Two separate field experiments were conducted to determine the influence of Ca sprays and N fertilizer rate on leaf tipburn incidence in `Snow Crown', `Self Blanche', and `Imperial 10-6' cauliflower. Incidence of leaf tipburn was highest in `Snow Crown' each year and varied with year in `Self Blanche' and `Imperial 10-6'. Delaying planting of `Snow Crown' by 3 weeks decreased tipburn incidence by 20% and decreased the number of tipburned leaves per tipburned plant by 60%. Sprays of CaCl2 or calcium chelate had no effect on cauliflower productivity, nutrition, or tipburn incidence. Increasing N fertilizer rate from 67 kg N/ha to 201 kg N/ha linearly increased yield without significantly affecting tipburn incidence. Concentrations of Ca in tips of nontipburned leaves were two to five times greater than those in tips of tipburned leaves of comparable physiological age. Basal leaf regions had similar Ca concentrations, regardless of tipburn status. Use of resistant cultivars appears to be the best method of reducing tipburn incidence in cauliflower.
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