Genetic diversity of populus ilicifolia populations in Kenya using amplified fragment length polymorphism (AFLP) markers.
Mutegi, Sammy Muraguri
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Many species in the genus Populus and their hybrids are economically valuable, fast growing, short rotation woody crops for producing wood, fiber, and biofuels, as well as sequestering atmospheric carbon in large plantations and agroforestry settings. Industrial facilities to produce liquid transportation fuels from Poplar feedstock are currently being built in the USA. Populus ilicifolia locally known as Tana River Poplar is the only species in the Populus genus that falls within the tropics. It occurs in river valleys of Tana, Athi, Ewaso Nyiro and Tsavo River in Kenya. P. ilicifolia is threatened by massive felling by humans, floods and destruction by large herbivores. As such the species populations have become decimated to IUCN vulnerable status. Unlike its relatives in Americas, Europe and Asia, P. ilicifolia have received very little attention for utilization and conservation. Incorporating this species into on-going tree improvement . and genom ics research on temperate Populus species is expected to have tremendous economic and scientific benefits to Kenya. The genome of P. trichocarpa a member of this genus has already been fully sequenced. Use of marker assisted breeding which reduces the tree improvement period by more than half will be the best approach. Samples will be collected from three locations along the species natural ranges (i.e. Athi, Ewaso Nyiro and Tana Rivers), and compared with 10 reference samples from the USA. This study will assess the genetic diversity of P. ilicifolia using amplified fragment length polymorphism (AFLP) markers and flowering loci (FTI and FT2) specific markers. FTI and FT2 genes are involved in reproductive and vegetative growth respectively of the species and have been extensively studied in the temperate species of genus Populus. Reproductive and vegetative growth is important for adaptation of a species to different environments. Upon assessment using these markers, molecular data produced will be analyzed by employing GenALEx 6.5 software. Genetic diversity of P. ilicifolia will be quantified by calculating the rate of polymorphism and the proportion of polymorphic loci based on the number of variants and the average expected heterozygosity based on the frequency of variants. The relationship among the P. ilicifolia populations will be displayed using a dendogram based on similarity matrices. The information generated will be important in laying down conservation and utilization strategies for the species. The assessment of the genetic relatedness of FT loci between P. ilicifolia and the template Poplar species will also has the potential for application in the species tree improvement through molecular breeding