Biochemical Characterisation of 18 Accessions of Sweet Potato (Ipomoea batatas L. Lam.) using Total Leaf and Tuberous Root Protein by SDS-PAGE

DNA-based markers,undeniably, provide potent tools for studying genetic relationships in plants; however, potential of protein-based markers using SDS-PAGE is quite promising, particularly in developing countries. Plant storage proteins serve as molecular reserves imperative for plant growth and maintenance and thus have proven to be essential for the survival of plant species. Storage proteins are also indispensable in plant defense mechanisms as insecticidal and anti-microbial proteins. They have also been widely employed as biochemical markers for genetic diversity studies. Eighteen sweet potato (Ipomoea batatas L. Lam) accessions with local or exotic origin were evaluated for genetic diversity using leaf and tuberous root protein via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Marked variations observed in the electrophoregrams of total leaf and tuberous root proteins gave an indication of intense variability among the accessions. Molecular size of proteins ranged from 20.23 to 28.89 kDa and 22.44 to 97.19 kDa, in the total leaf and tuberous root proteins, respectively. Two pairs of accessions SA/BNARI and UE 007 as well as HMA 1 and US 029 were identified as duplicates based on their banding patterns. Keywords: Biochemical, characterisation, SDS-PAGE, sweet potato, leaf& tuberous root protei

Study of the Reproductive Characteristics of Nine Cassava Accessions

Reproductive behaviour of two cultivars (AF and AN) and seven breeding lines (BA, AS, LA, BS-1, HO-008, ME and SE) of cassava (Manihot esculenta Crantz) was studied to obtain information pertaining to flowering habits and other reproductive characteristics of these potential parents required for future hybridization programmes. The accessions were grown on the Research Farm of the Biotechnology and Nuclear Agriculture Research Institute in the coastal savanna agro-ecological zone of Ghana between April 2008 and December 2009. For each accession, 40 stem cuttings, each bearing five to eight nodes, were prepared from the mid-section of healthy cassava stems and planted at a spacing of 1.5 m x 1.0 m while accessions were separated by a distance of 2 m. Ten plants were tagged per accession for the collection of data on key reproductive characteristics. All accessions flowered, suggesting that flower production may not be a limiting factor under the prevailing climatic conditions. Light microscopy revealed that one accession (BA) produced dysfunctional male flowers which were devoid of pollen. Mean days to flowering and fruiting varied significantly (P < 0.05) among the accessions, indicating the need to use different planting dates for different accessions to ensure synchronization of flowering. The accessions also differed significantly (P < 0.05) with respect to plant height at various levels of branching, as well as number of inflorescences, staminate and pistillate flowers, and fruit produced per branching level. There was also variation in percent seed set, embryo formation and fruit drop. The extensive variability observed among the accessions provides breeders with immense opportunities for carrying out cross combinations to generate new genotypes to meet specific objectives

Agromorphological Characterisation of 29 Accessions of Okra (Abelmoschus spp L.)

The West African sub-region is indisputably the region of greatest diversity of Okra (Abelmoschus spp L.) germplasm as it currently hosts some 1,769 accessions of Okra (representing 77.49%) out of the 2, 283 reported world-wide. These are largely uncharacterised, making it practically impossible to ascribe specific attributes to known accessions to facilitate breeding for further improvement to meet specific demands by end-users or industrial-scale production. Twenty six (26) local accessions and three (3) exotic lines of Okra were collected from eight geographic regions of Ghana. Their agro-morphological traits were evaluated under field conditions on the research farm of the Biotechnology and Nuclear Agriculture Research Institute. Hierarchical cluster analysis of results grouped the accessions into two major clusters and subsequently into five sub-clusters based on the qualitative characters studied. The pattern of clustering did not indicate any relationship with geographic origin of collection. The two most divergent accessions were Cs-Legon (local accession) and Clemson spineless (exotic line). There were no duplicates among the accessions which exhibited great variability with respect to all vegetative as well as reproductive characters, except one. Keywords: Okra; accession; characterisation; phenotypic variation; cluster analysis; genetic similarity index

Detection of TYLCV in Ten Genotypes of Tomato (Solanum spp L.) using Serological and Molecular Techniques in a Coastal Savanna Zone of Ghana

Use of resistant varieties is a proven way of controlling the tomato yellow leaf curl virus (TYLCV), which causes a devastating disease of tomato in tropical and warm temperate regions, resulting in significant yield losses. However, breeding for resistant varieties is slow due to lack of effective methods of virus detection that will lead to efficient selection of desired varieties. A study was conducted to evaluate the susceptibility or otherwise of ten tomato genotypes to TYLCV under field conditions. The ten (10) tomato genotypes were planted in the field and left to natural infection by whitefly vectors. Leaf samples were collected from symptomatic as well as asymptomatic plants at five weeks after transplanting (5WAT) for analysis by serological and nucleic acid-based techniques. Triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) detected TYLCV in five out of ten genotypes while polymerase chain reaction using six primers (virus-specific and degenerate) detected the virus in eight out of ten genotypes. The polymerase chain reaction (PCR) technique detected the virus in three samples that tested negative to TAS-ELISA, implying its enhanced sensitivity. A correlation of symptom expression in the field to the presence of TYLCV in test samples led to an effective and unbiased selection of tolerant/resistant genotypes which can be used in further breeding programmes. The study highlights the need for a combination of two or more detection techniques in breeding to enhance the efficiency of selection of TYLC-resistant lines. Keywords: Tomato yellow leaf curl virus, enzyme-linked immunosorbent assay, polymerase chain reaction, genotypes, resistant varieties, Solanum lycopersicon

