Apple blossoms grow in groups of four to six blooms attached to branches, and the center blossom is known as the king flower. This flower opens first in the cluster and usually grows the largest fruit. So, it is the key target of a robotic pollination system, according to researcher Long He, assistant professor of agricultural and biological engineering.

Insect pollination has traditionally been relied upon for apple productivity. However, evidence suggests that pollination services, both from domesticated honeybees and wild pollinators, is not matching increasing demands, He noted. Due to colony collapse disorder, honeybees around the world have been dying at alarming rates. As a result, producers need alternative methods of pollination.

This study is the latest conducted by He's research group in the College of Agricultural Sciences, which is devoted to developing robotic systems to accomplish labor-intensive agricultural tasks such as mushroom picking, apple tree pruning and green-fruit thinning. The primary goal of this project, He explained, was to develop a deep learning-based vision system that could precisely identify and locate king flowers in tree canopies.

"We think this result will provide baseline information for a robotic pollination system, which would lead to efficient and reproducible pollination of apples to maximize the yield of high-quality fruits," He said. "In Pennsylvania, we still can rely on bees to pollinate apple crops, but in other regions where bee die-offs have been more severe, growers may need this technology sooner than later."