UCUDIRBrowsing by Author "Kizito, Elizabeth B."

Browsing by Author "Kizito, Elizabeth B."

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Abundance, distribution and effects of temperature and humidity on arthropod fauna in different rice ecosystems in Uganda
(Journal of Entomology and Zoology Studies, 2017) Kizito, Elizabeth B.; Masika, Fred Bwayo; Masanza, Michael; Aluana, Goncalves; Barrigossi, Jose Alexandre Freitas
The study on abundance, distribution and effects of temperature and humidity on arthropod fauna was conducted in smallholder rice farming areas in three agro ecological zones of Lake Victoria basin, Northern moist farmlands and Western Savannah grasslands in Uganda. Arthropods were collected using a standard sweep net and a total of 17 orders representing 13,272 arthropods were recorded from the three agro – ecological zones during the study. Most arthropod fauna were collected in Bugiri, Lira and Kasese respectively. The most abundant orders throughout the survey included Homoptera, Coleoptera, Hemiptera, Diptera, Hymenoptera and Orthoptera. While the least abundant included Dermaptera, Zoraptera, Phasmatoda, Mantodae, Embioptera and Neuroptera. All orders except Embioptera, Mantodae, Neuroptera and Phasmatoda were collected in all the three agro ecological zones. The orders Diptera (p = 0.0282), Hymenoptera (p = 0.0051), Lepidoptera (p = 0.0149), Odonata (p = 0.0356) showed a significant difference in abundance in the three agro – ecological zones. Temperature and humidity had a significant effect on the arthropod population for example Aranea showed a positive correlation in their abundance with increase in temperature in all the agro – ecologies
Antioxidant potential of the farmer preferred selections of Solanum aethiopicum vegetable consumed in central Uganda
(European Journal of Biological Research, 2018-03) Sekulya, S.; Nandutu, A.; Namutebi, A.; Ssozi, J.; Masanza, Michael; Kabod, B.; Jagwe, J. N.; Kasharu, A.; Rees, Deborah; Kizito, Elizabeth B.
In addition to the rich micronutrient value, indigenous vegetables are regarded as possessing medicinal attributes. The Solanaceae family has over 1000 species worldwide, with a number of indigenous species originating in Africa. The most popular leafy vegetable in Uganda is the Solanum aethiopicum (Nakati). The objective of this study was to determine the selected phytochemical attributes, chlorophyll content, moisture content andtotal antioxidant activity of the farmer preferred selections within the landraces of Solanum aethiopicum leafy vegetable in Uganda. Theantioxidant activity was achieved by screening the leaf extracts for their free radical scavenging properties using diphenyl picryl hydrazyl (DPPH) and ascorbic acid as standard. The ability of the extracts to scavenge DPPH radical was determined Spectrophometrically at 517 nm. The study showed that all the landraces had a high polyphenol and flavonoid content with SAS185/P/2015 containing the highest flavonoid content (3.16±0.06 mg QE/g fw). SAS1641/2015 showed the highest total polyphenol content of 7.79±0.27 mg GAE/g fw and also showed the highest vitamin C content. This contributed to the high total antioxidant activity of 2.79±0.01 and 5.43±0.02 mg AAE/g fw when using FRAP and DPPH methods respectively. SAS145/2015 presented the highest chlorophyll content of 19.69±0.01 mg/g dwb. All the landraces showed a high percentage moisture content that ranged from 82.66±0.35 to 84.21±0.48%. These results are of nutraceutical significance and hence confirm their usage as medicinal vegetables.
Assessment of cassava diversity in Uganda using SSR markers
(2004) Kizito, Elizabeth B.; Castelblanco, W.; Omara, J.; Bua, A.; Egwang, T.G.; Fregene, M.; Gullberg, U.
