Abstract
Roselle (Hibiscus sabdariffa L.) is an annual plant that belongs to the family Malvaceae. It is a plant with a rich history of cultivation and utilization in traditional cuisines and medicinal practices. A field experiment was conducted to study the outcomes of different poultry manure rates and planting space on growth, yield, disease incidence and severity of Roselle plants. The research was carried out at the Research Farm of the Crop Science and Horticulture Department, Nnamdi Azikiwe University, Ifite-Ogwari, Anambra State Nigeria. The experiment was a 4×2 factorial laid out in a Randomized Complete Block Design (RCBD) with three blocks and eight treatment combinations. The two planting distances used were: 60×60 cm and 60×45 cm while poultry manure (PM) rates were: 0, 1.5, 2.5 and 3.5 t ha-1. Data on growth parameters, yield characteristics, and disease incidence were collected over a period of 12 weeks. Analysis of variance (ANOVA) was conducted using the SAS software, and significant differences among treatment means were evaluated using the Least Significant Difference (LSD) at a 5%probability level. The results showed that planting space (60×45 cm and 60×60 cm) and poultry manure rates (0, 1.5, 2.5, 3.5 tons) did not significantly affect plant height, number of leaves, leaf area, number of buds, number of flowers, or total yield. However, the interactive effects of planting space and manure rate showed some variations in growth characteristics. Despite non-significant variations in treatments, poultry manure at 3.5 tons per hectare consistently yielded the best growth parameters, particularly at a planting space of 60×60 cm. Furthermore, there was no significant difference in disease incidence and severity among the treatments. However, higher rates of PM were associated with increased disease severity. In conclusion, the significant effect of the PM rates and the planting space on growth and yield characteristics, disease incidence and severity may be due to the close proximity of the two planting spaces and the PM used. Farmers are recommended to adopt wider planting spaces and higher rates of PM for improved growth and yield. Additionally, purchasing disease-resistant seeds and planting at the onset of the rainy season are advisable practices to mitigate disease incidence and enhance overall crop productivity.