Browsing by Author "Odee, D.W."

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    Analysis of genetic diversity in Eucalyptus grandis (Hill ex Maiden) seed sources using inter simple sequence repeats (ISSR) molecular markers
    (Academic Journals, 2008-07-04) Okun, D.O.; Kenya, Eucharia U.; Oballa, P.O.; Odee, D.W.; Muluvi, G.M.
    Eucalyptus grandis is an economically important tree species that is native to the Australian continent and its northern neighbours, where it is grown primarily for its hard wood timber and pulp for paper industries. It is widely grown in tropical countries such as South Africa, Kenya, Angola, Ghana, and Zimbabwe. Five ISSR primers generated 41 scorable polymorphic bands which were used to analyse genetic diversity between and within the seed sources and for construction of neighbour-joining phenogram. Mean Genetic Diversity per each primer loci based on Nei (1987) statistics indicated significant genetic variation between seed sources with 26.4%, (Gst = 0.264) of the total variation attributed to differences between seed sources. The variation between populations could be due to ecological, geographical association and gene flow rates and hence they should be conserved to retain the full breadth of genetic variation of the species. Thus, ISSR-PCR technology is a reliable, rapid (high throughput) and cost effective marker system that can be used to study genetic variation and genetic relationships among E. grandis seed sources.
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    Evaluation of the Potential of Using Nitrogen Fixing Legumes in Smallholder Farms of Meru South District, Kenya
    (Springer, 2007) Mugwe, Jayne; Mugendi, Daniel N.; Odee, D.W.
    Soil fertility depletion in sub-Saharan Africa is a big constraint to increased food production to feed the ever-growing human population. Use of legumes to improve soil fertility is an option in the central highlands of Kenya and this study evaluated soil characteristics on farms and screened effectiveness of five rhizobia strains on four legumes. Soilssampled from 31 farms showed that the soils were generally acidic with more than 50% of the farms having pH inthe range of extremely acidic and strongly acidic (pH < 5.0). Organic carbon was low «2%) on most farms and total nitrogen was deficient with more than 80% having <0.2% N while P ranged from 1.3 to 15.8 ppm with more than70% of the farms being critically deficient in P. Nodulation on Mucuna pruriens and Crotalaria ochroleuca was observed to be variable within farms with individual farms having fewer nodules per plant than on-farm researcher managed trial. Consequently trials to evaluate effectiveness of rhizobia strains were conducted under glass house conditions. Results showed that KWN35 and TAL 1145 were highly effective on C. calothyrsus and L. trichandra and not on C. ochroleuca. Crotalaria ochroleuca nodulated effectively only with CP354 and NGR457. The NGR 457was highly effective on all the legume plants while NGR185 was only effective on L. trichandra. These studies showed that performance of legumes among the smallholder farms was likely to vary due to varying soil characteristics and that them could be potential for improving legume performance within the smallholder farms through inoculation