Browsing by Author "Geofrey Arinaitwe"

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Contrasting Effects of Shade Tree Species Diversity on Incidence and Damage of Pests and Diseases of Robusta Coffee
(Journal of Biology, Agriculture and Healthcare, 2024-01-31) Winnie Nanjego; Godfrey H. Kagezi; Samuel Kyamanywa; Judith Kobusinge; Geofrey Arinaitwe
In Uganda, most farmers grow their Robusta coffee, Coffea canephora in association with a diversity of shade tree species. Shade tree species diversity and density influence abiotic variables particularly, temperature and relative humidity. In turn, these may negatively or positively influence the population dynamics and damage caused by pest and diseases. Understanding these relationships is therefore vital for informing selection of shade tree species for ecological management of pests and diseases. We thus conducted a study in Kaweri Coffee Plantation Limited located in central Uganda to determine the effect of shade tree species diversity on the incidence and damage caused by pests and diseases on Robusta coffee. One plot measuring 100 x 100 m was demarcated in each of the four sections of the plantation: Kitagweta, Kyamutuma, Luwunga and Nonve. All the shade trees/shrubs and saplings (≤3 m) in the plot were counted and identified to species level. Additionally, incidence and damage of pests and diseases were assessed on 20 Robusta coffee trees selected along two diagonals in the plots. We recorded a total of 299 trees comprising of 22 species, with Solanum giganteum being the most abundant shrub (19.8 shrubs/ha) whereas, the most abundant shade tree species were Albizia chinensis (9.3 trees/ha) and Markhamia lutea (6.0 tree/ha). Eight (8) insect pests and two (2) diseases were recorded on Robusta coffee. These included, Xylosandrus compactus, Leucoptera coffeella, Leucoplema dohertyi, Epicampoptera andersoni, Prophantis smaragdina, Planococcus spp., Hypothenemus hampei, leaf eating beetles, Hemilleia vastatrix and Cercospora coffeicola. Our results further showed contrasting effects of shade tree species diversity on the incidence and damage of pests and diseases of Robusta coffee. Damage caused by X. compactus and E. andersoni as well as the incidence of H. vastatrix and C. coffeicola decreased significantly (p≤0.05) with increasing shade tree species diversity. Contrary, damage caused by all the other insect pests increased with increasing shade tree species diversity but, only significant (p≤0.05) in case of P. smaragdina, and Planococcus spp. There is therefore a need to thoroughly understand these dynamics if agroforestry systems are to be utilized as a strategy for ecological management of pests and diseases of Robusta coffee.
Farmers’ Knowledge and Perception of the Pest Status and Management Options for Termites in Buikwe District, Central Uganda
(East African Scholars Journal of Agriculture and Life Sciences, 2023-11-27) Godfrey H. Kagezi; Veronica Twesigye; Janet K. Musasizi; Israel Ssebugenyi; Eunice Namara; Gyavira Ssenoga; Godfrey Sseremba; Judith Kobusinge; Gerald Kyalo; Geofrey Arinaitwe
Termites are known to be serious pests, particularly in tropical and sub-tropical countries, causing damage to crops, forestry and structures/buildings. To design and implement effective and environmentally- friendly termite management strategies, there is a need to consider farmers’ knowledge and experience in defining and setting priorities. We therefore conducted a survey in the coffee agro-ecology of Buikwe district, central Uganda to determine farmers’ knowledge on the damage caused and control options for termites. Farmers were aware of the damaged caused by the termites, with 85.8% of them mentioning damage to crops in the field as the most important. However, 43.4% of them were of the view that the proportion of the whole coffee garden damaged by termites was generally low (1-25%). More than half of the farmers mentioned that they first observed termites in their gardens in the last 15 years and maize was the most (97.1%) damaged crop. In addition to crops, farmers mentioned that termites were also attacking mulching material, particularly maize stover (47.2%) and buildings (66%). Most farmers mentioned that they observed highest termite damage in the dry season (30.2%), at hill top (35.8%) and in reddish soils (55.7%). Also, >70% of the farmers mentioned that termite damage was generally decreasing in their coffee gardens, mainly due to destruction of termite mounds and bushes (39.6%). Furthermore, 83% of the farmers mentioned that they had attempted to manage termites, with most of them (>70%) acknowledging using chemicals. In addition to chemicals, farmers also mentioned that they were using cultural-based options such as destroying termite nests or mounds (68.7%), queen removal (34.9%) and weeding (30.2%), among others to control termites. Furthermore, in attempting to manage the termites, farmers mentioned that they faced several challenges, with most (36.8%) of them claiming that termites are impossible to control. In conclusion therefore, farmers had knowledge on the pest status of termites, conditions and seasons that support high termite damage as well as control options and the constraints they face in managing the termites. However, there is need to develop effective, cheap and environmentally-friendly integrated pest management (IPM) packages for termites but also, to conduct biological studies to relate termite damage to crop yield loss and determine the economic injury level (EIL), the basis for decision-making in most IPM programs.
