Herbaceous stock plant production and cutting harvest methods affect the performance of cuttings harvested from those stock plants. Specifically, the effect of daily light integral (DLI), ethephon spray applications, and the stock plant node position of hybrid impatiens stock plants on the flowering of the harvested cuttings were examined.
The DLI treatments were grouped in ranges of low, medium, and high levels. The stock plants were treated weekly with 0, 50, 100, 200, or 300 mg·L –1 ethephon. Cuttings were harvested from six NP SP, which refers to the location on the stock plants from which the cuttings were harvested. Time to flower of the harvested cuttings decreased as DLI increased from 5.1 to 12.0 mol·m –2 ·d –1 , as ethephon concentrations decreased from 300 to 0 mg·L –1 , and as NP SP moved from lower to upper positions within the stock plant canopy. Time to flower was highly correlated with the node position on the cutting (NP C ) where the first flower appeared. For example, when flowers appeared in the lowest NP C on the shoot (NP C 1), the first flower opened 2.5 weeks after sticking the unrooted cuttings in propagation, while flowers that appeared in NP C 7, the seventh-oldest node from the base of the cutting, opened at 9.0 weeks.
The results demonstrate how stock plant management practices can be manipulated to produce cuttings that allow growers to produce flowering plants on different schedules, i.e., production time can be shortened from conventional production schedules, which may allow hybrid impatiens to be marketed like bedding plant species such as impatiens (Impatiens walleriana).
The study is conducted by Mary Vargo and James E. Faust.
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