Morphological and molecular based diversity studies of some cassava (Manihot esculenta crantz) germplasm in Ghana

Cassava (Manihot esculenta Crantz) is an important food crop in many tropical countries in Africa, South America and Asia. However, yields are below the productivity of the crop. This requires breeding and selection for improved varieties. The current study therefore investigated genetic diversity among some Ghanaian preferred accessions which could be used for breeding purposes. Genetic diversity of 43 cassava accessions was determined using 14 morphological descriptors and 20 SSR primer pairs. Principal component analysis (PCA) indicated that the first three principal components accounted for 72.7% of the total variation with PCA1, PCA2 and PCA contributing 46.6, 14.7 and 11.4%, respectively. The size of amplified alleles ranged from 75 to 350 bp, most of which were closed to the published values. The polymorphic information content (PIC) values ranged from 0.07 for SSRY181 to 0.75 for SSRY175, with an average of 0.52. Gene diversity was high and the average observed heterozygosity was 0.77. Both morphological descriptors and SSR markers were able to group the accessions into distinct clusters independent of locality of collection. However, where the morphological descriptors indicated some accessions were the same, SSRs markers were able to distinguish them into distinct genotypes with some located in different clusters. The wider genetic diversity observed using SSR markers would be valuable for efficient management of germplasm and for effective utilization of materials in breeding programmes to produce hybrids of desirable characteristics. Therefore, the application of morphological descriptors in management of germplasm should be backed by the use of molecular markers.Key words: Cassava germplasm, simple sequence repeat (SSR), morphological descriptors, genetic diversit

The physiological responses of cacao to the environment and the implications for climate change resilience. A review

Cacao (Theobroma cacao L.) is a tropical perennial crop which is of great economic importance to the confectionary industry and to the economies of many countries of the humid tropics where it is grown. Some recent studies have suggested climate change could severely impact cacao production in West Africa. It is essential to incorporate our understanding of the physiology and genetic variation within cacao germplasm when discussing the implications of climate change on cacao productivity and developing strategies for climate resilience in cacao production. Here we review the current research on the physiological responses of cacao to various climate factors. Our main findings are 1) water limitation causes significant yield reduction in cacao but genotypic variation in sensitivity is evident, 2) in the field cacao experiences higher temperatures than is often reported in the literature, 3) the complexity of the cacao/ shade tree interaction can lead to contradictory results, 4) elevated CO2 may alleviate some negative effects of climate change 5) implementation of mitigation strategies can help reduce environmental stress, 6) significant gaps in the research need addressing to accelerate the development of climate resilience. Harnessing the significant genetic variation apparent within cacao germplasm is essential to develop modern varieties capable of high yields in non-optimal conditions. Mitigation strategies will also be essential but to use shading to best effect shade tree selection is crucial to avoid resource competition. Cacao is often described as being sensitive to climate change but genetic variation, adaptive responses, appropriate mitigation strategies and interactive climate effects should all be considered when predicting the future of cacao production. Incorporating these physiological responses to various environmental conditions and developing a deeper understanding of the processes underlying these responses will help to accelerate the development of a more resource use efficient tree ensuring sustainable production into the future

Responses of stomates of talinum triangulare and tradescantia virginiana to some growth regulators

No Abstract. Journal of the Ghana Association Vol. 2 (3) 1999: pp.137-14

Effects of sucrose on development of cultures of some accessions of Dioscorea spp

