STUDIES ON VARIETAL CHARACTERIZATION BASED ON MORPHOLOGICAL, BIOCHEMICAL AND MOLECULAR MARKERS IN CHILLI (Capsicum annuum L.)
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Date
2009-07-15
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University of Agricultural Sciences, Bangalore
Abstract
Varietal identification and use of specific markers for ensuring
genetically pure seed to reach the cultivar has been assuming critical
importance in seed industry and agricultural research and development.
In the present study 24 chilli cultivars were characterized based on
morphological, chemical, biochemical and molecular markers, which
serves as distinct identification marker and also intend to assess cultivar
diversity.
Among the 29 quantitative and 41 qualitative morphological traits
studied, hypocotyl colour, hypocotyl pubescence, stem colour, stem
length to first bifurcation, stem diameter, branching habit, tillering habit,
anther colour, fruit colour at intermediate and maturity stage, fruit
shape at pedicel and blossom end, neck at the base of the fruit, fruit
length, fruit width, pedicel length, dry fruit weight, 1000 seed weight and
seed size could be efficiently utilized for distinguishing the chilli
cultivars. Seasonal variations were observed for most of the quantitative
characters, while none of the qualitative characters were influenced by
the season. Significantly taller and wider plant, longer and wider leaves,
longer and broader fruits, heavier and larger seeds were noticed in Kharif
than in summer season. However, none of the traits individually could
distinguish all the 24 cultivars. Hence, keys based on a set of
morphological traits were developed, which was able to distinguish all
the cultivars.
The studied cultivars did not respond to phenol, modified phenol,
NaOH or KOH colour reaction but responded significantly for the
exogenous application of GA3, and Kinetin based on which the cultivars
could be grouped into different categories, while 2, 4-D at 10 ppm
concentration was found to be too toxic for the seeds to produce normal
seedlings.
Protein marker was able to identify all the twenty four cultivars
and can be employed effectively for identification of chilli cultivars, either
by presence or absence of bands or with intensity of bands. Malate
dehydrogenase isozyme marker gave very little polymorphism and was
found to be of little help for characterization studies in chilli cultivars.
RAPD markers were found to be an effective tool compared to
protein and morphological markers in differentiating the chilli cultivars.
Out of the twenty-decamer RAPD primers, ten primers produced
polymorphic bands for the studied cultivars. Primers viz., OPAC-07,
OPAC-02, OPAC-04, OPAC-5 and OPAC-11 were found to be most
efficient in generating polymorphic bands and distinguishing the
cultivars.
Finally the clusters developed using the morphological, protein and
molecular markers assisted in identifying the extent of variation between
closely related cultivars. The study has generated some important
morphological traits, protein marker and molecular markers that can be
effectively employed in distinguishing the chilli cultivars.
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