The genetic diversity of pawpaw has also been investigated. M13 DNA fingerprinting probing (Rogstad et al., 1991), isozymes (Huang et al., 1997), allozymes (Huang et al., 1998), RAPD-PCR (Huang et al., 2000), and ISSR-PCR (Pomper et al., 2003) are all methods which have been utilized in determining genetic diversity in pawpaw. The last four of these studies agreed that pawpaw exhibits at least a moderate level of genetic diversity, similar to that found in other long-lived woody perennial species. The study of Pomper et al. (2003) utilizing ISSR-PCR found a higher level of genetic diversity than previously thought. This could be due to the ISSR-PCR methodology being more discriminating in finding genetic differences between samples. These authors suggested that high levels of genetic diversity exist in pawpaw populations, despite previous studies and the supposition that pawpaw’s clonal reproductive habit would suggest otherwise (Rogstad et al., 1991).

In 1994, Kentucky State University (KSU), an 1890 land grant university located in Frankfort, Kentucky, was designated by the United States Department of Agriculture (USDA) as a National Clonal Germplasm Repository (NCGR) for Asimina species. The orchards at the KSU research farm contain over 1700 pawpaw accessions, collected from 17 different states across the native range. This collection includes over 40 named cultivars, many seedlings, hybrids of A. triloba, A. parviflora, and crosses between A. triloba and A. reticulata and A. longifolia, planted in the KSU orchards; and A. longifolia and A. tetramera, subtropical Asimina species, stored in the KSU greenhouses. As a USDA-NCGR site, one of our objectives is to maintain and build a diverse collection of Asimina species. A major goal toward this objective is to develop a research propagation method to propagate cultivars and other genotypes on their own roots. This would protect the germplasm collection in case of dieback or storm damage, and would ease the storage of valuable germplasm. To accomplish this goal, we are investigating and developing various methods of propagation.

Sexual propagation, or propagation by seed, is the predominant way many plants in the wild reproduce, and has been used and manipulated by humans throughout history (Hartmann et al., 1997). Advantages to seed propagation include high genetic diversity