Indian Society of Genetics & Plant Breeding

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Identification of a RAPD marker linked to sex determination in Momordica dioica Roxb.

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Sexual dimorphism is the rule in most animals. In plant
kingdom however, dioecy is found only in 4% of the
angiosperms. Dioecism has originated independently
in different families and genera [1] and several distinct
genetic mechanisms regulating dioecy have been found
in different plant species [2, 3]. Sex is the queen problem
in evolutionary biology and tracing of molecular factor(s)
for sex expression has potential importance in basic
and applied research. Sex determination mechanism
in plants is not well understood. Neither the genetic nor
the physiological basis of gender has been completely
resolved in any plant species, in spite of the striking
progress made over the floral development [4]. The
presence of sex chromosomes has been documented
in some plants [1]. More often, the sex ratio in dioecious
plant species is controlled by the expression of alleles
at one to several loci [2]. Genetic marker system based
on direct analysis of the genomic DNA have been used
widely for genetic mapping, disease diagnostics and
evolutionary studies and they could prove very useful
in the study of sexual determination in dioecious plants
such as pistachio [5], hemp [6] and basket willow [7].
There are three major sex strategies in angiosperms
such as bisexual, monoecious and dioecious forms.
Cucurbitaceae family exhibits similar sex spectrum.
Momordica dioica, commonly known as spine gourd, a
perennial cucurbitaceous rhizomatous distinctly
dioecious climber found in the forests of southern India
and Bengal. Tender fruits and tuberous roots are used
as vegetable and ayurvedic medicine. Medicinal
properties of this plant are sex specific and each sex
has its own medicinal value [8]. Karyomorphological
studies [9] reveal that male and female M. dioica exhibit
no morphological markers and possess homomorphic
chromosomes which enable sex screening. The sex
ratio in natural distribution is 3:1 (Male:Female). In the
present study, M. dioica plant was investigated for the
molecular basis of genotypic differentiation between
male and female plants using randomly amplified
polymorphic DNA (RAPD) technique. Identification of
sex through RAPD markers have been reported in Salix
viminalis [10], Carica papaya and Cycas circinalis [11].
A method to determine the gender of the plant before
flowering would facilitate breeding and selection by
enabling screening for gender at the seedling stage
simplifying the breeding of male and female plants for
different objectives, thereby saving time and economic
resources.
 

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Year: 2009
Volume: 69
Issue: 3
Article DOI: N/A
Print ISSN: 0019-5200
Online ISSN: 0975-6906

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