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Winter cold-tolerance thresholds in field-grown Miscanthus hybrid rhizomes.

Peixoto Mde M, Friesen PC, Sage RF - J. Exp. Bot. (2015)

Bottom Line: Two artificial freezing protocols were tested: one lowered the temperature continuously by 1°C h(-1) to the treatment temperature and another lowered the temperature in stages of 24h each to the treatment temperature.The results demonstrated that rhizomes from diploid Miscanthus lines have superior cold tolerance that could be exploited to improve performance in more productive polyploid lines.With expected levels of soil insulation, low winter air temperatures should not harm rhizomes of tolerant diploid genotypes of Miscanthus in temperate to sub-boreal climates (up to 60°N); however, the observed winter cold in sub-boreal climates could harm rhizomes of existing polyploid varieties of Miscanthus and thus reduce stand performance.

View Article: PubMed Central - PubMed

Affiliation: University of Toronto, Department of Ecology and Evolutionary Biology, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2.

No MeSH data available.


Related in: MedlinePlus

Survivability of Miscanthus rhizomes as a function of temperature in the continuous-cooling experiment. (A) M115; (B) M147; (C) M116; (D) M161; (E) M118. Symbols are observed values [mean±standard error (SE), n=6] and lines are predicted responses using a logistic regression. Filled diamonds, November 2009; open circles, January 2010; filled stars, August 2010. LT50 is the temperature at which a rhizome population is predicted to exhibit 50% mortality. Treatment temperature significantly affected the survivability of rhizomes (P<0.001), while differences between the Miscanthus varieties were not significant (P=0.53). The interaction between genotypes and temperature on survivability was significant (P=0.001), as was the interaction between genotype and sampling date (P=0.0014). Differences in sampling date were not significant (P=0.08).
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Figure 3: Survivability of Miscanthus rhizomes as a function of temperature in the continuous-cooling experiment. (A) M115; (B) M147; (C) M116; (D) M161; (E) M118. Symbols are observed values [mean±standard error (SE), n=6] and lines are predicted responses using a logistic regression. Filled diamonds, November 2009; open circles, January 2010; filled stars, August 2010. LT50 is the temperature at which a rhizome population is predicted to exhibit 50% mortality. Treatment temperature significantly affected the survivability of rhizomes (P<0.001), while differences between the Miscanthus varieties were not significant (P=0.53). The interaction between genotypes and temperature on survivability was significant (P=0.001), as was the interaction between genotype and sampling date (P=0.0014). Differences in sampling date were not significant (P=0.08).

Mentions: In the continuous-cooling study, the survivability of the rhizomes from five genotypes was similar when sampled in November 2009 and January 2010 (Fig. 3). LT50 values from the five genotypes ranged between –4.4 and –6.7 °C. Variety Illinois (the triploid used in Illinois trials by Heaton et al. 2008a and Dohleman & Long 2009) was the least cold tolerant, with 50% rhizome mortality at –5 °, and an estimated LT50 of –4.4 °C in January 2010. The diploid variety M115 was the most cold tolerant, with no mortality at –5 °C for the November 2009 and January 2010 samplings and corresponding LT50 estimates of –6.3 and –6.7 °C. Rhizomes sampled in the summer (August 2010) were as cold tolerant as winter-sampled rhizomes in the M115 and M147 lines but were less cold tolerant by approximately 2–3 °C in the triploid (Nagara and Illinois) and tetraploid (M118) lines (Table 1). For example, for the Illinois genotype, the estimated LT50 in the rhizomes for the August 2010 sampling rose to –1.5 °C, approximately 3 °C warmer than for rhizomes sampled in the previous winter. In all cases, no Miscanthus rhizome resprouted after exposure to temperatures of –10 °C or lower.


Winter cold-tolerance thresholds in field-grown Miscanthus hybrid rhizomes.

Peixoto Mde M, Friesen PC, Sage RF - J. Exp. Bot. (2015)

Survivability of Miscanthus rhizomes as a function of temperature in the continuous-cooling experiment. (A) M115; (B) M147; (C) M116; (D) M161; (E) M118. Symbols are observed values [mean±standard error (SE), n=6] and lines are predicted responses using a logistic regression. Filled diamonds, November 2009; open circles, January 2010; filled stars, August 2010. LT50 is the temperature at which a rhizome population is predicted to exhibit 50% mortality. Treatment temperature significantly affected the survivability of rhizomes (P<0.001), while differences between the Miscanthus varieties were not significant (P=0.53). The interaction between genotypes and temperature on survivability was significant (P=0.001), as was the interaction between genotype and sampling date (P=0.0014). Differences in sampling date were not significant (P=0.08).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4493781&req=5

Figure 3: Survivability of Miscanthus rhizomes as a function of temperature in the continuous-cooling experiment. (A) M115; (B) M147; (C) M116; (D) M161; (E) M118. Symbols are observed values [mean±standard error (SE), n=6] and lines are predicted responses using a logistic regression. Filled diamonds, November 2009; open circles, January 2010; filled stars, August 2010. LT50 is the temperature at which a rhizome population is predicted to exhibit 50% mortality. Treatment temperature significantly affected the survivability of rhizomes (P<0.001), while differences between the Miscanthus varieties were not significant (P=0.53). The interaction between genotypes and temperature on survivability was significant (P=0.001), as was the interaction between genotype and sampling date (P=0.0014). Differences in sampling date were not significant (P=0.08).
Mentions: In the continuous-cooling study, the survivability of the rhizomes from five genotypes was similar when sampled in November 2009 and January 2010 (Fig. 3). LT50 values from the five genotypes ranged between –4.4 and –6.7 °C. Variety Illinois (the triploid used in Illinois trials by Heaton et al. 2008a and Dohleman & Long 2009) was the least cold tolerant, with 50% rhizome mortality at –5 °, and an estimated LT50 of –4.4 °C in January 2010. The diploid variety M115 was the most cold tolerant, with no mortality at –5 °C for the November 2009 and January 2010 samplings and corresponding LT50 estimates of –6.3 and –6.7 °C. Rhizomes sampled in the summer (August 2010) were as cold tolerant as winter-sampled rhizomes in the M115 and M147 lines but were less cold tolerant by approximately 2–3 °C in the triploid (Nagara and Illinois) and tetraploid (M118) lines (Table 1). For example, for the Illinois genotype, the estimated LT50 in the rhizomes for the August 2010 sampling rose to –1.5 °C, approximately 3 °C warmer than for rhizomes sampled in the previous winter. In all cases, no Miscanthus rhizome resprouted after exposure to temperatures of –10 °C or lower.

Bottom Line: Two artificial freezing protocols were tested: one lowered the temperature continuously by 1°C h(-1) to the treatment temperature and another lowered the temperature in stages of 24h each to the treatment temperature.The results demonstrated that rhizomes from diploid Miscanthus lines have superior cold tolerance that could be exploited to improve performance in more productive polyploid lines.With expected levels of soil insulation, low winter air temperatures should not harm rhizomes of tolerant diploid genotypes of Miscanthus in temperate to sub-boreal climates (up to 60°N); however, the observed winter cold in sub-boreal climates could harm rhizomes of existing polyploid varieties of Miscanthus and thus reduce stand performance.

View Article: PubMed Central - PubMed

Affiliation: University of Toronto, Department of Ecology and Evolutionary Biology, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2.

No MeSH data available.


Related in: MedlinePlus