Desempenho de genótipos de Coffea canephora cultivados sob condições contrastantes de disponibilidade de irradiância e nitrogênio

• Autor(a) principal: Machado, Lindomar de Souza
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/13143
• topic: Melhoramento Vegetal; Coffea canephora; Melhoramento genético de cafeeiro; Melhoramento de planta para condições de estresse; Fisiologia da produção; Parâmetro alfa; Genetic breeding of coffee; Plant breeding for stress conditions; Production physiology; Alpha parameter; subject.br-rjbn

The coffee originates from the tropical forests of Africa, where it is found spontaneously as understorey vegetation. In Brazil, coffee plantations are being conducted almost exclusively in full sunshine, where production is in many cases greater than in shaded plantations. As a consequence, shading as a regular cultural practice has been virtually abandoned. However, it should be noted that full-sun coffee plantations are usually subsidized at the expense of large increases in input use, mainly nitrogen fertilizers, as well as increasing dependence on irrigation systems. However, in Brazil, C. canephora (Conilon / robusta coffee) genotypes currently selected were selected in full sun and therefore, such genotypes could potentially have adaptive limitations at low irradiance to a greater extent than possible selected genotypes exclusively for shaded environments. Due to the impacts of climate change, there has been an increasing interest in the adoption of shaded systems, particularly in marginal areas with large temperature fluctuations and occurrence of water deficit. As in shaded systems, ecosystem preservation and improvement of edaphoclimatic conditions, as well as improvements in beverage quality and attenuation of the biennial production cycle, are frequently observed. However, the search for shade tolerant materials requires the evaluation of a high number of genotypes under field conditions to obtain, at the end of several years, a few promising materials. The objective of this work (i) was to study the phenological variations in the growth and morphology of genotype production components, associating efficiency and / or responsiveness criteria, and (ii) to verify in a preliminary way the analysis of genetic parameters of morphophysiological characteristics for possible indirect selections as well as the diversity of the genotypes when cultivated under contrasting availability of irradiance and nitrogen. For this, 14 C. canephora genotypes, pre-improved in the experimental farm of Pacotuba, in the municipality of Cachoeiro de Itapemirim - ES, of the Capixaba Institute for Research, Technical Assistance and Rural Extension, were submitted to two irradiance conditions {full sun (PS) and 30% shading (SB)}, and two nitrogen (N) {25 (N25) and 100% (N100)} conditions of the recommended crop. The genotypic factors and irradiance are responsible for the greater portion of the variation verified; the nitrogen factor did not interfere in the productive levels evaluated. The 106-P genotype has dual irradiance capability. Genotypes 2B / 88-P, 108-P and 109-P are productive in shading. There is genetic diversity among the evaluated genotypes.