Factors Affecting Biomass Yield of Poplar Plantations In Minnesota: Past Experience and Research Needs.

Hybrid poplar is considered a potential energy crop nationally due to its widespread adaptability, ease of propagation and high growth rate.  Research has been ongoing in Minnesota over the past decade to develop production practices and improve genetics of Populus deltoides and hybrids for production of both fiber and energy.  The University of Minnesota’s poplar program involves breeding and field testing of a large set of native P. deltoides sources as well as hybrids of P. detoides, P. nigra, P. maximowiczii and P. trichocarpa produced in our breeding program.  This program is one of the largest of its kind in the world and results of ten years of genetic improvement research will be presented.  To date, results of long term field tests demonstrate the potential to improve biomass yield by a factor of 1.8 to 2.0 times that of current commercial hybrids.  Development of new genetic resources, particularly P. nigra, will be described as well as plans for future breeding and a national clone testing program.  Large-scale field fertilization studies and the long term effects of fertilization inputs on biomass yield will be presented.  The impact of research results on production economics will be highlighted as well as possible energy conversion pathways.  Based on the experience in Minnesota, research needs critical to the development of economically competitive woody energy crops on a national scale will be discussed.