Temperature regime, light conditions and sowing depths as determinants of germination potentials of green and red roselle, Hibiscus sabdariffa L.

Abstract

Hibiscus sabdariffa L. - Roselle is a nutraceutical crop whose nutritional and health benefits have been exploited for decades in most parts of the world. The plant is not commonly cultivated in South Africa and only red roselle is grown where found. To improve cultivation of roselle, germination  potentials and requirements of the plant in the region need to be determined as the species is propagated mainly by seeds. This study was aimed at assessing the effects of different sowing depths, temperature and light conditions on the germination of seeds of green and red cultivars of roselle to ascertain the best environmental conditions for their germination. Germination of both cultivars were determined under controlled conditions using completely randomized design. A one-way analysis of variance was used to analyze the data and means were separated using Fisher’s Least Significant Difference. This study revealed that seeds of both cultivars germinate optimally on soil surface at 20^oC. Also, it was discovered that green cultivar does not need light for germination while red roselle may require little light with much dark to germinate.