The genetic diversity and differentiation of 272 cassava landrace accessions collected in Uganda is assessed in this study. In addition to this, 20 Tanzanian material was included from a previous study of diversity in Tanzania, 20 material from the Ghanaian germplasm bank, 20 material from Guatemala and 18 from holdings at CIAT and IITA to represent the core collection from Latin America. All together 9 groups or samples, based on country of origin, were created to study genetic diversity and differentiation within each country and among countries. Using simple sequence repeat (SSR) markers, variation in allele frequency at many unlinked loci was used to estimate the parameters of genetic diversity and differentiation, and to estimate the strengths of various forces shaping them. SSR data was analyzed by GENSURVEY (Vekemans & Lefebvre,1997), FSTAT 2.9 (Goudet, 1995) and NTSYS-PC(Rohlf, 1993). Results affirm a genetic divergence between African and Latin American accessions. They also show a high genetic diversity and a low differentiation in the Ugandan accession. There is a substantial role played by the cassava mosaic disease (CMD) on cassava genetic constitution in respective districts.
Changes in Sensory and Quality Characteristics of S. Aethiopicum (Shum) and A. Lividus (Linn) Leafy Vegetables along the Supply Chain
(Science and Education Publishing, 2018-05) Apolot, Mary Gorret; Ssozi, Joshua; Namutebi, Agnes; Masanza, Michael; Kizito, Elizabeth B.; Rees, Deborah; Hedwig, Acham
Changes in sensory attributes of vegetables over time under different conditions have been reported, however, little has been done regarding profiling and assessing changes in sensory attributes of raw leafy vegetables particularly Solanum aethiopicum (S.) and Amaranthus lividus (L.). This study therefore fills an important knowledge gap of profiling sensory attributes and assessing changes in color, texture and appearance of S.aethiopicum and A.lividus leafy vegetables over time after harvest. A complete randomized design in a 3 ×3 factorial arrangement (each vegetable sample was subjected to three treatments (Time of the day) and three replicates) and data was collected by use of quantitative descriptive sensory analysis. Descriptive data was entered into Microsoft excel spread sheets, averages computed and graphs generated. The data was further subjected to ANOVA and a least significant difference test was used to compare means of samples for all attributes at 95% confidence interval. Correlation analysis using Statistical Package for Social Scientients’ (SPSS version 16.0) was also performed to assess relationship between sensory attributes. Descriptive sensory analysis results showed that all 9:00hrs samples were rated highly for each attribute compared to the 12:00hrs and 15:00hrs samples. ANOVA results for S. aethiopicum showed statistical significant (p<0.05) difference for all the attributes except for light green color of leaf stalk (p<0.05) whereas that for A. lividus showed significant differences for moist appearance, well spread appearance, smoothness and overall quality. Correlation results showed significant positive relationship (p<0.05) among attributes. This study observed that sensory attributes of leafy vegetables change with time after harvest andtraders are therefore encouraged to adopt local cooling systems to help preserve the sensory attributes of vegetables.
Diversity and distribution of African indigenous vegetable species in Uganda
(Academic Journals, 2017-11) Kizito, Elizabeth B.; Masanza, Michael; Sseremba, Godfrey; Kabod, Nahamya Pamela; Kasharu, Apolo Katwijukye; Jaggwe, John Nkalubo
African indigenous vegetable species (AIVS) provide a means of livelihood to many urban and peri-urban dwellers in Uganda. It was thus deemed necessary to understand the existing diversity and distribution of the traditional African vegetable species as a basis for recommending conservation and utilization strategies against biodiversity loss. A field survey was conducted in the four major agro-ecological zones of Uganda to provide information on a recent abundance of the various AIVS. Results from the survey showed that the Solanaceae (43.4%), Amaranthaceae (15.5%) and Malvaceae (11.6%) were the most prevalent families out of seven different families encountered. Twenty-three (23) species, a number lower than that initially reported in literature and distributed unevenly in the different regions were identified. Majority of the species were the indigenous rather than introduced vegetable species. Firstly, the study is informative of the superior importance of Solanaceous species compared to other AIVS. Secondly, the survey results indicate that the AIVS are becoming increasingly more important in Uganda than their introduced counterparts since all the 43.4% that composed the Solanaceae majority were of indigenous type. Research efforts should be devoted towards improved variety development and germplasm conservation to prevent a possible biodiversity loss of the most important AIVS for increased household incomes and nutrient security among the resource-poor majority in Uganda and other sub-Saharan Africa countries
