Browsing by Author "Nyomora, Agnes M. S."

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    Boron Determination in Biological Materials by Inductively Coupled Plasma Atomic Emission and Mass Spectrometry: Effects of Sample Dissolution Methods
    (Springer Link, 1997) Nyomora, Agnes M. S.; Sah, R. N.; Brown, Patrick H.; Miller, R. O.
    This study compares four sample dissolution methods for Boron determination in two National Institute of Standard and Technology (NIST) botanical Standard Reference Materials (SRMs) and three Agriculture Canada/NIST RMs, each having a reference (certified or best estimate) B concentration. The dissolution treatments consisted of: 1) dry ashing at 500° C, 2) wet digestion with HNO3 + H2O2, 3) extraction with hot HNO3 and 4) closed vessel microwave dissolution. The samples were spiked before and after imposing dissolution treatments to study B recovery by inductively coupled plasma mass spectrometric (ICP-MS) analysis. Microwave digests of NIST SRM 1515 and some in-house RMs were also used to compare the B values of ICP-MS and ICP-AES (atomic emission spectrometry). While all three digestion methods (dry ashing, wet ashing and microwave) dissolved botanical samples, only the microwave method worked well for animal tissues. In terms of B values in these materials, there was no significant difference among the three digestion treatments. Near 100% recovery of B spiked before and after the sample dissolution indicates that there may not be a significant loss of B during the dissolution process used in this study. Extraction with hot HNO3 was as effective as the three digestion treatments, and B values for this method agreed well with reference values. For the botanical materials studied, the B values determined by ICP-AES were not significantly different from ICP-MS values. This study shows that a simple, time and labor efficient hot HNO3 extraction is as effective as other digestion/dissolution methods for quantitative B recovery from biological materials.
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    Distribution and Abundance of the edible Orchids of the Southern Highlands of Tanzania
    (2009) Nyomora, Agnes M. S.
    All orchids have showy flowers and many are therefore popular as exotic houseplants as well as contributing significantly to eco-tourism. A special attribute of some orchid genera is the production of edible tubers, an attribute that can contradict eco-tourism if harvesting is not done sustainably. Such is the case in the Southern Highlands where for example, Kitulo Plateau has been gazetted to be a National Park but where edible orchid harvesting is a serious conservation problem. Botanically, unsustainable harvesting can mean the loss of important germplasm even before some species are known to exist. A field survey was undertaken for three weeks in March 2002 in the Southern Regions of Tanzania (Iringa, Mbeya, Rukwa and Ruvuma) to study aspects of the extent of the distribution, diversity and density of edible orchids. Tools for identification included structured questionnaire, on-the-spot identification as well as using herbarium voucher samples and keys. Analytical tools included Shannons’ diversity index and Canonical Community Ordination (CANOCO) and ANOVA in Microsoft Excel. A total of 13 edible species of orchids were documented during the survey all of them from the genera Habenaria, Disa and Satyrium. While Tandala and Molo hills had the highest species Diversity Index (over 1.2), Kitulo Plateau showed the greatest species density of over 200/30m2 quadrants. Local communities in Madaba in Ruvuma, Molo, and Mbisi in Rukwa regions used the orchids as vegetables and snacks in lieu of animal meat. The rest of the studied areas used orchids as a source of cash by selling to Zambian traders and or to their middlemen. More research is needed to monitor growth phases, reproductive/propagation studies as well as taxonomic and systematic studies preferably using molecular techniques to determine relationships amongst edible orchids and their non edible relatives
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    The Effect of Moisture and Seed Treatment on the In- Situ and Ex-Situ Regeneration of Dalbergia Melanoxylon (African Blackwood) in Pugu Forest Reserve
    (2014) Washa, W. B. A.; Nyomora, Agnes M. S.
