Sweet Sapphire Grape Variety Introduction and Detailed Planting Techniques

Author: Grape Planting Alliance

Sweet Sapphire Grapes, alias: moon drops, belongs to the Eurasian species. The patent for this variety is held by an institution that propagates seedless varieties through embryo rescue technology, and it was jointly developed and promoted by International Fruit Genetics and the University of Arkansas, among others.

Sweet Sapphire is a mid-season variety, maturing in open fields from August to September. After ripening, the berries do not shatter or develop rotten tips, and can remain on the vine for more than 1 month, with good storage and transport tolerance. It easily forms large clusters of over 1000 grams, is naturally seedless, and the berries can reach about 10 grams without hormone enlargement. The berries are long cylindrical, shaped like a small finger, about 5 cm long. The berry color is blue-black, coloring quickly and evenly. When cut into slices with a knife, the flavor is pure, crisp and sweet with no residue, and the soluble solids content is over 20%; in dry areas with little rain, the sugar content is even higher, and the berries are easily sun-dried into large blue-black raisins. The berries are not crowded, with no broken berries, making thinning less labor-intensive. The pedicel is tough, and the berries do not easily drop after ripening. In addition, using the small dragon trunk technique doubles the yield. It is expected to become a main planting variety, and has already been introduced into China.

Main Characteristics

Sweet Sapphire grapes grow vigorously, and the plump flower buds are positioned farther forward, so it is suitable for very long cane pruning and the small dragon trunk technique; the clusters are large and easy to color and ripen, so high yields are easy to obtain. In northern Shandong, buds break in early April, first flowering occurs in late May, full bloom at the end of May, the first young fruit enlargement occurs in mid-June, the fruit begins to color in mid-August, and it ripens in late August, with a long hanging period after ripening. This variety is relatively easy to cultivate; the berries are not crowded, with no broken berries and no rotten tips, making thinning less labor-intensive. The pedicel is tough, and the berries do not easily drop after ripening. The berries are resistant to anthracnose, black pox, white rot and powdery mildew, but the leaves are not resistant to downy mildew, so it is suitable for planting in greenhouses or under rain shelters.

Sweet Sapphire, when cut into slices with a knife, has a pure flavor, is crisp and sweet with no residue, and has a soluble solids content of over 20%; in dry areas with little rain, the sugar content is even higher, reaching as much as 27%, and it is easily sun-dried into large blue-black raisins, far surpassing the famous drying variety Blackcurrant.

Flower and Fruit Management Techniques

1. Promoting flower bud formation: The reason for few and small clusters is that the flower buds are not plump. The conditions for forming plump flower buds are:

① Heavy fertilizer and heavy water, ensuring that the reserve branches exceed 2 m before July 20;

② The side shoots on the reserve branches grow to a hand-span and are twisted downward;

③ Starting when the reserve branches reach 1.5 m, carefully spray No. 3 regulatory leaf fertilizer on the underside of the leaves;

④ Control pests and diseases and protect the leaves.

2. Protecting flowers and fruits: Balance fertilization to prevent excessive jointing growth. Apply medium and trace element fertilizers together, and spray Maozhuang leaf fertilizer after budding to prevent nutrient deficiencies. Spray No. 3 regulatory leaf fertilizer to form plump flower buds. For vigorously growing fruiting canes, pinch the tips at around 8 leaves, and remove the buds on the fruiting canes to promote the flow of nutrients to the fruit clusters. Do not spray pesticides carelessly during the flowering and young fruit stages. The air in the greenhouse should circulate, and pollination should be carried out every day from 11:00 to 13:00 during the flowering stage. During the flowering stage, the daytime temperature should not exceed 28 degrees, and the nighttime temperature should not be too high, so as to avoid excessive jointing growth. In winter-warm greenhouses, it is not suitable to water during the flowering stage, to prevent the soil temperature from dropping. In arched sheds, water in the morning when the flowering stage is hot and dry. Control pests and diseases in time and protect the leaves. Thin the fruit 20 days after fruit set, spray fungicide, and bag it with special grape bags.

3. Flower and fruit thinning: Keep 5 fruiting canes per main cane, and promptly remove the excess. Keep only 1 cluster of fruit per fruiting cane, and remove the excess as soon as the inflorescence emerges. Each cluster of fruit should be about 1000 grams; for example, for a variety with a berry weight of 10 grams, keep about 100 berries. Pinch off the tip of the cluster at full bloom, and 20 days after fruit set, thin out the small berries and overly dense berries.

Article source: I Will Plant, author: Fruit Seedling Cultivation Center

Editor: Forest Wood