Articles, Conference and Workshop Papers Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/38

Browse

Now showing 1 - 20 of 187

Cassava processing and dietary cyanide exposure in Tanzania
(Uppsala University, 1995) Mlingi, Nicholas L. V.
Mlingi, N.L.V. 1995. Cassava Processing and Dietary Cyanide Exposure in Tanzania. Acta Universitatis Upsaliensis, Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 571.69 pp. Uppsala. ISBN 91-554-3603-X. The relationship between dietary cyanide (CN) exposure from the cyanogenic glucoside linamarin in cassava and the methods used to process this impor tant root crop were studied in Tanzania. An outbreak of acute intoxications in southern Tanzania coincided with a drought in 1988. The affected population attributed intoxications to short-cuts made in the sun-drying of cassava roots. Processing experiments showed that these short-cuts yielded flour with high residual levels of cyanohydrin, a linamarin metabolite that is transformed to CN in the gut. A causal role of CN in the intoxications was supported by hundred-fold higher mean urinary levels of the main metabolite thiocyanate (SCN) in affected (1120 pmol/1) compared to non-aftected (7 pmol/1) population groups. An epidemic of the paralytic disease konzo, that has been attributed to CN exposure from cassava, occurred during a drought in northern Tanzania in 1985. Qualitative and quantitative interviews revealed that the estab lished way of heap-fermenting crushed cassava roots was shortened during the drought due to food shortage and intensive trade. Experiments showed that this chain of events resulted in high levels of cyanohydrin in flour. Low protein intake may have enhanced CN toxicity due to low supply of sulphur for CN to SCN conversion. Studies of 217 women from an iodine deficient area in western Tanzania showed that the total goitre rate of 73 % could be explained by iodine deficien cy as verified by a median urinary iodine of 3.6 pg/dl. Although 98% ate cassava roots daily their mean urinary SCN was only 128 pmol/1. Use of mechanical milling was associated with low SCN, probably because milling ensures complete drying of roots, which removes cyanohydrin. A mean urinary SCN of 36 pmol/1 indicated low CN exposure in 193 schoolchildren studied in Dar es Salaam. They consumed cassava roots without prior processing that effectively removes cyanogens. The low CN exposure can be explained by the use of non-bitter varieties with low linamarin levels and low consumption frequency and that ingested linamarin is partly excreted in the urine without releasing cyanide in the body.
The effect of mulching and staking on the development of early and late blights of tomato
(Tanzania Journal of Agricultural Sciences, 1998) Lyimo, H. F. I; Tiluhongelwa, T. D.; Maerere, A. P.; Njau, P.
The effect of mUlching and staking on the development of early and late leaf blight of tomato (Lycopersicon esculentum (Mill))· caused by Alternaria solani (Ell. & Md.rt.) and Phythophthora injestans (Mont.), respectively, were studied using a randomized complete block design replicatedfour times. Mulching and staking significantly (P = 0.05) reduced the incidence of early and late blights by 5 to 20% and increased fruit yield more t~an two folds compared to unmUlched and unstaked controls. The apparent rate of infection of the two pathogens was also significantly lower (P = 0.05) in mulched and staked tomato than in the controls. Mulching was more effective than staking in suppressing early and late blight diseases in tomato. Mulching and staking when combined significantly (P = 0.05) reduced the incidence of the two diseases' by 20% compared to when the two practices were used separately.
Evaluation of maturity characteristics and of yield components of high protein bean (Phoseolus vulgaris L.) varieties in Morogoro, Tanzania
(1998) Mduruma, Z.O.; Nchimbi-Msolla, S.; Reuberi, S.O.W.M.; Misangu, R.N.