Golden Bananas In The Field: Elevated Fruit Pro-Vitamin A From The Expression Of A Single Banana Transgene
(Plant Biotechnology Journal, 1016-12-15) Jean-Yves Paul; Harjeet Khanna; Jennifer Kleidon; Phuong Hoang; Jason Geijskes; Jeff Daniells; Ella Zaplin; Yvonne Rosenberg; Anthony James; Bulukani Mlalazi; Pradeep Deo; Geofrey Arinaitwe; Priver Namanya; Douglas Becker; James Tindamanyire; Wilberforce Tushemereirwe; Robert Harding; James Dale
Vitamin A deficiency remains one of the world’s major public health problems despite food fortification and supplements strategies. Biofortification of staple crops with enhanced levels of pro-vitamin A (PVA) offers a sustainable alternative strategy to both food fortification and supplementation. As a proof of concept, PVA-biofortified transgenic Cavendish bananas were generated and field trialed in Australia with the aim of achieving a target level of 20 lg/g of dry weight (dw) b-carotene equivalent (b-CE) in the fruit. Expression of a Fe’i banana-derived phytoene synthase 2a (MtPsy2a) gene resulted in the generation of lines with PVA levels exceeding the target level with one line reaching 55 lg/g dw b-CE. Expression of the maize phytoene synthase 1 (ZmPsy1) gene, used to develop ‘Golden Rice 2’, also resulted in increased fruit PVA levels although many lines displayed undesirable phenotypes. Constitutive expression of either transgene with the maize polyubiquitin promoter increased PVA accumulation from the earliest stage of fruit development. In contrast, PVA accumulation was restricted to the late stages of fruit development when either the banana 1-aminocyclopropane-1-carboxylate oxidase or the expansin 1 promoters were used to drive the same transgenes. Wild-type plants with the longest fruit development time had also the highest fruit PVA concentrations. The results from this study suggest that early activation of the rate-limiting enzyme in the carotenoid biosynthetic pathway and extended fruit maturation time are essential factors to achieve optimal PVA concentrations in banana fruit.
Inhibition Of Cell Death As An Approach For Development Of Transgenic Resistance Against Fusarium Wilt Disease
(Afr. J. Biotechnol., 2016-04-17) Betty Magambo; Khanna Harjeet; Geofrey Arinaitwe; Sali Tendo; Ivan Kabiita Arinaitwe; Jerome Kubiriba; Wilberforce Tushemereirwe; James Dale
Fusarium oxysporum f. sp. cubense (Foc) is one of the major threats to dessert banana (Musa spp.) production. In Uganda, ‘Sukali Ndiizi’ is one of the most popular dessert banana cultivars and it is highly susceptible to Fusarium wilt. Development of resistant cultivars through transgenic approaches has shown to offer one of the most effective control options for most diseases. The transgenic approaches for providing plant disease resistance have mainly been through either enzymatic destruction of pathogen structures, neutralization of pathogen and its products or production of metabolites that eventually kill the pathogen. However in recent years, methods that prevent cell death of host plant after infection especially for necrotrophic pathogens like F. oxysporum have registered success in providing resistance in several crops. We investigated whether the transgenic expression of a programmed cell death inhibition gene in Sukali Ndiizi could be used to confer Fusarium resistance to Foc race 1. Embryogenic cell suspensions of cv. ‘Sukali Ndiizi, were stably transformed with a synthetic, plant-codon optimise mCed-9 gene. Twenty-eight independently transformed plant lines were regenerated. The lines were inoculated with Foc race 1 and observed for 13 weeks in small-plant glasshouse. Three transgenic lines showed significantly lower internal and external disease symptoms than the wild-type susceptible ‘Sukali Ndiizi’ banana plants used as controls. This is the first report from Africa on the generation of Fusarium wilt tolerant transgenic ‘Sukali Ndiizi’, a very popular but rapidly diminishing African dessert banana.
Potential of Moisture Conservation Practices to Improve Soil Properties and Nutrient Status of Robusta Coffee Plant
(Agronomy, 2023-04-18) Judith Kobusinge; Geofrey Gabiri; Godfrey H. Kagezi; Godfrey Sseremba; Alice Nakitende; Geofrey Arinaitwe; Charles K. Twesigye
Soil moisture conservation practices (SMCPs) have been adopted in Uganda to adapt to the effects of climate variability. However, limited information exists on how conservation measures influence the physico-chemical properties of soil and coffee leaf nutrient concentrations. Thus, we determined the effects of selected SMCPs on the soil physio-chemical properties and leaf nutrient concentrations in Robusta coffee in a randomized incomplete block design, replicated three times, in Kituza, Uganda. Soil samples were collected from 0 to 20 cm and 20 to 40 cm depths, and analyzed in the laboratory following standard procedures for selected physio-chemical properties. Coffee leaf samples were picked from each treatment (open sun coffee (COSS), coffee cover crop, Desmodium intortum (CCS), coffee mulch, Miscanthidium violoceum (CMS), and coffee A. coriaria (ACS)). Bulk density was significantly (p < 0.001) the highest under ACS (1.61 gcm−3) and lowest under CCS (1.29 gcm−3), and it significantly (p < 0.001) increased with depth. The soil organic matter was higher than the optimum range of 1–3% at the 0–20 cm depth across different SMCPs, but within the optimum range at the 20–40 cm depth. Leaf nitrogen was significantly the highest under ACS (3.19%) and lowest under COSS (2.30%). Overall, the findings suggest that SMCPs improve the soil physio-chemical attributes and leaf nutrients for sustainable coffee productivity. However, ACS improved the leaf plant nutrition better compared to other SMCPs.
