Sexually-mature mungbean (Vigna radiata (L.) Wilczek) plants were efficiently regenerated from cotyledonary node explants. The explants were capable of directly developing multiple shoots on basal media devoid of any growth regulators. The shoot multiplication was influenced by media composition, growth regulators, age of donor seedling and explant type. The explants with both the cotyledons attached to the embryonic axis excised from 4-d-old seedlings, produced the highest number of shoots (5 or 6) in 100% of the cultures within 2 weeks on B5 basal medium (BBM) containing BAP or 2-iP, respectively, (at 5x10(-7)M) and 3% sucrose. Shoots elongated and developed better using BAP. Increasing micronutrients, carbohydrate and nitrogen levels in the medium above the original formulation of B5 basal medium appeared to be of no benefit for increasing the number of shoots. The shoots were rooted on basal MS medium or MS containing 10(-6) of NAA, IAA or IBA. This protocol was found applicable to six other cultivars of mungbean. One hundred rooted shoots were successfully established in soil in the glasshouse, where 90% of them survived. The regenerated plants flowered precociously, but produced normal pods and viable seeds.

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Conditions for plant regeneration from excised cotyledons of Vigna radiata were studied. Complete plant developed from the uncallused proximal ends of cotyledons on Murashige & Skoog's (MS), Gamborg's (Bs) and 'C' (MS salts + Bsvitamins) basal media. The basal medium 'C' was found to be best for plant regeneration. Regeneration frequency, however, varied with genotype, size, orientation and age of explant and the different plant growth regulators combination in the medium. Addition of cytokinins induced callusing at the proximal ends of cotyledons followed by multiple shoot formation. Out of 6-benzyl aminopurine (BAP), kinetin (KIN), N (A 2 isopentyl) adenine (2iP) and adenine sulphate (AS), only BAP and KIN were found to be more effective in enhancing the frequency of shoot regeneration. BAP at 1 x 10-SM induced maximum (60%) shoot regeneration whereas maximum number of shoots (8 to 9 shoots) per explant was observed with 5 x 10 6 M BAP. Cotyledons excised from two-day old seedlings were most regenerative. The regenerative response of cotyledons decreased when sliced into two equal parts either longitudinally or transversely. Callusing and organogenic differentiation occured only if the petiolar end of cotyledons was in contact with medium. None of the tested treatments were effective in inducing shoot bud differentiation from subcultured callus. Well developed shoots rooted when incubated on half strength MS, MS and MS basal medium supplemented with IAA (5 x 10-6M). The rooted plants were transferred to pots and later established in the field with 60% success.

A protocol for regeneration and micrografting of shoots of lentil (Lens culinaris Medik) was developed. Multiple shoots (4-5) were regenerated from cotyledonary node explants on Murashige and Skoog (MS) medium containing 8.8 mM 6-benzylaminopurine. In vitro regenerated shoots were micrografted on rootstocks with 96% efficiency. The successful grafts were transplanted to pots in Redi-earth TM , hardened off and were grown to maturity with 100% success. The success of the micrografting was independent of the nature and concentration of growth regulator used in shoot initiation medium and the time period for induction of shoots. The protocol was successful with several cultivars of lentil. The advantages of micrografting over in vitro rooting are discussed.

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Conditions for plant regeneration from excised shoot tips of Vigna radiata were studied. Complete plants were regenerated directly without an intervening callus phase from shoot tips on basal medium (MS salts + B 5 vitamins). Regeneration frequency varied with genotype, explant size and growth regulator combinations in the medium. Addition of cytokinins induced a variable amount of callus at the base of the shoot tip, followed by multiple shoot formation. Benzyladenine (BA), kinetin and zeatin at 5 x 10-6M each induced multiple shoots in 100% of the explants but the highest number of regenerants per explant (9) was produced with BA. The efficacy of BA for shoot multiplication was not improved when it was supplemented with naphthaleneacetic acid (NAA) or indoleacetic acid (IAA). NAA or adenine sulphate, when applied alone, induced complete plantlets. The growth regulator requirement of explants for the induction of multiple shoots varied with explant size. The shoot tip explants maintained proliferation ability on subculture. None of the treatments was effective in inducing shoot bud differentiation from callus. Regenerated shoots were rooted on MS basal medium and MS supplemented with either IAA or indolebutyric acid. The rooted plants were transferred to the field; 60% subsequently survived and grew.

A method for micropropagation of Dalbergia sissoo has been developed. Single node segments obtained from coppice shoots of a mature tree (20 -25 year old) produced 3 -4 shoots per explant on Murashige and Skoog (MS) medium containing 4.4 x 10 -6 M benzylaminopurine (BAP) and 4.4 x 10 -7 M of 13-naphthoxy acetic acid (NOA) (shoot multiplication medium) within 4 weeks. The in vitro regenerated shoots were 3 -4 cm in length and provided 2 to 3 culturable nodal segments which on shoot multiplication medium again produced 3 -4 shoots. Following this procedure 18 -24 shoots were produced from single nodal segment within 60 d. 80 % of the shoots directly produced five roots when they were firstly treated with MS medium supplemented with 10 -5 M indole-3-butyric acid (IBA) and subsequently transferred to half strength liquid MS medium containing 1% activated charcoal followed by half strength liquid MS free hormones, vitamins and activated charcoal. The in vitro raised plants were hardened for survival after transplantation to soil by exposing them to various humidity conditions, gradually from higher to low, with nearly I00 % transplant success.

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