Improvement in cowpea variety Videza for traits of extra earliness and higher seed yield.

The cowpea variety Videza, which was used as the control, matures early (70 days after planting), although it produces low yields. Gamma irradiation mutagenesis was used to induce Videza into extra-early maturing and higher yielding mutant genotypes. A single seed descend population was developed for radio-sensitivity test, and a Lethal Dose 50 (LD50) of 240.5 Gy was determined, and applied from a cobalt-60 (60Co) source, to acutely mass irradiate 1800 Videza seeds, at the Ghana Atomic Energy Commission. The irradiated seeds (M1) were planted to produce M2 seeds bearing plants and subsequently advanced to M3 plants for selection of nine induced plants based on extra earliness and significantly higher seed yields than the parental control. It took 48 days after planting (DAP) for the genotype coded P1N02#1 to reach 50 % maturity followed by 52 DAP for genotypes with codes P4N03#3; P3N01#5; P5N05#6, P4N14#7, P5N07#8, P5N05#10 and 54 DAP for genotype P4N14#11. P1N06#9 had the highest yield (97.38 g/plant), followed by P5N05#10 (95.97 g/plant), P1N08#13 (81.24 g/plant), P2N09#12 (73.94 g/plant), P6N10#19 (70.83 g/plant), P1N06#20 (65.36 kg/plant), P5N07#14 (61.23 g/plant), P4N14# (58.05 g/plant) and P1N08#17 (56.23 g/plant). M3 seeds were advanced to M4 plants for a Preliminary Yield Trial which revealed that induced plants P5N05#10 (1235 kg/ha), P2N09#12 (1206 kg/ha), P5N07#14 (1185 kg/ha), P1N06#20 (1171 kg/ha), P1N06#9 (1051 kg/ha), P1N08#13 (1041 kg/ha), and P6N10#19 (999 kg/ha) outperformed the control (517 kg/ha) and two other commercial varieties. Overall, the two highest performing candidates for further evaluation for varietal release were P5N05#10 and P2N09#12.

Assessment of Consumers' Perception of Chicken Eggs Consumption and Associated Health Implications in the Volta Region of Ghana.

Background: Rather erroneously, eggs consumption is linked to increase in plasma cholesterol content and incidents of cardiovascular diseases, cancer, stroke, or diabetes. This misconception which is more pervasive particularly in sub-Saharan Africa, has led to very low patronage of eggs intake. In this study, egg consumption patterns, desired egg characteristics, and the extent to which the perception of eggs consumption as a health risk is entrenched among consumers in the Volta Region of Ghana, were examined. Methods: The study used primary data for the analysis and the 2-stage sampling technique was employed. First, 5 districts (Keta, Ho, Krachi East, Nkwanta South and North Tongu) were selected and afterward, a sample was randomly selected from each of the district. A well designed and pretested questionnaires were administered to the respondents. Results: It was found that cheaper price and deep yellow yolk were the most persuasive parameters that motivate consumer purchase. The relationship between educational level and awareness on cholesterol types was significant. More than half of the respondents held the view that egg intake results in an increase in serum cholesterol and leads to the incidence of serious health problems. Recommendation: This study proves the urgent need for a concerted national public education effort to raise awareness about the nutritional and health benefits of eggs intake. Success in such awareness creation will go a long way to greatly minimize acute malnutrition in the Ghana.

Participatory approach of preferred traits, production constraints and mitigation strategies: implications for soybean breeding in Guinea Savannah zone of Ghana.

Soybean production is concentrated in the Guinea Savannah agro-ecological zone of Ghana. However, its cultivation is plagued with a number of constraints leading to low yields. A participatory approach was, therefore, used to identify farmers' and processors' preferred soybean traits and production constraints, climate change effects and strategies employed for mitigating these effects in three districts within the soybean growing areas in Northern Ghana. The study revealed that 72.0 % and 68.8 % of farmers in the Tolon and Savelugu districts, respectively, used improved soybean seeds for planting their fields. Over 13.0 % of farmers indicated late maturity as the most important constraint, followed by manual threshing difficulty and terminal drought which results in low grain yield and poor quality. About 70.0 % of farmers opined that climate change effects are causing obvious shifts in the rainfall pattern. Majority of the farmers (94.6 %) indicated that the onset of peak rainfall has changed in the past decade. Almost 44.0% of farmers also indicated that severe drought has affected pods filling in the past. A third (33.3%) of farmers indicated that drought usually sets in at pod initiation. The farmers enumerated some of the effects of early cessation of the rainfall in soybean production as drying up of immature and green seed (28.3%), low grain yield (27.1%) and poor seed quality (22.1%). Some of the mitigation strategies employed by the farmers include early planting (40.0%) and mulching (25.0%) to retain soil moisture for enhanced growth of crops. The order of farmers' preferences new soybean varieties were shattering resistance (16.0%), high grain yield (14.0%), large seeds size (13.1%), and early maturity (11.8%), whereas processors preferred varieties with large seed size (30.6%), high protein content (28.7%), pest resistance (15.9%) and short cooking duration (12.7%). Both the farmers and processors indicated their willingness to pay more for seeds with the desired traits. These findings will aid soybean breeders in developing new varieties that possess desired traits preferred by both farmers and processors for increased soybean cultivation and utilization.

