Antifungal effect of Polar and non polar extracts of Aframomum Sceptrum on Two Isolates of Oil Palm

In different parts of the world, attention is being paid to exploitation of higher plants as biodegradable fungicides in the control of most plant pathogenic fungi. Different spices of the Zingiberaceae family have been tested for their antifungal properties, but there exists little or no information on the antifungal potential of a particular member of that family; Aframomum sceptrum on fungal pathogens of some economic important palms in Nigeria. In this study, the phytochemical composition of the seed extracts of this spice was analyzed by standard methods while the antifungal activities of polar and non polar extracts of the spice was tested on two major isolates affecting the Oil palm, Fusarium oxysporum f.sp elaeidis and Hypocrea lixii (IMI 501885) Cold extraction using Acetone, Ethanol, Hexane, Methanol, and Diethylether solvents were used in the seed extract preparation. The broad spectrum fungicide, Mancozeb (80% wettable powder) was used as the positive control while the negative control was Dimethyl sulphoxide. The Dimethyl sulphoxide was also used to reconstitute the solvent extracts by dissolving the extracts and fungicides in appropriate amount of 15 % (v/v) to obtain a concentration of 0.0624g/ml. The phytochemical screening revealed the presence of the following phytochemicals in different quantities; Alkaloids, Terpenoids, Anthraquinones, Flavonoids Tanins, Saponins. Results obtained showed that all the extracts had a significantly higher antifungal effect (p< 0.05) than the broad spectrum fungicide, Mancozeb at 2000ppm. Non polar hexane seed extract had the highest percentage inhibition of 60.26% on Hypocrea lixii (IMI 501885 while the Polar ethanolic extracts with a percentage inhibition of 52.73 % on Fusarium f.sp elaeidis. Amongst all the extracts used in this study, the seed extracts that gave a low percentage inhibition of 42.45% was the non –polar acetone seed extract on Fusarium oxysporum fsp. elaeidis and methanol extract on H .lixii with the least percentage inhibition of 42.31%. The implications of these findings are discussed.Keywords: Oil palm, Antifungal, Phytochemical, DMSO, Pathogen

QTL analysis for early yield in a pseudo F2 population of cassava

Genetic mapping of early bulking in a full-sib population of cassava was continued in a selfed family of 268 cassava plants derived from a single progeny of the full-sib population. The pseudo F2 populationwas analysed with 122 segregating SSR markers. A previously constructed linkage map of cassava consisting of 22 linkage groups covering 1236.7 cM, with an average marker distance of 18 cM wasused for this study. The F2 population was evaluated for components of early yield, namely dry root yield (DR) at 7 months, harvest index (HI), and weight of fresh foliage (FF). Interval mapping, with single- and two-QTL models, was used to identify QTLs. The single-QTL model identified three QTLs each for DR, FF, and HI. The two-QTL model approach identified groups of QTLs that together explained 33% for FF, 43.5% for DR and 36% for HI. The identification of QTLs involved in early yield is an important step toward understanding quantitative genetic variation of early yield and implies reconsideration of breeding strategies for improvement of this complex trait

KASPar SNP genetic map of cassava for QTL discovery of productivity traits in moderate drought stress environment in Africa

Open Access Journal; Published online: 28 May 2021Cassava is an important staple in Sub-Sahara Africa. While its production has rapidly expanded to the dry savannahs of the continent, productivity is low in this ecology due to drought by farmers, extending the growth cycle from 12 months to 18, and sometimes 24 months to ensure better harvests. Yield is a complex trait and often difficult to manipulate for genetic gain in conventional breeding. Unfortunately, the dearth of molecular tools for decades has hampered molecular breeding (MB) to improve cassava productivity. This study was conducted to explore KASpar SNPs to generate more molecular tools to enhance genetic dissection of elite African germplasm for improved cassava productivity in dry environments of Africa where molecular resources are highly limited for crop improvement. To aid molecular genetic analysis of traits, a linkage map covering 1582.8 cM with an average resolution of 3.69 cM was constructed using 505 polymorphic SNP markers distributed over 21 linkage groups. Composite interval mapping using 267 F1 progeny in initial QTL mapping identified 27 QTLs for productivity traits in the dry savannah of Nigeria. The availability of KASPar SNPs are anticipated to improve the implementation of MB for the development of high performing drought-tolerant cassava varieties in Africa

Molecular-assisted selection for resistance to cassava mosaic disease in Manihot esculenta Crantz

The geminivirus complex known as cassava mosaic disease (CMD) is one of the most devastating viruses for cassava (Manihot esculenta Crantz). The aim of this study was to use molecular-assisted selection (MAS) to identify CMD-resistant accessions and ascertain promising crosses with elite Brazilian varieties. One thousand two hundred twenty-four accessions were genotyped using five molecular markers (NS169, NS158, SSRY028, SSRY040 and RME1) that were associated with resistance to CMD, along with 402 SNPs (single-nucleotide polymorphism). The promising crosses were identified using a discriminant analysis of main component (DAPC), and the matrix of genomic relationship was estimated with SNP markers. The CMD1 gene, previously described in M. glaziovii, was not found in M. esculenta. In contrast, the CMD2 gene was found in 5, 4 and 5 % of cassava accessions, with flanking markers NS169+RME1, NS158+RME1 and SSRY28+RME1, respectively. Only seven accessions presented all markers linked to the CMD resistance. The DAPC of the seven accessions along with 17 elite cassava varieties led to the formation of three divergent clusters. Potential sources of resistance to CMD were divided into two groups, while the elite varieties were distributed into three groups. The low estimates of the genomic relationship (ranging from -0.167 to 0.681 with an average of 0.076) contributed to the success in identifying contrasting genotypes. The use of MAS in countries where CMD is a quarantine disease constitutes a successful strategy not only for identifying the resistant accessions but also for determining the promising crosses

