Biometria, produtividade e fotossíntese de genótipos de Coffea canephora selecionados para qualidade de bebida
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Data
2019-12-19
Autores
Colodetti, Tafarel Victor
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Universidade Federal do Espírito Santo
Resumo
The study of biometric characteristics and crop yield of coffee has been useful for the process of selecting superior genotypes, due to the increasing demand for cultivars adapted to the most different cultivation conditions, contributing to the increase of competitiveness and sustainability of coffee crops. In addition, it is possible that a wide range of descriptors related to agronomic traits, aspects of the crop yield, photosynthetic performance, fruit morphology and water use for production can be used to study the variability among coffee genotypes. In this context, the main objective of this study was to analyze the biometrics, crop yield and photosynthesis of genotypes of Coffea canephora, selected for beverage quality, based on an experimental field with 27 genotypes of Conilon coffee (three clonal cultivars with nine genotypes each), following a randomized block design, with four replications, cultivated in the municipality of Castelo-ES, at an altitude of 126 m, using spacing of 3.0 × 1.0 m. In the first chapter, the variability for agronomic traits and crop yield of the 27 genotypes of C. canephora was analyzed. Fifteen characteristics related to canopy architecture, biometry of plagiotropic branches, classification of grains and mean yield along harvests were evaluated. In each harvest, the yield of each genotype was evaluated. With the results, it was possible to observe the expression of variability among the genotypes of Conilon coffee for the evaluated traits. There was a greater number of groups formed among genotypes based on the crop yield, classification of grains, canopy height, length of internodes of the plagiotropic branch, and total accumulation of dry mass per plagiotropic branch. The genotypes 108 and 201 were the most productive, considering the average of four harvests, highlighting the genotype 201 due to the smaller variation of crop yield, demonstrating greater stability over time. In contrast, the genotypes 203 and 307 were the least productive, while the genotype 106 presented the larger amplitude of production along harvests. In the second chapter, the variability for photosynthetic performance of the 27 genotypes of Conilon coffee was analyzed, by measuring the gas exchange rates and chlorophyll contents at the period most favorable for the photosynthetic activity of the plants (between 8 and 11 a.m.), during different stages of the reproductive cycle: flowering, fruit initiation (pellet-like berry), grain formation and fruit maturation. The photosynthetic performance was expressed as the average (weighted by the number of days) of the gas exchanges and chlorophyll contends sampled in the morning period and in the referred phenological stages of the 2017/2018 crop. With this, it was possible to verify the variability among the 27 genotypes for photosynthetic performance for the reproductive cycle. Among the physiological traits, the carbon assimilation rate, the stomatal conductance and the transpiration rate are highlighted as parameters for the study of variability, mainly due to their contributions to clustering the genotypes. The genotype 108 stood out for a high photosynthetic rate associated with higher chlorophyll contents, as well as reasonable water use efficiency; and the genotypes 205, 206 and 305 for the results in terms of instantaneous carboxylation efficiency, water use and carbon assimilation. In the third chapter, the objective was to evaluate the characteristics and dimensions of the fruit of the 27 Conilon coffee genotypes, as well as to assess the use of this information to study the variability among genotypes. Between the months of May and August 2018, samples of fruits from each genotype were harvested at the stage of maturation to evaluate 15 traits related to the dimensions and mass distributions of structures of ripe fruits and seeds. Among the analyzed traits, the longitudinal length, the total dry mass and the smaller transverse length of the fruits played a fundamental role in the study of variability and in the definition of clusters among genotypes. Overall, the genotype 208 presented fruits with larger main lengths, as well as larger surface area, unitary volume, total content of soluble solids and total dry mass of the fruits, in addition to a higher mass ratio allocated in the grains. The genotype 302 presented contrary results to those observed for the genotype 208. Lastly, in the fourth chapter, the objective was to evaluate the productive efficiency of the 27 genotypes of C. canephora considering the amount of water made available along the productive cycles. During each cycle, the amount of water added to the experimental field through irrigation and precipitation was accounted. After each harvest of the fruits, the crop yield of processed coffee for each genotype was calculated and, by dividing the coffee production of each genotype after each harvest by the amount of available water for that cycle, the efficiency of the production in function of the amount of available water was obtained. There was differential behavior among the 27 genotypes for production efficiency in each cycle, as well as significant differences in efficiency along the years for most genotypes. The genotypes 108 and 201 stood out for presenting, on average, the highest efficiencies, while genotypes 203 and 307 stand out for the lowest. The genotype 102 did not significantly change the production efficiency along cycles, being elected as the most stable among the genotypes. In the current climatic scenario of the regions where coffee is cultivated, the study of the behavior of genotypes of Conilon coffee for productive efficiency arises as a tool to contribute in the selection of genotypes with greater capacity to use the available water.
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Biometria , Cafeeiro Conilon , Genótipos , Produção , Uso da água , Variabilidade genética , Biometry , Conilon coffee , Genotypes , Crop yield , Water use , Genetic variability