    Abstract: A study was conducted to investigate the effect of moisture and seed treatment on the in-situ and ex-situ regeneration of Dalbergia melanoxylon in Pugu forest reserve. Seed germination experiments was conducted for three months between November and December 2005 in the nursery Botany Department of the University of Dare s Salaam while seedling growth rate measurements were conducted for 12 months between January and December 2006 in the Pugu forest reserve. A total of 2 kg of D. melanoxy seeds collected from Pugu forest reserve and some from Tanzania Tree Seed Agency (TTSA) were used for seed germination experiments. A total of 25 seedlings approximately 2 years old were randomly chosen from Pugu forest reserve for seedling growth rate experiments. A split plot experimental design was used for seed germination in the nursery where soaked and non-soaked seeds stood for main plot and different moisture level treatments stood for subplot. Parameters recorded were germination dates, germination percentages, seedling increase in height and seedling increase in girth. Manual computation of data was accomplished according to Zar, 1988 where LSD was used for mean separation to determine statistical differences between treatment means. Tables and Figures were used to facilitate presentation and discussion of results. Data analysis led to the conclusion that, a moderate ex-situ moisture level of 200ml in a 1L pot per day effectively promoted seed germination up to 21% in seeds previously soaked in water for 6 hours compared to high moisture treatment of 300ml in a 1L pot per day which effected seed germination only by 11.6%.. The maximum in-situ growth rate was concluded to be 0.01 cm/month. The study revealed that seeds and young seedlings of D. melanoxylon are vulnerable to high moisture level while older trees are water and light demanding. It was recommended that future researches should endeavour to increase seed viability by harvesting them immediately from their maturity and storage in sealed containers, conducting tissue culture to manipulate seedlings and hybridization experiments with related species to reduce growth period.
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    Establishment and Growth of Vetiver Grass Exposed to Landfill Leachate
    (2012-05-01) Nyomora, Agnes M. S.; Njau, K. N.; Mligo, L.
    Solid waste dumpsites in Dar es Salaam city are of environmental concern due to their associated leachate release into aquatic systems. They pose health risks to the Dar es Salaam residents due to the environmental pollution they cause. Currently, no control measures are employed. An effort to control leachate from Vingunguti dumpsite in Dar es Salaam using vetiver grass is in progress. Effectiveness of vetiver grass to control soil erosion and to treat wastewater is well researched; however, limited information exists on the response of vetiver grass growth to leachate and their effectiveness in phytoremediation of degraded dumpsites. This study aimed at assessing the survival of vetiver grass to landfill leachate so as to establish the use of vetiver grass in reclamation of dumpsites in Tanzania. Vetiver grass was subjected to various concentrations of leachate (0-50% v/v). The results showed that vetiver grass grew well only when it was exposed to leachate concentration of 10-30 (v/v) %. Above this concentration, vetiver grass growth was greatly reduced and complete death occurred at leachate concentrations of 75% (v/v) and above. Establishment and growth of vetiver grass Vingunguti dumpsite leachate would need approaches that limit the stress to young vetiver plants.
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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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    Fall Foliar-applied Boron Increases Tissue Boron Concentration and Nut Set of Almond
    (1997) Nyomora, Agnes M. S.; Brown, Patrick H.; Freeman, Mark
    Fruit set is the major determinant of productivity in almond [Prunus dulcis (Mill D.A. Webb)] where seed is the commercial product. Boron influences flowering and fruit set in a number of crops, but little has been reported on this subject in almond. Here, we investigated the effect of a fall foliar application of B on fruit set and tissue B concentration in open pollinated `Butte' and `Mono' almond over a 2-year period. Early fall B application significantly increased the vegetative, floral, and fruit tissue B concentration in the subsequent year. The greatest increase in organ B concentration was observed in flower buds, flowers, and hulls. Recent work has demonstrated that B forms a B-sorbitol complex in Prunus species. This B-sorbitol complex is phloem mobile and is transported to sink organs. Here we demonstrate that fall-applied B is absorbed by the leaf and is subsequently transported (presumably as the B-sorbitol complex) to floral buds where it is available to flowers and, hence, influences fruit set and yield. It is concluded that fall foliar-applied B is a useful fertilization strategy that can be used to optimize tissue B concentration in species in which B is phloem mobile. Boron applied at 245 and/or 490 ppm significantly increased fruit set in `Butte' and `Mono' and increased yield of `Butte' in 1994 on open-pollinated trees (yield was not determined in 1993). The highest initial and second fruit set was associated with either the 245 or 490 ppm B treatments in both cultivars and both years. This increased fruit set resulted in yield increases of 53% and 4%, respectively, for `Butte' and `Mono'. Of the two cultivars, `Butte', which had lower tissue B concentration before B application, responded more significantly in yield to B application. Application of 735 ppm B was less effective than either 245 and 490 ppm B; however, no visual symptoms of excess B were observed.
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    Foliar Application of Boron to Almond Trees Affects Pollen Quality
    (2000) Nyomora, Agnes M. S.; Brown, Patrick H.; Pinney, K.; Polito, V. S.
