Pyracantha coccinea `Kasan' and `Lalandei' Response to Uniconazole and Chlormequat Chloride

Abstract

Pyracantha coccinea M.J. Roem. `Kasan' and `Lalandei' were treated with a soil drench of 30 mg a.i. chlormequat chloride per container or 0, 0.25, 0.50, or 1.00 mg a.i. uniconazole per container or with a foliar application of 3000 mg a.i. chlormequat chloride/liter or 0, 25, 50, or 100 mg a.i. uniconazole/liter. Chlormequat chloride applied as a drench did not affect growth of `Kasan' or `Lalandei' until 17 weeks after application, when `Kasan' was taller and `Lalandei' shorter than untreated plants. `Kasan' plants drenched with chlormequat chloride had more leaves with greater total leaf area and higher leaf and stem dry weights than untreated plants. However, area per leaf, root dry weight, and root: shoot ratio were not affected by the chlormequat chloride drench. In `Lalandei', the chlormequat chloride drench did not affect any of these criteria, except stem dry weight. Foliar applications of chlormequat chloride had little effect on either cultivar. Height of `Kasan' and `Lalandei' decreased with increasing uniconazole rates for both application methods. Area per leaf increased in `Kasan' but decreased in `Lalandei' receiving a drench applied to the medium. Foliar and drench applications of uniconazole both resulted in decreased stem dry weight of both cultivars. Chemical names used: 2-chloro-N,N,N-trimethylethanaminium chloride (chlormequat chloride); (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole).