تعيين تنوع ژنتيكي توده هاي بومي پياز ايران با استفاده از نشانگر هاي ريز ماهواره اي

چكيده انگليسي :

Determination of Genetic Diversity of Iranian Onion Landraces Using Microsatellite Markers Zahra karimi Nafchi Bahar z23@yahoo com 10 3 2009 Department of Agricultural Biotechnology Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language Farsi1 Assoc Prof B E Sayed Tabatabei Supervisor sayedt@cc iut ac ir2 Assoc Prof M Mobli Supervisor Mobli@cc iut ac irAbstractOnion Allium cepa L is the most important edible Allium species recorded for over 4 000 years and ranks secondin value among cultivated vegetables Onion is an outcrossing biennial diploid 2n 2x 16 plant with a very large 32 pg 2 n genome It is proposed that the southwest Asian gene center of A cepa should be acknowledged as theprimary center of domestication and variability whereas other regions such as the Mediterranean basin where onionhas a great variability are secondary centers it is believed that with many landraces of onion exist across the Iranand a longstanding history of cultivation Iran is rich in genetic diversity of onion Despite many morphologicalstudy little is known regarding the genetic relationships among germplasm of onion in this country Therefore theobjectives of this study were based on determining genetic variations among onion landraces using Simple SequenceRepeat SSR and Inter Simple Sequence Repeat ISSR markers Eighteen Iranian onion landraces collected fromdifferent parts of Iran with five foreign cultivars were used Five plants per landraces were randomly selected andyoung green healthy leaves from each plant were collected for DNA extraction Total genomic DNA was extractedby the cetyl trimethyl ammonium bromaid CTAB method with modifications DNA concentration and quality wasdetermined by electrophoresis in a 0 7 w v agarose gel Fifteen primer pairs detecting SSR loci in onion wereused in the amplification The number of bands per primer varied from 2 to 6 with mean of 3 3 polymorphic band sand mean heterozygosity of 0 75 A dendrogram based on similarity coffecient and UPGMA algorithm grouped theonion landraces and foreign cultivars into five groups and one independent genotyp From SSR analysis a higherlevel of genetic variation was observed within populations compared to variation among populations in the onionlandraces and foreign cultivars Highest and lowest mean genetic diversity were obtained in Sephide Gorgan andYellow Sweet Spanich respectively Fourteen primers were used for PCR amplification Amplified DNA fragmentwere separated elecrtophoretically in a 1 5 w v agarose gel From these data a Squared Euclidian distance matrixwas calculated to estimate pair wise differences in the amplification product for all genotypes Cluster analysis wasdone using a UPGMA algorithm to construct a dendrogram A high degree of polymorphism was observed in thepresent material All 14 primers generated 7 to 14 polymorphic bands and the frequency of polymorphic markerswas as high as 96 The dendrogram grouped the onion landraces and foreign cultivars into five group and fourindependent genotyps From ISSR analysis a higher level of genetic variation was observed within populations compared to variation among populations in the onion landraces and foreign cultivars Highest and lower meangenetic diversity were obtained in Tarom and hybrids respectively The dendrogram resulted from SSR and ISSRcombined data indicated landraces and foreign cultivars more correspandance with morphological and geographicalcharacters The results of this research classified Hurand Maraghe and kinovat landraces and Dorcheh andGhermeze Azarshahr and kovar and Sephid eAbarkooh and Sephide Gorgan and Kazbier Zanjan and SephideGhome and Sephide Kashan in one groups indicating close genetic relationship between these landraces Clusteranalysis indicated the ability and usefulness of SSR markers for studying the differentiation and relatedness amongonion populations Key words Allium cepa microsatellite heterozygosity mean genetic diversity

كريمي نافچي، زهرا

تعيين تنوع ژنتيكي توده هاي بومي پياز ايران با استفاده از نشانگر هاي ريز ماهواره اي

هتروزيگوسيتي , تجزيه واريانس مولكولي , ميانگين تنوع ژنتيكي