The aspect of the flower bud differentiation of Aster pilosus, Willd and the influence of the initiation season and termination season of lighting on cut flower quality of it

In order to establish a method of lighting as a stable and high quality production technorogy by using 'Rose star' and 'New peakock' which were mainly cultivated species of Aster Pilosus Willd in Kochi prefecture, the influence of the initiation season and termination season of lighting on cut flower quality was investigated while the aspect of the flower bud differentiation was surveyed. 1. The critical day length to generate the flower bud differentiation was estimated as about 14 hours and 40 minutes. However, when about 30 days after the pinching were elapsed, it was considered that flower bud differentiation occur also under longer day length condition than this. 2. Because the splay formation had fallen into disorder remarkably to the initiation of lighting at the flower bud formation stage later than the flower bud initiaton, it was considered that the lighting was necessary to begin before the flower bud initiaton. Further, the limit season of the lighting initiation in the present prefecture was considered as about July 24 when a natural day length became a critical day length to induce the flower bud differentiation. However, in a practical scene, it was considered as the safe method that the lighting is initiated from the early period after planting in any cropping typeCbecause it was considered that the flower bud differentiation season under a natural day length was different in the most of pinching period, and that the day length is possibly different according to the weather. 3. In order to produce high quality cut flowers under a natural day length after the flower stem was extended with the lighting, it was necessary to terminate the lighting in the period from about August 19 to about April 27. It was considered that the short day treatment was necessary after the lighting ended in case the lighting was terminated at the outside of this period.