CHOLIN, SARVAMANGALAKULKARNI, CHAITRA. CG, RAGHAVENDRAD. S, AMBIKAPATIL, BAPURAUAGOUDACHITTAPUR, REKHA2018-11-232018-11-232017-06UHS15PGM583http://krishikosh.egranth.ac.in/handle/1/5810084283A Research work was conducted at University of horticultural Sciences, Bagalkot during 2016-17 for 96 diverse genotypes of carrot in order to study diversity, population structure and the marker-trait association for the economic root traits. An Augmented block design comprising of 3 checks (Ghataprabha Local, Vigro Kuruda and Pusa Vrishti) having 6 blocks was utilized to screen these 96 genotypes comprising of European and Asiatic types with diverse colors. 33 root morphological traits (18 quantitative and 15 qualitative) and 42 various molecular markers (SCAR, Indels, ESTSSRs and G-SSRs) were studied. Significant variation for all quantitative traits was observed based on ANOVA and variability estimates (GCV and PCV) indicated sufficient variability in the population. Higher heritability for harvest index, number of petioles, petiole length, vegetative weight, root length and root diameter indicated their effective phenotypic selection in breeding. Distinct classes were present for all 15 qualitative traits from frequency distribution. PCA exhibited six principal components explaining 77.71 % of the total variation for all 18 quantiative characters. D2 study classified genotypes into twelve major clusters wherein, I-Cluster contained 85 genotypes and remaining were solitary clusters. Diversity contribution of the root weight was maximum indicating the scope for selection of diverse parents for this trait. Correlation analysis indicated positive correlation of root weight with almost all the plant morphological characters. Genotyping of 42 polymorphic markers for 96 genotypes revealed 471 alleles with PIC value ranging from 0.0782(Y-Indel) to 0.928 (ESSR59) with average of 2 to 28 alleles per locus. Unrooted Neigbour joining tree from DARWIN showed three diverse groups but a single genotype in 3rd cluster. STRCTURE analysis also revealed 2 populations. Greater genetic variation was observed within the individuals (71%) than among the populations (13%) as shown by AMOVA indicating the possible gene flow among the genotypes of the populations. Marker-trait analysis by TASSEL identified significant markers for 13 phenotypic traits with the R2 value ranged from 0.31 (root colour-GSSR153) to 0.81 (root length-GSSR91) with the P value of <0.0001. Present study identified 15 superior genotypes suitable to tropical conditions and the markers identified would be further confirmed and validated for their exploration in carrot crop improvement.en-USnullThesis