Diversidade fenotípica e parâmetros genéticos de Coffea canephora Pierre ex A. Froehner no estado do Amazonas

Abstract

Coffee is one of the most widely consumed beverages in the world, being the second most exported product and one of the main sources of income in Brazil. Its cultivation is an important activity in the agricultural sector and extremely relevant for socioeconomic development in Brazil. Among the species of the genus Coffea, Coffea arabica and Coffea canephora stand out, representing 99% of world coffee production. The species Coffea canephora is diploid, perennial, allogamous, with easy vegetative propagation and presents a gametophytic self-incompatibility system that gives it a high genetic variability, making it an object of study in breeding programs in order to generate clones and varieties with adaptation skills, acclimatization, high productivity and better beverage quality. Some parameters are affected by the genetic variability that the species presents, so that the genotypes present varied responses under different conditions to which they are submitted. And one of these parameters is the nutritional status of the plant, since factors such as accumulation and absorption of nutrients as well as the efficiency of their use can be affected by genetic factors. Given the above, the objective of this work was to analyze inorganic components present in soils and in tissues and fruits of fifteen clones of Coffea canephora established in plantation at the Experimental Farm of UFAM, through the analysis of plant tissues and soils, to study the phenotypic diversity and genetic parameters, aiming to select superior genotypes to establish commercial plantation in the state of Amazonas. For the analysis of adaptation of the clones, quantitative characters were taken into account, such as: total plant height (m), length of the orthotropic branch (cm) and length of the plagiotropic branch (cm). For the quantification of mineral elements accumulated and absorbed by Coffea canephora, soil and tissue samples (leaves, roots and fruits) were collected from the experiment established at the UFAM experimental farm and were subjected to analysis by means of X-ray Fluorescence by total dispersion (TXRF). These data were submitted to tests of normality and homogeneity of variances. Phenotypic mass selection of superior genotypes was performed for selection, considering the average of the clones for height characters, inorganic components of the leaves that showed a significant difference, and the clone productivity data. The genotypes were grouped by the hierarchical method of mean distances (UPGMA) and graphical dispersion was performed by the Principal Coordinate Analysis Method (PCA) and non-metric multidimensional scaling analysis for inorganic component analysis. Soil samples indicated high levels of Al and contamination by trace elements, indicating that the species can be considered accumulating and tolerant. The Coffea canephora genotypes demonstrated the existence of genetic variability for plant height, accumulation of Cu, Rb, Hf and I in leaf tissues and for original and estimated grain yield and productivity. Indicating that there is a difference in adaptation and vegetative growth between the genotypes evaluated in the region of Manaus and that there is a possibility of selection of a superior genotype.