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Browsing by Subject "poplar breeding"

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    Comparison of hybrid poplar wood breakeven prices as affected by current and improved genetics
    (University of Minnesota Duluth, 2021-05) Lazarus, William F; Nelson, Neil D; Jackson, Jeffrey; Berguson, William E; McMahon, Bernard G; Buchman, Daniel; Cai, Meijun
    The impact of improved genetics from the University of Minnesota Duluth Natural Resources Research Institute (NRRI) hybrid poplar breeding program on breakeven hybrid poplar wood prices is discussed in this paper. After a review of previous economic analyses, the breakeven prices are presented that would cover costs other than land rent. Then, factors are provided for adjusting the price to reflect the land rental rate for a given location. The breakeven prices are presented both as stumpage and delivered to a mill. Breakeven delivered prices include the stumpage values plus conventional harvest and transportation costs to a hypothetical processing plant. Breakeven land rental rates are also provided at which poplar production would be profitable at recent aspen stumpage prices. The impact of improved genetics from the University of Minnesota Duluth Natural Resources Research Institute (NRRI) hybrid poplar breeding program on breakeven hybrid poplar wood prices is discussed in this paper. After a review of previous economic analyses, the breakeven prices are presented that would cover costs other than land rent. Then, factors are provided for adjusting the price to reflect the land rental rate for a given location. The breakeven prices are presented both as stumpage and delivered to a mill. Breakeven delivered prices include the stumpage values plus conventional harvest and transportation costs to a hypothetical processing plant. Breakeven land rental rates are also provided at which poplar production would be profitable at recent aspen stumpage prices. The analysis is based on a scenario where a biorefinery/bioproducts company owns and/or leases the land, controls the harvest and transportation of the wood, and delivers the wood to their own mill. The evaluation is based on two hybrid poplar annual growth increments: 3.6 dry tons and 5.4 dry tons per acre per year with a 9-, 10-, or 12-year rotation. 3.6 dry tons per acre per year is yield potential with current genotypes. 5.4 tons per acre per year is yield potential with new Gen 1.0 elite clones from our breeding. Stumpage prices without land cost included are lower than aspen stumpage prices for both unimproved and improved clones. Other things being equal, the improved genetics could be capitalized into a $36.37-per-acre increase in the financially permissible rental rate. Carbon credit markets could further improve returns on hybrid poplar plantations.
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    Inter-Tree Competition Effects in Hybrid Poplar Genotype Testing
    (University of Minnesota Duluth, 2022-02) Nelson, Neil D; Buchman, Daniel; Cai, Meijun; McMahon, Bernard G; Berguson, William E
    The effects of inter-tree competition on growth in family field trials (FFT), clone trials (CT) and yield blocks (YB) were studied in NRRI experimental field plots in Minnesota, USA. FFT and CT competition is inter-clonal , YB competition is intra-clonal. Two approaches were explored: (1) regression analysis of growth of individual trees versus growth of immediate neighboring trees in FFT and CT; (2) bole volume growth as measured by DBH2 in CT versus YB for the same clones on each site to determine whether inter- clonal competition in CT overestimates tree growth in YB. In CT on five sites planted the same year with the same population of clones (“simultaneous CT”), significant negative slopes, indicating the onset of inter-tree competition, occurred in the fifth and sixth years for the two fastest-growing CT. The top 50th growth percentile clone group in the fastest-growing of the simultaneous CT had a significant negative regression line slope; the lower 50th group did not. The three slower growing CT did not exhibit competition (significant negative slopes) from three through six years. A separate clone trial measured through 9 years showed little evidence of inter-tree competition. The regression slopes in FFT were almost all positive, indicating no inter-tree competition effects from three through ten years of stand age. All significant regression R2 values were low–a maximum of 24 % for CT, 22 % for FFT. Clonal genetic potential for growth likely predominates prior to significant inter-clonal competition, suggesting that randomization of single-tree replications of each clone within each block is effective in evaluating clone genetic growth potential within the initial six years selection window that we have used in our program. There was no significant difference between CT and YB for tree bole volume growth (yield) in a population of clones. There was wide variation in the YB/CT yield ratios between individual clones on a site. Some individual clones exhibited wide variation in YB/CT ratios between different sites, indicating a clone x site interaction for this trait. The commercial clone NM6, used as a check clone in most of our studies, had the widest variation of any clone in YB/CT ratios between sites, ranging from 53 % to 104 %. Of the 22 YB/CT yield ratios for specific clones on 14 sites, only four were above 100 %, indicating a clear trend for CT overestimating yields in YB. The average of the 22 YB/CT ratios was 86 %, again indicating overestimation of YB yield in the CT. The YB/CT ratio for NM6 averaged 79 %, while five elite (fast growing, disease resistant) clones averaged a YB/CT yield ratio of 89 % over the 14 sites. CT/YB yield ratios are too variable to use CT growth as an estimate of growth for specific clones under near commercial conditions (YB).