Assessment of genetic diversity among the wild tetraploid wheat Triticum turgidum var. dicoccoides (Körn. Schwein) populations by molecular markers (AFLP, RFLP)

vASSESSMENT OF GENETIC DIVERSITY AMONG THE WILDTETRAPLOID WHEAT Triticum turgidum var. dicoccoides (Körn. Schwein)POPULATIONS BY MOLECULAR MARKERS (AFLP, RFLP)(Philosophy of Doctorate)Özlem ÖZBEKGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYJanuary 2006ABSTRACTGenetic structure of natural populations of wild crop relatives has been thesubject of many studies. Yet, most of these studies have focused on theestimation of spatial genetic diversity, while information on long-term variation,affected by yearly changes, has been considered only in few studies. The aim ofthe present study is to estimate the spatial and temporal genetic variation inwild emmer wheat, Triticum turgidum ssp dicoccoides (2n=4x=28; genomeBBAA), the progenitor of most domesticated tetraploid and hexaploid wheat,populations collected from Israel and Turkey. For analyzing genetic diversityAFLP and RFLP techniques were used. For AFLP analysis first temporalgenetic variation was screened in the wild emmer wheat populations collectedfrom six different habitats in Ammiad site, Israel in 1988 and 2002 with 14primer combinations by AFLP fragment analysis. Of the scored 1545 AFLPloci, 1088 (%70.4) were polymorphic in 1988 and 1061 (%68.9) in 2002. Theobserved genetic diversity estimates, proportion of polymorphic loci (P) andgene diversity (He) were P=0.60 and He=0.15 in 1988 and P= 0.57 and He= 0.14in 2002 (p<%0.1). Then, Ammiad-02 populations were compared with sevenwild emmer populations collected from seven different altitudes in Diyarbakir,Turkey in 1998 by using seven primer combinations by AFLP. In total 788 lociviwere scored and 629 (%79.82) of these loci were polymorphic. Genetic diversityestimates were P=0.30 and He= 0.11. Finally, spatial variations among 18populations collected from different ecological and geographical locations inIsrael were examined by RFLP based Southern blot analysis. In this study,combinations of five restriction enzymes and 11 RFLP probe were used. Genediversity estimates of RFLP were P=0.34, number of polymorphic allele perlocus A=2.23 and He=0.15. In this study, Eco R I and WPG 176 were the mostpolymorphic restriction enzyme and probe respectively. Dendograms wereconstructed by using UPGMA (Unweighted Pair Group Method UsingArithmetic Averages) method based on AFLP and RFLP data. Wild emmerpopulations were classified into groups varying 3 to 5 according to their originof habitat and country. Significance of the results of this study in relation to themaintenance of polymorphism in natural populations was discussed. However,the temporal genetic diversity was smaller than the spatial and was proportionalto genetic diversity within habitats. The results indicate that there might begreat genetic differences in the population genetic structure in different years,mainly due to the predominance of different genotypes in different years. Thesignificance of the results in relation to the maintenance of polymorphism innatural populations as well as in in situ conservation was discussed.Science Code : 203.1.103Key Words : Spatial and Temporal Genetic variation, AFLP, RFLP,T. dicoccoidesPage Number : 123Adviser : Prof. Dr. Orhan ARSLAN