Effect of anti-hail nets with different colors on ‘Eva’ apple trees agronomical responses

Abstract The aim of the current research was to evaluate the impact of ‘Eva’ apple tress cultivation under nets with different colors as opposed to cultivation deprived of net treatment on the attributes related to the vigor of the plant, production and fruit quality. The evaluations were carried out during the 2017/18 and 2018/19 crop growing seasons at commercial production fields located in the municipality of Porto Amazonas, PR. The treatments in study consisted of a control (plants grown with no protecting net), along with plants protected by anti-hail nets of distinct colors such as white, crystal (transparent) and black. The following response variables were assessed herein: length and diameter of the branch, plant height and branch diameter as plant vigor measurements, crop production (kg plant-1) and yield (kg ha-1), and number of fruits per plant as to productive yield of the cropping system, as well as shape (height and diameter) of the fruits, mass, Hue angle, firmness, soluble solids and titratable acidity to test grade or fruit quality. There was no significant effect of protecting nets on both vigor and development of the plants. However, production and yield were consistently more expressive under crystal and white protecting nets throughout the second crop growing season. This demonstrated that ‘Eva’ apple trees were conducive to render as well as or even better than those plants bereft of protecting nets in view of the fact that the former treatments caused the plants to suffer less harmful impacts promoted by hail events, excess of wind, and sun burning disorders. The black anti-hail net resulted in negative outcomes as to coloration of the fruits in conjunction with titratable acidity, making them reddish and acidic and, therefore, less attractive for in natura commercial consumption. Resumo Este trabalho objetivou avaliar a interferência do cultivo de macieiras ‘Eva’ sob tela anti-granizo de diferentes cores, em comparação com o cultivo em pleno sol, sobre os atributos relativos ao vigor da planta, à produção e à qualidade de frutos. As avaliações foram realizadas durante as safras de 2017/2018 e 2018/2019 em pomar comercial localizado no município de Porto Amazonas-PR, Brasil. Os tratamentos consistiram em um controle (plantas sem cobertura) e plantas cobertas com telas antigranizo, nas cores branca, cristal (transparente) e preta. As variáveis avaliadas foram as seguintes: comprimento e diâmetro de ramo, altura da planta e diâmetro d