The effect of cassava mosaic disease on the genetic diversity of cassava in Uganda
(Springer International Publishing, 2005) Kizito, Elizabeth B.; Bua, Anton; Fregene, Martin; Egwang, Thomas; Gullberg, Urban; Westerbergh, Anna
Cassava (Manihot esculenta) is a tropical crop that is grown in Africa, Latin America and Southeast Asia. Cassava was introduced from Latin America into West and East Africa at two independent events. In Uganda a serious threat to cassava’s survival is the cassava mosaic disease (CMD). Uganda has had two notable CMD epidemics since the introduction of cassava in the 1850s causing severe losses. SSR markers were used to study the effect of CMD on the genetic diversity in five agro-ecologies in Uganda with high and low incidence of CMD. Surprisingly, high gene diversity was detected. Most of the diversity was found within populations, while the diversity was very small among agro-ecological zones and the high and low CMD incidence areas. The high genetic diversity suggests a mechanism by which diversity is maintained by the active involvement of the Ugandan farmer in continuously testing and adopting new genotypes that will serve their diverse needs. However, in spite of the high genetic diversity we found a loss of rare alleles in areas with high CMD incidence. To study the effect of the introgression history on the gene pool the genetic differentiation between East and West Africa was also studied. Genetic similarities were found between the varieties in Uganda and Tanzania in East Africa and Ghana in West Africa. Thus, there is no evidence for a differentiation of the cassava gene pool into a western and an eastern genetic lineage. However, a possible difference in the genetic constitution of the introduced cassava into East and West Africa may have been diminished by germplasm movement
Effect of Different Processing Conditions on Proximate and Bioactive Contents of Solanum aethiopicum (Shum) Powders, and Acceptability for Cottage Scale Production
(Science and Education Publishing, 2018-04) Akanyijuka, Sam; Acham, Hedwig; Tumuhimbise, Gaston; Namutebi, Agnes; Masanza, Michael; Jagwe, John N.; Kasharu, Apolo; Kizito, Elizabeth B.; Rees, Deborah
The purpose of this study was to investigate the effects of different processing conditions for production of dried Solanum aethiopicum (S.) leaf powder by comparing solar drying and cabinet drying processing techniques. Four (4) pre-treatments were done on S. aethiopicum leaves to inhibit enzyme action and prolong storage life. Treatments included dipping in; 10% saline solution, 10% vinegar solution, water (as the control), and steam blanching; done for both whole and sliced S. aethiopicum leaves. Each of the resultant samples were dried in both solar and cabinet dryers for a period of 24 hours. The dried leaf samples were grounded into powder using a coffee grinder and subjected to different laboratory analyses including; catalase activity, moisture content, vitamin C retention capacity and phytate content analyses. The results obtained were analysed using MINITAB version 16.0 at 5% significance level. The results showed that there was a reduction in catalase activity after pre-treatment and drying from 5.0±0.0 cm3 for the fresh un-treated leaves to a range of 4.5±0.7 – 3.0±0.0 cm3 for whole solar dried; 4.5±0.7-4.0±0.0 cm3 for sliced solar dried; 4.0±0.0 - 3.0±0.0 cm3 for whole cabinet dried and 3.5±0.7-2.3±0.7 cm3 for sliced cabinet dried leaf powder. Solar dried S. aethiopicum leaf powder contained significantly high moisture content than hot air cabinet dried one (24.9±0.5 % for saline treated sliced leaves to 8.9±0.8 % for blanched sliced leaves, than hot air cabinet dried one with 9.3±0.0 % for sliced plain water treated leaves to 7.0±0.2 % for sliced vinegar treated leaves; respectively). Cabinet dried S. aethiopicum contained significantly more vitamin C content (1.1±0.2 mg for whole blanched leaves compared to 0.6±0.1 mg for sliced vinegar treated leaves) than the solar dried one (1.0±0.2 mg for sliced plain water treated leaves to 0.6±0.1 mg for sliced vinegar treated leaves). There was no significant difference in phytate content between the hot air cabinet dried and solar dried i.e. 0.7±0.1 - 0.2±0.1 mg for solar and 0.7±0.1 - 0.3±0.3 mg for cabinet dried. Solar dried S. aethiopicum powder contained significantly higher catalase than the hot air cabinet dried one (4.5±0.7 - 3.0±0.0 and 4.0±0.0 - 2.5±0.7 cm3; respectively). However, in terms of acceptability, there was high preference for saline treated leaf powder soups compared to other soups. It can be concluded that High activity of catalase, moisture retention and high loss of Vit.C occurs in the solar drier than in cabinet drier. Whole leaf saline pretreated leaf powder soup is rated high compared to other dried soups. Therefore, the best method for production of dried S. aethiopicum powder is by slicing, dipping it in plain water and drying using a cabinet dryer. Under circumstances where cabinet drying is not achievable, solar drying is recommended using whole leaf, pretreated with saline water to promote preservation and consumption of the vegetable.