Basic concepts and methodologies of DNA marker systems in plant molecular breeding.

The concepts, methodologies and applications of some of the major molecular or DNA markers commonly used in plant science have been presented. The general principles of molecular marker techniques have been elucidated with detailed explanation of some notable basic concepts associated with marker applications: marker polymorphism, dominant or co-dominant mode of inheritance, agronomic trait-marker linkage, genetic mutations and variation. The molecular marker methods that have been extensively reviewed are RFLP, RAPD, SCAR, AFLP, SSR, CpSSR, ISSR, RAMP, SAMPL, SRAP, SSCP, CAPS, SNP, DArT, EST, and STS. In addition, the practicality of the retrotransposon-based marker methods, IRAP, REMAP, RBIP, and IPBS, have been discussed. Moreover, some salient characteristics of DNA markers have been compared and the various marker systems classified as PCR- or non-PCR-based, dominantly or co-dominantly inherited, locus specific or non-specific as well as at the levels of marker polymorphism and efficiency of marker reproducibility. Furthermore, the principles and methods of the following DNA markers have been highlighted: Penta-primer amplification refractory mutation system (PARMS), Conserved DNA-Derived Polymorphism (CDDP), P450-based analogue (PBA) markers, Tubulin-Based Polymorphism (TBP), Inter-SINE amplified polymorphism (ISAP), Sequence specific amplified polymorphism (S-SAP), Intron length polymorphisms (ILPs), Inter small RNA polymorphism (iSNAP), Direct amplification of length polymorphisms (DALP), Promoter anchored amplified polymorphism (PAAP), Target region amplification polymorphism (TRAP), Conserved region amplification polymorphism (CoRAP), Start Codon Targeted (SCoT) Polymorphism, and Directed Amplification of Minisatellite DNA (DAMD). Some molecular marker applications that have been recently employed to achieve various objectives in plant research have also been outlined. This review will serve as a useful reference resource for plant breeders and other scientists, as well as technicians and students who require basic know-how in the use of molecular or DNA marker technologies.

Novel microRNAs and microsatellite-like small RNAs in sexual and apomictic Boechera species.

Apomixis refers to plant asexual reproduction through seeds that give rise to progeny which are genotypically identical to the maternal parent. It has evolved from many different sexual taxa although the underlying genetic factors remain unknown. Previous analyses of the over-representation of transcription factors, in a comparison of microdissected ovules from apomictic and sexual Boechera, showed that many transcription factor mRNAs possessed microRNA (miRNAs) binding sites, thus pointing to miRNAs as potentially important factors that may be involved in the regulatory switch from sexual to apomictic reproduction. A microarray-based approach was used to identify (1) 673 microsatellitelike small RNAs (misRNAs) containing predominantly 2-7 repeats of (GAA)n/(CUU)n, (GCA)n/(CGU)n, (GGA)n/(CCU)n, (GGU)n/(CCA)n and (UGA)n/(ACU)n, and (2) 166 more typical non-repeat small RNAs. In total, 87 small RNAs were found to be located in cDNAs that could fold into stem-loop structures and thus represent miRNA molecules. In addition, 109 Boechera small RNAs including both misRNAs and non-repeat small RNAs, showed significant homology to 407 Arabidopsis thaliana small RNAs including the A. thaliana pollen-specific ath-miR5021. This indicates that only a fraction of the identified small RNAs are unique to Boechera. Ten small RNAs were validated using a Northern blot assay on flower and leaf tissues, eight of which showed flower-specific expression with varying abundance. The potential binding sites of many of the misRNAs and non-repeat small RNAs occur predominantly in exonic regions. This feature coupled with their flower-specific pattern of expression is suggestive of their probable role in post-transcriptional gene regulation. We propose that quantitative variation for misRNA target binding (and hence post-transcriptional gene regulation) could arise via microsatellite length polymorphisms occurring either in misRNA precursors or in their gene targets.

Analysis of conserved microRNAs in floral tissues of sexual and apomictic Boechera species.

