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Title: Chromosom Study of Local Farmers' Virieties of Opuntia ficus-Indica(L)Mill.(Cactaceae)from Tigiray,Northern Ethiopia
Authors: Azimitachew, Ayele
Advisors: Kifle Dagne(Dr)
Keywords: Chromosomes
Local farmers’ varieties
Opuntia ficus-indica
Polyploidy
Tigray
Copyright: Dec-2010
Date Added: 30-Jun-2012
Publisher: Addis Ababa University
Abstract: Opuntia ficus-indica (L.) Mill. is one of the drought resistant plants that play a significant role in rescuing the lives of people and livestock in arid and semiarid regions of the world. In Ethiopia, particularly in Tigray, it is used as food and forage until cereal crops are harvested as well as during drought seasons. Currently, about thirty-four local farmers’ varieties of O. ficus-indica are locally identified in the Southern and Eastern Zones of Tigray on the bases of their fruit characteristics and cladode morphology. The present study tried to assess the cytogenetic variability among these local farmers’ varieties through standard chromosome count method. Other three sample plants of opuntia species from Debre-zeyit, Dire Dawa and Addis Ababa were also included in the study for comparison of their chromosome count with that of the specimens collected from Tigray. The results of the study have shown that all the sample plants chromosomally investigated in the study are polyploids. All the local farmers’ varieties of O. ficus-indica, for which the somatic chromosome spreads were reliably counted, were found to have an octoploid cytotype, with the same somatic chromosome number of 2n = 8x = 88. The two specimens of O. ficus-indica plant, each from Debire-zeyit and Dire Dawa, have also shown the same ploidy level and somatic chromosome number with that of the local farmers’ varieties of O. ficus-indica collected from Tigray. On the other hand, the specimen of O. cylinderica plant collected from Science Faculty Campus of Addis Ababa University was found to have a different ploidy level with different somatic chromosome number of 2n = 11x = 121. The fact that all the local farmers’ varieties of O. ficus-indica included in the present study belong to the same ploidy level indicates that the variations among those local farmers’ varieties in fruit characteristics and cladode morphology could not be attributed to the variation in ploidy level. Further chromosome studies were also recommended to cover wider populations of O. ficus-indica from different parts of Ethiopia. It was also recommended to investigate the polyploidy nature, mode of seed formation and genetic variability of O. ficusindica using appropriate molecular techniques such as ISSR and AFLP.
Description: A thesis presented to the School of Graduate Studies of Addis Ababa University in partial fulfillment of the requirements for the degree of Master of Science in Biology (Applied Genetics)
URI: http://hdl.handle.net/123456789/3228
Appears in:Thesis - Biology

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