Several Bean growing areas in Tqnzania have unreliable and marginal rains necessitating use of short maturing and high yielding varieties. Such varieties however, are not, readily available. This'study was done to evaluate varieties for maturity, yield and its components in the bean growing areas of Morogoro, Tanzania. Sixty four varieties from the Sokoine University of Agriculture (SUA) collection and from a high percentage protein population were grown at two locations, Mgeta (high altitude) and SUA (low altitude) in 8 x 8 partial lattice with 3 replicatiqns during the 1991 season. Yield levels were low, ranging between 0.2 - 0.8 tlha at Mgeta and 0.06 - 2.Otlha atSUA. Earlier varieties were superior in yield due to' a higher yield efficiency. Varieties grown in the cooler higher altitude areas matured late with consequent reduction in yield. Significant G x E interaction effects were observedfor all the variables, except number of seeds per pod. Positive genetic correlations were significant (P ~0.01) at both locations between yield and number of pods per plant, yield efficiency and podjilling period. Yield was genetically and negatively corrected with days to first flower, 50% podfill and 85 % maturity. Path coefficient showed that days to first flower had a consistent negative direct effect o!'l yield. At both locations, the negative genetic relationship between days to 50% podfill with yield was attributed to the negative indirect influence through days to first flower. Earlier flowering anq maturity, longer podfilling with high pod production and yield efficiency are recomme.nded for higher yields of beans in the study area.
Why agro-biodiversity conservation - who is responsible for what?
(FAO, 1999) Reuben, S. O. W. M.; Mgembe, E.
Agro-biodiversity conservation is an important ingredient with potential for food security and for medicinal purposes. In the marginal semi-arid areas of the world, there is often nutritional deficiency due to low level of edible flora diversity during most parts of the year. Availability and knowledge on the utilisation of available indigenous and traditional flora as a food source is therefore important to alleviate nutritional and health problems of people in these areas. In Tanzania for example, there are several species of indigenous plants, both herbs, shrubs and trees available in both marginal and fertile areas with high rainfall areas which are either known or unknown to the local people as nutritional and medicinal plants. An example of such plants available in Tanzania is shown in Table 1. However, the current situation indicates that loss of agrobiodiversity is on the increase. It is estimated that about 34,000 species, constituting about 12.4% of plant species are in the danger of being extinct. This results into the depletion of food to the rural and urban people and loss of plants for healing various ailments for animals, plants and humans.
Research note on the distribution and relative importance of bean bruchid species aconthoscelides obtectus (say.) and zabrotes subfosciatus (boh.) in Tanzania
(2000) Misangu, R.N.; Nchimbi-Msolla, S.; Reuben, S.O.W. M.
Two bean bruchid species Acanthoscelides·obtectus (Say.) and Zabrotes subfasciatus (Boh.) are known to destroy beans in storage. However, the distribution and relative. importance of these species have not been established in Tanzania. In this study, a bf!an bruchid survey was carried out to find out if the two bean bruchid species occurred in th~ country. The survey was corzduded In 1993 and it was observed that both bean bruchid species were present in all regions surveyed. However, the speCies A. obtectus was more dominant in all. regions except in Ruvuma and therefore' appeared to be relatively more important than Z. subfasciatus. The occurrence of the two species in all surveyed regions indicates that both species are of economic importance in the country. There was no indication that the two species occur in well defined ecological zones.
Inheritance of resistance to bacterial blight in ten rice (oryza sativa l.) cultivars
(2000) Luzi-Kihupi, A.; Khush, G.S.
Ten rice cultivars from the International Rice Germplasm Centre originating from Bangladesh were analysedfor the~r genetics of resistance to bacterial blight. The test cultivars were selected on the basis of their high level ofresistance to races IV & VI ofXanthomonas oryzae pv. oryzae. The mode ofinheritance was studied by crossing the test cultivars with Taichung Native 1 (TNI) which is highly susceptible to the races 1,2,3;4 & 6 of X. Oryzae pv. oryzae. The genetic analysis revealed that the test cultivars have two recessive genes conferring resistance to races 1 (PX 061) and 6 (PX 079) of X. oryzae pv oryzae, respectively. The allelic relationship of genes conferring resistance with xa-S and xa-13 was studied in progenies derived from crosses between the cultivars and IRBBS and IRBB13 which are near isogenic lines carrying genes xa-S and xa-13 respectively. The Chi-square analysis of F2 populations revealed that resistance ilJ these cultivars to race 1 was conferred by xa-S. Resistance to race 6 was found to be conferred by another gene which was non-allelic to xa-13.
Performance of early maturing mutants derived from 'supa' rice (Oryza sativa L.) cultivar
(2001) Luzi-Kihupi, A.; Zakayo, J.A .
