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J.E. Barrett, J.C. Bradley, C.A. Bartuska, T.A. Nell, and D.C. Clark

More than 60 new poinsettia cultivars have been introduced in the past 3 years, and many of these have nontraditional bract color or plant form. About 75% of all poinsettias sold are red and `Freedom' represents more than 50% of the red poinsettia market in the United States In Fall 1999, 212 individuals were surveyed and asked to indicate their favorite 10 cultivars out of the 89 in a cultivar trial. The top choices were `Plum Pudding', `Winter Rose Dark Red', `Cranberry Punch', and `Monet Twilight', which were selected by 48%; 38%; 32%, and 31% of the participants, respectively. These cultivars are all nontraditional in appearance. The top red cultivars were `Freedom', `Orion', and `Red Velvet', which were selected by 27%, 26%, and 23%, respectively. The participants were then asked to rate on a 1 to 10 (most favorable) scale 15 plants that represented different poinsettia forms and colors. Five of these plants were cultivars with different shades of red that the industry easily separates. However, the participants' ratings of these were not significantly different, which indicates the shade of red in bract color may be more important to the industry than it is to the public. These results also indicate that there are strong differences in individual preferences for poinsettias. Each of the 15 plants received both high and low ratings. Also, of the participants that included `Freedom Red' in their top 10 selection, only 13% of those selected `Plum Pudding', which has purple bracts, and only 11% selected `Winter Rose Dark Red', which has a nontraditional plant form.

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C.E. Wieland, J.E. Barrett, C.A. Bartuska, D.G. Clark, and T.A. Nell

Salvia (Salvia splendens F.), vinca (Catharanthus roseus L.), and pansy (Viola × wittrockiana Gams.) were examined to determine efficacy of growth retardants for inhibiting stem elongation of seedlings in the plug stage and after transplanting to 10-cm pots. Studies on salvia showed plugs sprayed with single applications of ancymidol at 10 or 20 ppm, paclobutrazol at 30 or 60 ppm, or daminozide/chlormequat tank mix at 2500/1500 ppm inhibited plug elongation by 17% to 22%. Pansy plugs were sprayed either once or twice with ancymidol at 5, 10, or 15 ppm. Number of applications was statistically significant with two applications reducing elongation by an average of 35%, whereas a single application resulted in a 23% average reduction. Ancymidol concentration was significant in reducing stem elongation with increasing rates in pansy; however, the concentration and application time interaction was not significant. In both pansy and salvia, plant size at flowering was similar to controls after transplanting. Vinca plugs were sprayed with ancymidol at 5, 10, or 15 ppm either the 3rd week, 4th week, or both weeks after sowing. As ancymidol concentrations increased, plug height decreased, and the concentration effect was greater week 3 than at week 4. Two applications of ancymidol was most effective in retarding stem elongation (36%) followed by one spray the 3rd week (29%) and one spray during week 4 (20%).

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J.E. Barrett, R.K. Schoellhorn, C.A. Bartuska, D.G. Clark, and T.A. Nell

Uniconazole was applied as a spray to the surface of container media prior to planting bedding plant plugs. This medium spray was compared to a standard whole-plant spray applied 2 weeks after planting. For petunia (Petunia ×hybrida Vilm.) and coleus (Solenostemon scutellarioides L.) the efficacy of the medium spray was similar to the whole-plant spray. However, for impatiens (Impatiens wallerana Hook. f.) and vinca [Catharanthus roseus (L.) G. Don.] the medium spray had greater efficacy than the whole-plant spray. Increased concentrations of uniconazole in the medium spray decreased plant height; however, the effect of higher concentrations was greater in a medium with out pine bark compared to a medium with pine bark as a component. In the above experiments, uniconazole was applied in a volume of 200 mL·m-2. In a test where spray volume varied, there was a negative linear relationship between plant height and spray volume. Chemical name used: (E)-(+)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ane-3-ol (uniconazole).