The genetics team is developing guidelines to help growers understand where to plant specific southern pine seed sources given future climate scenarios and identify genes controlling traits such as growth, nitrogen responsiveness, cold hardiness, water usage, and resistance to southern pine beetle and fungal diseases.
Current seed deployment guidelines for southern pines are based primarily on survival and growth data from the Southwide Southern Pine Seed Source Study (SSPSSS) conducted from 1950 to the 1980s with wild seed under historical weather conditions. Since the SSPSSS, the tree improvement cooperatives have conducted more extensive, large-scale provenance, family, and clone tests across the physiographic regions. Provenance trials have demonstrated that loblolly pine from the East grows faster than the interior western material, which is better adapted to a more continental climate with more extreme temperatures and precipitation. This knowledge has led to widespread planting of field-tested Atlantic Coastal Plain families on industry lands in Arkansas, Mississippi, and Oklahoma rather than locally adapted stock.
The best planting decisions are based on growth and survival data obtained from genetic tests that are 10-20 years old. Such information, however, is available for only a limited set of environments, and the impacts of changing climate during the rotation are rarely taken into account. Thus, the goal of the genetics team is to inform future deployment decisions with projected climate change scenarios taking into account uncertainty and risk introduced by performance instability. Specifically, the team is investigating the basis of pine productivity and adaptive traits by conducting linkage and association mapping to identify alleles that can be screened in populations, helping to accelerate improvement of productivity and adaptive traits.
To understand how different genotypes respond to climate, the genetics and breeding team is using a uniform response function (URF) approach which models performance corrected for the weather at the progeny test site and climate at the source of origin for the select trees. The three tree improvement cooperatives involved in PINEMAP have each selected a set of progeny tests appropriate for this analysis and have developed databases with the locations for all progeny tests and select tree families. For the western region, the Western Gulf Forest Tree Improvement Program will analyze data from two series of tests (tags labeled "3" in the map). For the central part of the region, the North Carolina State University Cooperative Tree Improvement Program will analyze data from a series of tests planted across the region (tags labeled "1" in map). Finally, the Cooperative Forest Genetics Research Program at the University of Florida will analyze data from tests from four different coastal provenances (tags labeled "2" in map).
Studies are being conducted in three complimentary populations:
- Plantation Selection Seed Source Study (PSSSS)
- Comparing Clonal Lines On Experimental Sites (CCLONES)
- Allele Discovery of Economic Pine Traits2 (ADEPT2)
In addition, the team is developing a new population for a Southwide field test that includes region-wide crosses and material from extremes of the natural range.