The previous report pointed out that the growth substance could be successfully used to delay chrysanthemum flowering.
This paper discusses certain practical procedures for the application of growth substance.
The results of the experiment are summarized as follows.
(1) Variety “Okayama Heiwa” was propagated on May 25 by cuttings, planted on June 18 and pinched on July 12.
(2) The growth substance (NAA) of 5, 10, 50, 100 and 600ppm were applied by spraying during the growing season from early August to late September. The flower bud differentiation had not begun at the termination of the spray application.
(3) The doses of more than 50ppm were ef_??_ective in delaying flowering, but at concentrations above 100ppm, inhibition occurred to the growth of plant. At concentration of 100ppm flowering was delayed 12 days.
(4) The auxin supply before flower bud differ-entiation was effective in delaying flowering, but this was not the case when the auxin was supplied after budding.
(5) The number of leaves on the plants treated with 50 and 100ppm of NAA increased over that of the control. This fact indicates that the auxin accelerates the vegetative growth in spite of its inhibition of flowering.
(6) The same effectiveness was obtained by either application every 3rd day or everyday. Therefore the former may be recommended as more practical because of its cheeper cost and less labour.
