Browsing by Author "Kanyeka, Z. L."

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    Effect of Timing of Seed Collection and Provenance on Seed Viability and Germination of Dalbergia melanoxylon
    (Scientific Research, 2008) Amri, E.; Lyaruu, H. M. V.; Nyomora, Agnes M.; Kanyeka, Z. L.
    Dalbergia melanoxylon is one of the most expensive timbers in the world used for the manufacturing of musical instruments and decorative objects such as carvings. The effect of timing of seed collection and provenance on seed viability and germination were investigated. Percentages of germination capacity and germination energy were significantly higher for seeds collected 12 and 16 weeks after maturity. Seed viability was highest 59.8% at fruit maturity stage and significantly decreased to 25.7% for seeds collected 24 weeks after maturity. Significantly highest germination capacity 25.8% was obtained for seeds collected from Ubena provenance followed 20.5% for seeds collected from Mkundi provenance. Percentage of seed viability collected from Ubena was superior 57.56% to other provenances followed Mkundi provenance, which had 49.42%. Seed collection in D. melanoxylon should be done between 8-16 weeks after maturity from superior provenances to obtain seeds with high germination energy and germination capacity.
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    Evaluation of Genetic Diversity in Dalbergia Melanoxylon Populations Using Random
    (2009) Amri, E.; Kanyeka, Z. L.; Lyaruu, H. M. V.; Nyomora, Agnes M. S.
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    Evaluation of Provenances and Rooting Media for Rooting Ability of African Blackwood (Dalbergia Melanoxylon Guill. & Perr.) Stem Cuttings
    (2009) Amri, E.; Lyaruu, H. M. V.; Nyomora, Agnes M. S.; Kanyeka, Z. L.
    Vegetative propagation of Dalbergia melanoxylon Guill. & Perr. collected from six provenances was investigated in three rooting media (river sand, forest topsoil and mixture 1: 1 (v/v) of river sand and forest topsoil). The effect of provenance and rooting media were highly Significant (p<0.001) for the percentage rooted stem cuttings. Interactive effect on provenance and rooting media was not significant in all rooting parameters evaluated. The highest and lowest rooting percentages with respect to provenance were 22.7% and 12.4% recorded from Madale and Mikumi respectively. River sand media revealed significant highest rooting ability of cuttings in all rooting parameters among the three media tested (p<0.05). Significant positive correlation (p<0.01) was revealed between rooting parameters while rooting and sprouting parameters were negatively correlated. Vegetative propagation of D. melanoxylon is a means for promotion of this species for domestication, conservation and as an asset for clonal forestry.
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    Vegetative Propagation of African Blackwood (Dalbergia Melanoxylon Guill. & Perr.): Effects of Age of Donor Plant, IBA Treatment and Cutting Position on Rooting Ability of Stem Cuttings
    (Springer Netherlands, 2010) Amri, A.; Lyaruu, H. M. V.; Nyomora, Agnes M. S.; Kanyeka, Z. L.
    A study to determine the best vegetative propagation protocol was carried out for Dalbergia melanoxylon. Natural regeneration of D. melanoxylon is limited due to poor seed viability and germination. The effects of age of donor plant, indole-3-butyric acid (IBA) treatment and cutting position on rooting of stem cuttings were investigated. The effect of age of donor plant was significant (P < 0.001) only for percent rooting, position effect was significant for all studied parameters, and IBA treatment at 300 ppm was insignificant only for percent callusing. Interactive effects of cutting position × age of donor and cutting position × IBA treatment were significant for percent rooting and root number per cuttings while interactive effect of age × IBA was significant only for percent rooting. Observed difference in rooting performance could be due to uneven distribution of root promoting and inhibiting substances with respect to age of donor plant and IBA which intensified root formation. Cuttings from juvenile donor plant performed better in all rooting parameters than mature donor plant. The highest percentages in rooting were (71.11%) and (24.42%) for cuttings from juvenile and mature donor plants, respectively. IBA treated cuttings produced higher percentage rooting, number of roots and root length than untreated cuttings which revealed a strong IBA influence on rooting ability of stem cuttings in D. melanoxylon. It was concluded that stem cuttings should be taken from juvenile donor plants and basal cutting position should be used to produce high quality planting stock material for the afforestation and conservation programme of D. melanoxylon.