This document summarizes research on red-fleshed apples. It finds that nearly all red-fleshed apple varieties can be traced back to Niedwetzkiana, a wild form of Malus sieversii from Central Asia. The pigments that give red apples their color, anthocyanins, are flavonoids that may have health benefits as antioxidants. Breeding efforts aim to develop red-fleshed varieties suitable for fresh consumption through improving traits like size, storage ability, and taste. Independent testing of available varieties is needed to provide information to consumers and evaluate commercial potential.

1. Red fleshed apples
Apfelsorten mit rotem Fruchtfleisch
Mele a polpa rossa
Walter Guerra
Laimburg Research Centre
Interpoma 2012, Bolzano
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2. Origin of red flesh in apples
van Nocker et al. (2012). Genetic diversity of red-fleshed
apples (Malus). Euphytica 185:281–293
Phenotypical and genetic investigation on four big Malus
germplasm collections
-United States Department of Agriculture Malus Germplasm Collection at the Plant
Genetic Resources Unit in Geneva, NY, USA
-National Fruit Collection in Brogdale, Kent, UK
-Canadian Clonal Genebank in Harrow, Ontario, CAN
Michigan State University Malus collection in East Lansing, MI, USA
Almost all red fleshed accessions traced back to
Niedwetzkiana, a presumed natural form of M. sieversii
native to central Asia
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3. Browns Apple Piotosh Pink Pearl
Purple Shelley Sissipuk
Prince
Niedwetzkiana
05.11.2012 van Nocker et al. (2012). Genetic diversity of red-fleshed apples (Malus). 3
Euphytica 185:281–293 3

4. Anthocyanins
Pigments responsible for the colouration
Large family of flavonoids
More than 500 different anthocyanins reported
Most common ones in apple cyanidin-3-O-galactoside, cyanidin-3-O-arabinoside,
cyanidin-7-O-arabinoside, cyanidin-3-O-rutinoside, cyanidin-3-O-xyloside, cyanidin-
3-O-glucose
Accumulating in the cell vacuoles
Red fleshed crab apples as possible source of natural
anthocyanins?
Content can exceed 1 mg/g fresh weight in red fleshed crab apples (Mulabagal et
al., 2007)
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5. Anthocyanins
Putative health benefits
Strong in vitro antioxidants
May have preventive and therapeutic roles in a number of
human diseases
Research reports suggest that anthocyanins are
-nontoxic, nonmutagenic
-possess antioxidant, anti-inflammatory,
anticarcinogenic and antidiabetic properties
In vivo studies not yet sufficient to produce health claims
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6. Anthocyanins
Metabolic pathway
Chagné et al. (2007) BMC Genomics 8:212
Mapping a candidate gene (MdMYB10) for red flesh and
foliage colour in apple.
MdMYB10 identified as a transcription factor which
promotes the synthesis of various enzymes relevant in
the biosynthesis of anthocyanins
Biotechnological approach
Transformation of Royal Gala at PFR New Zealand (Espley, 2007)
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7. Red fleshed apples
Ornamentals and Processing
Bloody Ploughman Blush Rosette® Christmas Pink® Devonshire Quarrenden Dirleton Red
Apple
Red-fleshed apples
are not new to the
Dries Grenadine gardeningHuonville Crab
Hidden Rose and Pink Parfait® Pink Pearmain®
processing industry!
Pomfital® Purple Passion Red Devil Red Merylinn Roter Alatau Apfel
Roter Herbstkalwill Roter Mond Rubaiyat® Rubens Lilliputapfel Thornberry® Vitalstar®
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8. Home gardening and processing
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9. Breeding for Red Fleshed Apples
Fresh consumption
Trebuschenko, P.D. (1939). Inheritance of anthocyanin
coloration in apple-tree (a contribution to the problem of
breeding red-fruited and red-fleshed varieties of apples).
C.R. (Dokl.) Acad. Sci. URSS XXIII(9): 939-943
Early breeding activity in Michurin and California
Recent breeding activities with the concrete target of
fresh product started in the 90ies
Nowadays many breeder are following this trend
Few red-fleshed apples with European PVR application
Weirouge, LUBA0605, LUBA0905, LUBA2605, Baya Marisa® Bay 3484
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10. 2 distinctive phenotypes in breeding populations
• Red to dark red or purple • Pale pink to bright red
• Red pigment in 70-100% of • Red pigment in 1-80% of
fruit cortex and core cortex and not in the core
• In fruit from flowering • Often expressed late in the
through maturity season
• Developing leaves are red, • Always associated with
mature leaves may appear green colour of new leaves
green
05.11.2012 Volz et al. (2009). Breeding for Red Flesh Colour in Apple: Progress and 10
Challenges. Acta Hort. 814 1010

11. Experiences with Red Fleshed Apples at the
Laimburg Research Center
First plantings in spring 2010
More than 20 genotypes from several breeders in testing
on different microclimatic sites in the South Tyrolean
apple production area
Preliminary agronomic results not shown
It is too early and/or we are not allowed to show them yet
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12. Blind panel taste
Research Center Laimburg
October 2012
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13. Results blind panel taste
Samples out of normal cool storage
Intensity scale 1 to 9 (1= absent; 9= very intense)
9
8
7
6
Intensity 5
4
3
2
1
Crispness Firmness Juiciness Sweetness Acidity Flavour Astringency
Red fleshed genotypes
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14. Cool damage at 2 °C storage
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15. Red fleshed apples
The big potential
Novelty - Distinctiveness - Enhanced visual quality
External appearance very consistent
They colour in every climate!
Intensification of the breeding activity around the world
Increasing know how around the genetics and
metabolomics of the biosynthesis of anthocyanins
Health preserver/promoter – functional/nutraceutical food
Several clinical studies on putative health benefits of
anthocyanins planned
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16. Red-fleshed apples
The big challenge
Little (in some cases no) independent public research
results available
Improvement needed in terms of fruit size, agronomic
performance, texture attributes and/or storability
Consistency of flesh colouring around different climates?
Consumer acceptance
Negative image imprint of red-fleshed apples if the first
genotypes on the market will disappoint the consumer
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17. Red-fleshed apples
The contribution of Laimburg Research
Center
Independent variety testing of available genotypes
Interdisciplinary approach
pomology-physiology-plant pathology-post harvest-molecular biology-biochemistry
European EFRE project POMOSANO
Own red-flesh breeding started very recently
General aim
Conquer further “stomach share“ in our consumers for
apples which compete with other fruits and snacks
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18. Interpoma 2012, Bolzano
Thank you for your attention.
Danke für Ihre Aufmerksamkeit.
Grazie della Vostra attenzione.
Land- und Forstwirtschaftliches Versuchszentrum | Centro di Sperimentazione Agraria e Forestale
Research Centre for Agriculture and Forestry | Laimburg 6 – Pfatten (Vadena) | 39040 Auer (Ora) | Südtirol (Alto Adige) | Italy
T +39 0471 969 500 | F +39 0471 969 599 | laimburg@provinz.bz.it (laimburg@provincia.bz.it) | www.laimburg.it
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