37 research outputs found
Infectious structures and response of maize plants to invasion by Exserohilum turcicum in compatible and incompatible host pathogen systems
No full textUse of repetitive extragenic palindromic (REP), enterobacterial repetitive intergenic consensus (ERIC) and BOX sequences to fingerprint Exserohilum turcicum isolates
No full textRace Typing and Evaluation of Aggressiveness of Exserohilum turcicum Isolates of Kenyan, German and Austrian Origin
No full textA review of the Amplified Fragment Length Polymorphism (AFLP) technique in genotyping and DNA fingerprinting studies [Review Article]
No full textABSTRACT Amplified fragment length polymorphism (AFLP) is a marker based on polymerase chain reaction amplification of restricted fragments ligated to synthetic adaptors and amplified using primers which carry selective nucleotides at their 3' ends. The technique generates highly reproducible markers from DNA of any organism and allows high resolution genotyping. AFLP has broad applications and has been used to investigate genomes of different complexity from microbes to higher organisms for purposes of species, strains and varieties identification, systematics, pathotyping, population genetics, simple and complex trait mapping, population genetics, construction of linkage and physical maps. In addition, it is being used in medical diagnostics, forensic analysis and microbial typing. AFLP is superior compared to other markers in that it has time efficiency, generates more information, is highly reproducible and has a wide range of applications. The marker has a drawback in that it generates dominant rather than co-dominant markers and can also be expensive if automated systems are used
Production, purification and separation of phytotoxins from Exserohilum turcicum isolates of Kenyan, German and Austrian origin
No full textRace Typing and Evaluation of Aggressiveness of Exserohilum turcicum Isolates of Kenyan, German and Austrian Origin
No full textEvaluation of Genetic Variability of Kenyan, German and Austrian Isolates of Exserohilum turcicum using Amplified Fragment Length Polymorphism DNA Marker
No full textEighty nine Exserohilum turcicum isolates comprising 56 Kenyan, 26 German and 7 Austrian isolates were isolated from diseased maize plants and cultured on complete liquid medium to generate mycelium for DNA extraction. DNA extraction was done following the CTAB method, DNA purified using spermidin and fingerprinting conducted using Amplified fragment length polymorphism (AFLP) procedure. NTSYSpc, pop gene and Arlequin programs were used to analyze the data and to generate the dendograms. The number of amplified bands and polymorphism varied with the different primer combinations with primer combinations E-ACA/T-CCA, E-ACA/T-CAC, E-ACA/T-CGA, E-ACA/T-CTA revealing a high (79%) level of polymorphism. Cluster analysis of the 607 polymorphic bands from these primer combinations using UPGMA algorithms generated dendograms with 7 main AFLP groups with isolates from different localities grouping together with only two outliers. Pair wise similarity matrix derived with SIMQUAL program showed a wide variation in the AFLP fingerprint of the E. turcicum isolates. Nei’s genetic distance matrix showed that the three populations of E. turcicum isolates differed genotypically with the Kenyan isolates being more genetically related to Austrian isolates (genetic identity of 0.9998) whereas the isolates from Germany and Austria were more diverse (genetic identity of 0.9978). This study showed that AFLP marker is useful in the study of genetic variation of E. turcicum and the pathogen has a high level of genetic diversity
Effect of soil sterilisation on biological control of <i>Fusarium oxysporum</i> f. sp. <i>lycopersici</i> and <i>Meloidogyne javanica</i> by antagonistic fungi and organic amendment in tomato crop
No full textOne of the major challenges in the application of biological control agents into the soil is their inability to withstand competition from natural microflora. In this study a management programme involving fungal biological control agents Trichoderma harzianum (TH) and Purpureocillium lilacinium (PL), and the organic amendment neem was carried out for the control of Meloidogyne javanica and Fusarium oxysporum f. sp. lycopersici (FOL). The experiment was carried out in sterile and non-sterile soil in order to test the efficacy of biological control in natural soil conditions. This experiment was repeated twice. A Wilcoxon's Signed-Rank test indicated there were no significant (P < 0.05) differences in fusarium wilt control in sterile and non sterile soils in the treatments PL neem and TH neem, but there was significantly (P < 0.05) higher control of M. javanica in the same treatments in sterile soils compared to non sterile soils. The combinations of fungal antagonists and neem were effective in non sterile as in sterile soils in the control of fusarium wilt, while being less effective in the control of M. javanica. Thus the biological control agents can be very effective in the control of fusarium wilt in natural conditions where the soil is not sterilised, but be less effective in the control of M. javanica in the same conditions. There is therefore potential of integrated management of fusarium wilt and root-knot nematodes (RKN) by these biological control agents in natural soil field conditions as an alternative to using chemicals
Influence of Farming Practices on the Chemical Properties of Soil in Small Scale Tea Farms in Kirinyaga and Tharaka-Nithi Counties of Kenya
No full textSoil chemical properties are important for growth of plants as they determine the nutrient availability for their uptake. Farming practices are treatments applied to farms in efforts to maximize crop productivity. Experiments were set up in Kangaita, Kirinyaga County, and Weru, Tharaka-Nithi County using randomized complete bock design to establish the influence of farming practices on the chemical properties of soil in tea production areas. This was aimed at understanding the role of the farming practices on the availability of soil nutrients and their effect on tea productivity. Each study site was divided into three zones depending on elevation and three farming practices identified within each zone namely neglected farms, manure applied farms and chemical fertilizer (NPK) applied farm. Soil samples were collected randomly from farms in each zone and analyzed for chemical properties. Soil acidity increased from neglected farms through manure applied farms to NPK fertilizer applied (standard) farms. The soils had generally low levels of K, Mg and Zn due to rapid removal through harvesting of the young shoots and leaves. Manure application is recommended as it is less degrading to the soils
Comparison of the Effectiveness of Zero Tillage and Intercropping on Weed Management in Maize (Zea mays L.)
No full textMaize is an important cereal worldwide and weeds are a major constraint to production. A trial was conducted in Kigumo, Murang’a County, Central Province of Kenya in 2010 to compare the effects of glyphosate and intercropping maize with Dolicos lablab on weed and maize yield. Treatments comprised of DUMA SC41 and DK8031 maize varieties, glyphosate, intercropping and weedy arranged in a randomized complete block design in 5x3 m plots replicated three times and data collected in 3x1.5m area in each plot. Weed scores, biomass and maize yield were recorded. Data was analysed using Gen Stat software package, treatments effects compared using ANOVA and the means separated by Student New man Keuls. No significant differences in weed scores, biomass weight and maize yield in both seasons between glyphosate and intercropping at P < 0.05. Intercropping and glyphosate had similar effects on weeds and maize yield, the former can substitute herbicide use. Key words:,,Maize, grain yield, small scale farmers, tillage method
