Seven groups of seedlings from each of seven single parent (half-sib) families of sycamore, Platanus occidentalis L., were grown to a marketable size in 9.1 liter (#3) containers to test responses to container nursery production in south Texas. Seedlings were then transplanted to a field site (Brazos County, TX) in the fall, spring, and summer to assess seasonal effects on landscape establishment. Regional selections grew larger, both during container production and following subsequent transplant to the field. Growth of nonimproved local half-sib families equaled or exceeded that of genetically improved families from a distant region. Differential responses among genetically improved and non-improved sources were less pronounced when genotypes were grown in a region from which they did not originate. Fall and spring transplanted seedlings had substantially greater growth and survival than did summer transplants regardless of genotype. This study demonstrates a potential for regional market segregation of seed-propagated landscape trees.
This study was included as part of a thesis written in partial fulfillment of the requirements for the M.S. degree by L.J. Shoemake. The authors wish to thank the Lerio Corp., El Campo, TX, for donation of containers. The authors also wish to acknowledge the assistance of W.J. Lowe of the Texas Forest Service for help with statistical analysis and provision of seed, F.T. Davies. Jr. for consultation, and R.J. Rousseau for seed from Westvaco Corp. selections.
2Former graduate teaching/research associate.
3Assistant Professor of Landscape Horticulture, corresponding author.