Análise de diversidade genética e ecofisiologia de germinação de Theobroma cacao L.

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Lavanhole, Daniele Freisleben
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Universidade Federal do Espírito Santo
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.
Cacao , Espírito Santo , Drying period , Período de secagem , Rootstock , Porta-enxerto , Temperature , Temperatura
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.