A synthetic Bacillus thuringiensis (Bt) cry1C gene under the control of the 35S CaMV promoter was introduced into cauliflower (Brassica oleracea var. botrytis) by Agrobacterium tumefaciens- mediated transformation with hygromycin selection. A total of 35 transgenic plants were regenerated from six cultivars (Freemont, Candid Charm, Snow Crown, Cumberland, Majestic, and Cashmere) with average transformation efficiency of 0.3% to 6.4%. All the hygromycin-resistant transformants also carried the Bt gene, as shown by PCR with primers specific to the cry1C gene. ELISA analysis showed that the levels of Cry1C protein in independent transformants varied widely, from 0 to 0.2% of total soluble protein. The majority of the plants (61%) produced a high level of Cry1C protein (> 1000 ng mg_1 proteins). Insect bioassays demonstrated that plants producing Cry1C protein effectively controlled larvae of diamondback moths (Plutella xylostella), including ones resistant to Cry1A protein, as well as larvae of cabbage loopers (Trichoplusia ni). These cry1C cauliflower plants will be useful for further studies, especially in comparisons with cauliflower plants carrying the same cry1c gene under control of a light-inducible promoter.

Selection of Stagonospora nodorum (syn. Septoria nodorum) isolates with decreased sensitivity to propiconazole was attempted using foliar applications of propiconazole to experimental wheat plots inoculated with S. nodorum isolates in 1989 and 1990. The isolates evaluated represented the range of variation in sensitivity to propiconazole present in S. nodorum populations in commercial wheat fields in New York State during 1985-1989. Changes in the sensitivity of S. nodorum to propiconazole in inoculated field plots were determined by testing isolates collected before and after the application of propiconazole using trap plants (1989) or by direct sampling of infected leaves (1990). Significant differences in propiconazole-sensitivity phenotype were observed in 1989 but not in 1990 between plots treated with the commercial rate of propiconazole and plots receiving no propiconazole treatment. Applications of double the commercial rate of propiconazole in 1990 failed to select for isolates with decreased sensitivity to propiconazole. The selection of S. nodorum isolates with decreased sensitivity to propiconazole in 1989, but not in 1990, may have resulted from the manner in which the plots were sampled in each year. Very small changes in mean propiconazole sensitivity phenotype were detected in response to propiconazole treatment in both experiments. This was likely a result of limited variability in propiconazole-sensitivity phenotypes of the evaluated isolates or an insufficient number of reproductive generations occurring during these experiments.

We report the successful production of large numbers of fecund spontaneous and induced doubled haploid (DH) onion lines from pungent and mild materials developed in our long day onion breeding program. Culture of 3–5mm unopened flower buds on modified BDS medium was the most efficient and convenient method for recovery of gynogenic plants. Over 1100 gynogenic plants were produced from approximately 47,000 flowers cultured between 1999 and 2001. All groups of donors tested were responsive although the level of gynogenic response varied significantly among them. About 15% of the gynogenic plants recovered were spontaneous diploids. Most others (82%) were haploids, requiring induced chromosome doubling. High survival and doubling frequencies were achieved by colchicine treatment (200–400mg/l colchicine in liquid medium for 48h) of whole basal explants from 2- to 4-month-old in vitro haploid plants. Some shifts in ploidy classes were seen after bulbs were vernalized and re-sprouted. Viable selfed seeds were recovered from many diploid as well as mixoploid and tetraploid gynogenic plants. The number of seeds per plant varied from 2 to over 600. Progeny from two induced and five spontaneous diploid lines that were grown for observation showed uniform growth, similar to highly inbred lines. Bulbs of these plants showed excellent uniformity in shape and color with little variation in bulb size, indicating their DH origin. Advantages and difficulties of application of DH techniques in onion breeding are discussed.

Allium roylei is a non-bulbing wild relative of common onion (Allium cepa) with several desirable traits, including resistance to Botrytis leaf blight (BLB) and downy mildew. We obtained gynogenic plants by culturing flower buds from two A. cepa lines and several generations of plants derived from crosses of A. cepa and A. roylei. The donor plants used showed substantial differences in response to induction of gynogenesis. We obtained 59 plantlets from responsive A. roylei-derived plants. Backcross generations of A. roylei-derived plants (BC1F1 and BC1F2) provided the majority of the gynogenic plantlets; plants from earlier generations (F1 and F2), showed either very low or no gynogenic response. About half of the gynogenic plantlets continued to grow into plants. Flow cytometry revealed that most gynogenic A. cepa plants (86%) were haploids, while 9% were spontaneous diploids. In contrast, 77% of the gynogenic plants from A. roylei-derived plants were spontaneous diploids. Two gynogenic plants obtained from a BC1F1 and one from a BC1F2 plant produced small or medium size bulbs that dried down like A. cepa material; the remaining gynogenic plants produced non-dormant bulb-like structures. The possible contributions of doubled haploid A. roylei-derived plants to onion breeding are discussed.