2018 ASHS Annual Conference

Flowering success directly translates to yield potential in perennial fruit trees such as cherry. Thus, erratic weather events that affect flowering can have a deleterious effect on crop yield. For instance, in 2012 Michigan tart cherry growers lost 97% of their crop after sporadic freezing temperatures in April killed most floral buds. Events like these can have long-lasting negative economic impacts on the tree fruit industry. And, as global climate change intensifies, unpredictable weather events are becoming more frequent. Two potential ways to reduce the risk of crop loss from frost damage include: 1) Breeding trees that bloom later in the season, and 2) identifying the point in development when flower buds are most susceptible to frost damage. This second strategy would enable growers to employ cultural practices to increase temperatures in their orchards if needed. The development of both mitigation methods would benefit from a greater understanding of the biology behind the regulation of bloom time. As a first step in this direction, we tracked developmental changes that occurred in dormant flower buds from naturally early and late blooming tart cherry trees as they accumulated heat units. Differences in morphology as well as pollen development between the genotypes were evident.