Precocious Flowering of Kentucky State University Pawpaw Advanced Selections and Cultivars

The North American Pawpaw (Asimina triloba) is a tree fruit native to the Eastern U.S. which is being produced in commercial orchards across the U.S. and internationally, with a small but growing market. Pawpaw trees typically begin flowering and fruit set at 3-4 years for grafted trees, or 7-8 years for seedling trees. Precocious flowering and fruit production is a desirable trait in new cultivars so that growers’ orchards can come into production as early as possible. In June 2011, a pawpaw variety trial including three commercially available cultivars (KSU-Atwood, Mango, and Sunflower) and seven advanced selections from the National Clonal Germplasm Repository for Asimina spp. located at Kentucky State University (G4-25, G5-23, G6-120, G9-109, G9-111, Hi4-1, and Hy3-120) was established at the KSU Research and Demonstration Farm in Frankfort, KY. The trial was planted in a randomized complete block design, with four blocks and two replicate trees per block, for a total of 80 trees. In March 2014, flower buds were counted to determine which selections were flowering at 3 years after planting. Seventy-four percent of the trees across the entire planting produced at least some flower buds in their third year.  One hundred percent of the trees of the advanced selections G4-25, G9-109, and G5-23 flowered in their third year after planting. Only 33% of ‘Mango’ trees had flower buds three years after planting, with 60-85% of trees of the remaining selections and cultivars flowering in year three. The advanced selection G5-23 was the most floriferous, with an average of 53 flower buds per tree. The cultivar ‘Mango’ had the fewest flower buds, averaging less than one per tree. The remaining cultivars and advanced selections did not differ significantly from each other, ranging from 6 to 27 flower buds on average per tree.