3721

179 دكتري

دكتري

اصلاح نباتات

اصفهان : دانشگاه صنعتي اصفهان ،دانشكده كشاورزي

1386

هفده ،234 ،[II] ص : مصور، نمودار، جدول

ص.ع. به فارسي و انگليسي

آقا فخر ميرلوحي

عبدالمجيد رضايي، بدر الدين ابراهيم سيد طباطبايي

26/08/86

رضا بلالي ، بهروز شيران ، احمد ارزاني، بهرام شريف نبي

مهندسي كشاورزي

ID179 دكتري

به فارسي و انگليسي :قابل رؤيت در نسخه ديجيتال

Abstract This research was conducted to evaluate different basic aspects of tall fescuebreeding using classical and molecular approaches in five experiments In the firststudy genetic diversity between and within 46 Iranian and foreign accessions of tallfescue were evaluated The results indicated considerable variation between and withingermplasm for all traits and a better performance for Iranian accessions Correlationcoefficients for hay yield with phenological traits was negative and with dry matterpercentage plant height stem number crown diameter spring growth leaf length establishment rate and persistency was significantly positive Crown diameter establishment rate dry matter percentage plant height and stem number wererecognized as components of hay yield Applying UPGMA method of cluster analysison the studied attributes accessions of similar geographic origin were clustered in samegroups In the second study AFLP technique was used to detect the phylogenicrelationship and genetic diversity of 38 accessions representing six species From 12primer combinations 360 polymorphic markers were scored to differentiate betweenaccessions The results showed that coarse fescue had more genetic similarity withryegrass than fine fescues Accordingly AFLP analysis revealed that Iranian accessionswere more diverse than foreign accessions UPGMA cluster and Principal ComponentAnalysis PCA clearly separated species in distinct groups Tall fescue accessions wereclustered in six groups that largely supported the known origins and somemorphological characteristics of these accessions In the third study 25 superiorgenotypes were selected from base population and were evaluated in a clonal and EST SSR analysis Both morphological and molecular assessments showed considerablevariation between genotypes From 50 EST SSR loci 175 polymorphic alleles werescored and grouped genotypes in 7 clusters which mainly supported geographicalorigin Also there was a general agreement between morphological and moleculargrouping for selected genotypes Based on morphological and EST SSR geneticsimilarity indices the best genotypes for constructing mapping populations heteroticgrouping and developing fodder varieties were introduced The forth study wasconducted to estimate general combining ability GCA of the selected parents base onfield evaluation of their 25 half sib poly crossed family progenies and to evaluate theeffect of EST SSR variation on polycrossed progeny performance The GCA estimateswere congruent with the results of morphological and molecular genetic diversityassessments Narrow sense heritability estimates were medium to high for most of thecharacters Evaluation of hay yield stem number and crown diameter of polycrossprogenies showed that progenies from molecularly wide polycrosses to be significantlyhigher yielding The results provide evidence for an efficient application of molecularmarkers to select genetically diverse parents In fifth study six endophyte infected E and six un infected E clones of the same fescue genotypes were used to investigatethe effects of endophyte on seed production traits and their relationships Endophyteinfection resulted in significantly more seed yields mainly through increasing paniclenumber and seed number per plant However some genotypes were not affected by thisrelationship Genetic variance for seed number per plant in E was greater than E plants The endophytic fungi changed direct and indirect effects of components on seedyield In E clones panicle fertility had more direct effects but number of panicle perplant and seed per panicle had indirect effects on seed yield while in E clones anopposite trend was seen

آقا فخر ميرلوحي

عبدالمجيد رضايي، بدر الدين ابراهيم سيد طباطبايي

رضا بلالي ، بهروز شيران ، احمد ارزاني، بهرام شريف نبي