Influence of Colored Shade Nets and Salinity on the Development of Roselle Plants

Abstract

Adequate fertilizer concentration and use of shade nets can favor the development and yield of agricultural crops. The objective of this investigation was to evaluate the growth of roselle plants with nutrient solutions of different electrical conductivities (ECns) (1.0, 2.0, 3.0, 4.0 and 5.0 dS m−1) and under different colored shade nets (red, blue, black) compared with full sun. The experiments were conducted in a controlled greenhouse environment and in full sun in the Plant Production Department of ESALQ-USP, Piracicaba, SP, Brazil. The experiments were organized using a 4 × 5 randomized block design. The results of analysis of variance and regression showed a significant impact of EC and colored shade nets on plant height, stem diameter, number of leaves, number of flowers, fresh and dry mass of shoots and fresh and dry calyxes. The data were subjected to analysis of variance and regression, which showed a quadratic effect for the variables studied, with increasing values up to 3.0 dS m−1; after this value, there was a decrease. Increasing ECns up to approximately 3.0 dS m−1 promoted increments of 2.34% in plant height, 7.21% in number of leaves, 19.76% in shoot fresh mass and 12.38% in shoot dry mass.

Keywords

• <i>Hibiscus sabdariffa</i> L.
• medicinal plants
• nutrient solution
• solar radiation