Prerequisites for biocrops Up-Scaling II: An assessment of the vegetative method of propagation for oilferous plant species with potential for biodiesel production

The rooting ability of hardwood cuttings from six selected non- edible oilferous plant species with potential for biodiesel production namely Telfairia pedata, Jatropha curcas, Excoecaria bussei, Croton macrostachyus, Croton megalocarpus and Ricinus communis was assessed on 4 differentpotting media i.e. forest top soil, sandy, clay and loamy soil. The proportion of cuttings that rooted were evaluated for the root numbers, root length, root dry weight, sprouting and callus formation. Complete  randomized design (CRD) was adopted for the experiments and each of the species was replicated 4 times using 5 hardwood cuttings per plot (5 L capacity pots). An ANOVA was computed to test for the significance of variations between all treatments while Tukey-Kramer Multiple  Comparisons test was used to test for the differences between treatment means. Jatropha curcas rooted well both in a non-mist propagator and open nursery pots, Telfairia pedata rooted only in the nursery pots, Excoecaria bussei sprouted in both non-mist propagator and open nursery pots but did not root throughout the entire experimental period of 3  months. Croton macrostachyus, Croton megalocarpus and Ricinus communis neither sprouted nor rooted calling for propagation methods other than using hardwood cuttings. Possibly all Excoecaria bussei cuttings which callused would have eventually differentiated into roots had the experiment been allowed to run for more than 3 months.Key Words: Propagation, rootability, non-mist propagators, Excoecaria bussei, Telfairia pedat

Distribution and abundance of the edible orchids of the southern highlands of Tanzania

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. Tanzania Journal of Science Vol. 31 (1) 2005: pp. 45-5

Effect of storage time and temperature on germination ability of Escoecaria bussei

This study was conducted in Botany Department Nursery to evaluate the effect of storage time and temperature on germinability of Excoecaria bussei.   The orthodox seeds, collected from Dodoma and Singida regions were germinated monthly from September 2013 through June 2014. Each time, seeds were soaked in water for 6 hours to soften then sown in sterile potting media. A Split-Split plot was used to compare temperature [(15°C) and (30°C)] as main plots, populations (Maktupa, Kisalu and Ilola) as Sub plots and storage time (September 2013 through June 2014) as Sub-Sub-plots on percentage seed germination.  ANOVA revealed average germination percentages of 20.6±9 for Kisalu, 30.4±10 for Maktupa, and 33.1±7 for Ilola for seeds stored at low temperature (15°C). Seeds stored at 30°C showed respectively 5.52±1, 8.6±3 and 11.6±4germination percentages. Temperature and storage time conferred highly significant difference on germination percentage, while population did not at P >0.05. The interaction effects between population, storage period and storage temperature significantly affected germination percentage at P >0.05. Storage at 15°C can retain seed viability up to 9 months after harvesting but only 3 months at 30°C.  If suitable storage conditions are not provided, Excoecaria bussei seeds should be sown immediately for maximum germinability.Key words: Escoecaria bussei, Germinability, Seed Storage, Pawn tree, orthodox seed

Growth Response of Selected Mangrove Species to Domestic Sewage and Abiotic Stress

The sewage system of Dar es Salaam City, Tanzania, serves only 15% of the population, making sewage one of the leading sources of marine pollution. This study was initiated to assess the potential of peri-urban mangrove forests as filters and phyto-remediators of sewage and the growth of two mangrove species under sewage-inundated conditions.  One-year old Avicennia marina and Rhizophora mucronata wildlings were planted in 10 l buckets and treated with 0, 25, 50, 75 and 100% domestic sewage in triplicates for 12 h, 24 h or 1 week under a split-split plot design. Growth and physico-chemical characteristics of the system were recorded monthly for four months. Treated mangroves grew better than untreated plants and A.marina outperformed R. mucronata. Inundation with 75-100% sewage was more effective than <50% sewage but no significant differences were observed due to the relatively brief experimental period. Irrespective of the species, pH and electric conductivity (EC) increased by the end of each inundation. P and N removal by plants was highest in 50 and 75% sewage. Additionally, three sulfide levels of 0, 0.75 x 10-3, 1.5 x 10-3 M NH2S affected mangrove growth when applied in seawater concentrations of 0, 50 and 100%

The Effect of Moisture and Seed Treatment on the In-Situ and Ex-Situ Regeneration of Dalbergia Melanoxylon (African Blackwood) in Pugu Forest Reserve

A study was conducted to investigate the effect of moisture and seedtreatment 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 highmoisture level while older trees are water and light demanding. It wasrecommended 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.Key words: Regeneration, ebony tree, music plant, Mping

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

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.Key words: Dalbergia melanoxylon, non-mist propagator, rooting

Pollutants Removal Efficiency of two Mangroves Species (Avicennia marina and Rhizophora mucronata) in Treating Domestic Sewage

