Growth and calyx yield response of roselle (Hibiscus sabdariffa L.) to fertilizer in southwest Nigeria

Roselle (Hibiscus sabdariffa L.) is an important but underexploited traditional vegetable. The dearth of information on its fertilizer requirement has curtailed its production on a commercial scale. Field trials were conducted at Abeokuta and Ibadan southwest Nigeria, respectively, to evaluate the response of roselle to fertilizers. Fourteen treatment combinations were fitted into randomized complete block design with three replicates. Seven fertilizer rates including NPK 15-15-15 fertilizer at 200, 300 and 400 kg ha^-1; 'Alesinloye' organic fertilizer (AOF) at 2.5, 5.0 and 7.5 t ha^-1; and no fertilizer (control) applied to white and red varieties of roselle. Data were collected on plant height, number of leaves and branches, shoot dry weight, number of calyx plant^-1 and weight of dry calyx. Application of 7.5 t ha^-1 AOF gave significantly (p<0.05) more leaves in white roselle compared to the red varieties at both locations. Also, AOF at 7.5 t ha^-1 produced significantly (p<0.05) higher dry calyx yield for white roselle relative to red in Abeokuta and Ibadan, respectively. Since AOF at 7.5 t ha^-1 elicited crop performance compared to other fertilizer treatments, it is recommended for production of roselle in southwest Nigeria.