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Calyx Yield and Nitrogen Use Efficiency of Roselle Hibiscus sabdariffa L as Affected by Variety and Levels of Nitrogen Fertilizer

Hailu Lire Wachamo, Amsalu Nebiyu, Tesfaye Shimbir

Roselle (Hibiscus sabdariffa L.) is an important beverage and leafy vegetable plant. Constraints such as poor soil fertility and a lack of improved varieties have an impact on its growth and yield characteristics. A field trial was conducted to evaluate Roselle’s calyx yield response and nitrogen use efficiency. In this study, two roselle varieties (WG-Hibiscus-Jamaica and WG-Hibiscus-Sudan) and six levels of nitrogen fertilizer (Kg ha^-1 (0, 23, 46, 69, 92, 105) were used in a factorial combination arrangement with three replications in a randomized complete block design. Data on calyx yield, growth variables, and nitrogen use efficiency parameters were recorded. WG-Hibiscus-Jamaica exhibited higher plant height (196.2cm) and branch number plant^-1 (34.9) from the application of 115kg ha^-1 N, while lower values were recorded on an unfertilized plot of both varieties. Variety WG-Hibiscus-Sudan exhibited the highest number of calyx plant^-1 (50.3), fresh calyx yield ha^-1 (5934 kg), and dry calyx yield ha^-1 (1866 kg) from the application of 92 kg ha^-1 N, while lower values were recorded from the unfertilized plot of the WG-Hibiscus-Jamaica variety. A higher nitrogen efficiency ratio (42.5 kg kg^-1) was recorded from WG-Hibiscus-Sudan while a lower value was recorded from WG-Hibiscus-Jamaica. Higher (12.5kg) and lower (0.7kg) agronomic efficiency were recorded from the application of 92 and 115 kg ha^-1 N respectively. WG-Hibiscus-Sudan was effective but not reactive, while WG-Hibiscus-Jamaica was not effective but reactive. In conclusion, for maximum commercial produce, calyx yield and profitability, applying 69 kg ha^-1 N on WG-Hibiscus-Sudan and 92 kg ha-1 on WG-Hibiscus-Jamaica was found best.