Sustainable Land Management

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Browsing Sustainable Land Management by Subject "Kenya Forest Research Institute"

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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
    Promotion of Terminalia brownii in Reforestation by Development of Appropriate Dormancy Breaking and Germination Methods in Drylands; Kenya
    (Elsevier, 2020-06-01) Okeyo, Michael; G., Obwoyere; Makanji, Lubanga; Njuguna, Jane; Omondi, Jackline
    Terminalia brownii Fresen in the Combretaceae family, is one of the indigenous tree species used in agroforestry, afforestation and reforestation programmes in drylands of Kenya. It is widely distributed in the semi-arid lands of East, Central and West Africa. It is an important drought tolerant and multipurpose agroforestry species whose potential is underutilized due to poor seed germination. Its products such as timbers, posts, charcoal and curving wood among others are not available in required quantities for domestic and industrial use. Exploitation of T. brownii is on the increase, but efforts to promote its planting are thwarted by lack of seedlings attributed to poor seed germination. This study investigated dormancy and germination of T. brownii seeds. Mature T. brownii fruits were harvested from Ikanga, Mbumbuni, Kabururu and Kimose sites; in Kitui, Makueni, Tharaka Nithi and Baringo counties of Kenya respectively. Flowering and fruiting was monitored and mature fruits harvested for dormancy and germination tests. To conduct germination tests, one hundred fruits and extracted seeds were subjected to each of the following treatments: mature whole fruits (control), dewinged fruits, fruits nipped at the distal and proximal ends and extracted seeds in four replicates. Extracted seeds started germinating after incubation for 7 days, while fruits nipped at the distal end took 21 days. The control and all other treatments from all sites failed to germinate after an incubation period of 60 days. Extracted T. brownii seeds recorded the highest germination with the best at 76% from Ikanga, while those nipped at the distal ends recorded a mean germination of 13% across all sites. There is evidence suggesting that T. brownii fruits recorded poor germination due physiological seed dormancy probably imposed by the hard samara fruit. These findings suggest that T. brownii fruits from Kimose should be nipped at the distal end, while those from Eastern Kenya (Kitui and Makueni Counties) should be extracted completely by removing the seed from the fruit to enhance germination. These results will inform choice of propagation of T. brownii seeds and enhance its planting in various agroforestry practices and afforestation programmes.