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Abstract
Seed production in southern pine seed orchards can be evaluated by estimating the efficiency of four separate stages of cone, seed, and seedling development. Calculated values are: cone efficiency (CE), the ratio of mature cones to the initial flower crop; seed efficiency (SE), the ratio of filled seeds per cone to the seed potential; extraction efficiency (EE), the ratio of extracted seeds per cone to the total seeds; and germination efficiency (GE), the ratio of germinated seeds per cone to the filled seeds. The product of these four efficiency values is the overall seed orchard to nursery efficiency (SO-NE). With SO-NE, the orchard manager can compare the actual yield of seedlings produced from the orchard to the maximum biological potential of a given flower crop to produce viable seeds. The two approaches to increasing production of seed orchards are to increase flower production and to increase CE, SE, EE, or GE values. Computation of efficiency values pinpoints major types of seed losses and shows where corrective actions should be concentrated.
Parent Publication
Citation
Bramlett, David L. 1977. Efficiency of seed production in southern pine seed orchards. In: Proceedings of the Thirteenth Lake States Forest Tree Improvement Conference; Gen. Tech. Rep. NC-50. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 17-25
