As part of a breeding programme, exploration and systematic selection exercise of kola (Cola spp.) was carried out in Nigeria from the large number of kola populations in the country based mainly on yield and various nut characteristics. The exercise gave rise to a collection of many accessions of the genus including five wild species that are currently being maintained in field genebanks of Cocoa Research Institute of Nigeria (CRIN), Gambari experimental station, Idi-Ayunre, Ibadan. In order to fully exploit the variability in these plants for genetic improvement, the plants were characterized and their morphological variability described. A list of descriptors, developed by International Plant Genetic Resources Institute (IPGRI) for Avocado, with modifications was employed recording 60 descriptors consisting of 33 qualitative and 27 quantitative characters. The characterization data revealed enormous morphological variability among the plants studied and have strong bearing on the taxonomy of the groups. The result also confirmed that the wild species of Cola form a special group with enormous agronomic traits that are yet to be exploited in kola breeding. Wild species identified with high nut and pod numbers, thick indehiscent pods and fruit size uniformity is recommended for use in interspecific hybridization programme.

The study assessed the genetic diversity of pearl millet accessions grown in Nigeria and India based on morpho-agronomic traits in order to identify genotypes with superior characters which could be utilized in breeding programmes. Twenty-four pearl millet accessions were grown and evaluated for agronomic and morphological traits during the dry and wet seasons of 2015-2016. Data collected on the accessions using standard descriptors were analysed statistically. IP22281 had the highest mean plant height (108.90 cm) while NGB00531 recorded the lowest (61.02 cm). Significant intra-specific variation existed in number of leaves per plant, leaf length, leaf width, number of nodes and internode length, however, stem girth was similar for the accessions. Tillering was generally poor with the highest value (1.60 tillers per plant) found in NGB00531. A significant positive correlation occurred between plant height, number of leaves, leaf length and leaf width. Panicles emerged between 44 and 56 days and NGB00548 had the shortest maturity time. Also, panicle length and peduncle diameter varied significantly for the accessions. The highest grain yield and 1000-grain weight were recorded in NGB00616 and the lowest yield and weight were recorded in IP22269. The principal component analysis grouped the accessions into four clusters, comprising mixtures of Nigerian and Indian members. Similarly, the dendrogram grouped the accessions into two main groups which were sub-divided into smaller clusters with accessions from Nigeria and India in the same cluster. The study concludes that variations in morpho-agronomic and yield characters among the accessions studied could be harnessed for crop improvement. The clustering pattern of these accessions indicated their genetic relatedness, possibly from the same progenitor, but separation by geographical or ecological isolation mechanisms.

The genetic diversity in seed lipid and fatty acid composition in nine accessions of sesame, comprising six cultivated and three wild relatives, was studied and compared. Seed oil content was 53.23-55.12% in cultivated and 53.35-58.56% in wild accessions. The principal fatty acids in the accessions were palmitic, stearic, oleic (OLE), linoleic (LIN) and linolenic (LIL) acids, of which lower OLE and higher LIN acids were observed in all the accessions. Principal component analysis revealed that OLE acid, total unsaturated fatty acids, total saturated fatty acids (SFAs), LIN acid and the unsaturated to SFA ratio had the highest loading in the first component, which accounted for 54.01% of the total variation. For the second principal components, lauric, palmitoleic, capric, lignoceric, arachidic and LIL acids had the highest loading, accounting for 26.94% of the total variation. Three principal components explained 89.01% of the total variation. The dendrogram generated by the UPGMA cluster analysis grouped the nine accessions into five distinct clusters, indicating genetic diversity; this can be used to plan crosses and maximise the expression of heterosis. Practical applications:This research work provides information on the fatty acid profile of seed oil from nine morphologically distinct accessions of sesame selected from thirty-three accessions collected in 2003. This is intended to establish genetic diversity on the basis of fatty acid profile, identify accessions with high seed oil quality that may be adopted for large scale cultivation in Nigeria and justify the suitability of the nine accessions in serving as base materials in the ongoing breeding efforts for sesame seed oil quantity and quality improvement.

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