EFFECTS OF PROHEXADIONE-CA, UNICONAZOLE AND PACLOBUTRAZOL ON ORNAMENTAL KALE GROWTH AND PERFORMANCE UNDER HIGH TEMPERATURES

The effects of one foliar spray of prohexadione-Ca (0, 50, 100, 200, 400 and 600 mg a.i./L) or soil drench of uniconazole (0.5, 1, 2 and 4 mg a.i./pot) and paclobutrazol (2, 4 and 8 mg a.i./pot) were investigated on cabbage cvs. ‘Nagoya Red’ and ‘Nagoya White’. The plants were potted on 10 August in 12-cm pots, treated with growth regulators on 18 September and kept in greenhouse at 22-25 and 16-18°C during the day and overnight, respectively.
Advanced leaf colouring was the most important effect of prohexadione-Ca treatments, starting from 100 and 200 mg a.i./L, respectively, for ‘Nagoya White’ and ‘Nagoya Red’; 600 mg a.i./L shortened the growing period by as much as 27-20 days for the two cultivars.
An earlier colouring makes it possible to sell plants before outer leaf yellowing and, hence, with a larger diameter.
Optimal rates of prohexadione-Ca to control plant height resulted 200 mg a.i./L for the white cv. (-14.9%) and from 50 to 400 mg a.i.,/L for the red cv. (-29.2% on average). The paclobutrazol and uniconazole soil drench applications generally prolonged the vegetative period. Effective rates to reduce plant height proved to be 0.5 and 4.0 mg a.i./pot respectively.
Both prohexadione and paclobutrazol modified plant shape from open cup to cone.

VI International Symposium on Protected Cultivation in Mild Winter Climate: Product and Process Innovation

R. Bazzocchi, M.E. Giorgioni

Brassica oleracea var. acephala ´Nagoya´, ornamental cabbage, growing period, canopy architecture, plant quality.

https://doi.org/10.17660/ActaHortic.2003.614.74