Browsing by Author "Sharma, Kuldeep"

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Identification of sex in Simmondsia chinensis (Jojoba) using RAPD markers
(Springer, 2007) Agrawal, Veena; Sharma, Kuldeep; Gupta, Sarika; Kumar, Ravindra; Prasad, Manoj
Simmondsia chinensis (Link) Schneider, a multipurpose dioecious shrub of arid zones, has emerged as a cash crop. It is being cultivated for its seeds which store liquid wax whose properties are similar to spermaceti (Sperm whale oil), a substitute for petro products and precious high-priced lubricants. Jojoba is a slow-growing desert shrub having a male biased (5:1; male:female ratio) population. Since there is no method available to determine the sex at the seedling stage, current investigations have been carried out to generate a sex-specific random amplified polymorphic DNA (RAPD) marker in jojoba which is based on the PCR amplification of random locations in the genome of plant. Of the 72 primers tested, only one random decamer primer, OPG-5, produced a unique *1,400 base pairs fragment in male DNA. To validate this observation, this primer was re-tested with the individuals of male and female samples of four cultivars. The unique *1,400 bp fragment was present in male individuals of all the four cultivars and completely absent in respective female individuals tested. To the best of our knowledge, this is the first report to ascertain the sex of jojoba plants at an early stage of development of the taxon.
ISSR marker assisted selection of male and female plants in a promising dioecious crop-Jojoba (Simmondsia chinensis)
(Springer, 2008) Sharma, Kuldeep; Agrawal, Veena; Gupta, Sarika; Kumar, Ravindra; Prasad, Manoj
Simmondsia chinensis (Link) Schneider, a multipurpose and monogeneric dioecious shrub from arid zones, has emerged as a cash crop all over the globe. Its seed propagation poses severe problems due to its male-biased population: the male:female ratio is 5:1. Investigations have been carried out to generate a sex-specific Inter-simple sequence repeat (ISSR) marker for the early detection of male and female plants. Of the 42 primers analysed with a bulk sample of pooled male DNA and a bulk sample of pooled female DNA, only one primer, UBC-807, produced a unique ~1,200 base-pair fragment in the male DNA. To validate this observation, this primer was re-tested with individual male and female samples from eight cultivars. A similar unique ~1,200 bp fragment was present in the male individuals of all eight cultivars and completely absent in the female individuals tested. This is the first report of the use of ISSR markers to ascertain sex in physiologically mature S. chinensis plants.
Review on different mechanisms of sex determination and sex-linked molecular markers in dioecious crops: a current update
(Springer, 2015) Heikrujam, Monika; Sharma, Kuldeep; Prasad, Manoj; Agrawal, Veena
Flowering plants are known to exhibit vast diversity of sexual systems encompassing bisexual, monoecious and dioecious conditions. Dioecy offers opportunities to explore separately the male and female programmes giving an insight to the evolutionary, developmental and molecular processes leading to separate mechanisms for sex expression. Mechanisms controlling sex can either be genetic or epigenetic (physiological and environmental). Plant hormones too influence sex expression. An active Y sex determination system and an X to autosomes ratio systems are common amongst the flowering plants. Advances in our understanding of sex determination has been addressed both by conventional as well as molecular approaches. Using conventional techniques mainly cytogenetics, sex chromosomes in some dioecious plants have been identified and characterized. Surprisingly, the presence of well defined sex chromosomes was found in only few species. Some sex linked genes have also been identified and characterized using molecular approaches but none of these genes have a direct link to sex determination. Molecular markers have been employed to resolve the enigma associated with dioecism to a certain extent. Its application in plant breeding is immensely beneficial. Positively, it would be beneficial for validation of sex prior their sex expression at larger perspectives. The present review therefore emphasizes the mode of sex determination among dioecious plants vis-a-vis summarizes the works related to gender specific markers generated using male and female plants from agriculturally important dioecious crops.