Murashige and Skoog's (MS) basal medium with benzylaminopurine (BA), kinetin (KN), zeatin (Z), and thidiazuron (TDZ) were tested for induction of multiple shoots from mature-tree-derived axillary meristems of Pongamia pinnata. Sprouting of buds was 64% on medium devoid of plant growth regulators (PGR). Incorporation of BA, KN, or Z was ineffective in enhancing sprouting frequency or induction of multiple shoots. Sprouting was completely suppressed in the presence of TDZ. Caulogenic buds appeared in nodal meristems of these explants after withdrawal of TDZ. The number of shoot buds was more on explants precultured in higher concentrations. At higher concentrations of this PGR, a swelling developed at the axil. Multiple shoot primordia appeared and differentiated from this swelling after culturing these explants on MS medium for six passages of 2 wk each. Shoots were harvested and cultured on 0.45 μM TDZ for further proliferation. Primary explants after harvesting of shoots were identified as 'stump'. Reculturing of stumps on 0.45 μM TDZ produced more shoots. This step was followed for six cycles to obtain additional shoots in each cycle. Shoots maintained on 0.45 μM TDZ elongated and rooted (70%) on growth regulator-free medium. Rooted shoots (65%) survived transfer to a sand/soil mixture. This report describes the protocol for micropropagation of P. pinnata using mature-tree-derived nodal meristems. Recycling of mature stock to produce a stream of useable shoots for subculturing and eventual stabilization is of great value and can possibly be generalized as an isolation protocol especially for woody species. Repeated proliferation of caulogenic buds from the same origin may also find application in rescue of endangered germplasm.

Role of Thidiazuron (TDZ) in inducing adventitious organogenesis in Pongamia was studied. TDZ at different concentrations (0, 0.45, 2.27, 4.54, 6.71, 9.08, 11.35, 13.12 and 22.71 lM) were used for induction of caulogenic bud formation in deembryonated cotyledon explants. Each cotyledon was cut into three segments and identified as proximal, middle and distal. Duration of TDZ exposure, influence of the segment and orientation of the explant were studied. TDZ at 11.35 lM concentration was optimum for the induction of shoots and rapid elongation. Shoots induced at higher concentration elongated after several passages in growth regulator free medium, thereby extending the period of differentiation. Exposure of the explant for 20 days yielded more number of buds than 10 days. Proximal segment of the cotyledon was more responsive. Contact of abaxial surface in the medium was more effective and generated more buds than the adaxial side. Buds differentiated and elongated on transfer to MS basal medium for 8-12 passages of 15 days each. Rooting and elongation of shoots was achieved in charcoal supplemented half-strength MS medium. Rooted plantlets survived on transfer to sand soil mixture. The plants were hardened and transferred to green house. This is the first report on in vitro regeneration of Pongamia pinnata via adventitious organogenesis using TDZ. This protocol may find application in studies in genetic transformation, isolation of somaclonal variants and in induction of mutants. It also provides a system to study the inhibitory role of TDZ on shoot differentiation.

Failure of peanut somatic embryos to convert into plantlets is attributed to the abnormal development of the plumule. Thidiazuron (TDZ) was effective in the conversion of peanut somatic embryos to plantlets by triggering morphogenetic activity in the abnormal plumules of the rooted somatic embryos. The present study aimed to induce normal embryo differentiation by culturing the embryogenic masses in embryo development medium containing 2,4-D and various concentrations of TDZ. Although this was not achieved due to restricted somatic embryo development in the presence of TDZ, bud-like projections appeared in the embryogenic masses when these were cultured in media containing combinations of 2,4-D and TDZ. These projections developed into buds, which subsequently formed shoots and plantlets. The response varied with the concentration and exposure of TDZ. At lower concentrations, the buds appeared in a defined row in the equatorial region of the explant, and with extended incubation, more and more buds appeared in rows alongside the initial row. Induction of multiple buds in a defined row in this specific site (equatorial region) suggested the presence of potent cells around this region. At higher concentrations, these projections appeared in large numbers spread over the whole upper part of the embryogenic mass starting from the equatorial region. The ability of embryogenic mass to convert into organogenic mass and to produce large number of organogenic buds provides an excellent system for basic studies and for the genetic transformation of peanut.

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Plant based pesticides are known as phytopesticides. Phytopesticide formulations offer a more eco-friendly approach to Insect Pest Management than chemical pesticides. The biological compounds present in these formulations have several biological activities against insect pests. In the present work, an attempt has been made to study the antifeedant activity of Gliricidia sepium leaf extracts using three solvents, i.e; petroleum ether, ethyl acetate and methanol against third instar larvae of Helicoverpa armigera. All extracts exhibited as significant antifeedant activity at LC 50 . Methanol extract deterred feeding potential of the insect larvae by 62.38% at 1000 ppm, followed by ethyl acetate (46.67%) and petroleum ether (40.37%). Hence this naturally occurring plant extracts could be useful for managing the Helicoverpa armigera population.