Peak Root and Starch Weights of Ten Early Bulking Cultivars of Cassava (Manihot Esculenta

Peak yields of total fresh root weight (TFRW), total dry root weight (TDRW) and total starch weight (TSW) of ten cassava (Manihot esculenta Crantz) cultivar are reported. Planting of the cassava cultivars was carried out in a randomized complete block design with three replications. The cassava roots were harvested first at 5 months after planting (MAP) and every month thereafter. The percentage starch content was determined using a UV-spectrophotometer at 690nm wavelength. Four main periods after planting could be identified for early bulking cultivars: (7 MAP - cultivars 115, DMA 030, HO 001 and UCC 096; 9 MAP - cultivars 126 and HO 015; 11 MAP - cultivars 90 and MQA98/11; 12 MAP - cultivars CR001/102 and HO 008). Time to achieve peak yield differed in some cultivars but was the same for TFRW, TDRW and TSW. Cassava cultivar HO 008 had the highest peak of TDRW and TSW in roots while cultivar MQA98/11 had the lowest. On dry weight basis, starch content was higher than 72%. Yield loss estimates due to delayed harvest of the cultivars are presented.. Journal of the Ghana Science Association Vol. 9 (2) 2007: pp. 54-6

Identification of RAPD markers linked to pubescent trait in cassava (Manihot esculenta CRANTZ)

The presence of pubescence on the leaves of cassava confers resistance to mealybug, an important pest of cassava in Africa. We therefore, investigated RAPD markers linked to the pubescent trait in four descendants of cassava clone TMS 4(2)1425, namely, diploid (2X) 4(2)1425 pubescent, diploid (2X) 4(2)1425 non-pubescent, tetraploid (4X) 4(2)1425 pubescent and tetraploid (4X) 4(2)1425 non-pubescent as well as forty-eight F1 plants obtained from crossing diploid pubescent and diploid non-pubescent lines. Segments of the extracted DNAs were amplified under standard amplification conditions using Operon primer series A, B, and C making a total of 60 primers. Most primers produced monomorphic fragments. However, two primers, OPA 13 andOPC 19 produced 798bp and 752 bp polymorphic fragments respectively. These were present in non-pubescent but absent in pubescent clones. The 48 F1 hybrids segregated for these markers in a ratio close to 1:1. The markers 798bp-OPA13 and 752bp-OPC19 may be useful for distinguishing between pubescent and non-pubescent cassava clones

YELLOW MAIZE BREEDING FOR HIGHER BETA-CAROTENE: FARMERS’ PERCEPTIONS OF VITAMIN-A DEFICIENCY CONSEQUENCES AND READINESS TO GROW IMPROVED VARIETIES IN GHANA

Vitamin A deficiency poses serious health concerns among the Ghanaian populace, particularly children and pregnant women. The production and consumption of yellow maize, which contains pro-vitamin A carotenoids such as beta carotene, is therefore encouraged. Consequently, yellow maize consumption is fast gaining acceptance. However, in the near future comensurate increases in production must be achieved to ensure food security. In this regard, the aims of the study were to: evaluate farmer willingness to cultivate yellow maize varieties with enhanced beta carotene content, ascertain extent of farmers’ knowledge on production constraints and mitigation, and evaluate farmers’ perception on nutritional benefits of yellow maize and the effects of vitamin A deficiency. The survey was conducted between January and May 2018 and it covered four districts representing the forest and guinea savanna ecological zones in Ghana. In each district, five communities with 10 participants each were covered. Most yellow maize farmers (78 %) were between 15 and 55 years, 42.5 % of the farmers had no formal education, 29 % had secondary education and only 8 % had tertiary education. The main challenges facing yellow maize (YM) farmers were pest control and low yield due to erratic rainfall. Majority (70 %) of the farmers had heard about vitamin A deficiency and also noticed stunted growth, mental retardation and poor eye sight in their communities but did not link such symptoms to vitamin A deficiency. Most respondents (70 %) were not aware that yellow maize contains beta carotene. Majority (70 %) of the respondents opined that improvement in the beta carotene content of yellow maize will greatly help to drastically minimize vitamin A deficiency and enhance food security. The information elicited from farmers will guide future development of yellow maize varieties for improved production and nutrition