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Predicting Planting Stock Quality

Author(s) or contact(s): S.J. L'Hirondelle, D.G. Simpson, and W.D. Binder
Source: Research Branch
Subject: Seedling Production
Series: Posters
Other details:  Published 2006. Hardcopy is available.
 

Abstract

Storability

Stock-testing facilities need a fast, reliable method to estimate overwinter storability of seedlings (ability to survive and grow after cold storage). We compared two methods using container-grown seedlings of coastal and interior Douglas-fir, interior spruce, lodgepole pine, and western larch from British Columbia nurseries.

  • Fall frost hardiness was estimated using visible injury of foliage or stems (VI) and chlorophyll fluorescence of shoots (CF) after freezing to -18C. Seedlings were then put into overwinter cold storage (-2C).
  • In spring, seedlings were planted in nursery beds; survival and growth assessed after one growing season.
  • There were close correlations (r >= 0.93) between VI and CF.
  • Seedlings lifted after reaching >= 69% for CF and <= 25% for VI had over 90% survival at harvest and doubled shoot dry weight compared with seedlings lifted earlier.
  • Measuring CF was the fastest and most easily replicated method to estimate successful storability, and reduced testing time by 6 days relative to VI tests.

Field Performance

After cold storage, conifer seedlings in British Columbia are tested for field growth potential before planting. We compared two tests of performance potential using container-grown conifer seedlings.

  • Thawed seedlings were assessed for root growth potential (RGP) and CF.
  • Seedlings were planted in nursery beds; survival and growth were assessed after one growing season.
  • Performance tests were significantly correlated with each other (r >= 0.53).
  • The best performance predictor was CF + RGP (R2 = 0.79 for 78 seedlot x lift-date combinations), which minimized the risk of planting poor seedlings and not planting good seedlings.
  • A sum of 83 for CF + RGP provided a threshold above which survival and growth were good.
  • We recommend a combination of CF + RGP to assess vigour of shoot and root systems before planting.

Poster 78 (low resolution) (385 KB)

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Updated July 24, 2015