STUDIES ON GENETIC DIVERSITY OF WHITEFLY, Bemisia tabaci (Genn.) (HEMIPTERA: ALEYRODIDAE) AND MOLECULAR ANALYSIS FOR ITS RESISTANT TRAITS IN TOMATO
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Date
2019-08
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University of Horticultural Sciences, Bagalkot
Abstract
The present study was conducted at College of Horticulture, Bagalkote and
Bengaluru, University of Horticultural Sciences, Bagalkote during 2016-17 to 2019.
The morphometric analysis for different characters of adult male, female and puparia
revealed the existence of unique population from Chikkaballapura district and has
recorded significantly higher values for majority of the characters studied which was
evident in cluster analysis. The genetic diversity and population structure of B. tabaci
recorded significant genetic diversity among eleven populations of B. tabaci. The
Analyses of Molecular Variance (AMOVA) across all the populations exhibited 49.79
per cent variation among the populations and 50.21 per cent within population with a
mean fixation index of 0.498. The clustering analysis from both morphometrics and
molecular analysis revealed almost similar type of results. The population genetic
structure analyses of B. tabaci populations indicated the presence of fourteen genetic
clusters (K=14) which spread across all the sampled populations from eleven districts
of Karnataka, forming genetically mixed populations. Among the population studied,
30.90 per cent of the individuals were detected with monopartite virus particles, 1.82
per cent with bipartite and 10.36 per cent of the individuals detected with both mono
and bipartite virus particles which were amplified at 270 bp and 477 bp regions,
respectively.
Field evaluation of 260 tomato minicore accessions was done during rabi and
summer seasons of 2016-17. The trichome density and trichome type played an
important role in whitefly resistance on tomato combined with phenol and terpinoid
content which were exhibited significant and negative correlation with whitefly
population at 45 DAT. The molecular analysis of 260 tomato minicore accessions
indicated the presence of significant genetic diversity among five clusters population.
Population genetic structure analyses of tomato accessions indicated the presence of
seven genetic clusters (K=7) which spread across all the populations, forming high
level of genetically mixed population. Association analysis between biochemical,
biophysical traits and SSR markers revealed that, phenols were associated with three
markers, tannins with nine markers, two markers with terpinoid, chlorophyll with
seven markers and trichomes were associated with three markers.