GENETIC DIVERSITY, POPULATION STRUCTURE AND MARKER-TRAIT ASSOCIATION FOR ROOT TRAITS BY ASSOCIATION ANALYSIS IN CARROT (Daucus carota L.)
Loading...
Date
2017-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT
Abstract
A 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.
Description
Keywords
null