LIGHT ENVIRONMENT WITHIN MATURE RABBITEYE BLUEBERRY CANOPIES INFLUENCES FLOWER BUD FORMATION

P. Yáñez, J.B. Retamales, G.A. Lobos, A. del Pozo
Blueberries are an understory species. Light interception and distribution within the canopy impact on fruit quantity and quality. The aim of this experiment was to characterize light distribution in rabbiteye blueberries cv. Choice and determine its impact on flower bud formation. Fourteen-year-old plants growing in a commercial planting in Coihueco, Chile (36°21’S; 71°50’W) were used. Photosynthetically active radiation (PAR) was measured on sunny days (December 2006 to March 2007), with a ceptometer at 7 levels separated every 20 cm from the top edge of the canopy. In July 2007, four canes from each plant were removed from the center (interior) of four plants (reps) and the number of flower buds present in each 20 cm section was measured. Full sun PAR was 1,200-1,693 μmol m-2 s-1. Data, expressed relative to light levels on top of the canopy as percent full sun (% FS), show a strong reduction in PAR towards the canopy center; thus light at 20 cm from the top was 51-80% FS, 39-58% FS at 40 cm, 17-37% FS at 60 cm, and only 9-18% FS at 80 cm. The first 60 cm from the canopy top contained 63.7% of total flower buds, while the first 80 cm accumulated 83% of this total. Only 13.4% of flower buds were formed in the basal 120 cm when light was less than 66 and 96 μmol m-2 s-1 in December and January, respectively. Light is reduced as distance from canopy edge increases. On each position there is a clear relationship between light availability and flower bud numbers, which implies that growers should maintain certain light levels to allow flower bud formation within the canopy of rabbiteye blueberries.
Yáñez, P., Retamales, J.B., Lobos, G.A. and del Pozo, A. (2009). LIGHT ENVIRONMENT WITHIN MATURE RABBITEYE BLUEBERRY CANOPIES INFLUENCES FLOWER BUD FORMATION. Acta Hortic. 810, 471-474
DOI: 10.17660/ActaHortic.2009.810.61
https://doi.org/10.17660/ActaHortic.2009.810.61
light distribution, environmental factors, light intensity
English

Acta Horticulturae