Browsing by Author "Lyaruu, H. M. V."

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    The Effect of Anthropogenic Disturbances on Population Structure and Regeneration of Scorodophloeus Fischeri and Manilkara Sulcata in Coastal Forests of Tanzania
    (2011) Mligo, Cosmas; Lyaruu, H. M. V.; Ndangalasi, Henry J.
    Scorodophloeus fischeri (Fabaceae, subfamily Caesalpinoideae) and Manilkara sulcata (Sapotaceae) are examples of tropical African hardwood species and are endemic to East African coastal forests. These plant species are threatened by human activities beyond natural recovery in some forests. This study aimed to assess the effects of anthropogenic disturbance on the natural regeneration potential of S. fischeri and M. sulcata in the selected coastal forests of Tanzania. Transects were established in various vegetation communities and a nested quadrat technique was used to assess the natural regeneration. Scorodophloeus fischeri regenerates best in Zaraninge forest with high density of trees with diameter at breast height (DBH) between 10–50 cm and a higher seedling density than in other forests. Similarly, M. sulcata regenerates best in Pande forest, although many trees had a DBH of 10–30 cm, implying that the trees with size classes above these are missing. It was concluded that the minimum level of human disturbances in Zaraninge favoured high potentials of natural regeneration of S. fischeri. Disturbances through human activities contributed to the variation in the natural regeneration potentials for S. fischeri and M. sulcata in these forests. Conservation attention is likely to improve population structure and natural regeneration patterns of S. fischeri and M. sulcata in East African coastal forests.
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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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    Improving Propagation Success of D. Melanoxylon (African Blackwood) In Tanzania (II): Rooting Ability of Stem and Root Cuttings of Dalbergia Melanoxylon (African Blackwood) In Response to Rooting Media Sterilization in Tanzania
    (2012) Washa, W. B. A.; Nyomora, Agnes M. S.; Lyaruu, H. M. V.
    Dalbergia melanoxylon is a plant with valuable wood in the world and therefore is over harvested for timber while its regeneration is very low. The propagation efforts by techniques such as tissue culture or mycorrhiza have not been investigated which instigated conduction of this study. Soil and cuttings were collected from Kilwa, Kilosa and Babati for rooting test, potting media and soil characterization. The results showed that fresh soil improved rooting characteristics while sterilized soil did not due to the presence of mycorrhiza in fresh soil compared to none in sterilized media. The overall rooting in fresh soil in non-mist propagator was higher, 100% for softwood and 37% for root cuttings while none rooted in the open nursery. The results revealed that there was no significant correlation between rooting and collection sites while cutting type and the soil type used significantly influenced rooting. Softwood cuttings that weighed less than 15g significantly increased rooting at (P < 0.05) compared to cuttings that weighed above 15g. It was recommended to propagate Dalbergia melanoxylon using softwood cuttings placed in a non-mist propagator and using fresh soil infected with mycorrhiza.
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    Improving propagation success of Dalbegia melanoxylon (African blackwood) in Tanzania (I): Characterization of mycorrhizal associated with D. melanoxylon (African blackwood) in Tanzania
    (2012) Washa, W. B. A.; Nyomora, Agnes M. S.; Lyaruu, H. M. V.
    Dalbergia melanoxylon Guill & Perr is a plant with quality wood in the World and therefore is over harvested for timber while its regeneration capacity is very low. The propagation techniques such as tissue culture or use of mycorrhiza have not been investigated which instigated conduction of this study by investigating the presence of mycorrhiza that might be useful for its regeneration. Some 120kg of soil and 120 roots of D. melanoxylon from Kilwa, Kilosa and Babati were sampled to identify mycorrhiza related with regeneration of the species. Cleaning the tissues was done by soaking the root pieces in 1.79M KOH, and 0.1M Hcl. Staining was done using 0.05% Trypan blue and de-staining in 14:1:1 lactic acid: glycerol: water and mounting on slides for observation. Soil was soaked in water overnight and the mycorrhiza was separated using a stereo microscope at 50X. Separated mycorrhiza were incubated for observation using a compound microscope at 400X. Twenty six (26) ECM resembling Inocybe and Laccaria sp were isolated from the root pieces and 18 VAM resembling Glomus species were isolated from soil. It is recommended that future research should investigate proper inoculum types and time for inoculating the species in nurseries for propagation
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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.