Timing of Nitrogen Fertilization Influences Color and Anthocyanin Content of Apple (Malus domestica Borkh. cv ‘Royal Gala’) Fruits

Figures & data

TABLE 1 Mean Daily Maximum Temperature, Mean Daily Minimum Temperature, and Mean Daily Maximum Global Radiation during a 30-Day Period Prior to Harvest for the 2006/2007, 2007/2008, and 2008/2009 Seasons

Season	Mean daily maximum temperature (°C)	Mean daily minimum temperature (°C)	Mean daily maximum global radiation (W m^−2)
2006/2007	31.2	14.1	717.7
2007/2008	30.6	13.8	707.7
2008/2009	32.5	13.6	739.1

Table 2 Lightness and HUE Angle Mean Values ± SE of Fruits Apple Trees of cv ‘Royal Gala’ under Different Fertilization Treatments in 2006/2007, 2007/2008, and 2008/2009 Seasons

	2006/2007		2007/2008		2008/2009
Treatment	Lightness	Hue angle	Lightness	Hue angle	Lightness	Hue angle
SNAH	53.6a ^z	41.9a	53.5ab	34.4a	48.0ab	34.1b
FNAH	54.1a	41.4a	51.6a	34.7a	47.0ab	32.4ab
SNS	55.1a	44.8a	56.2b	34.1ab	49.7b	40.8c
C	53.9a	39.5a	54.6ab	37.2b	45.5a	28.3a
^zDifferent letters within each column indicate significant differences (p < 0.05).
SNAH: soil N application after harvest; FNAH: foliar N application after harvest; SNS: soil N application in spring; C: control (no N applied).

FIGURE 1 Mean values ± SE of percentage of coverage color of the fruits of cv ‘Royal Gala’ apple trees under different fertilization treatments. (A) 2007/2008 season; (B) 2008/2009 season. SNAH: soil N application after harvest; FNAH: foliar N application after harvest; SNS: soil N application in spring; C: control (no N applied). Different letters indicate significant differences (p < 0.05).

FIGURE 2 Anthocyanin concentration ± SE (μg g⁻¹ fresh weight) of the fruit skin of cv ‘Royal Gala’ apple trees under different fertilization treatments. (A) 2006/2007 season; (B) 2007/2008 season; (C) 2008/2009 season. SNAH: soil N application after harvest; FNAH: foliar N application after harvest; SNS: soil N application in spring; C: control (no N applied). Different letters indicate significant differences (p < 0.05).