Effect of Different Rates of Poultry Manure and Bio-Slurry on the Yield of Solanum aethiopicum Shum
(Canadian Center of Science and Education 158, 2018-03) Nanyanzi, Mary; Kizito, Elizabeth B.; Masanza, Michael; Sseruwu, Godfrey; Makoma, Moses Tenywa
Poor soil fertility remains the major cause of low crop productivity on smallholder farms that are engaging in vegetable production in sub-Saharan Africa. Appropriate soil fertility regimes are therefore critical for improving crop productivity. Its yield has remained low mainly due to poor soil fertility. A field experiment in two different seasons was planted in a Completely Randomized Block Design using Solanum aethiopicum Shum (Nakati). The treatments were 3 sole fertilizer options applied at the following rates: poultry manure and bio-slurry manure at 5, 10, 15, 20, 25 and 30 t ha-1, NPK (25:5:5) at the recommend application rate for tomato which is a sister crop and a control without any fertilizer. Crop budgets were used to determine the economic optimum rates of both sole applications of manure and combinations of manure with NPK. The sole applications and showed significantly (p ≤ 0.05) increased the yield of S. aethiopicum compared with the control. The established biological optimum rates were at 24.19 t ha-1 and 21.51 t ha-1 for poultry manure and bio-slurry respectively. Using the crop budgets it was concluded that the established economic optimum rates were 20 t ha-1 and 10 t ha-1 for sole poultry manure and bio-slurry respectively. Recommendations for use of sole poultry manure and bioslurry at the rate of 20 t ha-1 and 10 t ha-1 respectively were made.
Effect of Post-Harvest Handling Practices, Storage Technologies and Packaging Material on Post-Harvest Quality and Antioxidant Potential of Solanum Aethiopicum (Shum) Leafy Vegetable
(Science and Education Publishing, 2018-05) Sekulya, S.; Nandutu, A.; Namutebi, A.; Ssozi, J.; Masanza, Michael; Jagwe, J. N.; Kasharu, A.; Rees, Deborah; Kizito, Elizabeth B.; Hedwig, Acham
Several studies have supported the use of vegetables as foods as well as medicinal plants. However, most especially for the leafy types of vegetables, their high moisture content gives them a short shelf life. On average Solanum aethiopicum (Shum) has a shelf life of one day, making it unable to keep fresh for a long time. The objective of this study was to determine the effect of post-harvest handling practices and storage technology on the post-harvest quality and antioxidant activity in S. aethiopicum, as well as determine the packaging material that could be able to maintain a high post-harvest quality during storage. The post-harvest handling and storage technologies were tested under three experimental conditions. Experiment one involved placing 2.0 kg of the harvested S. aethiopicum with roots intact (RI) and others with roots cut-off (RC) in a charcoal cooler (-CC), 21.0±1.00 °C, 95.67±3.01 %rh; in ambient storage (-AC), 23.8±2.86 °C, 69.38±6.72 % rh; and in cold room (-CR), 7.17±1.30 °C, 95.80±3.19 %rh. Experiment two involved storing 2.0 kg of S. aethiopicum in charcoal cooler with no water treatment (TT-) and in ambient storage while immersing in portable water for 2 to 3 seconds during the day (TT+). Experiment three involved packing 1.0 kg of S. aethiopicum sample of both RC and RI state to assess the effectiveness of the packaging materials (0.1 cm meshed perforated polyethylene (RC0.1), 0.5 cm meshed perforated polyethylene (RC0.5) and a 60 μm perforated polyethylene (RC60μm) in maintaining quality of the vegetables. The edible parts of the vegetable were tested for moisture content, percentage weight loss, chlorophyll content, polyphenol content and total antioxidant activity (as measures of post-harvest quality and shelf life) after every 24 hours. The antioxidant activity