New Zealand Journal of Crop and Horticultural Science
abstracts
Non-destructivechlorophyll fluorescence and colour measurements of ‘Braeburn’ and ‘Royal
Gala’ apple (Malus domestica) fruit development throughout the
growing season
Dennis H. Greer
School of Wine and Food Sciences
Charles Sturt University
Locked Bag 588, Wagga Wagga
NSW 2678, Australia
email: dgreer@csu.edu.au
Abstract Fruit size, skin colour determinations, and chlorophyll
fluorescence of two apple (Malus domestica) cultivars, ‘Braeburn’ and ‘Royal
Gala’, were followed throughout the growing season to assess fruit development.
Chlorophyll fluorescence was measured with a pulse-amplitude modulated fluorometer
on the blush and back sides of the fruit and skin colour with a tristimulus
colorimeter giving colour coordinates as hue angle, chroma, and lightness coefficient.
Fruit of both cultivars followed a single sigmoid growth pattern with ‘Royal
Gala’ apples attaining full size at c. 140 days after full bloom (DAFB)
and ‘Braeburn’ fruit at c. 168 DAFB. Fluorescence peaked at 80
DAFB then declined in all instances. Hue angle varied consistently throughout
the growing season in both cultivars, indicative of shifts in colour from yellow-green
to red. Background and blush colours of ‘Braeburn’ remained distinct
throughout the growing season whereas for ‘Royal Gala’ the two
sides merged to the same colour. Skin colour intensity also differed between
the two sides initially but merged to a uniform intensity at the end of the
growing season. Hue angle was best able to discriminate between the two cultivars
in ripening patterns and thus would be a useful technique to quantify fruit
development in an objective manner.
Keywords apples; colorimeter; chlorophyll fluorescence; fruit
colour
New Zealand Journal of Crop and Horticultural Science, 2005, Vol. 33:
413–421
0014–0671/05/3304–0413 © The Royal Society
of New Zealand 2005
H04084; Online publication date 9 November 2005
Received 12 October 2004; accepted 24 August 2005
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