Morpho-agronomic and physiological characterization of African roselle (Hibiscus sabdariffa L.) accessions at Hawassa, Ethiopia

Roselle ( Hibiscus sabdariffa L.) is an important multi-purpose crop utilized as a source of food as well as raw material for industries and medicinal purposes. Recent trends in research and commercial production of roselle have shown promising results in Ethiopia. Wider introduction and characterization of roselle accession for improvement and adaptation are important prerequisites to unlock the potential of the crop in the country. The aim of this study was to characterize morpho-agronomic and physiological diversity, genetic variability and association of characters in roselle accessions collected from different African countries (Benin, Burkina Faso, Egypt, Ethiopia, Gahna, Mali and Niger). A total of 81roselle accessions were evaluated using 9 x 9 simple lattice designs during 2021 main cropping season at Hawassa University research site. A total of 34 qualitative and quantitative morpho-agronomic and physiological traits were scored and analyzed. Analysis of variance revealed significant differences (P ≤ 0.01) for 16 morpho-agronomic and physiological traits among roselle accessions. The highest calyx yield (1840.7kg ha ^− 1 ) was obtained from accession Ben-Hib-05djou-barienou, while the lowest calyx yield (187.36 kg ha ^− 1 ) was obtained from accession H08. The best performing five accessions, namely Ben-Hib-05djou-barienou, Gahna-Accra-08, H16, ETH-Asarc 09/1415, and Ben-Hib-20 Kandi-kassakou, gave the highest calyx yield from the studied roselle accessions. Three times greater yield advantages existed in accession Ben-Hib-05djou-barienou than in previously released varieties (WG-hibiscus-Sudan and WG-hibiscus-Jamaica). High and low genotypic and phenotypic coefficients of variations were recorded for stomata conductance (51.96 and 54.18%) and days to 95% maturity (4.43 and 4.51%) respectively. High heritability coupled with high genetic advance as a percentage of the mean were obtained for days to 50% emergence, days to 50% flowering, stomata conductance, number and weight of fruits per plant, number of seeds per fruit, and calyx yield per hectare. The first six principal components contribute 74.2% of the total variation. The studied accessions were grouped in to five clusters, which indicating divergence. These study show that crosses between the Cluster IV and V and cluster I and V will give maximum number of segregants and could contribute to varietal improvement. Considering calyx yield, plant height, number of branches per plant, and number of fruits per plant as selection criteria is important for a successful breeding program of roselle. The average Shannon diversity index of the qualitative traits in the accessions was 1.01. All qualitative characters had shown high variability except plant growth habit (0.46) and inner corolla color (0.48). The highest diversity index from the qualitative traits was observed in leaf base shape (1.55). To support the results, it would be better to characterize these materials using molecular markers. Furthermore, across location and over season trials could highlight GXE interactions on the variability of accessions.