was determined by screening for free radical scavenging properties using diphenyl picryl hydrazyl (DPPH), Ferric reducing antioxidant power (FRAP) and ascorbic acid as standard. The results revealed that Shelf life was found to increase (from one day to four days) when the vegetable was intermittently immersed in portable water for 2 to 3 seconds after every one hour during the day for vegetables in ambient storage both with roots intact (RI(TT+)-AC and with roots cut-off RC(TT+)-AC). The samples stored in cold room and charcoal cooler showed slow and comparable reduction (percent) of weight for both intact and roots cut. The chlorophyll content decreased in all storage conditions, with ambient conditions showing the most rapid decrease. The total polyphenol fluctuated within relatively small limits for both with intact and roots cut-off when stored in cold room and charcoal cooler (6.25±0.05 to 9.35±0.05 mgGAE/gfw; respectively) within the four days of storage. Storage in ambient conditions indicated an increase in total polyphenol content from 9.35±0.05 to 14.77±0.12 mgGAE/gfw for that with roots intact (RI-AC) and to 13.65±0.06 mgGAE/gfw for roots cut-off (RC-AC). The increase in total polyphenol content in the ambient storage led to increased total antioxidant activity compared to that stored in cold room and charcoal cooler that remained almost constant. The 60 μm perforated polyethylene and 0.1 cm meshed perforated polyethylene retained more moisture (84.55±0.18 % and 85.20±0.03 %; respectively) and showed minimal percentage of weight loss (9.69±0.25 %) with the highest chlorophyll content (8.06±0.02 mg/g dwb) on day four when stored in the charcoal cooler, making it the best tested packaging material.
Evaluation of Ugandan cassava germplasm for drought tolerance
(International Journal of Agriculture and Crop Sciences, 2013) Turyagyenda, Laban F.; Kizito, Elizabeth B.; Baguma, Yona; Osiru, David
Increased pressure on prime arable land for agriculture to meet food demand for global population has resulted in shifting agriculture to marginal areas where drought is frequent. Focusing research towards development of drought tolerant varieties is thus necessary. Replicated field trials for farmer preferred cassava genotypes were established to evaluate their morphological and yield trait responses and adaptability to moisture stress. Results showed significant (P<0.05) differences among genotypes for all the parameters evaluated. Moisture stress resulted in a decline in Harvest Index by 22.34%, Fresh Root Yield by 37.04%, Number of Roots by 19.43%, Dry matter content by 16.58%, Root starch content of 20.81%, Leaf Retention by 25.72% and Plant height by 16.62%. Results therefore, evidently showed that water stress has significant devastating effects on vegetative and yield parameters of cassava. Breeding strategies to develop drought tolerant cassava varieties to cope up with increased water scarcity and semi-arid conditions are thus paramount. Varietal variability in response to water stress reported is a cornerstone in the breeding process. Besides genetic effects were dominant indicating breeding objectives would be easily achieved. Genotypes MH96/0686, Magana, Yellow, TME 204, Nyamutukura, MH97/2961, NASE 1, NASE 2 and NASE 12 were least affected by drought and may provide gene sources for cassava improvement. Genotype x Location was significant (P<0.05) suggesting that rational distribution of genotypes to agro-ecological zones with different levels of drought stress is possible. Some genotypes had stable yield and its components suggesting that cassava can easily adapt to dry environments
Genetic and Root Growth Studies in Cassava (Manihot esculenta Crantz): Implications for Breeding
(Swedish University of Agricultural Sciences Uppsala, 2006) Kizito, Elizabeth B.
