Faculty of Science

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https://dir.muni.ac.ug/handle/20.500.12260/318

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Browsing Faculty of Science by Author "Alicai, T."

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    Effects of gamma irradiation and ethyl methane sulphonate on morphometric traits and prevalence of common viral diseases and whiteflies in cassava.
    (African Journals Online, 2021-08-23) Baguma, J.K.; Ogwok, Emmanuel; Elegba, W.; Sarkodie, A.; Otu, S.; Apio, H.B.; Kawuki, R.S.; Bua, A.; Danso, K.; Alicai, T.
    Cassava (Manihot esculenta Crantz) is an important staple and food security crop for millions of people in Africa. However, its nutritional value is limited; yet its productivity is constrained by several pests and diseases. Induced mutagenesis is one approach with the potential to overcome such biotic stresses. The objective of this study was to assess the variability in morphometric traits and prevalence of common viral diseases and whiteflies in cassava to different doses and concentrations of gamma irradiation and ethyl methane sulphonate (ems) treatments. The effects were assessed on seed germination and growth of stakes, as well as foliar viral disease symptoms and whitefly counts. Radio-sensitivity tests revealed LD50 for sprouting as 37.6Gy for g-irradiation and 0.08% for EMS treatment. There was notable decrease in sprout, epicotyl length, shoot height, petiole length and number of leaf lobes, with increasing g-ray doses and EMS concentrations. Contrastingly, total chlorophyll content increased with increasing doses of g-rays and EMS concentrations. Basing on foliar whitefly counts and disease symptoms, there was a general increase in susceptibility to whitefly infestation and cassava mosaic disease (CMD) incidence. Significantly varying levels of resistance or tolerance to whiteflies and CMD were observed among plantlets derived from irradiated and EMS treated stems, compared to the controls. These findings lay a foundation for more future research on breeding for various traits, including disease resistance in cassava using induced mutagenesis approach.
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    First report of Moroccan watermelon mosaic virus and other viruses infecting watermelon (Citrullus lanatus) in Uganda
    (New Disease Report, 2025-05-15) Masika, Fred Bwayo; Mahipal, S. K.; Alicai, T.; Shimelis, H.; Ddamulira, G.; Athman, S. Y.; Ipulet, P.; Osingada, F.; Salman, F. A.; Tugume, A. K.
    This study reports the first detection of Moroccan watermelon mosaic virus (MWMV) and multiple other viruses infecting watermelon (Citrullus lanatus) in Uganda. Using high-throughput sequencing of leaf samples collected from commercial farms across three districts, we identified six viruses, including MWMV, pepo aphid-borne yellows virus (PABYV), Citrullus lanatus cryptic virus, Cucumis melo cryptic virus, Watermelon crinkle leaf-associated virus, and a novel E. coli virus. The complete genome sequences of MWMV and PABYV were obtained, and virus presence was confirmed through RT-PCR. Observations indicated that mixed infections led to more severe symptoms such as mosaic patterns, leaf mottling, and stunting, affecting approximately 30–40% of cultivated plants. These findings underscore the emerging viral challenges in Ugandan watermelon production and emphasize the importance of vigilant disease monitoring and management strategies.