Viability of Deficit Irrigation Pre-Exposure in Adapting Robusta Coffee to Drought Stress
(Agronomy, 2023-02-25) Godfrey Sseremba; Pangirayi Bernard Tongoona; Pascal Musoli; John Saviour Yaw Eleblu; Leander Dede Melomey; Daphne Nyachaki Bitalo; Evans Atwijukire; Joseph Mulindwa; Naome Aryatwijuka; Edgar Muhumuza; Judith Kobusinge; Betty Magambo; Godfrey Hubby Kagezi; Eric Yirenkyi Danquah; Elizabeth Balyejusa Kizito; Gerald Kyalo; Emmanuel Iyamulemye; Geofrey Arinaitwe
Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well exploited, can sustain coffee productivity amidst climate change effects. Drought and heat stress are major global threats to coffee productivity, quality, and tradable volumes. It is not well understood if there is a selectable variation for drought stress tolerance in Robusta coffee half-sibs as a result of watering deficit pre-exposure at the germination stage. Half-sib seeds from selected commercial clones (KR5, KR6, KR7) and a pipeline clone X1 were primed with deficit watering at two growth stages followed by recovery and later evaluated for tolerance to watering deficit stress in three different temperature environments by estimation of plant growth and wilt parameters. Overall, the KR7 family performed the best in terms of the number of individuals excelling for tolerance to deficit watering. In order of decreasing tolerance, the 10 most promising individuals for drought and heat tolerance were identified as: 14.KR7.2, 25.X1.1, 35.KR5.5, 36.KR5.6, 41.KR7.5, 46.KR6.4, 47.KR6.5, 291.X1.3, 318.X1.3, and 15.KR7.3. This is the first prospect into the potential of C. canephora half-sibs’ diversity as an unbound source of genetic variation for abiotic stress tolerance breeding.
Within-Canopy Distribution of Incidence and Damage of Pests and Diseases of Robusta Coffee, Coffea Canephora and Implications for their Management
(International Journal of Sciences: Basic and Applied Research, 2024-03-03) Winnie Nanjego; Godfrey H. Kagezi; Samuel Kyamanywa; Judith Kobusinge; Geofrey Arinaitwe
Due to its perennial and robust vegetative growth nature, the Robusta coffee harbors a diversity of pests and diseases that are not necessarily evenly distributed within the coffee canopy and this has management implications. We thus, conducted a study in a Kaweri Coffee Plantation Limited in central Uganda to determine the distribution of incidence and damage caused by the pests and diseases within the Robusta coffee canopy. In each of the four section of plantation (Kitagweta, Kyamutuma Luwunga and Nonve), a plot measuring 100 x 100 m was demarcated and 20 Robusta coffee trees were systematically selected along two diagonals in each of the plots. All the stems on each of the selected coffee tree were assessed for pest and disease incidence and damage on the leaves, berry clusters and berries. The coffee canopy was divided into three sections (lower, middle and upper) and incidence and damage of the pests and diseases were determined on coffee leaves, berry clusters and berries. Results showed that the pests and diseases were not evenly distributed within the canopy. On the leaves, the incidence and damage caused by Leucoptera coffeella, Leucoplema dohertyi and Hemilleia vastatrix varied significantly (p≤0.05) across the canopy sections, with the highest levels (23.1, 36.1 and 30.5%) being recorded in the lower section. On the other hand, though the damage caused by Epicampoptera andersoni and the leaf eating beetles was not significantly (p≥0.05) different within the canopy, the highest infestation was recorded in the upper (26.9%) and middle (19.3%) sections, respectively. For the berry cluster, only damage caused by Planococcus spp. varied significantly (p=0.0188) across the canopy, with the highest infestation (18.6%) being recorded in lower section. However, incidence and damage caused by Prophantis smaragdina and Cercospora coffeicola were not significantly (p≥0.05) different within the canopy but, the highest levels were recorded in the upper section of the canopy (15.8 and 24.4%, respectively). On the coffee berries, the incidence and damage of both Hypothenemus hampei and Cercospora coffeicola did not significantly (p≥0.05) across the canopy sections but the highest levels were recorded in the lower (28.5%) and upper (20.7%), respectively. Our findings enlightened the understanding of the vertical distribution of the incidence and damage of pest and disease within the Robusta coffee canopy. This information will contribute to developing and implementing monitoring techniques and regimes as well as ecologically-informed management strategies for these pests and diseases.