Browsing by Author "Wanjala, B.W."
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Item Diversity and Population Structure of Local and Exotic Lablab Purpureus Accessions in Kenya as Revealed by Microsatellite Markers(eSciPub LLC, 2021) Kamau, E.M.; Kinyua, M.G.; Waturu, C.N.; Kiplagat, O.; Wanjala, B.W.; Kariba, R.K.; Karanja, D.R.; Kenya Agriculture and Livestock Research Organization ; University of Eldoret ; World AgroforestryLablab purpureus is an important pulse crop in some parts of sub-Saharan Africa and Asia but has largely remained underuti-lized. Understanding the genetic diversity is prerequisite for ge-netic improvement and utilization of this leguminous crop. The relationships of the local lablab genotypes and those collected from other diverse geographic origins including the wild acces-sions remain unknown in Kenya. The study was undertaken to determine genetic diversity and population structure of germ-plasm accessions collected from Kenya and other global regions. Eight simple sequence repeat primer pairs were used to genotype the 189 lablab accessions. A total of 39 alleles were re-vealed by eight SSR with an average of 4.88 alleles per polymor-phic loci. The average PIC was 0.42. The gene diversity among the accessions ranged from 0.26 to 0.52 with an average of 0.38, indicating moderate genetic diversity. Germplasm collected from Kenya showed a moderate genetic diversity of 0.36. Higher ge-netic diversity (He<0.5) was detected within the Ethiopian and South Africa populations. Analysis of molecular variance (AMO-VA) revealed that 94% of the allele diversity was attributed to in-dividuals within populations while only 6% was distributed among the populations. The Bayesian model-based Structure method and Principal coordinate analysis (PCoA) scatter plot clustered the accessions into three groups with germplasms collected from Kenya showing distribution among all the three groups. The wild accessions clustered mainly with those from Southern and Eastern Africa confirming earlier suggestions that lablab is of Af-rican origin. The results of this study are discussed in light of the crop improvement of this crop.Item Loop-Mediated Isothermal Amplification Assays for On-Site Detection of the Main Sweetpotato Infecting Viruses(Elsevier B.V, 2021) Wanjala, B.W.; Ateka, E.M.; Miano, D.W.; Fuentos, S.; Perez, A.; Low, J.W.; Kreuze, J.F.; International Potato Center SSA Regional Office ; Jomo Kenyatta University of Agriculture and Technology ; University of Nairobi ; International Potato Center Avenida La Molina 1895Globally, Sweet potato feathery mottle virus (SPFMV) and Sweet potato chlorotic stunt virus (SPCSV) occur frequently and in combination cause sweetpotato virus disease (SPVD). Many viral diseases are economically important and negatively impact the production and movement of germplasm across regions. Rapid detection of viruses is critical for effective control. Detection and quantification of viruses directly from sweetpotato remains a challenge. Current diagnostic tests are not sensitive enough to reliably detect viruses directly from the plant or require expensive laboratory equipment and expertise to perform. We developed a simple and rapid loop- mediated isothermal amplification (LAMP) assay for the detection of SPFMV, SPCSV and begomoviruses related to sweet potato leaf curl virus (SPLCV). Laboratory validation recorded 100 % diagnostic sensitivity for all the three viruses. The LAMP assays were customized for field testing using a lyophilized thermostable isothermal master mix in a ready-to-use form that required no cold chain. The average time to positivity (TTP) was: SPFMV 5 30 min, SPCSV 15–43 min s and begomoviruses 28 45 mins. LAMP on-site testing results were comparable to PCR and RT-PCR confirmatory laboratory tests. The LAMP assay is a powerful tool for rapid sweetpotato virus detection at a reasonable cost and thus could serve as quality control systems for planting materials.