Supa rice (Oryza saliva L.) cultivar which is very popular in Tanzania was sent for irradiation at the Seibersdorf Laboratory, Vienna, Austria in 1994. The dry seeds were irradiated with gamma rays using three doses (170, 210 and 240Gy) from Cobalt 60 (60CO) in order shorten the plant height and maturity period. From the resulting mutantbpopulations originating from modified single seed descent method, five very early maturing lines plus the original cultivar were evaluated in replicated trials at two sites (SUA and Dakawa) in 1999. The trial was laid in a Randomised Complete Block Design replicated three times. The data generated include plants height, days to 50% flowering, panicle length number of productive tillers per plant, 1000 grain weight, percent filled grains per panicle and grain yield. The mutants and the parent were also screened for grain quality characteristics. The data collected were subjected tp the Analysis of Variance and correlation analysis using MSTAT -C. Path coefficient analysis was also performed to determine the cause - effect relationship. The analyis of variance revealed that there were significant differences between the mutants and their parent for all the characters tested except 1000 grains weight and panicle weight. The mutants flowered up to 24 days earlier than the parent. Further analysis revealed that grain yield was positively correlated with percent filled grains per panicle. Days to 50% flowering and 1000 grain weight exerted negative direct effect on yield. Changes in grain quality were also observed emphasizing the importance of conducting cooking and taste panel tests.
Variation and inter-relationship, between yield and, some agronomic characters in induced rice (Oryza sativa L.) mutants
(2001) Luzi-Kihupi, A.
A high yielding, locally adapted cultivar Salama of rice (Oryza sativa L.) which was recommended for cultivation in Tanzania since 1978 was irradiated with gamma rays using two doses (170 & 210 grays) from Cobalt 60 (60C0) in order to shorten the plant height. Twenty three mutant lines in M5 and M6 generations plus two controls were sown in a randomised complete Block Design (RCBD) and replicated three times at the Sokoine University of Agriculture (SUA) farm in Morogoro, Tanzania. The objective of the study was to estimate genetic parameters and the association of various traits with yield. The combined analysis over two years was used to estimate genetic variances heritability and expected genetic gain from selection. The data generated were also used to perform correlation and path coefficient analysis. Analysis of variance revealed significant differences, among the tested genotypes for all the characters tested. Significant genotype X Year interactions were observed for all the characters except number of tillers per plant and 1000 grain weight. High genotype coefficient of variation heritability estimates and expected genetic advance were recorded for plant height number of tillers per plant and 1000 grain weight. Correlation and path coefficient analysis revealed that days to 50% flowering and number of panicles per square metre were important characters that incluenced yield
Resistance of arcelin incorporated bean (Phaseolus vulgaris L.) hybrids and their parental cultivars against the bean bruchid Zabrotes subfasciatus (Boh)
(2001) Misangu, R.N.; Nchimbi-Msolla, S.; Reuben, S.O.W.M.
A hybridization bean breeding programme aimed at breeding beans resistant against the bean bruchid species Z. subfasciatus which destroys beans in storage was carried out at Sokoine University of Agriculture (SUA) Morogoro. Tanzania between 1994-1997. Five potential local bean varieties/lines were crossed to a bruchid resistant bean line RAZ 24-2 which was developed at SUA by selection from ClAT segregating RAZ bean populations. Seeds of RAZ lines contain arcelin a protein which confers resistance against Z. subfasciatus and can be transferred into other varietiess by hybridization. The backcross breeding procedure was adopted and five arcelin containing progenies were developed from this breeding programme. Seed of the developed progenies and those of the parents were then tested for resistance against Z. subfasciatus a randomized complete block design with 5 replications. There were significant difference, (P < 0. 05) in resistance against Z. subfasciatus among the genotypes. Results indicated that arcelin incorporated genotypes were superior over the arcelin deficient parents for resistance against Z. subfasciatus. Generally, the presence of arcelin in bean seeds delayed bruchid development reduced the number of emerged bruchids damage on bean seeds. However, bruchids managed to lay many eggs on seeds of all cultivars tested suggesting that bruchids are not inhibited from laying eggs on archelin containing seeds.
