The genotypes
evaluated were Common, TSH-1188, ESFIP-02, CCN-51, Ipiranga-01, SJ-02, PH-16,
PS-1319, CEPEC-2002 and Catongo. Data were submitted to analysis of variance
and the means were grouped by the Scott-Knott test (p <0.05). Multivariate analysis
and estimated genetic divergence were performed by the Tocher and UPGMA
grouping method. Genetic divergence was observed among the cacao genotypes,
with fruit length, fresh seed weight and lower diameter being the characteristics that
contributed most to dissimilarity. The TSH-1188 genotype presented higher averages
for the physical characteristics of the seeds, while, ESFIP-02 and SJ-02 presented
the highest ºBrix. The second chapter entitled "Ecophysiology of germination of
Theobroma cacao L. genotypes" was aimed at evaluating the interaction of genotype
with temperatures and drying periods on germination and post-germination
development of cacao. In the germination test, the temperatures evaluated were 15,
20, 25, 30, 35 and 40ºC constant and 15-25ºC and 20-30ºC alternated, and the
desiccation tolerance was evaluated in the seeds arranged under laboratory
conditions (25ºC + 1ºC of temperature and 65% + 5% of humidity) for 0, 2 and 4
days. Germination and vigor were determined based on root protrusion and normal
seedling formation. The analysis of variance was performed and the means were
compared by the Scott-Knott test (P <0.05). Multivariate analysis was performed and
genetic divergence was estimated by the Tocher and UPGMA grouping method. The
experimental design was a completely randomized design with four replicates of 25
seeds. Regarding thermal extremes, the TSH-1188 genotype can be considered the
most tolerant, while CEPEC-2002, the most sensitive. Both the germination process
and the post-germinative process were influenced by the genotype. TSH-1188,
ESFIP-02 and Ipiranga-01 presented a higher percentage of normal vigorous
seedlings.
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Palavras-chave
Cacao , Espírito Santo , Drying period , Período de secagem , Rootstock , Porta-enxerto , Temperature , Temperatura
Citação
LAVANHOLE, Daniele Freisleben. Análise de diversidade genética e ecofisiologia de germinação de Theobroma cacao L.. 2018. 48 f. Dissertação (Mestrado em Agricultura Tropical) - Programa de Pós-Graduação em Agricultura Tropical, Universidade Federal do Espírito Santo, São Mateus, 2018.