ASHS 2025 Conference

Verifying Parentage of Offspring from Crosses of the Pawpaw (Asimina triloba) Cultivar ‘Sunflower’ and the Cultivars ‘Susquehanna’ and ‘KSU-Chappell’ using Simple Sequence Repeat (SSR) Markers Nabin K. Adhikari, Dr. Kirk W. Pomper, Jeremy Lowe, Dr. Srijana Thapa Magar, and Sheri Crabtree College of Agriculture, Health and Natural Resources, Kentucky State University Pawpaw (Asimina triloba), a North American tree fruit in the early stages of commercialization, is typically found in clonal patches in forest understories. Cultivated pawpaws exhibit superior size, flavor, and appearance compared to their wild counterparts. Pawpaw is generally considered self-incompatible due to its protogynous flowers, though anecdotal evidence suggests self-compatibility in the ‘Sunflower’ variety. Previous research at Kentucky State University used simple sequence repeat (SSR) markers, a class of co-dominant genetic markers that target hypervariable regions of the genome, to confirm that ‘Sunflower’ is capable of self-pollination. However, there is little information on optimal pollinizer relationships and which cultivars serve to promote fruit set in cross-pollinations. This study aims to verify the parentage of offspring from crosses between ‘Sunflower’ and the cultivars ‘Susquehanna’ and ‘KSU-Chappell’, as well as the advanced selection 7-90 using simple sequence repeat markers. Leaves of parent trees and offspring were collected for DNA extraction. Young leaves were collected and were frozen (-15 ºC) until DNA extraction. DNA extraction was carried out using a DNAMITE Plant Kit (Microzone Ltd. Haywards Heath, West Sussex, UK). PCR was performed using SSR markers developed by Pomper et al., 2010. PCR products will be separated using a SeqStudio (Applied Biosystems, Foster City, CA) capillary electrophoresis system, and genotyping will be performed with GeneMapper software (Applied Biosystems, Foster City, CA). Parentage verification will be determined by looking for the presence or absence of alleles from the purported parents in the offspring. Offspring were categorized as self-pollinated if only alleles from the pollen recipient parent were present in the offspring, expected cross-pollinated if alleles from both parents were present, or unexpected if unknown alleles were detected.