Multivariate repeated measures analysis of plant growth regulators on Tradescantia virginiana

Little information is available on cultural requirements for greenhouse production of Tradescantia virginiana L. We tested three plant growth regulators (PGRs) at ascending rates on T. virginiana 'Angel Eyes,' 'Blue Stone,' and 'Red Cloud' in an effort to find appropriate application levels for height suppression. Treatments applied two weeks after transplant. Each PGR was applied once at the following rates: paclobutrazol at 0, 40, 80, 120, or 160 mg·L^-1, uniconazole at 0, 15, 30, 45, or 60 mg·L ^-1, or flurprimidol at 0, 15, 30, 45, 60, or 75 mg·L ^-1. Repeated measures experimental design and multivariate analysis was used to examine plant responses to PGRs over time. The most effective paclobutrazol rate for adequate height suppression was 120 mg·L ^-1. Uniconazole at 30 to 45 mg·L^-1 and flurprimidol at 45 to 60 mg·L^-1 resulted in adequate height control. 'Blue Stone' and 'Red Cloud' appeared more responsive (greater suppression of height at rates applied) to both uniconazole and flurprimidol than 'Angel Eyes.' These results suggest that cultivars respond in a different manner to PGRs applied to them; more compact growth can be obtained for cultivars tested using these suggested rates. Chemical names used: trifuloromethoxy phenyl-5- pyrimidinemethanol (flurprimidol); [(±)-(R*,R*)-β-((4- chlorophenyl) methyl)-?-(1,1,-dimethylethyl)-1H-1,2,4,-triazole-1-ethanol)] (paclobutrazol); uniconazole.