PRELIMINARY STUDIES OF APOMIXIS IN PAPAYA (Carica papaya L.)
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Date
2020-11-06
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University of Agricultural Sciences, Bangalore
Abstract
Papaya is one of the most economically important fruit crop cultivated in tropical and subtropical regions. Apomixis is a naturally occurring mode of asexual reproduction in flowering plants that results in seed formation without the involvement of meiosis or fertilization of the egg. The present investigation deals with the development of a double haploid line from the process of gynogenesis in vitro in papaya. Unpollinted flower buds were bagged, harvested 30, 45 and 60 days after bagging and the ovules were cultured in vitro. The best response of 30 and 45 days explant was observed in media combination of NAA (0, 0.1, 0.2mg/L) with BAP (0, 0.5, 1.0, 1.5, 2.0 mg/L). The highest amount of callus (95 per cent) in treatment P15 was observed with 45 day explants. Fresh papaya pollens were collected and were exposed to different gamma irradiation doses (0, 25, 50, 75 and 100 Gys) followed by pollination and were allowed to develop into fruits. The ovules from 30 and 45 days harvested fruits were cultured in vitro. The results suggested that the induction of callus from parthenogenetic ovules was highest from 25, 50 and 75 Gys fruits of 30 days in treatment T14 when compared to 45 days. The ovules were least
responsive in the highest dose of 100Gy. The callus regenerated was yellow to whitish in colour and glossy or opaque in nature. The present studies will be a milestone for the development of double haploid lines of papaya in future.