conference schedule and program with abstracts - Horticulture ...

P-93
Development of table and raisin grapes with high anthocyanins using a leaf disk assay
D.W. Ramming* 1 and P. Cousins 2
1 USDA-ARS San Joaquin Valley Agricultural Sciences Center, Parlier, California, USA;
2 USDA-ARS Grape Genetics Research Unit, NYS Agric. Expt. Station, Geneva, New York,
USA
*Corresponding author: david.ramming@ars.usda.gov
Anthocyanins are considered an excellent source of antioxidant phytochemicals for health
benefits. The majority of wine, table and raisin grapes have anthocyanins only in their colored
skin. Anthocyanin content of grapes would be increased if their flesh also contained
anthocyanins. The ‘Rubired’ wine grape has black skin and red fleshed berries. It was used as a
pollen parent to introgress red flesh in a cross with a seedless female flowered table grape
selection C33-30. It has red skin and white flesh berries. The F1 progeny segregated in a 3
colored:1 white skin and 1 red:1 clear flesh ratio for colored berries. Seedlings expressing the
highest level of anthocyanins in the flesh and skin were equivalent to ‘Rubired’. Seven modified
backcross families were created by crossing red flesh seeded F1 selections with seedless red skin
table or white skin raisin grapes. Skin color segregated as a single dominant gene as expected.
One red flesh parent was heterozygous for skin color and the rest were homozygous. Only
seedlings with colored skin had red flesh. Flesh color segregated as a 1 red:1 clear in three of the
families or in a 2:1 ratio indicting either a single dominant gene or several genes, with red flesh
being predominant. One red flesh parent produced an abnormally high percentage (>80%) of red
flesh seedlings. The assay consisted of placing leaf disks in 10% sucrose solution and observing
the development of anthocyanins after 5-10 days under 12 hr photoperiod at 26C. When no
anthocyanin developed in the leaf disks, their seedlings had clear flesh with white, red or black
skin (30% of population) and could be discarded with confidence. Red skin seedlings with light
red to red flesh as well as black skin with dark red flesh were identified accurately (>50% red in
leaf disk). In some cases seedlings with red or black skin and clear flesh produced anthocyanins
in the leaf disks and were not easily differentiated from black skin with light red or red flesh.
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