REPRODUCTIVE BIOLOGY, PHENOLOGY AND GENETIC DIVERSITY OF Osyris lanceolata (HOSCHT AND STEUDEL) IN KENYA
Osyris lanceolata (Hoscht and Steudel) is an evergreen, drought resistant, African tropical tree species of Santalaceae family. It‘s facing extinction due to over-exploitation for its essential oil used for making expensive cosmetics and drugs. The study aimed at: (1) describing reproductive biology and phenology of O. lanceolata; (2) exploring the extent of its genetic diversity using morphological and Inter-simple sequence repeat (ISSR) molecular markers. Observations, treatments and samples collection were done in Gwasii, Meru, Baringo, Kabarnet, Margat, Kitui, Wundanyi, Mt. Elgon and Mau populations. Variations in phenology, reproductive biology and morphological traits were analyzed using ANOVA in SPSS package 12.0. The F-test for the parameters was run at 95% level, Duncan Multiple Range Test (DMRT) performed to partition means. Molecular data was analyzed using GenAlex 6.1 and Popgene 1.31 soft-wares. Results showed that O. lanceolata is a biannual outcrossing species flowering from January to June and September to December for first and second phase respectively with each phase taking about 109±16 days. Assisted pollination increased its reproductive success by 40%. Most morphological traits clustered Kitui population in the first cluster, Gwasii in the second and, Kabarnet and Marigat in the third cluster. Six primers generated 96 fragments, ranging from 150 to 1000 base pairs (bp). Percentage polymorphic loci (P) ranged from 51.04% (Wundanyi) to 82.29% (Gwasii) with a mean of 64.73%. Unbiased gene diversity index (UHe) was highest in Gwasii (0.321) and lowest in Wundanyi (0.175) with overall mean of 0.253. Mean number of effective alleles (Ne) was 1.430 while Shannon Information Index (I) mean was 0.365. Gwasii was the most genetically diverse followed by Mt. Elgon and least was Wundanyi. Overall coefficient of differentiation Gst was 0.3429. Analysis of molecular variance (AMOVA) indicated within population variation of 62%. Principle Coordinate Analysis (PCoA) grouped six populations in a distinct cluster with allelic overlap except Baringo. Dendrogram partitioned the populations into two clusters, based on breeding systems, population sizes, gene flow, genetic drift and natural selection but not on geographic proximity. The study concluded that, O. lanceolata experiences low reproductive success which was attributed to limited pollen transfer. The moderate high genetic diversity observed indicate small restricted populations with limited gene flow. It was therefore recommended that assisted pollination strategy and introduction of genotypes from Gwasii, Mt. Elgon Mau and Baringo populations should be adopted to enhance gene flow and male/female ratio in in-situ conservation and allow for increase in their regeneration capacity, which will eventually increase the population sizes as well as their genetic diversities.
SubjectOsyris lanceolata (HOSCHT AND STEUDEL)REPRODUCTIVE BIOLOGY, Osyris lanceolata PHENOLOGY, Osyris lanceolata GENETIC DIVERSITY, Osyris lanceolata (HOSCHT AND STEUDEL) IN KENYA
- ANDIEGO KEN PATRICK.pdf
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