ISHS Acta Horticulturae 635: XXVI International Horticultural Congress: Managing Soil-Borne Pathogens: A Sound Rhizosphere to Improve Productivity in Intensive Horticultural Systems
NITROGEN MANAGEMENT AND CULTIVAR EVALUATION FOR CONTROLLING PETIOLE SPOTTING AND BACTERIAL SOFT ROT OF CHINESE CABBAGE |
| Authors: | J. Warner, R. Cerkauskas, T. Zhang |
| Keywords: | Brassica campestris ssp. pekinensis, Erwinia carotovora, Nappa, gomasho, disease resistance |
| Abstract:
Field studies at the Greenhouse and Processing Crops Research Centre (GPCRC) were conducted over 3 years (1999 to 2001) to determine the effects of nitrogen (N) source and rate on petiole spotting (gomasho), bacterial soft rot (Erwinia carotovora ssp. carotovora) and yield of Chinese cabbage, one of the most extensively grown Asian vegetables in southern Ontario. Using ‘Kasumi’ as the test cultivar, three N fertilizer sources (ammonium nitrate, urea, and calcium nitrate), were evaluated at 60, 110, 160 and 210 kg N/ha in 1999 and at 100, 200 and 300 kg N/ha in 2000 and 2001 with a zero N rate each year, using a randomized complete block design. ‘Ohken 75’, a second test variety, was added as a subplot treatment in 2000. Assessments were made during 1999 and 2000 to determine the effect of storage on the incidence of petiole spotting. Results indicated that both source and rate of N fertilization affected the incidence of petiole spotting and bacterial soft rot, depending on year and cultivar. ‘Kasumi’ was very susceptible to both petiole spotting and soft rot while ‘Ohken 75’ was fairly resistant to the disorders. Petiole spotting severity increased during 4 weeks of storage at 2°C. In a separate experiment, 15 Nappatype cultivars arranged in a randomized complete block design were evaluated for petiole spotting, bacterial soft rot, head size and other horticultural characteristics. Cultivars with resistance to the disorders which are also suitable for commercial production in Ontario were identified. | |
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