Assessing freeze-tolerance in St. Augustinegrass: temperature response and evaluation methods

Jennifer A. Kimball, Tan D. Tuong, Consuelo Arellano, David P. Livingston, Susana R. Milla-Lewis

Research output: Contribution to journalArticlepeer-review

Abstract

Winter hardiness is a major-limiting factor for St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] grown in the transitional climatic region of the United States. Lab-based freeze tests that mimic the range of field winter survivability in St. Augustinegrass can contribute to the selection of cold hardy genotypes. This study used a whole container method, four freezing temperatures, and two data collection systems to evaluate the freezing response of nine St. Augustinegrass genotypes ranging in their winter hardiness. Results indicated −3 and −4 °C with average regrowth ratings of 33.6 and 17.8% respectively, were more suitable temperatures for evaluating freeze survival in St. Augustinegrass than −5 and −6 °C with average regrowth ratings of 0.4 and 0%, respectively. Visual ratings of surviving green tissue and regrowth were generally well correlated when evaluated over a six week period post-freeze with Pearson correlation coefficients ranging of 0.17–0.62 for −3 °C freeze tests and 0.79–0.93 for −4 °C freeze tests. Additionally, measurement of percent green cover using digital imaging techniques commonly utilized in turfgrass field studies were significantly correlated (0.66) with visual ratings averaged across weekly post-freeze evaluation measurements for both −3 and −4 °C freezing temperatures. These results provide evidence that digital imaging analyses are useful in estimating surviving green tissue and regrowth in lab-based freeze tests. This study provides additional information regarding freezing temperatures, genotype responses, and data collection methods in St. Augustinegrass, which should aid breeders in the improvement of freeze tolerance in the species.

Original languageEnglish (US)
Article number110
JournalEuphytica
Volume213
Issue number5
DOIs
StatePublished - May 1 2017
Externally publishedYes

Bibliographical note

Funding Information:
The authors would like to thank Dr. Aaron J. Patton for critical review of this manuscript. This research was supported in part by funding provided by the North Carolina Crop Improvement Association and the North Carolina State University Center for Turfgrass Environmental Research and Education.

Publisher Copyright:
© 2017, Springer Science+Business Media Dordrecht.

Keywords

  • Breeding
  • Freezing tolerance
  • St. Augustinegrass
  • Turfgrass

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