RATE OF CARNATION SHOOT GROWTH AS AFFECTED BY VARIATION IN LIGHT CONDITIONS DURING THE SEASON OF HIGH LIGHT INTENSITY
There have been a number of reports on the effects of yearly distribution of solar energy on the flower development of the carnation (e.g.Holley 1942, Nelson & Kiplinger 1957, Puustjarvi 1973). Generally the main object of the studies has been to compare flower development at the season of high light intensity with development at the season of low light intensity. Nelson & Kiplinger (1957) found that the interval between pinching and the peak of crop production could range from three months in the summer to eight months in the winter.
Less information is available on the effects of changes in light conditions during the period of high light intensity on growth and flower development of the carnation. However, observations made by commercial growers in Finland have shown that the rate of growth and flower development under Finnish conditions varied considerably during the months of high light intensity and sometimes caused difficulties in the timing of production. Experiments designed to provide information on the nature of this variation in carnation flower development were started in 1971. This paper reports some results from a part of this study in preliminary form.