Kaur, RajinderSharma, Neha2017-06-032017-06-032013http://krishikosh.egranth.ac.in/handle/1/5810017093The present investigation on Stevia rebaudiana was carried out with the objective to construct frame work genetic linkage map of stevia by employing multiple marker systems. Before starting the work on linkage map construction, genetic diversity was analyzed amongst the available genotypes/ clones/ accessions/ morphotypes of Stevia rebaudiana to confirm two parents with differences in rebaudioside-A and stevioside content. This study represents the first genetic linkage study of Stevia rebaudiana comprising of multiple marker systems together. Among the collected 16 accessions polymorphism was studied using 27 RAPD, 26 ISSR and 50 EST-SSR. Results were analyzed in the form of dendrograms, similarity, disimmilarity matrices and polymorphism information content. For linkage map construction, F2 population was used as a mapping population. To survey the polymorphism among contrasting parents 170 RAPD, 26 ISSR and 89 EST SSR were employed and it was observed that 36 RAPD, 10 ISSR and 33 EST – SSR primers were found to be polymorphic. These primers were then used for the genotyping of the mapping population. Phenotyping was carried out by using High Performance Liquid Chromatography (HPLC) of parents as well as segregating population. Both genotypic and phenotypic data were used to construct a linkage map using MAPMAKER/EXP ver 3.0b. A total of four linkage groups were constructed spanning a distance of 927.3 cM with an average distance between loci as 16.29 cM. First linkage group (LG1) comprised of 33 markers, second linkage group (LG2) contained 6 markers and third (LG3) and fourth group (LG4) had 16 and two markers, respectively. On QTL identification, a total of 53 QTL locations were found for both trait 1 (rebaudioside-A) and trait 2 (stevioside). Among 53 QTL locations of trait 1, two major QTLs were found for rebaudioside-A viz., in the marker interval of L67- L71 (ISSR HB-11) - (IISRS-3-L) in LG1 and in the marker interval L38 - L40 (Sigma-5383-027)- (Sigma-5383-029) in LG3 at LOD of 2.5 and 2.7, respectively.engenetics, rapd, stevia, polymorphism, stevia rebaudiana, chromosome mapping, planting, dna, replication, harvestingThesis