Comparative effectiveness of animal manures on soil chemical properties, yield and root growth of amaranthus (Amaranthus cruentus L.)
(AJST, 2001) Maerere, A. P.; Kimbi, G. G.; Nonga, D. L. M.
Pot and field experiments were conducted to compare the effects of dairy cow, goat and poultry manures on soil available levels of N and P and amaranths yield and root growth. The three amendments were applied on Oxisols at 100, 150 and 170 kg N/ha in a split plot design and replicated three times. Pot experiment lasted for one month whereas field experiment was conducted over three monthly crop cycles. Results of both experiments indicated that applications of the three manures significantly (P < 0.01) increased soil available levels of N and P shoot dry matter yield, taproot length and root dry weight. Comparison of the responses from the three manures revealed that for all the parameters evaluated the trend was; Poultry manure > goat manure > dairy cow manure. This was largely attributed to differences in total N, total P, C/N and C/P ratios of the amendments. Field experiment results revealed that responses were highest after the third crop harvest suggesting that mineralization of organic N and P increased with time. Based on fertilizer recommendations of N and P for Southern highlands of Tanzania and the highest rate used in this study (170 kg N/ha), applications of 5.8 tons/ha, 9.8 tons/ha and 13.4 tons/ha of poultry, goat and dairy cow manure will suffice the requirement of 40 kg N/ha and 20 kg P/ha recommended for most field crops.
Effect of harvest methods on yield and quality of Marketable flowers of greenhouse rose cultivars of different growth habits
(2001) Msogoya, T.J.; Morisot, A.
This study was carried out to determine the effects of harvest methods (proximal and median harvests) on yield and quality of marketable flowers of greenhouse hybrid tea rose (Rosa hybrida L.) cultivars of different growth habits. The cultivar Grant Galla represented cultivars of vigorous growth habit whereas 'Vivaldi' respresented those non-vigorous growth habit. The proximal harvest method significantly reduced the number of marketable flower stems of non-vigorous cultivars but did not significantly affect the number of flower stems of vigorous cultivars. The proximal harvest method also improved flower quality in terms of grades, lenghts and weights of individual flower stems of both vigorous and non-vigorous cultivars. According to market studies, the proximal harvest method would increase revenue from vigorous cultivars and decrease revenue from non-vigorous ones. The median harvest method should be applied to non vigorous Rose cultivars.
Comparative performance of low and high volume herbicide sprays for weed control in lowland rainfed rice (Oryza satica L)
(2002) Sibuga, K.P.
Pre- and post emergence herbicides, were evaluated for weed control in lowland rice -(Oryza sativa L)) in field trials during 1998 and 1999 cropping seasons. Herbicides; were applied at high volume (416 1/ha) using a knapsack sprayer (CP 15), or at low volume (30 l/ha) using a controlled droplet application (c.da.) equipment. the Herbi-4 sprayer. The herbicides tested at varying dosage rates were saturnvalor. Ronstar and Basagran PL 2. In both seasons. Cyperus rotundus L (purple nutsedge) was the most dominant weep spp. A variety of broad leaf and grass weeds were also observed. All herbicides used stunted the growth of purple nutsedge but none was able to control the weed completely. Hand-weeding was most effective in reducing weed growth and resulted in the highest 2-season average yields in rice (2. Z t/ha). Rice yields were reduced to their lowest levels averaging 1.1 1.1 t/ha where no weeding was done. All the herbicide treatments resulted in similar (p>0.05) but relativeiy lower yields to handweeding in both years. These results suggest that the high volume formulations of Satumvalor and Basagran PL 2 and Ronstar can be succesfully used for weed control in rice using a c.d.a equipment
Genetic and phenotypic parameters of reproduction and lactation traits of Friesian X Boran crossbred cattle in Kagera region, Tanzania
(2002) Mwatawala, H.W.; Kifaro, G.C.; Petersen, P.H.