Cassava (Manihot esculenta Crantz) is a perennial tropical crop grown for its starchcontaining tuberous roots. It is cultivated mainly by small-scale farmers and consumed daily by an estimated 500 million people. Cassava mosaic disease (CMD) has long been recognized as a major limiting factor to cassava production in Africa and severe epidemics hit Uganda in the late 1920’s and late 1980’s. In spite of its importance as a major food crop it is the least researched major crop and many questions regarding its genetics are still unresolved. This thesis has therefore dealt with studies on: i) the effect of CMD on the genetic diversity of cassava in Uganda, ii) the composition of varieties and the genetic structure within and between varieties on small farms in Uganda, iii) the genetic basis of two agronomic important traits, cyanogenic glucoside potential (CNP) and dry matter content (DMC) in cassava roots, using quantitative trait loci (QTL) mapping and iv) the effect of nutrient availability on the growth and tuber formation. The outcome of these studies is relevant for developing strategies for breeding and gene conservation programmes. CMD did not have a strong selective effect on the genetic diversity of cassava in Uganda in spite of earlier reports on losses of varieties due to the latest CMD epidemic. However, a loss of rare alleles in areas with high CMD incidence in Uganda was found. The composition of varieties differed widely between villages and districts and the genetic variation was surprisingly large within varieties although the variation was larger among varieties. The like-named varieties in different villages were genetically similar, demonstrating farmers’ ability to differentiate and maintain the same variety over large areas. We detected two QTL on two different linkage groups controlling CNP and six QTL on four different linkage groups controlling DMC. One QTL for CNP and one QTL for DMC mapped near each other, suggesting pleiotrophy or linkage of QTL. In the root studies, production of storage roots was found to be regulated by nutrient availability and appeared to be positively affected by a gradually increasing limitation of mineral nutrients during the growth of the plants.
Genetic diversity among farmer-preferred cassava landraces in Uganda
(African Crop Science Society Journal, 2012) Kizito, Elizabeth B.; Turyagyenda, L.F.; Ferguson, M.E.; Baguma, Y.; Harvey, J.W.; Gibson, P.; Wanjala, B.W.; Osiru, D.S.O.
Understanding of genetic diversity among a breeding population is an important requirement for crop improvement as it allows for the selection of diverse parental combinations and formation of heterotic pools for genetic gain. This study was carried out to determine genetic diversity within and among 51 farmer-preferred cassava (Manihot esculenta) landraces and 15 elite accessions grown in Uganda. Twenty six simple sequence repeat (SSR) markers used for genetic diversity assessment in this study revealed a total of 154 alleles, of which 24% were unique alleles present only in landraces. The genetic diversity and observed herozygosity in landraces were slightly higher than in elite accessions. Elite accessions clustered with some of the landraces indicating that there were some alleles in common. However, 58.8% of the landraces fell into 3 different clusters independent of the elite accessions. Including these landraces with unique alleles in cassava breeding schemes will increase the chances of producing farmer preferred adapted elite cultivars. The study also revealed genetic differentiation among accessions from different regions providing an opportunity for establishment of heterotic pools within a breeding programme.
Linear Discriminant Analysis of Structure Within African Eggplant ‘Shum’
(African Crop Science Society, 2018) Sseremba, G; Tongoona, P; Eleblu, J.S.Y.; Danquah, E.Y; Kizito, Elizabeth B.
African eggplant (Solanum aethiopicum) lags behind in terms of research attention; leading to, among other gaps,scantiness of information on intra-group genetic diversity. Hierarchical clustering was applied to reveal structure in a pioneer 20-entry set of S. aethiopicum Shum group accessions at Africa Solanaceae Research Network secretariat in Uganda, using 61 morpho-agronomic variables collected from a complete randomised design (CRD) with 12 plants per accession in screen-house. A MANOVA preceded linear discriminant analysis, to model each of 61 variables, as predicted by clusters and experiment to filter out non-significant traits. Four distinct clusters emerged, with a cophenetic relation coefficient of 0.87 (P<0.01). Canonical variates that best predicted the observed clusters include petiole length, sepal length (or seed color), fruit calyx length, seeds per fruit, leaf fresh weight (or leaves per plant), fruit fresh yield, seedling vigour, fruits per plant, harvest index and plant growth habit. Results suggest prospects for variety discrimination at various stages; seedling, vegetative and reproductive. The observed diversity will boost chances of effective selection for desired traits; while the canonical discriminant traits are potential morphological markers, within S. aethiopicum ‘Shum’ for a low-cost germplasm characterization approach.
