Cultivation of yellow melon subjected to different irrigation levels and application of arbolina® biostimulant

ABSTRACT The objective was to evaluate the physiological and biochemical characteristics during flowering, and the total and marketable fruit yield of yellow melon subjected to different irrigation depths and application of the biostimulant Arbolina®. The experimental design was randomized blocks, in a 2×2×5 factorial arrangement of split-split plots, with four replicates. Plots consisted of 2 forms of biostimulant application (fertigation and spraying), subplots consisted of 2 irrigation depths (40% and 100% of crop evapotranspiration - ETc) and sub-subplots consisted of 5 doses of the biostimulant Arbolina® (0; 0.1; 0.2; 0.4; and 0.8 L ha-1). Melon seedlings were transplanted into the soil at a spacing of 2.0 × 0.3 m, with drip irrigation. Basal and topdressing fertilization was performed via fertigation. The variables evaluated were: for total yield and marketable yield, photosynthetic rate, stomatal conductance, internal CO2 concentration, transpiration and leaf temperature, chlorophyll a and b contents, water use efficiency and relative water content. The biostimulant application by spraying had a better effect on the production process of yellow melon plants, promoting better metabolic efficiency in organ-forming cells, including the process of morphological formation and biochemical constitution of the fruits. It is recommended to use of the biostimulant doses of 0.446 and 0.443 L ha-1 combined with the use of 100% of ETc to achieve the highest total and marketable productivity. RESUMO Objetivou-se avaliar as características fisiológicas e bioquímicas durante a floração, e a produtividades de frutos totais e comerciais de melão amarelo submetidas à a diferentes lâminas de irrigação e aplicação do bioestimulante Arbolina. O delineamento experimental foi em blocos casualizados, em arranjo fatorial 2×2×5 de parcelas sub-subdivididas, com quatro repetições. As parcelas consistiram de 2 formas de aplicação de bioestimulante (fertirrigação e pulverização), as subparcelas consistiram de 2 lâminas de irrigação (40% e 100% da evapotranspiração da cultura - ETc) e as subsubparcelas consistiram de 5 doses do bioestimulante Arbolina® (0; 0,1; 0,2; 0,4; e 0,8 L ha-1). As mudas foram transplantadas para o solo com espaçamento de 2,0 × 0,3 m, com irrigação por gotejamento. As adubações de plantio e cobertura foram realizadas via fertirrigação. As variáveis analisadas foram: produtividade total e comercial, taxa fotossintética, condutância estomática, concentração