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Knowledge of combining ability and mode of inheritance is important in devising strategies to breed compatible and high yielding plant varieties. This study determined combining ability and understood the mode of inheritance of sexual compatibility in Cola nitida, a crop in which incompatibility was reported. 10 × 10 complete diallel mating design was used to cross ten (10) elite clones of kola. Data collected included percentage pod set and nut traits of the various crosses. Percentage pod set differed significantly among crosses (p 80% pod set) as compared to crosses between red and pink colour nut genotypes. Both additive and non-additive gene effects were significant (p

The African oil palm (Elaeis guineensis. Jacq.) is an oleaginous tree belonging to the family Arecaceae. The crop is naturally a diploid species (2n = 2x = 32) and the most important oil bearing perennial tree crop cultivated in tropics. In spite of its huge economic importance, it has a very narrow genetic base making its improvement using conventional techniques very difficult. All commercial planting materials are hybrids derived from heterozygous pisifera and dura parents. The imperativeness of generating adequate novel materials with sufficient genetic diversity in order to increase progress in oil palm improvement is therefore, very essential. Genomic manipulations through chromosome doubling may present opportunities to broaden the genetic base and increase the diversity within the commercial oil palm species. Developing an efficient genome doubling protocols using anti-mitotic agents is very important in this respect. It will also complement haploid/doubled haploid production efforts by enabling successful deployment of doubled haploids in oil palm breeding programmes. The objectives of this study were, therefore, to optimize genomic doubling in oil palm by determining optimum colchicine concentrations and also outline procedures for screening for putative polyploids. Oil palm seedlings were subjected to colchicine treatment at concentrations of 0, 1.26, 3.76, 6.26 and 8.76 mM for 0, 3, 6, 12 or 24 hours. The colchicine treatment produced variable physio-morphologies in the treated seedlings. Principal component analysis and agglomerative hierarchical clustering of genotype dependent treatments were carried out to provide an ordination guide. The response of oil palm seedlings to colchicine treatment showed genotypic, concentration of colchicine applied and treatment duration dependency. Ploidy level analysis of the colchicine treated seedlings revealed that polyploidization in oil palm increased significantly (p ≤ 0.05) with increasing colchicine concentration. Seedlings of the genotype G-131 responded more favourably to the colchicine treatment than seedlings of G-132. Optimal colchicine concentration for genome doubling in G-131 (28.9 %) and G-132 (17.8 %) was 8.76 mM applied for a period of 24 h. A population of 154 tetraploids out of 1800 seedlings of the two genotypes mutagenized has been identified and being raised for further evaluation and genetic exploitation.

Build-up of free radicals in the human body can cause oxidative stress which may invariably lead to degenerative diseases and eventual death. Antioxidants such as polyphenols and flavonoids found in fruits and vegetables have been shown to protect the body against the damaging effects of these free radicals. Roselle contains high amounts of antioxidants and its leaves are often used for sauces or in herbal preparations to treat certain ailments. Several landraces of roselle occur in Ghana but have not been screened for antioxidant activity. Leaf samples of roselle acessions were harvested 60 days after sowing, freeze dried and analysed for total phenolic content (TPC), total flavonoid content (TFC) as well as total antioxidant activity (TAA) using UV-VIS Spectrophotometer (Shimadzu, 1201, Japan). No statistically significant differences were observed in TPC which ranged from 20 ± 0.6 µg/g (RNL) to 90 ± 0.6 µg/g (Sob-4). TFC and TAA in the leaf samples; however, showed statistically significant variation and ranged from 10.04 ± 0.31 µg/g (WH-S2V) to 49.79 ± 0.48 µg/g (Don-1) and 37.48% (Don-4) to 58.58% (WNL-HS), respectively. Higher leaf phenolic or flavonoid content did not necessarily translate into a higher antioxidant activity. This suggests that other forms of antioxidants other than phenolics or flavonoids might be responsible free radical scavenging activity in roselle leaves. Nevertheless, very high free radical percentage inhibition observed in the roselle leaves makes it an excellent material for mitigation against the adverse effect of free radicals. Nine promising accessions with high free radical scavenging activity have been identified for further improvement. Key words: Hibisicus sabdariffa, roselle, antioxidant activity, flavonoids, phenolic content.

A study was conducted to evaluate the reaction of two local and seven exotic pepper cultivars to four viral diseases in the coastal savanna zone of Ghana. The objective was to evaluate the response of the pepper cultivars to the viruses under natural field conditions. The plants were assessed for symptom severity as well as disease incidence. Symptom expression varied among the cultivars, with severity ranging from 0.5% at 4 Weeks after Transplanting (WAT) to 47.2% at 14 WAT. Disease incidence also varied significantly among the cultivars and ranged from 1.1% at 4 WAT to 61.3% at 14 WAT. Enzyme-Linked Immune Sorbent Assay (ELISA) was performed against PVMV, TMV, CMV and PMMV for each cultivar. The test showed the presence of all four viruses in the leaf extracts, with each cultivar infected by at least one of the four viruses. PVMV and CMV were the predominant viruses identified. Mixed infections of two or more viruses were observed in all the cultivars. TMV was detected in all cultivars except the two hybrids, Sunny F 1 and Forever F1, while PMMV was detected in only cv. Legon 18 which had a mixed infection of all four viruses.

Increasing exploitation of roselle (Hibiscus sabdariffa L.) and its products require that commercial varieties with superior attributes are developed to replace landrace varieties and to meet the growing demand for commercial-scale cultivation of the crop. In this study, twenty landrace varieties of roselle collected from three geographical regions of Ghana were artificially crossed in a pairwise mating scheme. The aim was to obtain relevant information pertaining to fertility status and extent of crossability among the accessions to facilitate breeding of improved varieties. Attempts at hybridisation were made both between and among 6 accessions of Hibiscus sabdariffa var Altissima and 14 accessions of Hibiscus sabdariffa var Sabdariffa. Crosses between accessions of Hibiscus sabdariffa var Altissima and Hibiscus sabdariffa var Sabdariffa yielded no hybrids, suggestive of a crossability barrier between the two mating groups. All intra-varietal crosses involving accessions of Hibiscus sabdariffa var Altissima were successful regardless of direction of cross while only few of the crosses among those of Hibiscus sabdariffa var Sabdariffa produced successful hybrids. Also fertility estimates of members of Hibiscus sabdariffa var Altissima were significantly higher (30.00%-80.00%) compared to those of var Sabdariffa (0.00%-43.00%). This implies that complete pairwise design could be used for intra-varietal crosses involving accessions of Hibiscus sabdariffa var Altissima, whereas only a partial pairwise design is feasible for members of Hibiscus sabdariffa var Sabdariffa.

In an effort to improve upon tomato varieties on the Ghanaian market, this study was carried out to identify genotypes with desirable qualities for further breeding work. The study was executed by crossing some varieties of Solanum lycopersicon; cherry red, cherry yellow, roma and wosowoso with a wild tomato, Solanum pimpinellifolium. The progenies were cultivated for four generations to obtain these lines. Fruits harvested from these lines of F4 were analysed for the following physico-chemical properties; dry matter, pH, total titratable acidity, total soluble solids and vitamin C. The total soluble solids and total titratable acidity were used to deduce flavour and sweetness indices for the fruits. Significant (p