Lupinus havardii Wats. is a promising new specialty cut flower crop, but data on its greenhouse culture and management are limited. Two experiments investigated senescence-delaying activity of preharvest Ca fertilization and postharvest preconditioning with 1-MCP on L. havardii `Texas Sapphire' cut flower stems (racemes). In the first study, Ca (as CaCl2) was added to the nutrient culture solution at concentrations of 0, 2.5, 5.0, and 10.0 mm for 88 days in a greenhouse. Additional CaCl2 supply did not affect the total number of racemes produced per plant, the average number of flowers per raceme, or the retention of individual flowers on cut racemes over a 7-day vase period. However, Ca concentration in cut raceme tissues, ranging from 5.3 to 7.6 mg·g-1 dry weight, increased linearly with increasing Ca concentration in the nutrient solution, which was accompanied by a linear increase in average fresh weight retention per raceme and individual mature flowers (up to 7% above controls) during the 7-day vase period. In the second study under similar plant culture and vase conditions, 1-MCP applied at harvest resulted in an average fresh weight retention increase of 9% above controls during 7 days in the vase. Equivalent levels of desiccation in control racemes (loss in fresh weight retention) were delayed by 1.5 to 3 days in racemes with the highest Ca concentrations and those that had been preconditioned with 1-MCP. In view of the physiological significance of desiccation in cut flower quality loss, preharvest Ca fertilization and postharvest 1-MCP preconditioning may be useful techniques for delaying senescence and maintaining vase quality of cut L. havardii racemes. Chemical name used: 1-methylcyclopropene (1-MCP)
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