Comparative analysis of laboratory freezing methods to establish cold tolerance of detached rhizomes and intact crowns in garden chrysanthemums (Dendranthema × grandiflora Tzvelv.)

Dong Chan Kim, Neil O. Anderson

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Since 1926, the University of Minnesota herbaceous perennial breeding program has released N = 84 garden chrysanthemum cultivars (Dendranthema × grandiflora) with important traits for northern temperate climates, such as winter hardiness. Recent breeding objectives have identified the need for development of non-destructive phenotypic markers and destructive laboratory freezing tests for co-selection of cold tolerance in Dendranthema, Gaura, and other herbaceous perennial flower crops. Such methods have become critical to flower breeding programs in northern temperate regions during periods of above-average winter temperatures and minimal snow cover due to the 'el Niño' effect. Two different, destructive laboratory freezing tests were evaluated for their effectiveness in determining cold tolerance. Acclimated crowns of n = 6 garden chrysanthemum genotypes, ranging from hardy to non-hardy in USDA Z3-4, were used in Omega Block (using detached, emergent rhizomes) and chamber (using entire, intact crowns with emergent, non-emergent rhizomes) freezing test methods. Comparative winter survival in the field was monitored over locations and years. Cold tolerance was assessed at 0 to -12 °C with varying ramp and soak time periods. LT50 temperatures and number of living emergent rhizomes were also determined. Rhizome quality at 1, 3, and 5 cm depths was rated for regrowth on a 0 (dead) to 5 (undamaged) scale. The chamber freezing method was the most powerful to discern accurate LT50 values. Cold tolerant genotypes included 'Duluth' and Mn. Selection 98-89-7 (LT50 = -12 °C). Four genotypes were rated as non-hardy (LT50 = ≤-10 °C). Cold-tolerant genotypes also had significantly higher regrowth ratings for rhizomes at 1 and 3 cm depths. Future research will implement the chamber freezing method to assay the inheritance of winter hardiness in intact crowns of segregating populations.

Original languageEnglish (US)
Pages (from-to)345-352
Number of pages8
JournalScientia Horticulturae
Volume109
Issue number4
DOIs
StatePublished - Aug 15 2006

Bibliographical note

Funding Information:
This research was funded by grants from the KOSEF (Korea Science and Engineering Foundation), Chungnam RDA (Rural Development Administration), and the University of Minnesota Agricultural Experiment Station.

Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

Keywords

  • Crowns
  • Freezing method
  • Herbaceous perennials
  • Rhizomes
  • Winter hardiness

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