This study was done to estimate genetic and phenotypic parameters for Friesian x Boran crossbred dairy cattle of Kagera region. Parameters estimated were heritability, repeatability and phenotypic correlations of various lactation and reproductive traits. Variance component (VARCOMP) procedure and general linear models (GIM) Procedure of SAS were employed in data analyses. Heritability estimates for 100-day milk yield, 305-day miik yield lactation milk yield (LMY) lactation length (LL). dry period (DP) age at first calving and calving interval (CI), were 0.27, 0.40. 0.40. 0.00. 0.04. 0. 05 and 0.06, respectively. Heritabilities first, second and third CI were 0.02, 0.06 and 0.11 re.spectively. Coefficients soil repeatability for 100-day. 305-day. LMY, LL, DP and CI were 0.34, 0.40, 0.38, 0.15, 0.12 and 0. 16, respectively. Correlation coefficients between mean dairy milk yield (DMY) in a month with 100-day and 305-day milk yield and LMY ranged from 0.11 to 0.90, 0.35 to 0.78 and 0.42 to 0. 63, respectively. Correlation coefficient between -100day miik yield and 305-day milk yield (rc=0.87) was higher than correlation coefficient between, 100-day and total lactation yield (rc=0.70). The correlation coefficient between 305-day milk yield and LMY was 0.85. All correlations were highly significant (P < 0.001). Heritability estimates were moderate for milk yields and l0w for LL, DP, AFC, and CI. Selection for genetic improvement in milk yield is possible while low estimates for LL, DP, CI and AFC, suggest that environment plays a major role in affecting these traits.
Reproductive and lactation performance of crossbred dairy cattle in Kagera region, Tanzania
(2002) Mwatawala, H.W.; Kifaro, G.C.; Petersen, P.H.
This study was done to evaluate reproductive and lactation performance of crossbred dairy cattle in Kagera region, Tanzania. Traits studied were age at first calving (AFC), calving internal (Cl), lactation milk yield (LMY) and lactation length (LL). Records for the various traits were compiled covering the period between 1979 and 1999. The General Linear Models procedure of SAS was used in data analyses. The mean AFC and CI were 39.0 months and 464. 7 days, respectively. The mean IMY and LL were 2332.5 kg and 367.2 days respectively. The influences of year of birth and genetic group on AFC were highly significant (P<0.001). Heifers having 5/8 Friesian blood tended to calve 3. 4.6 and 5 months earlier than 5/8 Friesian crosses FI and F2 respectively. Genetic group parity, district and the interaction between season and year of calving highly significantly (P<0.001) influenced CI. Cows in fourth parity out yielded those in first parity by 276 kg of milk. Year of calving and genetic group x district interaction were highly significant (P< 0.001) sources of variation in LMY. LL was significantly (P < 0.00l) influenced by genetic group, parity and year of calving. LL in Bukoba rural district was 28 days longer (P<0.05) than in Biharamulo district. It is concluded that both genetic and non-genetic factors considerably influenced reproduction and lactation performance of crossbred dairy cattle in Kagera region. Increased level of exotic blobd has led to having animals with shorter AFC and CI and higher LMY up to 5/8 Friesian blood. Genetic group by district interactions revealed that some genetic groups performed differently among districts reflecting differences in environmental effects between.
Evaluation of field performance and storage of some tropical short-day onion (Allium cepa L.) cultivars
(West African Journal of Applied Ecology, 2005) Msuya, D. G.; Reuben, S. O.; Mbilinyi, L. B.; Maerere, A. P.; Msogoya, T.; Mulungu, L. S.; Misangu, R. N.
The storage of bulbs of onion (Allium cepa L.) is very crucial to ensure its availability throughout the year. Experiments were conducted at Sokoine University of Agriculture to evaluate the growth and yield characteristics of some tropical short–day onion cultivars and the storability of their bulbs after harvest. The first experiment in 1994 involved 21 cultivars evaluated for their growth and yield variables. The second experiment, involving six cultivars, was carried out in 1996 and in addition to performance evaluation, the storability of bulbs was investigated. Results showed significant differences among the cultivars in yield, yield components and storability. Granex 429 had the highest yield among cultivars in both trials, but had very poor storability. Serrana and XPH 6074 had long storability and maintained more than 50% of their weight after 5 months of storage. These two cultivars are promising as good sources of genes to incorporate storage traits in other cultivars of onion.
