EFFECTS OF SHADE ON STRAWBERRIES IN HYDROPONIC CULTIVATION

In order to make full use of space in hydroponic strawberry production, different kinds of frames are being used that result in shading of plants.
The purpose of this study was to investigate the behavior of ‘Akihimei’ strawberry (Fragaria ×ananassa Duch.) at different positions of the double-decked frame in the greenhouse under different light conditions, especially when lower levels were in the shade.
The results showed that on the southern exposed upper level the light was strongest (100%), while on the northern lower level the light was the weakest (57%). The net photosynthetic rate was linear with light intensity (y=0.0092x+1.7738, r=0.72**). Compared with plants grown on upper tier that received 100% light, the shaded strawberry plants had smaller leaves, though they also expanded in 12 days and became mature in 30 days.
The leaf area of plants on the southern upper level was twice as that on the northern lower level.
Early flowering and green fruit stage of the strawberries under shade were two days and five days longer, respectively, than those in full light.
Strawberries under shade had about 38% early yield, 50% total yield, 57% early fruit number, 71% total fruit number, and about 30% smaller fruits compared to plants in full light.
These indexes were significantly correlated with light intensity.
Therefore, light intensity was a key factor in improving strawberry production.
As for fruit qualities, such as firmness, SSC, ASA, TA, there were no significant differences between fruits grown under shaded conditions or in full light conditions.
Furthermore, plants grown under shading conditions produced 50% fewer stolons than those under full light.
We can conclude that reducing shade by developing suitable frame designs, might increase the value of protected horticulture.

VII International Strawberry Symposium

Jiayi Wang, Hongqing Wang

strawberry, Fragaria ×ananassa, double-decked frame, light intensity, yield, fruit quality

https://doi.org/10.17660/ActaHortic.2014.1049.114