Molecular Diagnostics for Lassa Fever at Irrua Specialist Teaching Hospital, Nigeria: Lessons Learnt from Two Years of Laboratory Operation

Background: Lassa fever is a viral hemorrhagic fever endemic in West Africa. However, none of the hospitals in the endemic areas of Nigeria has the capacity to perform Lassa virus diagnostics. Case identification and management solely relies on non-specific clinical criteria. The Irrua Specialist Teaching Hospital (ISTH) in the central senatorial district of Edo State struggled with this challenge for many years. Methodology/Principal Findings A laboratory for molecular diagnosis of Lassa fever, complying with basic standards of diagnostic PCR facilities, was established at ISTH in 2008. During 2009 through 2010, samples of 1,650 suspected cases were processed, of which 198 (12%) tested positive by Lassa virus RT-PCR. No remarkable demographic differences were observed between PCR-positive and negative patients. The case fatality rate for Lassa fever was 31%. Nearly two thirds of confirmed cases attended the emergency departments of ISTH. The time window for therapeutic intervention was extremely short, as 50% of the fatal cases died within 2 days of hospitalization—often before ribavirin treatment could be commenced. Fatal Lassa fever cases were older (p = 0.005), had lower body temperature (p<0.0001), and had higher creatinine (p<0.0001) and blood urea levels (p<0.0001) than survivors. Lassa fever incidence in the hospital followed a seasonal pattern with a peak between November and March. Lassa virus sequences obtained from the patients originating from Edo State formed—within lineage II—a separate clade that could be further subdivided into three clusters. Conclusions/Significance: Lassa fever case management was improved at a tertiary health institution in Nigeria through establishment of a laboratory for routine diagnostics of Lassa virus. Data collected in two years of operation demonstrate that Lassa fever is a serious public health problem in Edo State and reveal new insights into the disease in hospitalized patients.Organismic and Evolutionary Biolog

A genome scan for quantitative trait loci affecting cyanogenic potential of cassava root in an outbred population

<p>Abstract</p> <p>Background</p> <p>Cassava (<it>Manihot esculenta </it>Crantz) can produce cyanide, a toxic compound, without self-injury. That ability was called the cyanogenic potential (CN). This project aimed to identify quantitative trait loci (QTL) associated with the CN in an outbred population derived from 'Hanatee' × 'Huay Bong 60', two contrasting cultivars. CN was evaluated in 2008 and in 2009 at Rayong province, and in 2009 at Lop Buri province, Thailand. CN was measured using a picrate paper kit. QTL analysis affecting CN was performed with 303 SSR markers.</p> <p>Results</p> <p>The phenotypic values showed continuous variation with transgressive segregation events with more (115 ppm) and less CN (15 ppm) than either parent ('Hanatee' had 33 ppm and 'Huay Bong 60' had 95 ppm). The linkage map consisted of 303 SSR markers, on 27 linkage groups with a map that encompassed 1,328 cM. The average marker interval was 5.8 cM. Five QTL underlying CN were detected. <it>CN08R1</it>from 2008 at Rayong, <it>CN09R1</it>and <it>CN09R2 </it>from 2009 at Rayong, and <it>CN09L1 </it>and <it>CN09L2 </it>from 2009 at Lop Buri were mapped on linkage group 2, 5, 10 and 11, respectively. Among all the identified QTL, <it>CN09R1 </it>was the most significantly associated with the CN trait with LOD score 5.75 and explained the greatest percentage of phenotypic variation (%Expl.) of 26%.</p> <p>Conclusions</p> <p>Five new QTL affecting CN were successfully identified from 4 linkage groups. Discovery of these QTL can provide useful markers to assist in cassava breeding and studying genes affecting the trait.</p

The GCP molecular marker toolkit, an instrument for use in breeding food security crops

Crop genetic resources carry variation useful for overcoming the challenges of modern agriculture. Molecular markers can facilitate the selection of agronomically important traits. The pervasiveness of genomics research has led to an overwhelming number of publications and databases, which are, nevertheless, scattered and hence often difficult for plant breeders to access, particularly those in developing countries. This situation separates them from developed countries, which have better endowed programs for developing varieties. To close this growing knowledge gap, we conducted an intensive literature review and consulted with more than 150 crop experts on the use of molecular markers in the breeding program of 19 food security crops. The result was a list of effectively used and highly reproducible sequence tagged site (STS), simple sequence repeat (SSR), single nucleotide polymorphism (SNP), and sequence characterized amplified region (SCAR) markers. However, only 12 food crops had molecular markers suitable for improvement. That is, marker-assisted selection is not yet used for Musa spp., coconut, lentils, millets, pigeonpea, sweet potato, and yam. For the other 12 crops, 214 molecular markers were found to be effectively used in association with 74 different traits. Results were compiled as the GCP Molecular Marker Toolkit, a free online tool that aims to promote the adoption of molecular approaches in breeding activities