`Wisconsin 38' tobacco (Nicotiana tabacum L.) leaf discs were transformed with the disarmed Agrobacterium tumefaciens strain EHA101 carrying the rolC gene from A. rhizogenes (Oono et al., 1987) and NPT II and GUS genes. Shoots that regenerated on kanamycin-containing medium were confirmed as transgenic through GUS assays, polymerase chain reaction (PCR), Southern blot analyses, and transmission of the foreign genes through the sexual cycle. Transgenic plants were as short as half the height of control plants; were earlier flowering by up to 35 days; and had smaller leaves, shorter internodes, smaller seed capsules, fewer seeds, smaller flowers, and reduced pollen viability. The number of seed capsules, leaf number, and specific root length were similar between transgenic and control plants. Transgenic clones varied in the expression of the rolC-induced growth alterations as did the first generation of seedlings from these clones. Such differences suggested the potential for selecting for different levels of expression. Transformation with the rolC gene presents a potentially useful method of genetically modifying horticultural crops, particularly for flowering date, height, and leaf and flower size. Chemical names used: neomycin phosphotransferase (NPTII), β-glucuronidase (GUS).

Normal nodal segments ofPetunia hybrida were grown on Murashige and Skoog salts containing varied levels of Gelrite and sucrose. Higher concentrations of Gelrite decreased vitrification while increased sucrose concentrations promoted vitrification. Leaves of vitreous plants had higher levels of reducing sugars and sucrose but lower or undetectable levels of inositol as compared to normal plants. Normal plants on medium void of inositol have the ability to synthesize inositol and maintain levels equal to that found in plants from inositol containing media.

Dodder is a serious parasitic weed in the crops in which it is a problem (particularly citrus).Alternaria destruensis the active ingredient in a registered bioherbicide for control of dodder species. In greenhouse studies, the treatments applied to citrus parasitized with field dodder were a nontreated control; oil at 7.5% v/v in water; ammonium sulfate at 0.125% w/v in water; glyphosate at 0.02 kg ae/L;A.destruensat 1.8 × 1010spores/L;A.destruens(1.8 × 1010spores/L) + oil at 7.5% v/v in water; and a mixture ofA.destruens(1.8 × 1010spores/L) + oil at 7.5% v/v in water + glyphosate at 0.02 kg ae/L + ammonium sulfate 0.125% w/v (the mixture treatment). The highest disease or damage severity rating out of all treatments, measured as the area under the disease or damage progress curve (AUDPC), was obtained for the mixture treatment. By 35 d after treatment, all field dodder plants that received the mixture treatment were dead but the host plant, citrus, was not. These results indicate the feasibility of integrating glyphosate, ammonium sulfate, andA. destruensto manage dodder.

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