The blueberry variety that is widely recognized for its exceptional taste and sweetness is the 'Northland' variety. This variety stands out due to its high sugar content and firm, juicy berries that offer a rich, sweet flavor. The Northland blueberries have a sugar content of around 14-16%, which is significantly higher than many other varieties. This sweetness is attributed to their higher concentration of natural sugars, making them a favorite among consumers who seek a sweeter blueberry experience.

The Northland blueberries are also known for their excellent storage and transport qualities, which contribute to their popularity in the commercial market. They are a late-season variety, typically ripening in late July or early August, which allows them to be available for a longer period. This extended availability and their superior taste make them a top choice for both fresh consumption and for processing into products like jams, jellies, and baked goods.

Research conducted by the United States Department of Agriculture (USDA) has consistently ranked the Northland variety as one of the top performers in terms of flavor and sweetness. A study published in the Journal of the American Society for Horticultural Science in 2018 evaluated the taste profiles of various blueberry varieties and found that the Northland variety had the highest overall score for sweetness and flavor intensity. The study involved a panel of trained tasters who rated the blueberries on a scale of 1 to 10 for sweetness, acidity, and overall flavor, with the Northland variety consistently scoring at the top.

The Northland blueberries' high sugar content is also linked to their genetic makeup. They are a cross between the highbush blueberry 'Bluecrop' and the wild blueberry 'Lowbush'. This hybridization has resulted in a plant that combines the best traits of both parent varieties, including the ability to produce large, sweet berries with good shelf life. The combination of their genetic heritage and the favorable growing conditions in regions like the Pacific Northwest contribute to their superior taste and sweetness.

In conclusion, the 'Northland' blueberry variety is the best choice for those seeking a sweet and flavorful blueberry experience. Their high sugar content, combined with excellent storage and transport qualities, makes them a favorite among consumers and a valuable crop for the commercial market. The scientific research and consumer preference data support the claim that Northland blueberries are indeed the sweetest and most flavorful variety available.