Morphological distinctiveness between Solanum aethiopicum Shum group and its progenitor
(Academic Journals, 2017-08) Kizito, Elizabeth B.; Sseremba, Godfrey; Tongoona, Pangirayi; Eleblu, John Savior Yaw; Danquah, Eric Yirenkyi; Kabod, Nahamya Pamela
Use of morphological markers offers an alternative in germplasm discrimination of research-neglected crop species. A collection of 25 accessions including five wild progenitors was evaluated in screen house to identify the morphological difference between Solanum aethiopicum Shum and Solanum anguivi. An Unweighted Pair Group Method with Arithmetic mean hierarchical clustering revealed presence of moderate structure with a cophenetic correlation coefficient of 0.73. Five distinct clusters were produced; the progenitor accessions for the S. aethiopicum Shum were grouped in their own cluster. The Richness, Shannon-Weaver and Simpson indices were also different among qualitative variable categories. A ‘prcomp’ function based Principal component analysis (PCA) in R on quantitative variables indicated that days to germination and emergence, cotyledonous leaf length, cotyledonous leaf width, shoot biomass, plant height, petiole length, days to first flowering opening, plant width, plant branching, and number of leaves per plant are the major drivers of variability in the study accessions. Further, results from canonical discriminant analysis to discern between the S. aethiopicum and its progenitor accession groups showed that the days to germination and emergence provide the best separation; with the former emerging earlier than the latter. The mean values for flowering time, leaves per plant, number of branches per plant and plant height were more favorable for the Shum than its wild progenitor accessions. The study revealed that morphological markers are useful in distinguishing between the S. aethiopicum Shum and its progenitor accessions.
Performance of Solanum aethiopicum Shum group accessions under repetitive drought stress.
(2018-01) Nakanwagi, Mildred Julian; Sseremba, Godfrey; Masanza, Michael; Kizito, Elizabeth B.
Drought is a serious climatic hazard to crop production, more especially when it occurs repeatedly. This created a need to identify repetitive drought tolerant varieties that recover following exposure to drought. Twenty accessions of Solanum aethiopicum Shum group were evaluated for their response to repeated drought exposure in a screen house at Uganda Christian University stressed and well-watered conditions in a split-plot arrangement. Data was collected on growth and yield parameters namely leaf area, plant canopy width, plant height, plant branching, fresh leaf weight, fresh shoot biomass, and harvest index. Exposure of plants to repetitive drought stress led to significant decrease in all evaluated growth parameters at p<0.001 except for plant branching. Similarly, yield parameters exhibited a highly significant difference among accessions and between water levels at p<0.001. Principal component analysis of growth rate traits showed that leaf area contributed to the highest variation for recovery from repetitive drought stress among accessions. The accessions that recovered best from drought stress include SAS108/2015, SAS163/P/2015, SAS183/G/2015, and SAS168/G/2015. For yield parameters, the accessions SAS137/2015, SAS148/2015, SAS108/P/2015, and SAS160/2015 had the highest dry shoot biomass. These findings indicate prospect for improvement of tolerance to repetitive drought stress in S. aethiopicum Shum group.
Physiological and molecular characterization of drought responses and identification of candidate tolerance genes in cassava
(aobplants.oxfordjournals.org, 2013-02) Turyagyenda, Laban F.; Kizito, Elizabeth B.; Ferguson, Morag; Baguma, Yona; Agaba, Morris; Harvey, Jagger J. W.; Osiru, David S. O.
Cassava is an important root crop to resource-poor farmers in marginal areas, where its production faces drought stress constraints. Given the difficulties associated with cassava breeding, a molecular understanding of drought tolerance in cassava will help in the identification of markers for use in marker-assisted selection and genes for transgenic improvement of drought tolerance. This study was carried out to identify candidate drought-tolerance genes and expression-based markers of drought stress in cassava. One drought-tolerant (improved variety) and one drought-susceptible (farmer-preferred) cassava landrace were grown in the glasshouse under well-watered and water-stressed conditions. Their morphological, physiological and molecular responses to drought were characterized. Morphological and physiological measurements indicate that the tolerance of the improved variety is based on drought avoidance, through reduction of water loss via partial stomatal closure. Ten genes that have previously been biologically validated as conferring or being associated with drought tolerance in other plant species were confirmed as being drought responsive in cassava. Four genes (MeALDH, MeZFP, MeMSD and MeRD28) were identified as candidate cassava drought-tolerance genes, as they were exclusively up-regulated in the drought-tolerant genotype to comparable levels known to confer drought tolerance in other species. Based on these genes, we hypothesize that the basis of the tolerance at the cellular level is probably through mitigation of the oxidative burst and osmotic adjustment. This study provides an initial characterization of the molecular response of cassava to drought stress resembling field conditions. The drought-responsive genes can now be used as expression-based markers of drought stress tolerance in cassava, and the candidate tolerance genes tested in the context of breeding (as possible quantitative trait loci) and engineering drought tolerance in transgenics.
