Abstract:The appearance characteristics of the fruits of 21 blueberry varieties were observed，and the sugars and acids in the fruits were detected，which would provide a basis for the breeding，cultivation，and fresh-eating variety selection of blueberry.The results showed that the 21 blueberry varieties all had the shape index below 1.Most of the varieties had oblate spherical fruits，and a few had nearly spherical or cake-shaped fruits.The varieties had the single fruit weight of 0.52 g-2.63 g，among which the variety 'Darrow' had the single fruit weight more than 2.5 g.The fruits of most varieties were blue with white powder on the surface.'Pink Lemonade'was a rare variety with red fruit and little white powder，and 'Black Pearl' was a rare variety with black fruit and no white powder on the fruit surface.The variety with big and flat fruit generally had high water content.The blueberry fruit contained two soluble sugars（fructose and glucose），five organic acids（oxalic acid，quinic acid，malic acid，shikimic acid，and citric acid），and two phenols （chlorogenic acid and catechin）.The content of the compounds followed the trend of soluble sugars＞organic acids＞phenols，with significant differences.In the same variety，the glucose content（48.81 mg/kg）was slightly higher than the fructose content（44.41 mg/kg），and the fructose sweetness（7 771）was significantly higher than the glucose sweetness（3 661），which indicated that blueberry belonged to the fructose-accumulating fruit.The content of fructose，glucose，and total sugar presented similar trends and ranges with the sweetness.The fruit with high fructose content and high glucose content was generally sweet.'Sierra'and'Sunrise'were elite high-sugar varieties.Citric acid presented the content（6.31 mg/kg，76.52% of the total acids）significantly higher than other organic acids，which indicated that blueberry was a citric acid-dominant fruit.The content of quinic acid varied greatly among different varieties，with the difference more than 1 000 folds.'Patroit'was a variety with high content of quinic acid，and'Liberty'and'Bluegold'were the varieties with high content of citric acid，all of which had rich acids.The fruit flavor was affected by the total sweetness（total soluble sugar content）and determined by organic acid content.The results of comprehensive evaluation indicated that'Sierra'，'Sunrise'，'Biloxi'，'N5'，'Black Pearl'，and'Reka'were the varieties suitable for fresh eating.