Browsing by Author "Okeyo, Michael M."

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  • Publication
    Publication
    Fungal diseases attacking floral phenology of Terminalia brownii in Drylands, Kenya
    (CEON/CEES, 2019) Okeyo, Michael M.; Obwoyere, Gilbert O.; Makanji, Dickson L.; Njuguna, Jane W.; Omond, Jackline A.
    Terminalia brownii is among the dominant multipurpose tree species in the Kenyan drylands whose regeneration is hampered by poor seed germination. It is used for building, fencing, herbal medicine, wood carving, and woodfuel among others. A study to assess fungal pathogens that infest T. brownii floral phenophases was conducted in Baringo, Kendu Bay and Kitui Bay. Flower-buds, flowers and immature were sampled for culturing from 30 trees selected randomly within 5.0 ha area in each site and GPS coordinates recorded. Samples of 100 flowerbuds, flowers, immature and mature fruits were surface sterilized using 10% sodium hypochlorite for 2 minutes and rinsed in distilled water. These were plated on Malt Extract Agar (MEA) media and incubated at 28 ± 2°C for seven days; fungal colonies were evaluated and subcultured to obtain pure cultures and pathogens were identified using morphological characteristics. Statistical analyses were carried out using GENSTAT version 18 and means separated using Turkeys test. Common fungal pathogens isolated were Pestalotia (53-57%), Fusarium spp (12-19%), Rhizopus (16-21%) and Cladosporium species (1-5%). While that of Bostrosphaeria, Trichoderma and Alternaria species were less than 2.5% in all sampled floral phenophases. There were significant differences (p<0.05) of fungal infestation between flowerbuds, flowers, immature and mature fruits, but not across sites. Flower-buds had the least of isolated fungal pathogens, thus indicating that infestation took place during and after flowering. These fungi may affect seeds and germination by either causing seed deterioration or affecting the germinants hence lowering seed quality.
  • Publication
    Publication
    Seed Borne Fungal Organisms Associated with Germination Success of Terminalia brownii (Fresen) in Kenya
    (Scientific Research Publishing, 2021-09-24) Atieno, Jackline; Obwoyere, Gilbert O.; Makanji, Dickson L.; Okeyo, Michael M.
    Terminalia brownii is an indigenous tree species highly valued in the Kenyan drylands for its products such as timber for wood curving, medicine, and charcoal production, among others. Due to this high value followed by overutilization, its population in the drylands is dwindling. Concern about the species’ low regeneration as shown by low germination has been raised. This research was conducted on the seed borne fungal organisms that are associating with the germination of this species. T. brownii seeds were collected from cluster patches of the species in Kendu Bay, Kimose and Ndumoni in Homabay, Baringo and Kitui counties of Kenya respectively. The seeds were harvested for fruit probing for maturity confirmation. Random sampling was used in selecting thirty trees, 50 meters apart, from which fresh fruits were uniformly collected from the crowns. The research adopted a complete block experimental design where one hundred seeds each from the three sites, were subjected to a germination test, seed borne fungal organisms’ presence, identified organisms cultured and DNA and DNA sequencing carried out for identification. Fungal organisms associated with germination success of T. brownii were Fusarium equiseti, Pestalotia sp, and Alternaria alternata. Paired t test run between germinants versus the number of sown seeds gave N = 12, p-value of 0.000, t = 16.29. On the other hand, paired t test run between fungal infected seeds with the number of germinants gave N = 12, p-0.000, t = 8.78. Fungi associated with germinants included Penicillium sp, and the data analyzed using Mann-Whitney U test run showed significant difference at a p value of 0.000. Identified organisms associating with none germination and germination success on the other hand were analyzed using descriptive analysis. Fungal organisms associating with germination success of T. brownii significantly affect germination of freshly extracted seeds from the field, hence, for maximum germination achievement, seeds should be sown while still fresh.