Abstract
The effects of defoliation timing on fruit growth and abortion were monitored in gynoecious, parthenocarpic ‘NK×AN8’ cucumber. In control, non-defoliated plants, fruit attained marketable size at 14 days after anthesis (DAA), whereas some of the fruit from the plants (leaf-to-fruit ratio=2) defoliated at different time points were either stunted or aborted. Stunted and aborted fruit ceased to grow at about 7–8 DAA and at 4 DAA, respectively. When plants were defoliated at 4 DAA or earlier, more than 20% of the fruit aborted, whereas no fruit aborted when defoliated at 6 DAA or later. For fruits neither aborted nor stunted, the relative growth rate (RGR) of a fruit was almost the same for the period between 8 and 14 DAA irrespective of defoliation timing. In plants defoliated at 0 to 8 DAA, however, RGR decreased temporarily after defoliation. These results suggested that sufficient amount of photoassimilates should be continuously transported into fruits up to 4 DAA and 7–8 DAA in order to prevent fruit abortion and stunting, respectively.
