Walnut genetic improvement at the start of a new century

Since the early 1960s, researchers in programs to improve black walnut for timber have struggled to meet some basic breeding objectives. Promising avenues of research had been identified by the early 1950s, and conventional methods to breed forest trees were widely adopted as suitable for walnut. Progress has been slow however, due to practical problems related to field plot establishment and maintenance. Many plantings are of no scientific value because of poor site selection, insufficient experimental blocking, and a lack of long-term care. From good test plantings, we have learned that regional adaptation exists for walnut, and that traits such as growth rate and timber form are genetic and may be improved through selection and breeding. The pace of walnut improvement in the next forty years should be much greater because of lessons learned from the past and because of the availability of new molecular tools to modify genetic backgrounds and track genetic gains. Scientists at the Hardwood Tree Improvement and Regeneration Center are seeking to overcome practical problems in tree improvement research so that we can produce high quality research plots that will provide improved walnut for Midwestern hardwood forests throughout the next century.