Browsing by Author "Faustine, Christopher"

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    Asessment of resistance of Tanzanian and Brazilian cotton cultivars (g. hirsutum l.) to fusarium wilt, bacterial blight and root-knot nematodes
    (University of Dar es Salaam, 2014) Faustine, Christopher
    Fusarium wilt and bacterial blight are the main diseases of cotton in Tanzania, especially in the Western Cotton Growing Area. Deployment of resistant varieties is the most reliable and long-term strategy to manage such diseases. In this study, four cultivars from Brazil and three local cultivars were evaluated to assess field performance under local conditions and screened for resistance against Fusarium wilt, bacterial blight and root-knot nematodes. Generally, all the cultivars evaluated showed good adaptability to the local growth conditions and statistical differences were observed among the cultivars for plant height, number of bolls per plant, number of sympodial branches per plant, (p<0.0001), days taken to set first flower (p<0.001) and seedcotton yield (p<0.0303) whereas no statistical differences was observed among the cultivars for boll weight and number of seeds per boll (p>0.05). When screened for markers linked to Root-Knot nematodes resistance using SSR markers, none of the samples tested had resistance allele at the BNL3661 locus while only one plant of Araça presented the resistance allele at CIR316 locus. For Bacterial blight, one SNP and SSR markers were used and more frequencies of resistance alleles were observed in cultivars UK91, UK08 and UKM08 than in Ipê, Aroeira, Cedro and Araça. All Tanzanian cultivars had the alleles for resistance against blue disease at the loci NG0204310 and DC20027 unlike the Brazilian germplasm that some had no such allele. Assessment of Fusarium wilt resistance was done by inoculation and the cultivars Ipê and Aroeira had lower disease severity index and higher plant survival suggesting that they might be used as potential candidates in local breeding program for Fusarium wilt resistance.