    The effect of boron (B) on in vivo and in vitro development of almond [Prunus dulcis (Mill.) D.A. Webb (syn. P. amygdalus Batsch)] pollen and pollen tubes and the resultant effect on fruit set was studied in mature trees. The cultivars Mono (pistil donor) and Butte (pollinizer) in an orchard with low soil B in Fresno, California were sprayed with B at 0, 0.8, 1.7, or 2.5 kg·ha–1 during Fall 1993. Pollen viability as indicated by the fluorescein diacetate method (FDA) was >85% and was not affected by field-applied B, however, in vivo pollen germination and tube growth were enhanced by foliar-applied B. More effect of applied B on in vivo growth appeared as pollen tubes progressed toward the ovary. For in vitro germination, foliar-applied B reduced bursting of tubes, and addition of B to the culture media significantly increased pollen germination and pollen tube growth
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    Foliar Boron Application Enhances Almond Yields
    (1996) Brown, Patrick H.; Hu, Hening; Nyomora, Agnes M. S.; Freeman, Mark
    A three-year study in California shows that foliar boron (B) applications can increase yield in almonds even where there are no visible leaf symptoms of B deficiency. Data suggest that foliar applications act specifically to enhance the number of flowers that set fruit.
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    Genetic diversity between Cultivated and Non-cultivated Moringa Oleifera Lam. Provenances Assessed by RAPD markers
    (2010-11-08) Mgendi, Mariam G.; Manoko, Mkabwa L. K.; Nyomora, Agnes M. S.
    Knowledge of population genetic diversity is one of the prerequisites for development of plant species conservation strategies. In the case of wild species that represent genetic resources for cultivated plants, an understanding of their genetic diversity is essential as they are the source of genetic material that are used to improve elite varieties. A total of 12 RAPD primers were used to investigate the genetic diversity between and within cultivated and non-cultivated provenances of Moringa oleifera Lam. from costal regions of Tanzania. Cluster analysis using NTSYS-pc and UPGMA program produced five clusters with similarity ranging from 54% to 96%. Clustering pattern revealed a trend of genetic separation between cultivated and non-cultivated individuals which could be attributed to genetic changes taking place in escapees’ individuals as they adapt to the natural environment. Based on the results, selection of elite germplasm and conservation of M. oleifera genetic resources could be achieved by considering individuals both from wild and cultivated plants.
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    Growth and Yield Performance of Selected Upland and Lowland Rainfed Rice Grown in Farmers and Researchers Managed Fields at Ifakara, Tanzania.
    (Academic journal, 2019-01-24) Kitilu, M. J. F.; Nyomora, Agnes M. S.; Charles, J.
    Bridging the yield gaps is of major concern to rice breeders and agronomists under rainfed rice cultivation. The yield performance of lowland and upland rainfed rice varieties was investigated in farmers’ and researchers’ field conditions at four locations in Ifakara. Selected agronomic practices namely; recommended fertilizer (80 kgN/ha), spacing of 20 cm × 20 cm, weed free fields and high yielding varieties of TXD306, Komboka and Tai for lowland rainfed, and NERICA1, NERICA2 and NERICA4 for upland rainfed rice. Moreover, farmer selected varieties Supa India and WahiPesa were used as the local control in this research. The study revealed that yield performance of lowland rainfed rice varieties and in farmers’ fields ranged between 2.9 and 6.9 t ha-1, while in the upland rainfed rice the yield ranged between 2.5 and 5.4 t ha-1. This was similar to yield that was obtained from the researchers’ fields which ranged between 2.4 and 8.5 t ha-1 in lowland and between 1.8 and 4.8 t ha-1 in upland fields. The yield gap analysis revealed that the gap of between 35 and 60% previously reported in lowland rice was narrowed to 0 to 12.1%, while in the upland rice from 24.5 to 28.6% previously reported to 0% and excess yield over the potential yields and yields previously reported by farmers. The performance of all improved rice varieties at farmers and researchers’ field were significantly higher compared to the local check varieties Supa India and WahiPesa. It was concluded that, providing farmers with selected good agronomic practices and supervision of farmers in field management activities enhanced rice productivity under farmers’ conditions and narrowed or bridged the yield gaps that existed.