Role of sorghum genotype in the interaction with the parasitic weed striga hermonthica
(Sokoine University of Agriculture, 2005) Hermonthica Striga
Rodenburg, J., 2005. The role of sorghum genotype in the interaction with the parasitic weed Striga hermonthica. PhD thesis, Wageningcn University, Wagcningen, The Netherlands, 138 pp. with English, French and Dutch summaries. This thesis presents a study on the interaction between the parasitic weed Striga (S. hermonthica [Del.] Bcnth.) and the cereal crop sorghum (5. bicolor [L. | Moench). Its main objective was to find suitable measures for the selection of breeding material (crop genotypes) with superior levels of resistance or superior levels of tolerance to Striga. To meet this objective the physiological background of tolerance, the relation between Striga infestation, infection and yield loss and the effect of host genotype on Striga parasitism and reproduction were studied. These host-parasite interactions were studied with 4-10 different sorghum genotypes differing in level and mechanism of defence against Striga. Field experiments carried out in Mali were used for yield assessments and development and validation of selection measures. Through pot and agar-gel experiments, aboveground resistance measures were validated with observations on belowground stages. Pot experimentation was also used to create infection response curves and to measure photosynthesis and chlorophyll fluorescence to develop tolerance measures. Striga parasitism and reproduction, and the detrimental effect of Striga on crop yield can significantly be reduced through crop genotype choice. Maximum aboveground Striga number is a reliable selection measure for resistance. Striga flowerstalk dry weight can be used to identify genotypes that reduce Striga reproduction. The maximum relative yield loss is a suitable selection measure for tolerance in susceptible genotypes, while for more resistant genotypes the relative yield loss per Striga infection seems more appropriate. For these tolerance measures, yield assessment of nearby uninfected controls is indispensable. Chlorophyll fluorescence, more precisely photochemical quenching and electron transport rate, may enable screening for tolerance without this requirement.
Field performance of micropropagated east African banana (musa AAA east Africa) in the eastern zone of Tanzania
(Asian Network for Scientific Information, 2006) Msogoya, T. J.; Maerere, A. P.; Grout, B. W.
This study was conducted to evaluate yield performance of micro-propagated CM.Pd) East African cooking banana (Musa AAA East Africa) cv. Uganda and cv. Bukoba in the Eastern zone of Tanzania. Plant size of MPd cv. Bukoba was significantly bigger (p
Biodiversity of fruit flies (Diptera, Tephritidae) in orchards in different agro-ecological zones of the Morogoro region, Tanzania
(Cirad/EDP Sciences, 2006) Mwatawala, Maulid W. M; De Meyer, Marc; Makundi, Rhodes H.; Maerere, Amon P
Introduction. Fruit flies (Diptera, Tephritidae) are among the major constraints in commercial horticulture in many African developing countries. Knowledge of the tephritid spectrum in any given area is a prerequisite for the development of an IPM program to alleviate the pest problem. We studied the fruit fly diversity in four main agro-ecological zones which are significant fruit-producing areas in the Morogoro Region, Tanzania. Materials and methods. Fruit fly diversity was investigated for one year (October 2004 – October 2005). Parapheromones, synthetic food attractant and protein-bait traps were used to trap the flies at the different locations in Morogoro region, Tanzania. One mixed orchard was selected at each of four locations representing the different agro-ecological zones of the region. Results. The recently intro- duced alien species, Bactrocera invadens, and three indigenous pest species, Ceratitis rosa, Dacus bivittatus and D. punctatifrons, were found at all the four sites, while Bactrocera cucurbitae, Ceratitis cosyra, Dacus chiwira and D. humeralis were found in three out of the four sites. The Sokoine University of Agriculture (SUA) Horticulture Unit and Mikese sites had the highest species diversity while the Mkindo and Nyandira sites had the lowest diversity. The between-habitats diversity (Beta diversity) was similar among the SUA, Mkindo and Mikese sites. Only the Nyandira site had a higher dissimilarity in comparison with the other three sites. Discussion. The most abundant species at low- and mid-elevation sites was Bactrocera invadens while, at high elevation, Ceratitis rosa was the dominant species. Protein-baited traps attracted the highest diversity of fruit flies in comparison with the more specific parapheromones. The synthetic food attractant (three-component lure) was less efficient compared with the protein bait. The large dissimilarity at the Nyan- dira site is probably due to the different types of host fruits found and grown in high altitude areas (mainly temperate fruits). Fruit fly species associated with these types of fruits, e.g., Ceratitis rubivora and Tri- rhithrum coffeae, were found only at this site.
