PART I RESEARCH NOTES Ancora, G. In vitro plant regeneration from leaf cultures of Lycopersicon esculentum Mill. (submitted by K. Sree Ramulu) The cultivar Vesuvio, often used in the crossing program involving the diploid and triploid clones of L. peruvianum (Ancora unpubl.), was used for the in vitro cultures of leaves to analyze the morphogenetic behavior of leaf tissue. The cotyledonary and fully expanded leaves, excised from three week old plants, were surface sterilized in 70% ethanol for 10 sec, immersed in sodium hypochlorite solution (4%) for 20 min, thoroughly rinsed in sterile water, cut into three or four pieces and cultured on the medium (termed here as GA) containing macro and micro elements of Murashige and Skoog (1962), vitamins is in B5 of Gamborg et al (1968), sucrose 3%, agar (Difco Bacto) 0.8%, benzyladenine 10-5 M and indole acetic acid 10-6 M. The pH of the medium was adjusted to 5.8 before adding agar. The cultures were maintained in a growth chamber under alternate light (16 h) and darkness (8 h) at 25°C. After one week, some of the leaf explants showed cell proliferation in the subepidermal layers. Afterwards, very compact calli were produced, and shoots appeared on their surfaces. After transferring these calli with shoots to the same medium (GA) freshly prepared, many plantlets with roots developed. Until now, ten plants were available at adult stage for cytological analysis. Among these plants, six were diploid and four tetraploid. References Gamborg, O. L., R. A. Miller and K. Ojima. 1968. Cell Res. 50:151-158. Ancora, G. In vitro plant regeneration from stem internode  cultures of hybrid, Lycopersicon esculentum Mill. X L. peruvianum Mill. (submitted by K. Sree  Ramulu) The self-incompatible diploid hybrid of L. esculentum cv. San Marzano Baldoni X L. peruvianum (S1S4), previously described by de Nettancourt et al. (1974), was used for invitro cultures of stem internodes to analyze the morphogenetic behavior and to produce tetraploids, which can be used for analyses on the compatibility behavior and on the relationship between the genetic elements governing self-incompatibility and unilateral interspecific incompatibility. The stem segments taken from below the floral branches of plants grown in the greenhouse were surface sterilized in 70% ethanol and subsequently immersed in sodium hypochlorite solution (4%) for 20 min. The explants of approximately 1 cm in length were cut from stem internodes and cultured with intact epidermis on the medium, gand 1 + coconut milk + kinetin (for details on the composition see Sree Ramulu et al. 1976). The pH of the medium was adjusted to 5.8 before adding agar. The cultures were maintained under alternate light (16 h) and darkness (8 h) at 25°C. Under these cultural conditions, there was callus formation and shoot regeneration. When these calli with small shoots were transferred to the GA medium used for L. esculentum (see preceding note), plantlets with roots developed. Both diploid and tetraploids were regenerated. The results on the tissue cultures of L. esculentum and of the hybrid show that the degree and extent of polyploidy in vitro tend to increase with the increasing age of the cultures or under particular hormonal regimes, e.g. quantitative ratios of cytokinin and auxin, as has been found for L. peruvianum (Sree Ramulu et al. 1976; Devreux et al. 1976; Ancora et al. 1977).

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