cultivars and advanced selections are propagated by grafting or chip budding onto a seedling rootstock (Layne, 1996).

One clonal propagation method that has not been reported in the literature of pawpaw is layering. Layering is a form of clonal plant propagation in which the shoot of a plant is induced to root while still attached to the mother plant. Layering may be used to propagate difficult-to-root species that may be impossible to propagate by any other method (Hartmann et al., 1997). Root initiation during layering may be induced by light exclusion (etiolation) and by various mechanical treatments (girdling or wounding) to slow or block downward movement of translocated compounds (Westwood, 1993). Rooting occurs just above the point of blockage. Etiolation causes several physiological changes in the plant that may enhance rooting (Hartmann et al., 1997). Several fruit and nut crops that are difficult to root using other methods may be induced to root once shoots are etiolated, including apple (Delargy and Wright, 1978) and chestnut (Biricolti et al., 1994). Girdling has also been shown in other studies to enhance rooting in pecan (Wood, 1989) and pistachio (Dunn and Cole, 1995).

Mound layering, or stooling, is a method of layering in which the shoots of the mother plant are cut back within a few inches above the soil surface, and soil or some other type of rooting substrate such as sand or sawdust is mounded around the plant to cause etiolation of the new shoots, and provide a medium for root growth of the shoots (Hartmann et al., 1997). After one season, if the new shoots have produced adventitious roots, they can be separated from the mother plant; and the process is begun again for the next growing season.

Mound layering is used to propagate many woody plant species, especially tree fruit root stocks such as apple and pear (Westwood, 1993, Webster, 1995, Hartmann et al., 1997). Several nut crops that have proven difficult to root via other methods have been successfully propagated using mound layering. Hazelnut (Corylus avellana) cultivars are usually grown on their own roots, without a rootstock, and mound layering is commonly used by nurseries and growers for propagating additional trees (Bissal et al., 1991). Pecans, like pawpaw, are extremely difficult to root and are often propagated as a scion cultivar grafted onto a seedling rootstock (Wood, 1989). A study conducted in India found that ringed pecan shoots rooted in a mound layering system, even with no 3-