Resumo

CASIERRA-POSADA, Fánor  e  ROJAS B., Javier F.. Effect of seedbed exposition to colored covering on development and productivity of broccoli (Brassica oleracea var. italica)  . Agron. colomb. [online]. 2009, vol.27, n.1, pp.49-55. ISSN 0120-9965.

The effect of different light spectrum ranges on broccoli seedling growth was studied by covering the seedbed with yellow, blue, red, orange and transparent plastic films, leaving an uncovered control. At the moment of sowing the seeds in the soil, the colored covers were extended 60 cm above soil surface. Thirty days after germination, the seedlings were transplanted to the field. At that moment, some plantlets were taken out to measure leaf area, dry matter content, plant height and stem diameter of some plantlets were measured. The rest of them were planted in completely randomized plots with four replications per treatment. During the early (seedbed) vegetative stage, the plantlets grown under red cover reached higher dry matter production (0.21 g) than the other treatments or the control, which reached 0.14 g, whereas the plantlets under blue cover showed the poorest dry matter content (0.03 g). This trend was maintained during the field stage, despite the fact that plants there grew fully exposed to sunlight. In effect, red film covered plants showed larger head weight and diameter, as well as better growth. Yield and morphology showed negative results under yellow, blue, orange and transparent covers when compared to those growing under red cover. This effect is here attributed to the differential stimulating effect of the tested light wavelengths on the plantlets during the seedbed stage, which confers concomitant phytotechnical advantages.

Palavras-chave : wavelength; photomorphogenesis; Emerson effect; transmission.

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