Assessment of Germination Potential and Population Status of Melia Volkensii Gürke in Kitui County, Kenya
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Date
2022
Authors
Njehu, Mukami Jane
Journal Title
Journal ISSN
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Publisher
Kenyatta University
Abstract
Melia volkensii Gürke is a native tree species that grows in the arid and semi-arid areas of East Africa. There has been overutilization of this tree which may lead to risk of rapid decrease in its community and genetic diversity. Additionally, planning and implementing planting programmes and conservation plans of M. volkensii have been hindered by insufficient knowledge on its seed storage behavior. This study sought to develop optimal protocols for seed germination and assess population status of Melia volkensii to enhance conservation and supply chain management in Kitui County. Melia volkensii fruits were collected from Tiva Forest and the germination experiment was carried out in KEFRI Kitui within nursery conditions. Seed germination experiments were arranged in a completely randomized design with three factors – extraction state, storage container and storage temperature. For extraction, seeds were divided into two lots – extracted seeds and unextracted seed (nut). Two types of storage containers were used namely sealed and unsealed. The storage temperatures were room temperature (30oC) and cold storage (-20oC). Germination tests were done before storage, and later after 2, 4 and 6 months in storage from each of the storage conditions. A hundred seeds and nuts each were sown for each experimental unit. The rate of seedling sprouting was recorded for a duration of 10 days as a percentage of seeds sown. Variation in germination percentages “was tested using two-way analysis of variance (ANOVA) at 95 % confidence interval and means separated using fisher’s protected least significant difference” in R and SAS statistical software. The highest percentage (89 %) was scored in nuts kept in unsealed containers at 30oC at 6 months and the lowest (14 %) in seeds stored in similar conditions for 2 months.The differences were significant. These results indicate that the germination rates of M. volkensii seeds increased with increase in period of storage. Additionally, plant population was determined in situ across seven transect lines measuring 1050 meters in length. Sampling was carried out in five plots measuring 50 x 50 m established at intervals of 200 meters. Transect 1 and 7 were laid in farmland while the transects between these two were laid in bushland. All tree species represented in each plot were counted. “Height and diameter at breast height (DBH) were measured for all M. volkensii trees within the plots. Melia volkensii seedlings and coppices were counted in 5 x 5 m nested plots within the larger plots. One-way analysis of variance (ANOVA) at 95 % confidence interval was used to test for variance in parameters measured and means separated using Tukey’s HSD. There were significant differences in height and DBH” means of M. volkensii among transects. Transect 2 had the lowest mean height and DBH while the tallest trees were in transects 1, 3, 4, and 6. Transect 1 had highest mean DBH. Means of seedlings were not significantly different among transects. Coppicing was significantly highest in transects 1 and 4. Moreover, relative abundance, species richness and diversity of plant species observed were analyzed “using Simpson’s index of biodiversity and Shannon-Wiener species diversity index. Melia volkensii was the most frequently occurring species with 12.2% (n=67) followed by Acacia tortilis10.0 % (n=55). Calotropis strophela, Commiphora capensis, Maerua crassifolia were the least represented relative abundance of 0.18 %. Values of indices used varied among transects and did not follow the location of transect implying that diversity was not determined by land disturbance. In conclusion, nuts stored unsealed at room temperature have the highest longevity. Based on diversity and relative abundance of M. volkensii and associated tree species in the study area, tree exploitation in Kasaala Location does not cause
Description
“A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Plant Ecology) in the School of Pure and Applied Sciences of Kenyatta University”, May, 2022
Keywords
Germination Potential, Population Status, Melia Volkensii Gürke, Kitui County, Kenya