Lycopersicon cheesmanii f. minor selections could be useful for introducing high soluble-solid genes into the cultivated tomato (1). Because of interest in high-solids tomatoes, seeds of several L. cheesmanii accessions (LA 483, 526, 747, 929, 1403, 1411, 1508 and 1627) were obtained from Dr. C. M. Rick (Department of Vegetable Crops, University of California, Davis).
Seeds were soaked for 1 hr in 2.63% NaOC1, rinsed for 15 min in 2 changes of autoclaved deionized water, cultured individually in 20 mm test tubes containing 4 ml Murashige-Skoog (2) medium (0.6% Bacto agar), and placed in 18 hr light (18 Em^-2^s^-1^ visible (1500 lux)] at a constant 26 deg.C. After 1 wk, ungerminated seeds rescued by removing the seed coat with a scalpel while viewing through a dissecting microscope. Once germinated, seedlings were placed in higher light [66 Em^-2^s^-1^ (5500 lux)], and after 2 wks, those having 2 true leaf pair were cut into nodal sections and transferred to vessels (Magenta Corp) containing 20 ml of the same medium supplemented wtih 4.0 M benzyladenine. Shoots were subcultured to fresh medium triweekly and those 15 mm or longer were rooted in vivo using Techniculture peat plugs (Castle & Cooke Techniculture, Salinas, CA) in a humidity chamber. An aqueous solution of 1/4 tsp/gal Captan, Benlate, and 20-20-20 fertilizer was used to wet trays. After 10 days, clones were transplanted into pots and greenhouse acclimated in 3 days.
Approximately 50% of the seeds germinated within 4 days after one treatment. An even higher percent germinate if the seed coat is removed. Thus, only one treatment may be needed if seeds are left in the bleach solution until the seed coats slough. All cultures except LA 1508 proliferated rapidly (5 X in 3 wks). Cultures of LA 1508 callused more than the other accessions, but still multiplied at a useful level. All plants transferred to the greenhouse flowered normally.
An unexpected event was the formation of adventitious shoots from leaves which came in contact with the medium. This also occurred when individual leaves were cultured, and differences existed in the frequency of shoot production between accessions. The highest frequency occurred in LA 526 and 747 whereas none occurred in LA 1508.
Literature cited:
1. Garvey, T.C. and J. Hewitt. 1984. A survey of Lycopersicon cheesmanii for high soluble solids. Tomato Genetics Coop 34:4-5.
2. Murashige, T. and F. Skoog. 1962. A revised medium for rapid growth and bioassays with tobacco cultures. Physiol. Plantarum 15:473-479.