H. Miura, M. Yoshida, A. Yamasaki
Strawberry plants, cultivated in a plastic greenhouse, were shaded by a black cheesecloth with about 60% light transmittance to investigate the effect of the light intensity on the growth, size, coloration and sugar content of a primary fruit in a truss. In the absence of treatment, the changes in the fruit minor diameter after anthesis followed a double sigmoidal pattern, that is, the growth rate (mm/day) showed an early peak 5–6 day after anthesis, immediately after the onset of the measurement, and a second peak 27–29 days after anthesis. The L* value (lightness) of the fruit surface color slightly increased from 23 days to 28 days after anthesis (white stage), and thereafter it decreased considerably. The a* value (redness) rapidly increased after 28 days, then it reached a value of 10 at 30 days (turning-red stage) and a value of 40 at 36 days after anthesis (full red stage). In contrast, the b* value (yellowness) gradually decreased with the number of days after anthesis. In the shade treatment, the growth pattern of the fruit also showed a double sigmoidal curve. The second peak occured at 31 days after anthesis, but it was lower than the peak observed in the absence of treatment. The L* value was high from 23 to 30 days after anthesis (white stage). A rapid increase of the a* value occured after 30 days, while the value of 10 was reached at 32 days (turning-red stage) and the value of 40 at 38 days after anthesis (full red stage).

Although the fruits in the shade treatment required a longer period of time after anthesis to reach the full red stage, the size (minor diameter, fresh weight and dry weight) was smaller, e.g., 18% decrease in dry weight, and the contents of fructose, glucose, and sucrose were also lower than those in the fruits in the absence of shading.

Miura, H., Yoshida, M. and Yamasaki, A. (1993). EFFECT OF LIGHT INTENSITY ON GROWTH AND RIPENING OF STRAWBERRY FRUIT. Acta Hortic. 348, 394-394
DOI: 10.17660/ActaHortic.1993.348.78

Acta Horticulturae