Commercial nut production offers a sustainable alternative to the traditional agronomic crops grown in southwest Missouri. Pecan (Carya illinoensis) and black walnut (Juglans nigra) appear to have the greatest potential for profitability. Commercial pecan production has a proven track record within the state while commercial black walnut production based on improved cultivars has yet to be documented. This multi-faceted study is designed to demonstrate and evaluate the potential for commercial pecan and black walnut culture in southwest Missouri.

Two major components of this study will evaluate the productivity of the best known pecan and black walnut cultivars for this region. Blocks of seedling trees, planted in 1993, have mostly been grafted to six cultivars of each species (Table 1). Detailed horticultural and economic data will be collected over many years to determine the potential profitability and feasibility of such an enterprise.

Another component of the overall study is the development of a nut tree germplasm collection. One hundred thirty-four border-area trees are being grafted to a wide variety of nut tree cultivars and species not being used in the main experiments (Table 2). Such a collection will allow observation and subjective evaluation of numerous cultivars under southwest Missouri conditions while providing an ideal environment for future nut tree breeding and numerous other research projects.

Grafting efforts by members of the Missouri Nut Growers Association and the staff of the Southwest Research Center began in 1996 and continued through 2004. Unfortunately, an early, sudden hard freeze on October 7, 2000 that was preceded by very hot dry weather killed or injured many of the grafts in the orchard. Of the trees that were already grafted, we lost 61% of pecan grafts and 25% of black walnut. The pecans were so hard hit that many died to the ground, but all but two trees survived. The majority of both walnut and pecan grafts have now been reestablished.

Table 1. Commercial nut cultivars in variety trials at the Southwest Research Center.

Table 2. Cultivars in the Southwest Center's nut tree germplasm collection.