BACKGROUND: Apomixis or asexual seed formation represents a potentially important agronomic trait whose introduction into crop plants could be an effective way to fix and perpetuate a desirable genotype through successive seed generations. However, the gene regulatory pathways underlying apomixis remain unknown. In particular, the potential function of microRNAs, which are known to play crucial roles in many aspects of plant growth and development, remains to be determined with regards to the switch from sexual to apomictic reproduction. RESULTS: Using bioinformatics and microarray validation procedures, 51 miRNA families conserved among angiosperms were identified in Boechera. Microarray assay confirmed 15 of the miRNA families that were identified by bioinformatics techniques. 30 cDNA sequences representing 26 miRNAs could fold back into stable pre-miRNAs. 19 of these pre-miRNAs had miRNAs with Boechera-specific nucleotide substitutions (NSs). Analysis of the Gibbs free energy (ΔG) of these pre-miRNA stem-loops with NSs showed that the Boechera-specific miRNA NSs significantly (p ≤ 0.05) enhance the stability of stem-loops. Furthermore, six transcription factors, the Squamosa promoter binding protein like SPL6, SPL11 and SPL15, Myb domain protein 120 (MYB120), RELATED TO AP2.7 DNA binding (RAP2.7, TOE1 RAP2.7) and TCP family transcription factor 10 (TCP10) were found to be expressed in sexual or apomictic ovules. However, only SPL11 showed differential expression with significant (p ≤ 0.05) up-regulation at the megaspore mother cell (MMC) stage of ovule development in apomictic genotypes. CONCLUSIONS: This study constitutes the first extensive insight into the conservation and expression of microRNAs in Boechera sexual and apomictic species. The miR156/157 target squamosa promoter binding protein-like 11 (SPL11) was found differentially expressed with significant (p ≤ 0.05) up-regulation at the MMC stage of ovule development in apomictic genotypes. The results also demonstrate that nucleotide changes in mature miRNAs significantly (p ≤ 0.05) enhance the thermodynamic stability of pre-miRNA stem-loops.

Selection of reference genes for quantitative real-time PCR expression studies of microdissected reproductive tissues in apomictic and sexual Boechera.

BACKGROUND: Apomixis, a natural form of asexual seed production in plants, is considered to have great biotechnological potential for agriculture. It has been hypothesised that de-regulation of the sexual developmental pathway could trigger apomictic reproduction. The genus Boechera represents an interesting model system for understanding apomixis, having both sexual and apomictic genotypes at the diploid level. Quantitative qRT-PCR is the most extensively used method for validating genome-wide gene expression analyses, but in order to obtain reliable results, suitable reference genes are necessary. In this work we have evaluated six potential reference genes isolated from a 454 (FLX) derived cDNA library of Boechera. RNA from live microdissected ovules and anthers at different developmental stages, as well as vegetative tissues of apomictic and sexual Boechera, were used to validate the candidates. RESULTS: Based on homologies with Arabidopsis, six genes were selected from a 454 cDNA library of Boechera: RPS18 (Ribosomal sub protein 18), Efalpha1 (Elongation factor 1 alpha), ACT 2 (Actin2), UBQ (polyubiquitin), PEX4 (Peroxisomal ubiquitin conjugating enzyme) and At1g09770.1 (Arabidopsis thaliana cell division cycle 5). Total RNA was extracted from 17 different tissues, qRT-PCRs were performed, and raw Ct values were analyzed for primer efficiencies and gene ratios. The geNorm and normFinder applications were used for selecting the most stable genes among all tissues and specific tissue groups (ovule, anthers and vegetative tissues) in both apomictic and sexual plants separately. Our results show that BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ were the most stable genes. Based on geNorm, the combinations of BoechRPS18 and BoechEfα1 or BoechUBQ and BoechEfα1 were the most stable in the apomictic plant, while BoechRPS18 and BoechACT2 or BoechUBQ and BoechACT2 performed best in the sexual plant. When subgroups of tissue samples were analyzed, different optimal combinations were identified in sexual ovules (BoechUBQ and BoechEfα1), in anthers from both reproductive systems (BoechACT2 and BoechEfα1), in apomictic vegetative tissues (BoechEfα1 and BoechACT2) and sexual vegetative tissues (BoechRPS18 and BoechEfα1). NormFinder ranked BoechACT2 as the most stable in the apomictic plant, while BoechRPS18 was the best in the sexual plant. The subgroups analysis identified the best gene for both apomictic and sexual ovules (BoechRPS18), for anthers from both reproductive system (BoechEfα1) and for apomictic and vegetative tissues (BoechACT2 and BoechRPS18 respectively) CONCLUSIONS: From a total of six tested genes, BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ showed the best stability values. We furthermore provide detailed information for the accurate normalization of specific tissue gene expression analyses of apomictic and sexual Boechera.

Bacillus subtilis diacylglycerol kinase (DgkA) enhances efficient sporulation.

The sn-1,2-diacylglycerol kinase homologue gene, dgkA, is a sporulation gene indispensable for the maintenance of spore stability and viability in Bacillus subtilis. After 6 h of growth in resuspension medium, the endospore morphology of the dgkA mutant by standard phase-contrast microscopy was normal; however, after 9 h, the endospores appeared mostly dark by phase-contrast microscopy, suggesting a defect in the spores. Moreover, electron microscopic studies revealed an abnormal cortex structure in mutant endospores 6 h after the onset of sporulation, an indication of cortex degeneration. In addition, a significant decrease in the dipicolinic acid content of mutant spores was observed. We also found that dgkA is expressed mainly during the vegetative phase. It seems likely that either the DgkA produced during growth prepares the cell for an essential step in sporulation or the enzyme persists into sporulation and performs an essential function.