Biomass production and essential oil in yarrow cultivated under colored screen types

We evaluated the production of biomass, essential oil, pigments and carbohydrates in plants of yarrow grown under colored screen types. Plants were grown in five environments: full sunlight and under Aluminet (R) and black, blue and red screens (50% irradiance). The experiment was carried out in a completely randomized design with four replications and four plants per plot, one plant per pot. Evaluations were done in two moments, the first one at 120 days and the second one at 180 days after planting (regrowth). The highest dry biomass of shoots (36.8 g plant(-1)) and oil yield (4.45 g plant(-1)) were obtained under full sunlight in the second crop. The major oil constituent was chamazulene, which ranged between 19.9 to 46.9%. Growing in full sunlight provides greater accumulation of biomass and essential oil yield. Qualitative and quantitative chemical difference were found in the essential oil compounds among the treatments.