Poinsettia Demonstrations

Carl Lasco will be constructing some demonstrations that highlight some very important cultural points one must keep in mind when growing poinsettias. You task is to observe the trials as they grow, and become familiar with the concepts that form the basis of the demonstration. Each student will be required to submit an abstract summary of each of the five demonstrations. You may use the ASHS (American Society For Horticutlural Science) format for your abstract. The graduate students in the class can help you find the templates. Each abstract will be on a seperate sheet, typed and turned in by December 1st, 2004. This exercise is worth 125 points.

Experiment I
Influence of the number of Short Photoperiods (SD) on
Time to flower and Flower Quality of Poinsettia

Purpose- To demonstrate the influence of various numbers of short photoperiods (SD) on flowering poinsettia.

Planted- Plants will be grown under long photoperiods (LD) until pinching. After pinching, photoperiod will be determined by treatment.

Treatments-

1. Continuous LD

2. 1 wk SD followed by LD

3. 2 wk SD followed by LD

4. 3 wk SD followed by LD

5. 4 wk SD followed by LD

6. 5 wk SD followed by LD

7. 6 wk SD followed by LD

8. Continuous SD

Observations-

1. Plant height

2. Stage of bract color

3. "Plant picture"

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Experiment II

Influences of Growth Regulator on
Poinsettia Growth and Flowering

Treatments (Listed in order)
Concentration Growth Regulator Chemical,Type of Application,Number of Applications
1 Control 0 ppm - - -
2 3000 ppm CCC Foliar 1
3 1500 ppm CCC Drench 2
4 1500 ppm CCC Foliar 2
5 3000 ppm CCC Drench 1
6 30 ppm Bonzi Foliar 2
7 60 ppm Bonzi Foliar 1
8 2 ppm Bonzi Drench 2
9 4 ppm Bonzi Drench 1

Time of Application 1 - 2 inch breaks - 1 week apart.

Observations:

Plant height
Days to flower
Damage rating

Experiment III
Influence of Light drift on Time of Flower
of Poinsettia

Purpose- To demonstrate the importance of absolute darkness during the long night period.

Treatment- Plants will be subjected to decreasing intensity of light during the dark period.

Observation-

1. Plant height

2. Date of flower

Purpose-To evaluate the effect of different fertility regimes of poinsettia

Treatments-

Fertilizer Concentrations (ppm N)
Treatment, Initial, Final
1 0 200
2 75 200
3 150 200
4 300 200
5 450 200
6 600 200

Initial concentration will be given for the first 7 weeks after potting, at which time all treatments will then receive 200 ppm N.

Observations-

1. Time to flower

2. Foliar damage

3. Soluble salts

4. Plant height

If you have any questions about this exercise, please contact your teaching assistant, Stephanie.

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