Burema B.S.,Center for Crop Systems Analysis |
Buck-Sorlin G.H.,Center for Crop Systems Analysis |
Damen T.,Center for Crop Systems Analysis |
Vos J.,Center for Crop Systems Analysis |
And 2 more authors.
Acta Horticulturae | Year: 2010
Growing in lower planting density, rose plants produce more assimilates, which can be used to produce more and/or heavier flowering shoots. The effect of planting density was investigated during a period including the first five flowering flushes of a young crop. In a heated greenhouse two cut-rose cultivars were grown under bent canopy management. Akito on own-roots and Ilios on Natal Briar rootstock were planted with densities of 8 and 4 plants per m2. Starting at the end of June 2007, flowering shoots were harvested over a time span of eight months. Based on flowering flushes, times of high harvest rate, the harvesting time span could be divided into five consecutive periods, each including one flush. The cultivars showed contrasting responses to planting density. In the first three periods the response in Ilios was extraordinary, because at low density plants did not produce more flowering shoots, as would be expected. However, the response in shoot fresh weight was larger for Ilios than for Akito, 35% compared to 21% over the entire study period. The results imply that there was a genetic difference in the effect of assimilate availability and/or local light environment. During the first three periods, these factors can not have influenced shoot number in Ilios, while they did in Akito. It is suggested that decreases of assimilate availability in winter caused the shoot number response to emerge for Ilios later on.