scholarly journals Cold Hardiness of Weigela Cultivars

1998 ◽  
Vol 16 (4) ◽  
pp. 238-242 ◽  
Author(s):  
Steve McNamara ◽  
Harold Pellett
Keyword(s):  
Low Temperature ◽  
Cold Hardiness ◽  
Temperature Tolerance ◽  
Cold Injury ◽  
Late Winter ◽  
Freeze Thaw ◽  
Lethal Temperatures ◽  
Low Temperature Tolerance ◽  
Temperature Controlled ◽  
Cold Hardy

Abstract Laboratory freezing tests of stem hardiness were conducted to develop cold hardiness profiles for 18 weigela (Weigela sp.) cultivars during the fall and winter of 1994–95. Tests were performed on containerized plants held in a temperature-controlled greenhouse to prevent exposure to potentially lethal temperatures. No cultivar survived below −6C (21F) in the October 3 test. Subsequent differences in rates of acclimation resulted in cultivars differing in hardiness by as much as 13C (23F) on November 14. Taxa also differed greatly in their maximum midwinter low temperature tolerance with ‘Centennial’ and ‘Eva Supreme’ hardy to −44C (−47F) and −28C (−18F) in mid-January, respectively. None of the cultivars deacclimated substantially in response to a week of artificially-imposed diurnal freeze/thaw cycles in early February. Taxa with the greatest midwinter hardiness also maintained the greatest hardiness in early March. Overall, ‘Centennial’, ‘Java Red’, and ‘Samba’ were the most cold hardy cultivars tested, while ‘Boskoop Glory’, ‘Bristol Snowflake’, and ‘Variegata’ were the least hardy. Cold injury of susceptible weigela cultivars appears to be a consequence of late hardening and/or insufficient midwinter hardiness rather than rapid deacclimation in response to periods of warm temperatures in mid-to late-winter.

scholarly journals Effects of Nitrogen and Potassium Fertilization on Perennial Ryegrass Cold Tolerance During Deacclimation in Late Winter and Early Spring

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 842-849 ◽  
Author(s):  
D.E. Webster ◽  
J.S. Ebdon
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Cold Tolerance ◽  
Perennial Ryegrass ◽  
Cold Hardiness ◽  
Shoot Growth ◽  
Temperature Tolerance ◽  
Freezing Injury ◽  
Late Winter ◽  
Exchangeable K

Turf loss from freezing injury results in costly re-establishment, especially with turfgrasses such as perennial ryegrass (Lolium perenne L.) having poor low-temperature hardiness. Studies are limited as to the influence of N and K on cold tolerance during dehardening periods in late winter when grasses are most susceptible to freezing injury. The objective of this study was to evaluate perennial ryegrass low temperature hardiness during deacclimation in response to N and K and associated effects on crown hydration, median killing temperature (LT50), shoot growth rate, tissue K concentration, soil exchangeable K, and low temperature disease. Treatments included five rate levels of N (49, 147, 245, 343, and 441 kg·ha-1·yr-1) in all factorial combinations with 3 rate levels of K (49, 245, and 441 kg·ha-1·yr-1). Low temperature tolerance was assessed using whole plant survival and electrolyte leakage (EL). Interactions between N and K were detected for all field measurements. The effects of N and K on survival LT50 were detected only during late winter periods in February 2004, N and K differences were lost by March. Late winter cold survival was negatively correlated with crown moisture, growth rate, and tissue K. Tissue K concentrations ranged from 28.6 to 35.9 g·kg–1 DM while soil K ranged from 121 to 261 mg·kg–1. Soil extractable K was not correlated with tissue K. Survival and EL LT50 were uncorrelated due to N and K interaction. Survival LT50 ranged from –9.0 to –13.6 °C. Maximum cold hardiness occurred when low to moderate N (49 to 147 kg·ha-1·yr-1) was applied with medium-high to high levels of K (245 to 441 kg·ha-1·yr-1), which corresponded to soil exchangeable K levels ranging from 200 to 260 mg·kg–1. Alternatively, similar K fertilization and soil K levels combined with high rates of N (343 and 441 kg·ha-1·yr-1) increased freeze stress and low temperature fungi (Typhula incarnata). At N rates routinely applied to perennial ryegrass, higher soil extractable K beyond those levels currently recommended for optimum shoot growth could provide some benefit in enhancing cold hardiness. Late fall applied N did not appear to increase the potential for winter injury.

