Diversity And Ethnobotanical Studies Of The African Rice (Oryza Glaberrima) And Its Wild Relatives In The Volta Region Of Ghana

ABSTRACT The study aimed at collecting, characterizing, storing and assessing the ethnobotanical uses of the African rice and its wild relatives collected from the Volta Region of Ghana. It also aimed at detecting the concentrations of mineral elements namely: nitrogen (N), phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd) and arsenic (As) in soils of the different accessions collected. Seven accessions of rice were collected from paddy fields in fourteen locations in five districts of the Volta Region. The study revealed that wild rice accessions were not present in the paddy fields. Newer and more productive rice varieties (O. sativa) were more commonly cultivated in farmers’ fields, while the African rice was hardly cultivated. On the very few farms where the African rice was found, only a small portion of the land was allocated for its cultivation. The wild rice species were not found on farmers fields because they are seen as weeds. In Adaklu-Waya, where the wild rice was found, sections of the plants had been destroyed by a heavy duty truck which accesses water from the river where the wild rice grows. This provides evidence that the African rice and its wild relatives are severely threatened in the Volta region of Ghana. Agro-morphological characterization was carried out to verify the authenticity of the O. glaberrima accessions collected. Cluster analysis separated the different varieties collected into two groups based on the agro-morphological traits examined. Cluster 1 had three varieties belonging to the O. glaberrima species, namely; Kamugbaa, Kawomor (black) and Kawomor (red) while Cluster 2 had four varieties belonging to the O. sativa species, namely; Mansa, Viwotor, Ewe Moli (Wegbe) and Ewe Moli (Worawora). There were variations seen for most of the agronomical traits examined which could be used in breeding programmes. The herbarium voucher of wild rice in the Ghana herbarium aided in determining the wild rice collected. It was determined to be O. barthii because of features such iv as spongy roots, very long awns and its bunch growth. It was found amidst other grasses and grew by the bank of a river. Ethnobotanical studies were carried out only for the local rice varieties because the wild rice was found growing in the wild. The results showed that 62% of the farmers encountered were women, suggesting that women dominate rice cropping in the Volta Region and are very knowledgeable at selecting seeds. The ethnobotanical studies further revealed that the decline in the cultivation of the African rice in the Volta Region was due to its low yield, difficulty in de-husking seeds and poor consumer demands. The few farmers who still cultivate it do so because of its good taste, drought tolerance, good grain quality, pest and disease resistance and its good cooking quality. The desirable traits mentioned by farmers indicate that the African rice possesses useful genes which could be used to improve cultivated rice and breed new rice varieties. At P≤ 0.05, the soil analyses showed significant differences in pH, EC, particle sizes, N, P, K, Fe and Zn concentrations. Cu and Pb were not significantly different while Cd and As were below detection in soils of the different accessions. Based on these results, the soils were characterized as acidic (4.68 ± 0.14 to 6.71 ± 0.16), with low salinity concentrations (98.00 ± 16.64 to 222.33 ± 21.39 µScm-1) and higher percentage of sand (68.15 ± 7.88%) as compared to silt (17.78 ± 4.05 %) and clay (18.91 ± 4.71%). Furthermore, despite the significant differences in N, P, K, Fe and Zn concentrations in soils of the various accessions, it was obvious that the wild rice has the ability to tolerate very low concentrations of N (0.05 ± 0.01%), P (0.02 ± 0.00 %) and K (0.03 ± 0.01 %) as compared to the other rice accessions, hence may possess genes that can adapt to nutrient - deficient soils.