Seed orchard of boreal tree species

Seed orchards consist of plus trees have been established for Abies sachalinensis, Larix kaempferi, Larix gmelinii and Picea glenhii at several places over Hokkaido island. It is expected that genetically improved seeds are produced in the seed orchards, however, flowering of the species is different year by year and seed production is poor frequently. Therefore, the management of seed orchards is required to supply the improved seed meet the demand. is required. Our study indicated that improvement of light condition by thinning is efficient to increase seed production. In addition to that, the effective application of girdling or plant hormone treatment are also examined.

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Time course of the flowering index in each tree species
The indices cosist of no flower = 1, maximum flowering =5
Means from all observed seed orchards

 

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A larch seed orchard after row-thinning to improve light condition

 

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Scoring to promote flowering

 

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