The method of micropropagation was used to establish nodal cultures of D. rotundata, D. alata, D. praehensilis, D. dumetorum, D. esculenta and D. cayenensis on 6 ml or 8 ml MS medium supplemented with 2.5 μM kinetin. The cultures were incubated at 28ºC and 16 h photoperiod at 4500 Lux, on 3%, 5%, 7%, and 10% sucrose, with a sucrose-free medium as control in a CRD design. Generally, increase in sucrose concentration significantly (P≤0.05) enhanced the rate of survival and growth of the Dioscorea cultures. Mean shoot height and root formation were high-est in D. rotundata cultures on full-strength MS medium containing 10% sucrose compared to half-strength MS medium. However, 7% sucrose stimulated the highest rate of vigorous growth of healthy cultures, leaf formation and plantlet production among the Dioscorea spp. It also enhanced development of bud primordia to regenerate plantlets in D. rotundata meristem cultures. There was a positive correlation (r=0.983) between the rate of leaf production and shoot height. It was evident that 5% and 7% sucrose were more effective for culture development towards multiple bud, lateral and terminal bud differentiation in most of the Dioscorea spp as well as re-duced the duration for plantlet development and the demand for regular sub-culturing since the growth phase of cultures could be prolonged. However, D. esculenta cultures appeared to grow better on 3% sucrose than the other Dioscorea spp tested, suggesting that the optimum sucrose concentration required to initiate and establish culture differs significantly among various Dioscorea species

The Ghanaian currency notes and coins: A medium of exchange for pathogenic microbes

The microbial load of the “old” and “new” Ghanaian Cedi notes and coins obtained from vari-ous sources in Cape Coast, Ghana was studied using the dilution plate technique between September 2005 - March 2006 and September 2008 - March 2009. Isolations were made on Mac-Conkey agar for coliforms and other enteric bacteria, Plate Count agar for total viable bacteria and Sabouraud agar for fungi. Generally, the notes carried significantly higher microbial loads than the Cedi coins (p < 0.001). Yeasts were the dominant microorganisms on both banknotes and coins, followed by moulds and coliform bacteria were the least. The enteric bacteria isolated were of the lactose-fermenting (coliforms) and non lactose-fermenting types. The presence of coliforms on the banknotes and coins indicated faecal contamination and thus implicated poor hygienic practices involved in the handling of Ghanaian currency notes and coins. The sources of collection of the banknotes and coins seemed to determine the types and population of micro-organisms on the notes and the coins. There was however no significant difference (p>0.05) be-tween bacterial loads isolated from the “old” notes and coins on one hand and “new” Cedi notes and coins on the other hand suggesting that the Ghanaian currency notes and coins were being mishandled by majority of the populace. The presence of various types of bacteria and fungi on the “Cedi” notes and coins suggests that they may act as vehicles for pathogens of some communicable diseases

Regulatory effects of cultar and iat siol treat on soybean (Glycine max (L) Merr.)

No Abstract. Journal of the Ghana Science Association Vol. 2 (2) 1999: pp.15-2

Evaluation of agro-morphological diversity in some segregating lines of cowpea (Vigna un-guiculata L. WALP)

A study was conducted to evaluate agro-morphological characteristics of some segregating lines of eight accessions of cowpea (Vigna unguiculata L. Walp.) using seeds from a first cycle generation progenies. Eight cowpea accessions [GH36841 (red), GH3684B4 (mottle brown), GH 3684B5 (mottle brown), GH3684A2 (red), GH3684C2 (red), GHUCO1BL (black), GH3684BL, (black) and GH7184BL (black with spots)] and an out group IT97K-499-35 (white) were culti-vated under field conditions. Twenty three agro-morphological traits were assessed for thirty three lines of cowpea. A dendrogram generated using 23 agro-morphological characters distinguished the cowpea accessions into two lineages, with the out-group being the most diverse. Generally, morphological polymorphism revealed discriminations among the cowpea accessions studied. Seed weight, plant height, number of branches, length of branches, number of leaves, number of peduncles, length of peduncles and number of seeds per pod as well as number of pods per plant differed significantly (p ≤ 0.05) among the cowpea accessions. The evidence showed that there were variations in morphological characteristics expressed by the cowpea ac-cessions and these were segregations in one trait or the other. The cowpea accession GH UCO1BL is possibly a cross between IT97K-499-35 x SARC-LO2. The segregation lines of GH 3684 had the greatest diversity probably due to genotype environment interactions