Study of reproductive biology and in vitro propagaton techniqes in kumizhu (gmelina arborea roxb)

Abstract

The present study ‘Study of reproductive biology and in vitro propagation techniques in kumizhu’ was undertaken in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara during 2004-2006. The study comprised of two major experiments namely (i) Studies on reproductive biology and (ii) Studies on micro propagation

The trees started blooming in January when new flushes sprouted out and continued upto the end of March. Inflorescence is a terminal cyme blooming in an irregular manner. The flowers are short stalked, pubescent, large, bisexual and scented. Calyx persistent, tubate and five lobed at tip. Corolla brownish yellow and has a short tube with the upper tip formed by two lateral petals. Stamens four, epipetalous. Anthers dithecous and dehisce longitudinally. Ovary bicarpellary, style long. Stigma short with two unequal lobes. Anthesis from late mid night to 3.00 am. Stigma receptive during anthesis and the receptivity lasts for 4-5 hours. Fruit set was absent under artificial selfing while under natural cross pollination upto 16.5 per cent fruit set was recorded. Fruit drupe with one strong seed. Seeds oval shaped, tapering to one end.

MS medium was best medium suited for callus induction and bud expansion. Nodal segments were the explants for direct organogenesis and for indirect organogenesis. Surface sterilization was done by soaking explants in 70 per cent alcohol for 30 seconds, followed by soaking in HgCl2 0.1 for 4 minutes. MS+BA 5 mg/l+NAA 0.5 mg/l produced leaf bud expansion. Pronounced callus formation was observed when explants were inoculated on medium containing 2, 4-D at various levels (0.5 mg/l to 2 mg/l). BA upto 3 mg/l and kinetin upto 1 mg/l induced callusing. WPM was found to be more suited for callus proliferation as the time for response was almost half of that of MS medium. WPM supplemented with adenine recorded maximum callus proliferation.