Quantitative trait loci controlling cyanogenic glucoside and dry matter content in cassava (Manihot esculenta Crantz) roots
(Hereditas, 2007) Kizito, Elizabeth B.; Stljung, Ann-Christin Ro¨ Nnberg-Wa¨; Egwang, Thomas; Gullberg, Urban; Fregene, Martin; Westerbergh, Anna
Cassava (Manihot esculenta Crantz) is a starchy root crop grown in the tropics mainly by small-scale farmers even though agro-industrial processing is rapidly increasing. For this processing market improved varieties with high dry matter root content (DMC) is required. Potentially toxic cyanogenic glucosides are synthesized in the leaves and translocated to the roots. Selection for varieties with low cyanogenic glucoside potential (CNP) and high DMC is among the principal objectives in cassava breeding programs. However, these traits are highly influenced by the environmental conditions and the genetic control of these traits is not well understood. An S1 population derived from a cross between two bred cassava varieties (MCOL 1684 and Rayong 1) that differ in CNP and DMC was used to study the heritability and genetic basis of these traits. A broad-sense heritability of 0.43 and 0.42 was found for CNP and DMC, respectively. The moderate heritabilities for DMC and CNP indicate that the phenotypic variation of these traits is explained by a genetic component. We found two quantitative trait loci (QTL) on two different linkage groups controlling CNP and six QTL on four different linkage groups controlling DMC. One QTL for CNP and one QTL for DMC mapped near each other, suggesting pleiotrophy and/or linkage of QTL. The two QTL for CNP showed additive effects while the six QTL for DMC showed additive effect, dominance or over dominance. This study is a first step towards developing molecular marker tools for efficient breeding of CNP and DMC in cassava.
Stalk-eyed fly, Diopsis sp. population dynamics under varying temperature and Relative Humidity in rice ecosystems
(2018-02) Kayongo, Charles; Mbogga, Michael S.; Goncalves, de Abreu Aluana; Masika, Fred; Masanza, Michael; Barrigossi, Jose Alexandre Freitas; Kizito, Elizabeth B.
Although the stalk-eyed fly (Diopsis sp.) has been observed in Ugandan rice fields, there is limited information on the fly’s population and its potential threat to rice production. This study assessed the stalk-eyed fly (Diopsis longicornis and Diopsis apicalis) population dynamics under varying temperature and relative humidity in rice ecosystems of Uganda. It was conducted in purposively selected small scale rice farming sub-counties in low land rain fed and irrigated rice agro-ecologies (Lake Victoria Crescent, Kasese transition zone and Northern moist farmlands). Diopsis sp. populations were monitored by sampling rice fields every 40 days for a period of 17 months. Weather parameters including air temperature and humidity were recorded by use of data loggers throughout the study period. R-statistical tool and MS Excel were used to assess the population dynamics and interactions of the diopsids. D. longicornis fly was dominantly abundant in rice fields of Lake Victoria Crescent and Northern Moist zones while D. apicalis was dominant in Kasese transition zone. There was significant mean count variations per survey for both species in all the agro-ecological zones with P-values of 0.000958 (D. longicornis) and 1.12e-12 (D. apicalis) in Lake Victoria crescent, 0.000473 (D. apicalis) and 0.0173 (D. longicornis) in Northern moist farmlands, 0.0188 (D. apicalis) and 0.0353 (D. longicornis) in Kasese transition zone. Temperature and relative humidity had a direct effect on the population of both species in Northern moist zone and only on D. apicalis in Kasese transition zone. The optimum/favorable temperatures for abundance were between 27oC and 29oC. Interpretation of the results? Integrated pest management strategies and introduction of improved Diopsis pest resistant rice varieties are some of the recommendations for managing the stalk-eyed fly populations in these rice ecosystems.

Browsing by Author "Kizito, Elizabeth B."

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