Bucket experiments were conducted to evaluate the effect of domestic sewage loading and inundation time on pollutants removal efficiency for cells planted with Avicennia marina and Rhizophora mucronata mangroves species. Domestic sewage from the University of Dar es Salaam primary facultative waste stabilization pond was loaded onto buckets planted with the two mangroves species and unplanted buckets (bare sediment) used as control units. Sea water was used to dilute the sewage to make desired sewage strength of 0, 25%, 50%, 75% and 100%. Inundation times of 1 week, 24 hours and 12 hours were used in these experiments. Based on the obtained results, units planted with mangroves showed optimal removal of phosphates, total phosphorous and ammonium-nitrogen at sewage loading of 100% when inundated for 1 week. There was a significant reduction in concentration of phosphorous, total phosphorous and ammonium-nitrogen observed in planted units. However, there was insignificant difference in nutrients removal between the two mangrove species. While Avicennia marina units removed phosphorous, total  phosphorous and ammonium-nitrogen by 94.49%, 93.25% and 94.76% respectively, removal efficiency of the same pollutants by Rhizophora mucronata units were 94.00%, 92.82% and 94.05%, respectively.  Generally, the removal percentage of phosphorous, total phosphorous and ammonium-nitrogen were significantly higher in 1 week inundation time than in both 24 hours and 12 hours inundation time. Based on the  performance of mangrove on nutrient removal, it was concluded that the two mangrove species could be used as phytoremediators of domestic wastewater in mangroves constructed wetlands in coastal areas.Key words: Avicennia marina, Rhizophora mucronata, domestic sewage, inundation

Improving propagation success of Dalbegia melanoxylon (African blackwood) in Tanzania (I): Characterization of mycorrhizal associated with D. melanoxylon (African blackwood) in Tanzania

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.Key words: Dalbergia melanoxylon, non-mist propagator, rooting

Assessment of African Blackwood (Dalbergia melanoxylon) Population Structure in Kilwa District, Tanzania

Overharvesting and limited conservation efforts have posed a serious threat to future availability of Dalbergia melanoxylon in Tanzania in recent years. The study was conducted between 2018 and 2020 covering Mitarure Forest Reserve (MFR) and 2 surrounding community forests of Ngea and Nambawala in Kilwa District. The purpose of the study was to assess the existing population status of the species in Tanzania. A total of 36 circular plots in Mitarure and 15 plots in each community forest were laid down. Data were recorded for the number of stems per plot, and then converted on per hectare basis where the basal area and densities per hectare were calculated. Data was disaggregated into 5 Diameter at Breast Height (DBH) generated distribution classes ranging from DBH 0 to more than 45 cm. The results revealed that, there was a contrast between the Mitarure Forest Reserve and community forests in terms of individual number of trees per unit area, basal area and densities. The numbers of stems per hectare for the species were found to be 16, 10 and 8 stems/ha in Mitarure, Ngea and Nambawala forest, respectively. Dalbergia melanoxylon in Mitarure forest was normally distributed. The respective basal area was over 80 m2 per ha in Nambawala against over 60 in MFR and Ngea. The results suggest success of the communities in conserving the species after previous overharvest. Authorities should frequently visit forests to increase the population of the species and reduce unauthorised harvesting. Keywords: Dalbegia melanoxylon, Population structure, Mitarure forest reserve, Ngea and Nambawala community forests

Seasonal diversity of entomofauna, their impact and management practices in tomato fields in Meru District, Tanzania

Tomato is a highly cultivated vegetable in Tanzania. The intensive tomato cultivation and production in Tanzania has resulted in high pests and diseases build-up. A survey to identify and quantify entomofauna diversity in different seasons and pest management practices in Meru District was conducted. In addition, a laboratory experiment was done to assess the effectiveness of commonly used pesticides SnowBecco (Thiamethoxam) and Belt (Flubendiamide) against two dominating insect pests, white flies (Bemisia tabaci (Gennadius, 1889)) and leaf miner (Tuta absoluta (Meyrick, 1917)), respectively. The results obtained revealed that, tomato fields in Meru District had significantly higher entomofauna build up during dry season than the rainy season (U0.05 (df, 24) = 45, p = 0.0441). More than 70% of all collected entomofauna were dominated by the whiteflies (Bemisia tabaci) and tomato leaf miners (Tuta absoluta) belonging to orders Hemiptera and Lepidoptera, respectively. It was also observed that, the common pesticides management practices were the use of pesticidal cocktail, broad spectrum insecticides, use of botanical pesticides, frequent application of pesticide and insecticides over dosage. Moreover, yield reduction due to whiteflies and tomato leaf miners infestation were observed in terms of reduced fruits number per plant (38 and 18.4%), fruit size (22.4 and 14.2%), and fruits weight per plant by 43.6 and 26.2%, for Bemisia tabaci and Tuta absoluta, respectively. The study showed that the recommended doses in both tested insecticides caused significant pest mortality (F0.05 (df, 19) = 4.367, p = 0.0199) and (F0.05 (df, 19) = 4.761, p = 0.0147) for B. tabaci and T. absoluta, respectively, within a specified period of time. The results suggest that high insect pest infestations could be caused by factors other than development of insecticidal tolerance including inappropriate identification of insect pests due to lack of training, and inappropriate selection and application of insecticides. Consequently, frequent application of broad spectra insecticides not only increases production expenses but also disrupts agroecosystem by killing beneficial entomofauna and disrupting soil organisms that are susceptible to insecticide toxicity