RESUMO
The objective of this study was to characterize the genetic divergence and selection gains of the physicochemical grains traits of 68 genotypes of C. canephora most cultivated in the Western Amazon. For this purpose, the following characteristics were evaluated over two harvests: aqueous extract, ash, acidity, pH, protein, ether extract, soluble solids, phenolic compounds, soluble sugars, reducing sugars, and non-reducing sugars. The genotype × measurement interaction effect was significant for all characteristics, with a predominant simple interaction, resulting in smaller changes in the ranking of genotypes. Out of a total of 45 genotypic correlation estimates, 8 were significant, of which 5 were related to acidity. The dispersion of the first two components associated with reference points shows that the genotypes BRS3193, AS1, AS2, AS3, N16, CA1, and AS7 were closest to the ideal type of higher performance. Selection for the main characteristic of soluble sugars resulted in estimates of genetic progress lower than those observed using selection indices. The genetic materials present high genetic diversity, allowing the selection of reference plants with high levels of sugars (BRS3193, AS3, GJ25, and LB30), proteins (BRS2357), lipids (GJ30), and phenolic compounds in their green beans (BRS3193) and high water solubility (AS2).
RESUMO
The nutritional management of the coffee clonal garden influences the production and physiological quality and seedlings production of vegetative propagules. Thus, this study aimed to analyze the seedlings' production from clonal cuttings taken from Coffea canephora mother plants grown with increasing nitrogen mineral doses. The cuttings were taken from C. canephora var. botany Robusta, from the Embrapa Genetic Improvement Program of Rondônia. The mother plants received nitrogen fertilizer at different doses: 0 (Control); 50; 100; 150; 200; 250 and 300 kg of N per hectare divided into 4 applications, during 150 days of orthotropic stems growth (shoots). The following parameters were evaluated: Dry mass of cuttings, nutritional content of cuttings, and seedlings production, with growth analysis at 0, 48, 61, 80, 101, 122, 143, and 164 days after staking (DAS) and analysis of vegetative characteristics at 122 DAS. The nitrogen fertilization in the mother plant resulted in the variation of macronutrient accumulation in cuttings, but the order K> N> Ca> P> Mg> S was maintained, regardless of N dose. In addition, a positive correlation between nitrogen doses and dry matter accumulation, as well as the physiological quality of seedlings was identified.
O manejo nutricional do jardim clonal de cafeeiros influencia a produção e qualidade fisiológica dos propágulos vegetativos e na produção de mudas. Assim, objetivou-se analisar a produção de mudas a partir de estacas clonais retiradas de plantas matrizes de Coffea canephora cultivada com doses crescentes de nitrogênio mineral. As estacas foram retiradas de plantas matrizes de cafeeiros C. canephora var. botânica Robusta, do Programa de Melhoramento Genético da Embrapa-RO. As plantas matrizes receberam adubação nitrogenada nas doses: 0 (Controle); 50; 100; 150; 200; 250 e 300 kg de N por hectare, parceladas em quatro aplicações, durante 150 dias de crescimento das hastes ortotrópica (brotos). Os seguintes parâmetros foram avaliados: massa seca das estacas, conteúdo nutricional das estacas e a produção de mudas, com análise de crescimento, aos zero, 48, 61, 80, 101, 122, 143 e 164 dias após o estaqueamento (DAE) e a análise das características vegetativas, aos 122 DAE. A adubação nitrogenada na planta matriz resultou na variação do acúmulo de macronutrientes nas estacas, mas a ordem K > N > Ca > P > Mg > S foi mantida independente da dose de N. Além disso, foi verificado que há correlação positiva entre as doses de nitrogênio e o acúmulo de massa seca, assim como, a qualidade fisiológica das mudas.