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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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    Rate and Time of Boron Application Increase Almond Productivity and Tissue Boron Concentration
    (1999) Nyomora, Agnes M. S.; Brown, Patrick H.; Krueger, Bill
    Previous studies with tree species have demonstrated that foliar boron (B) promotes flowering, fruit set, and yield. However, for most species the optimum time for foliar B application has not been determined. This investigation was undertaken to study the effects of time and rate of B application on almond [Prunus dulcis (Mill D.A.Webb)] tissue B concentration, fruit set, and yield. Solubor (Na2B8O13.4H2O), a commercial product containing 20.5% B, was applied with a handgun sprayer either in September (3 weeks postharvest), December (dormancy), or February (budbreak) at rates of 0, 0.8, and 1.7 kg·ha–1 B to almond cv. Butte at one site (Parlier, Fresno County, Calif.), and of 0, 0.8, 1.25, 1.7, and 2.1 kg·ha–1 B on the same cultivar in August, September, or February at a second site (Orland, Glenn County, Calif.) using Borosol, a polyboronated commercial product containing 10% B. At site 1, September application was more effective in increasing tissue B concentration, fruit set, and yield than were December or February applications. The optimal rate was 0.8 to 1.7 kg·ha–1 B when applied in September. At site 2, application in 1996 and 1997 increased tissue B concentration almost linearly, especially when applied in August and February. Application at the highest rate (2.1 kg·ha–1 B) in September produced the greatest final fruit set and yield in 1996. February applications increased initial fruit set at both sites but were less effective than September applications in increasing yield. Application of B did not affect any yield variable in 1997. These results suggest that B should be applied immediately postharvest (September) for optimal effect on tissue B concentration, fruit set, and yield in almond
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    Screening of Peach Fruit Cultivars in the Southern Highlands of Tanzania
    (1988) Nyomora, Agnes M. S.
    The Southern Highlands of Tanzania lie between Latitudes 6° 31'S and 10° 75'S at a Longitude of 30° 30'E and 36° 30'E. More than 30% of the area is at an elevation of between 1 500 m to above 2 500 m.a.s.l. The weather is generally cool. Temperature range between a mean maximum of 23°C and mean minimum of 14°C. The coolest months May, June, July and August have mean minimum temperatures below 10°C decreasing with increasing altitude. Frost during these months is common. Rainfall totals over 800 mm, with the rainy season being between the months of November - April. The soils are generally of medium to high fertility. The potential for growing temperate fruits in the Southern Highlands of Tanzania is therefore very high. The important temperate fruits grown in the region include peaches, plums, apples and pears produced mainly at the subsistence level of 15–30 trees per household. A few farmers and public institutions have bigger orchards of between 2 and 5 acres yielding between 10 and 20 kg per tree compared to 30–40 kg obtained in average orchards elsewhere. The main problems of temperate fruit production in the region are low fruit yield per tree and poor quality fruits as a result of poor cultivars, management practices and inadequate chilling. Research activities have been in existence since 1973. The fields of investigation are collection of improved cultivars and screening them for adaptability as well as management trials. Research work on peaches has advanced much more than that on apples, pears and plums. The latter are still at the level of observation orchards. Of the local collection of peaches results to date are in favour of TCEC, DF no. 58, and Dabaga no. 14. Flordabelle peach and Sunred nectarine, of the cultivars imported in 1976, do well in our tropical climate.
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    Supporting Tanzania’s Cocoa Farmers
    (2012) Nyomora, Agnes M. S.; Kanyeka, Z.; Ndunguru, A.
    Agriculture is the leading sector of the Tanzanian economy, and the most critical for inclusive pro-poor growth. Agriculture provides employment for more than three quarters of the population, accounts for 75% of the country’s exports, and contributes almost 50% to Gross Domestic Product (GDP). Cocoa was introduced into Tanzania in the 1950s, and was being grown commercially within a decade. Although it tends to be considered a relatively minor non-traditional cash crop, it is currently supports an estimated 25,000 farmers and their families (or around 100,000 people). At the moment, around 80% of the country’s crop comes from a single district – Kyela in Mbeya region – where conditions for cocoa cultivation are near perfect. The majority of plants are grown there in organic conditions, by smallholders on plots well below a hectare, and sold directly from farms for export. The distinctive flavour of Tanzanian cocoa has recently been attracting the attention of the international cocoa world, but much is still needed for the country’s crop to reach its full potential
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    Using Morphological Markers to Assess Variations between and within Cultivated and Non-cultivated Provenances of Moringa Oleifera Lam. in Tanzania
    (2011-05-30) Mgendi, Mariam G.; Nyomora, Agnes M. S.; Manoko, Mkabwa L. K.
    The use of morphological markers to assess variations between and within cultivated and non-cultivated provenances of Moringa oleifera Lam. from selected coastal regions of Tanzania was studied. A descriptors list of 15 selected morphological characters was used to generate a character state matrix. Cluster analysis using NTSYS-pc and UPGMA program produced six clusters with similarity ranging from 66% to 100%. The majority cultivated and non-cultivated clusters with similarity ranging from 86-100% and 97-100% respectively reflected a clustering pattern based on the status of individuals whether cultivated or non-cultivated. Most individuals from same population clustered differently indicating high morphological variations within populations than between populations. The present results suggest that selection and conservation of elite germplasm could be achieved by considering individuals from both cultivated and non-cultivated plants.
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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.