Breeding of a new early-maturing grape variety Guanchao Chunzao

The grape cultivar Guanchao Chunzao is a new very early-maturing Vinifera-labrusca hybrid variety derived from a bud mutation of Summer Black. It was bred to meet the demand for early-season, high-quality table grapes in Jiangxi Province, China, and enrich the germplasm resources of earlymaturing varieties. The fruit cluster is conical or occasionally bifid-shouldered, with an average cluster weight of 615.01 g. The berries are nearly round, blue-black in color, and seedless. The flesh is firm and crisp, the skin separates readily from the flesh, and the berries are seedless, juicy, and sweet, with a pronounced strawberry-like aroma. Following gibberellin treatment, the average berry weight reaches 9.04- 12.41 g. The skin is moderately thick, brittle, and easy to separate from the flesh. The soluble solids content ranges from 19.0% to 22.6%, and titratable acidity is between 0.31% and 0.43%. The fruit flavor is well balanced, with excellent taste and texture, making it suitable for fresh consumption. Under protected cultivation in Xinyu, Jiangxi, the vines bud in mid-March and ripen in late June, approximately 10- 15 days earlier than Summer Black. The fruit development period is about 61 days. The cultivar shows a high bud break rate (85%- 90% ), fruit- bearing shoot rate above 95% , vigorous growth, and stable yield performance, indicating strong early- ripening potential and high productivity. The vines exhibit strong growth vigor, good resistance to white rot and other common grape diseases, and strong environmental adaptability. No berry cracking has been observed under standard management conditions. The thick and crisp skin provides moderate resistance to mechanical damage, allowing short-term storage and long-distance transportation without significant quality loss. Guanchao Chunzao performs best under greenhouse or rain- sheltered conditions in the middle and lower reaches of the Yangtze River, Jiangxi Province, and other areas with similar ecological environments. Its early maturity, excellent fruit quality, strong disease resistance, and high adaptability make it a promising cultivar for industrial application. The successful breeding of Guanchao Chunzao enriches early-season grape germplasm, extends the fresh grape market supply period, and contributes significantly to improving economic benefits and regional grape industry development.