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    Author(s): T.D. Byram; F.E. Bridgwater
    Date: 1999
    Source: Proceedings of the 25th Biennial Southern Forest Tree Improvement Conference, New Orleans, Louisiana, USA
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (149 KB)


    The economic success of controlled mass pollination (CMP) depends both upon the value of the genetic gain obtained and the cost per seed. Crossing the best six loblolly pine (Pinus taeda) parents currently available in each deployment region of the Western Gulf Forest Tree Improvement Program will produce seed with an average additional gain in mean annual increment at age 20 of 16.1 compared to seed from open-pollinated seed orchards with 30% pollen contamination. The presenf value of this additional gain in growth rate is $0.177 per seed, which compares favorably to the estimated production cost $0.05 per seed. Three different CMP scenarios were evaluated by varying the number of female strobili per isolatior bag, the cost of CMP per isolation bag, and the seed obtained per strobilus pollinated. The distributions for the possible number of strobili per isolation bag and cost of CMP per isolation bag were estirnatd from two pilot-scale CMP programs. CMP cost per isolation bag included the cost of pollen collection, the installation and removal of the isolation bag, and a single pollen application. Distributions for strobili per isolation bag and the cost per isolation bag were assumed to be the same for all three scenarios. Data fiorn three loblolly pine control-pollination programs were used to estimate thy distribution for the average annual seed yield per strobilus pollinated and formed the basis for the three different scenarios. The average annual cost of CMP seed production varied substantially among programs. Where seed yields were high and consistent, the annual CMP cost averaged $0.0535 per seed with a range of $0.0119 to $0.1844. If seed yields were high but twice as variable, the annual CMP cost averaged $0.0594 per seed with a range of $0.0112 to $0.4129. Where seed yields were both lower and less dependable, the annual CMP cost ranged Tom $0.0096 to $12.120 per seed with an average of $0.1275. However, when CMP seed costs were weighted by seed production across years, all thre scenarios were economically attractive. CMP seed production weighted for total seed production we $0.0473, $0.0475 and $0.0555 for the three scenarios. The much larger quantity of cheap seed produced in good years more than offset the expensive seed produced in poor years. The annual expense per seed exceeded the breakeven cost of $0.177 only 0.2, 1.1 and 10.3 percent of the time, respectively.

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    Byram, T.D.; Bridgwater, F.E. 1999. Risk Analysis of Loblolly Pine Controlled Mass Pollination Program. Proceedings of the 25th Biennial Southern Forest Tree Improvement Conference, New Orleans, Louisiana, USA


    mass pollination, risk analysis, Pinus taeda, seed production

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