EFFECTS OF IAA, NAA AND GA ON FLOWERING RESPONSE OF CHRYSANTHEMUM

Carrying on the researches on chemical regulation of chrysanthemum flowering, two more experiments have been stated.
In the first one, Yellow Spider, Yellow Giant Indianapolis and White Bonnie Jean were treated three times a week in the earlier four weeks, spraying NAA and IAA at 100 ppm.
NAA treatments produced an average flowering delay of three weeks but with a corresponding small increase in stem length; the Y. Spider plants only were 16.6 cm taller than those in natural short days.

In the second trial NAA and IAA at 25, 50, 100 ppm combined or not to 50, 100 ppm of GA were tested on Y. Spider.
Plants were sprayed three times a week during 1, 2, 3 and 4 weeks.
It was confirmed the delaying effects of NAA and IAA on chrysanthemum flowering and the promoting action of GA; moreover the effectiveness increased with treatments number.

NAA 100 ppm alone or with GA 50 ppm deferred 4 weeks flowering and reverse effect had GA alone or with the lowest NAA and IAA concentrations.
On the other hand stem lengths were shorter than expected.

International Symposium on Flower Formation in Ornamentals

G. Serra, M.G. Carletti

https://doi.org/10.17660/ActaHortic.1977.68.20