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Pollination and seed production in western white pine

Owens, J.N., Fernando, D.D.
Canadian journal of forest research = 2007 v.37 no.2 pp. 260-275
Pinus monticola, seed productivity, forest trees, seed cones, seeds, orchards, pollination, seed abortion
The reproductive biology of western white pine (Pinus monticola Dougl. ex D. Don) at the Saanich seed orchard (SSO; a coastal seedling seed orchard) and the Kalamalka seed orchard (KSO; an interior clonal seed orchard) is described. Seed-cone development and morphology determine seed potential and affect filled seed production. Seed potential was high, commonly over 200 seeds per cone and filled seeds per cone averaged 50-60 at both orchards in 1999 from open pollinations combined with operational supplemental mass pollinations (OP-SMP). Filled seeds per cone at SSO in 2004 averaged 115 with open pollinations and OP-SMP. About 30% of ovules aborted before pollination. Another 25% aborted probably because of self-incompatibility at fertilization. Seed efficiency (SEF) was only 5% at KSO with open pollination but increased to 30% with OP-SMP. SEF was the same at SSO with or without OP-SMP. Reproductive success was very low at KSO without OP-SMP but increased to about 10%, similar to that of SSO, with OP-SMP. The optimal time for control pollinations was at cone stages 4 and 5 and optimal amount of pollen per pollination bag was 0.3-0.4 mL. Western white pine is a very good seed producer and can be easily managed in seed orchards to give very high seed production per cone and per tree.