Winter Bud Cold-hardiness of Interstem Peach Trees

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541e-541
Author(s):  
Gregory L. Reighard ◽  
David R. Ouellette
Keyword(s):  
United States ◽  
Cold Hardiness ◽  
Southeastern United States ◽  
Cold Injury ◽  
Late Winter ◽  
Varietal Differences ◽  
Large Fluctuations ◽  
Cold Hardy ◽  
Peach Trees ◽  
Chronic Problem

Large fluctuations in annual peach production is a chronic problem in the southeastern United States. Winter and spring cold injury to flowers reduces the potential peach crop almost every year in the Southeast. A bloom delaying peach interstem has consistently delayed phenology in the Southeast, but its effect on bud hardiness is unknown. Nine varieties (650–1050 chill hours) budded to `Ta Tao 5' (P.I. 101667) interstems on Lovell rootstock or budded to only Lovell rootstock (i.e., controls) were sampled monthly from November or December to late February in 1996–97 and 1997–98 from an interstem test established in 1993 near Clemson, S.C. High-chill varieties such as `Contender', `Encore', and `Redhaven' were 1 to 2 °C more cold-hardy on interstem trees in late winter. General trends showed that varieties were slightly more cold-hardy on interstems in 1996–97, but no differences were observed from Nov.1997 through early Jan. 1998. Significant varietal differences in cold-hardiness were found on each sampling date, but no trends were observed.

A comparison of the cold hardiness of populations of Delia radicum (L.) (Diptera: Anthomyiidae) from southern England and the Canadian Prairies

1990 ◽  
Vol 68 (5) ◽  
pp. 830-835 ◽  
Author(s):  
W. J. Turnock ◽  
P. M. Reader ◽  
G. K. Bracken
Keyword(s):  
Low Temperature ◽  
Cold Hardiness ◽  
Cold Injury ◽  
Delia Radicum ◽  
Supercooling Point ◽  
Canadian Prairies ◽  
Canadian Population ◽  
English Population ◽  
Cold Hardy ◽  
The Relationship

The Canadian population of Delia radicum is more cold hardy than the English population in that the supercooling point is slightly lower and overwintering pupae are less sensitive to lower temperatures and longer exposure times. However, the Canadian population is slightly less cold hardy at higher temperatures within the cold injury zone. Female D. radicum were more susceptible to cold-induced mortality than males among the Canadian population, but this sex difference was not significant in the English population. The proportion of malformed adults and the rate of postdiapause development were not related to cold injury in either population. The bounds of the cold injury zone for species or populations of freezing susceptible, diapausing insects plus the sensitivity of the species to cold injury within this zone can provide an ecologically sound method of describing cold hardiness. Sensitivity, measured by the slope of a regression describing the relationship between survival and the duration of exposure at a low temperature, can also be used to calculate the rate at which cold injury occurs at any temperature within the cold injury zone. This slope may reflect the overwintering conditions of a species or population because Canadian populations of both D. radicum and Mamestra configurata (Noctuidae) have similar coefficients, but these are very different from the coefficient of the English population of D. radicum. The supercooling point did not provide a useful indication of the susceptibility of these cold-hardy diapausing insects to cold injury.

scholarly journals Responses of Five Container-grown Herbaceous Perennial Species to Laboratory Freezing

1993 ◽  
Vol 3 (2) ◽  
pp. 192-194 ◽  
Author(s):  
Jeffery K. Iles ◽  
Nancy H. Agnew
Keyword(s):  
Low Temperature ◽  
Cold Hardiness ◽  
Normal Growth ◽  
Temperature Tolerance ◽  
Perennial Species ◽  
Plant Materials ◽  
Protection Measures ◽  
Low Temperature Tolerance ◽  
Commercially Important ◽  
Herbaceous Perennial

The capacity of plant materials to resume normal growth after exposure to low temperature is the ultimate criterion of cold hardiness. We therefore determined the low-temperature tolerance of five commercially important herbaceous perennial species. Container-grown blanket flower (Gaillardia ×grandiflora Van Houtte. `Goblin'), false dragonhead [Physoste- gia virginiana (L.) Benth. `Summer Snow'], perennial salvia (Salvia ×superba Stapf. `Stratford Blue'), painted daisy (Tanacetum coccineum Willd. `Robinson's Mix'), and creeping veronica (Veronica repens Loisel.) were subjected to 0, -2, 4, -6, -8, -10, -12, -14, -16, and -18C in a programmable freezer. The percentage of survival of most species was adequate when exposed to -10C. Producers of container-grown perennials are advised to provide winter protection measures that prohibit root medium temperatures from falling below -10C.