Effects of mulch and cultivar on strawberry productivity under tropical highland conditions
(2006) Isutsa, O. K.
A study was conducted to determine effects of four mulches (cut grass, clear polyjilm, black polyjilm, and none) on productivity of four strawberry (Fragaria x ananassa Duch) cultivars (Pajaro, Aiko, Fern and Douglas) under tropical hig~land conditions. It was hypothesized that polyjilm would hasten growth and increase yield more than cut stargrass (Cynodon dactylon), or no mulch, through warming soil, improving nutrient uptake and conserving moisture. The experiment was set up as split plots in randomised complete block design; mulches were assigned to main plots, whereas cultivars were assigned to sub-plots. Each of the sixteen treatments was replicated three times. Cultivars were planted at the beginning of long rains in March 2002. Data were recorded from the fourth month after planting (MAP) and analysed. Polyjilm hastened growth from 2 to over 5 stolons, 18 to 30 leaves, 31 cm to 35cm diameter at 4 MAP, and increased flowering and yield from 9 to 12 flower stalks, 22 to 29 berries, and 30 g to 35 g berry fresh weight at 9 MAP. Most of the time, black polyjilm growth and yield parameters were higher than those for cut grass or no mulch. Positive effects of cut grass mulch developed slowly, while those of clear polyjilm mulch diminished over time. Nine months after planting, black polyjilm gave significantly (P<0.05) higher yields, and hence is recommended. Clear polyjilm is recommended only for hastening plant growth. 'Douglas' was often inferior in all response variables compared to the other three cultivars and hence is least recommended for growing under tropical highland conditions. Mulch did not significantly (P>0.05) interact with cultivar, implying that it does not alter the potential of cultivars grown under tropical highland conditions.
Biodiversity of fruit flies (Diptera, Tephritidae) in orchards in different agro-ecological zones of the Morogoro region, Tanzania
(Fruits, 2006) Mwatawala, M. W.; De Meyer, M.; Makundi, Rhodes H.; Maerere, A. P.
Introduction. Fruit flies (Diptera, Tephritidae) are among the major constraints in commercial horticulture in many African developing countries. Knowledge of the tephritid spectrum in any given area is a prerequisite for the development of an IPM program to alleviate the pest problem. We studied the fruit fly diversity in four main agro-ecological zones which are significant fruit-producing areas in the Morogoro Region, Tanzania. Materials and methods. Fruit fly diversity was investigated for one year (October 2004 – October 2005). Parapheromones, synthetic food attractant and protein-bait traps were used to trap the flies at the different locations in Morogoro region, Tanzania. One mixed orchard was selected at each of four locations representing the different agro-ecological zones of the region. Results. The recently introduced alien species, Bactrocera invadens, and three indigenous pest species, Ceratitis rosa, Dacus bivittatus and D. punctatifrons, were found at all the four sites, while Bactrocera cucurbitae, Ceratitis cosyra, Dacus chiwira and D. humeralis were found in three out of the four sites. The Sokoine University of Agriculture (SUA) Horticulture Unit and Mikese sites had the highest species diversity while the Mkindo and Nyandira sites had the lowest diversity. The between-habitats diversity (Beta diversity) was similar among the SUA, Mkindo and Mikese sites. Only the Nyandira site had a higher dissimilarity in comparison with the other three sites. Discussion. The most abundant species at low- and mid-elevation sites was Bactrocera invadens while, at high elevation, Ceratitis rosa was the dominant species. Protein-baited traps attracted the highest diversity of fruit flies in comparison with the more specific parapheromones. The synthetic food attractant (three-component lure) was less efficient compared with the protein bait. The large dissimilarity at the Nyandira site is probably due to the different types of host fruits found and grown in high altitude areas (mainly temperate fruits). Fruit fly species associated with these types of fruits, e.g., Ceratitis rubivora and Trirhithrum coffeae, were found only at this site.

Browse

Browsing Articles, Conference and Workshop Papers Collection by Issue Date