Basal Temperature and Thermal Constant for the Production of Cacao Tree Seedlings
Robson Prucoli Posse *
Federal Institute of Espírito Santo – Campus Itapina, Highway BR-259, Km 70, Countryside, Post Office Box 256, CEP: 29709-910, Colatina, Espírito Santo, Brazil
Francielly Valani
Federal Institute of Espírito Santo – Campus Itapina, Highway BR-259, Km 70, Countryside, Post Office Box 256, CEP: 29709-910, Colatina, Espírito Santo, Brazil
Carlos Alberto Spaggiari Souza
Cacao Research Station “Filogônio Peixoto” - CEPLAC, Highway BR 101 N, Km 150, CEP: 29900- 000, Linhares, Espírito Santo, Br
Sheila Cristina Prucoli Posse
Instituto Capixaba de Pesquisa, Assistência Técnica e Extensão Rural – INCAPER, Street Afonso Sarlo, 160, CEP: 29052-010, Vitória, Espírito Santo, Brazil
Ramom Amaro de Sales
Center for Agrarian Sciences and Engineering – Federal University of Espírito Santo, Alto Universitário Street, S/No, Guararema, CEP: 29500-000, Alegre, Espírito Santo, Brazil
Evandro Chaves de Oliveira
Federal Institute of Espírito Santo – Campus Itapina, Highway BR-259, Km 70, Countryside, Post Office Box 256, CEP: 29709-910, Colatina, Espírito Santo, Brazil
Waylson Zancanella Quartezani
Federal Institute of Espírito Santo – Campus Montanha, Highway ES 130, Km 01, CEP: 29890-000, Montanha, Espírito Santo, Brazil
Marta Cristina Teixeira Leite
Federal Institute of Espírito Santo – Campus Itapina, Highway BR-259, Km 70, Countryside, Post Office Box 256, CEP: 29709-910, Colatina, Espírito Santo, Brazil
*Author to whom correspondence should be addressed.
Abstract
The temperature is one of the climatic factors of greater importance in the physiological processes of the plants, being directly related to its growth and development, which need a thermal accumulation to complete its phenological cycles. The objective of this work was to evaluate the contribution of temperature to cacao tree seedlings (genotype TSH1188) development, thus determining its lower basal (Tb) and upper (TB) temperature as well as the thermal sum in degree-day (DD) required for its production with quality. The study was carried out in the Horticulture sector of the Federal Institute of Espirito Santo - Campus Itapina, Colatina/ES, conducted under a completely randomized design in three planting seasons with different climatic conditions. For the estimation of Tb, four different estimation methods were used: standard deviation in degree-day (SDdd), the standard deviation in days (SDd), the coefficient of variation in degree-day (CVdd) and relative development (RD). The upper basal temperature (TB) was estimated similarly to Tb, with the exception of the RD method. The basal temperatures (Tb and TB) were estimated by means of the average values obtained in the methods used and the thermal sum, obtained in each planting season, using the mean Tb value, from the emergence of the seedlings, by the sum of the degree-days. The estimated values of lower and upper basal temperature were respectively 10°C and 37°C and the mean thermal sum for a quality cacao tree seedling production is 1018°C. In order to obtain a production of quality cacao tree seedlings in different climatic conditions, it is possible to evaluate the development of the variables height, stem diameter and number of leaves of the cacao tree seedlings as a function of accumulated degrees. The time required for the production of cacao tree seedlings varies according to the season of the year. Cacao tree seedlings conducted in periods with higher temperatures took less time to form with quality.
Keywords: Theobroma cacao L., degree-days, vegetative development, heat units, genotype TSH1188, phenology