Studies on genetic uniformity of Chowghat Green Dwarf and Malayan Green Dwarf varieties of coconut using molecular and morphometric methods
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Date
2015-08
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Abstract
Two coconut varieties viz., Chowghat Green Dwarf (CGD) and Malayan Green Dwarf (MGD) were subjected to morphometric
and molecular studies to assess their genetic uniformity. Since both these varieties possess traits for high yield and resistance to
root (wilt) disease, they have already been released for cultivation in the root (wilt) disease prevalent tracts. Forty two CGD palms
from ‘disease hotspots’ were analyzed using 43 simple sequence repeat (SSR) primers. Monomorphic bands were detected in all
the CGD samples with 41 primers, which is an indication of its genetic uniformity. A single CGD palm showed polymorphism
with two SSR primers. Forty eight MGD palms were analyzed using 24 SSR primers. The MGD palms clustered at 62 per cent
similarity. Analysis of morphological and fruit component characters of CGD and MGD population revealed that both the populations
were phenotypically uniform. Breeding behaviour studies revealed that both CGD and MGD were predominantly self pollinated,
like other dwarf varieties of coconut. There was complete overlapping of male and female phases in almost 96 per cent of CGD
palms. Almost 100 per cent self-pollination was ensured in these palms as male phase prolonged even after completion of female
phase. However, only 60 per cent of the MGD palms showed complete overlapping and in the remaining 40 per cent palms, there
was only partial overlapping of male and female phases. From the present study, it is inferred that breeding behavior and genetic
uniformity could be highly correlated in coconut. Collection of seed nuts preferably from mother palms with overlapping of male
and female phases could possibly ensure production of true to type progenies in dwarf varieties of coconut. Present study also
indicated that molecular markers like SSRs may be used to identify genetically pure mother palms for varietal improvement
programmes in coconut.
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Keywords
Coconut, CGD, MGD, microsatellites, morphometric studies
Citation
Journal of Plantation Crops,August 2015,Vol.43. No.2,p.89-96