scholarly journals Relationship between low-temperature tolerance and vernalization response in wheat and rye

1996 ◽  
Vol 76 (1) ◽  
pp. 37-42 ◽  
Author(s):  
D. B. Fowler ◽  
A. E. Limin ◽  
Shi-Ying Wang ◽  
R. W. Ward
Keyword(s):  
Low Temperature ◽  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Temperature Tolerance ◽  
Temperature Acclimation ◽  
Rate Of Change ◽  
Curvilinear Relationship ◽  
Vernalization Response ◽  
Low Temperature Tolerance ◽  
Winter Cereals

Vernalization response and low-temperature acclimation are survival mechanisms that cereals have evolved to cope with low-temperature stress. Both responses have similar optimum temperature ranges for induction, and they are controlled by genetic systems that are interrelated. It has also been suggested that the completion of vernalization is responsible for the gradual loss in low-temperature tolerance observed in winter cereals maintained for long periods of time at temperatures in the optimum range for low-temperature acclimation. In the present study, two experiments were conducted with the objective of clarifying the relationship between vernalization response and low-temperature tolerance in wheat (Triticum aestivum L.) and rye (Secale cereale L.). The plants of all cultivars began to low-temperature acclimate at a rapid rate when exposed to a constant 4 °C. The rate of change in low-temperature tolerance then gradually slowed and eventually started to decline, producing a curvilinear relationship between low-temperature tolerance and stage of acclimation. A close relationship was observed between the time to vernalization saturation and the start of the decline in low-temperature tolerance of cultivars held at 4 °C. However, cereal plants retained at least a partial ability to low-temperature acclimate following exposure to warm temperatures after vernalization saturation, indicating that vernalization saturation does not result in a "switching off" of the low-temperature tolerance genes. The possibility that vernalization genes have a more subtle regulatory role in the expression of low-temperature tolerance genes could not be ruled out, and future avenues for investigation are discussed. Key words: Cold hardiness, winter hardiness, cold resistance, low-temperature acclimation, deacclimation, vernalization, wheat, rye

scholarly journals Low Temperature Tolerance of Apple Cultivars of Different Ploidy at Different Times of the Winter

2017 ◽  
Vol 71 (3) ◽  
pp. 127-131 ◽  
Author(s):  
Zoya Ozherelieva ◽  
Evgeny Sedov
Keyword(s):  
Frost Resistance ◽  
Cold Hardiness ◽  
Temperature Tolerance ◽  
Late Winter ◽  
Low Temperature Tolerance ◽  
Russian Research Institute ◽  
Apple Cultivars ◽  
Artificial Freezing ◽  
In The Beginning ◽  
Winter Buds

AbstractArtificial freezing was used to evaluate diploid and triploid apple cultivars from the All Russian Research Institute of Fruit Crop Breeding at Orel throughout three winters. The studied apple varieties were developed by breeder E. N. Sedov and cytological analysis was carried out by cytologist G. A. Sedysheva. In early winter, all cultivars exhibited high tolerance to cold. In mid-winter buds and wood were severely damaged, while bark was more resistant for most cultivars. Basic components of hardiness were estimated: component I - frost resistance at -25 °C in the beginning of winter; component II - maximum value of frost resistance at -40 °C developed by plants during hardening; component III - ability to retain the hardened condition at -25 °C after a period of three-day thaw at +2 °C; and component IV - the ability to restore frost resistance at -30 °C after repeated hardening and three-day thaw at +2 °C. During late-winter thaws, buds suffered from frosts, while the bark and wood retained frost hardiness. Late in winter all cultivars demonstrated high resistance to repeated frosts. Triploid cultivars exhibited the highest level of cold hardiness of vegetative buds, bark and wood of annual shoots throughout the winter; these cultivars included ‘Zhilinskoye’, ‘Vavilovskoye’, ‘Osipovskoye’, ‘Patriot’, ‘Sinap Orlovski’, ‘Spasskoye’, ‘Turgenevskoye’, and diploids ‘Bolotovskoye’, ‘Sokovinka’, and ‘’Ranneye Aloye’.

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