Journal of the Japanese Society for Horticultural
Science 67:1121-1123. 1998.
Mechanical conditioning for controlling excessive elongation in transplants
Thomas Björkman
Department of Horticultural Sciences, New York State Agricultural Experiment
Station, Cornell University, Geneva, NY 14456
ABSTRACT Excessive stem elongation in transplants hinders
mechanical transplanting and reduces plant survival in the field. Mechanical
stimulation is an effective method for reducing stem elongation during
transplant production. This investigation determined how to optimize the
treatment and the consequences it has on subsequent field performance.
This research examined the effects of varying the dose, the interval between
brush strokes during stimulation, the time of day that stimulation was
applied and the time application was started. Tomato seedlings grown
at 2100 plants per m2 were reduced in height by 20% when brushed
with 10 strokes per day from canopy closure until they were ready to set
out. More intense treatment did not further reduce the height. The interval
between strokes could range from none to 10 minutes with no difference
in the effect. The treatments were similarly effective whether applied
in the morning or in the late afternoon. Treatments begun at different
canopy heights were shorter in direct proportion to the number of days
of treatment. The plants grew 6 mm per day when they were not treated and
3 mm per day during treatment. In the field, treated and untreated
processing tomatoes recovered from transplant shock equally based
on the resumption of elongation growth. Leaf area development and
yield were also equal. Furthermore, fresh-market tomatoes were unaffected
in earliness, and no treatment-related defects were noted in the fruits.
Treated plants were more tolerant of wind. In wind-tunnel tests, treated
plants resisted wind speeds about 4 km/h higher. A field planting subject
to 70 km.h-1 wind had 12% mortality in untreated plants but
only 2% in treated plants. Mechanical conditioning with brushing and impedance
produced transplants with desirable qualities without adverse effects on
field performance.
Back
to publication list