Variation among Highbush Blueberry Cultivars for Frost Tolerance of Open Flowers

Injury of open flowers often occurs in fruit crops by late winter or early spring frosts and can result in significant reduction in yield. In this study, freezing tolerance of open flowers of five highbush blueberry cultivars, Bluecrop, Elliott, Hannah’s Choice, Murphy, and Weymouth, was determined using two freezing methods. Methods involved either placing whole plants in a radiation frost chamber or detached shoots in a glycol-freezing bath. In both methods, plants (or excised shoots) with opening flowers were exposed to temperatures ranging from –2 to –10 °C. After freeze treatments, several flower parts were evaluated for damage and the lethal temperature50 (LT50) determined. In order, from the most sensitive flower part to the least sensitive on average, were the corolla, filament, anther, style, exterior ovary, stigma, ovules, interior ovary, and placenta. A two-way analysis of variance (ANOVA) found no significant effect of the freezing method on the calculated freeze damage to most of the various flower parts. However, a significant genotype effect was found on freeze damage to the style, filament, anthers, and exterior ovary. Overall, ‘Bluecrop’ was the most sensitive to freezing, whereas ‘Hannah’s Choice’ and ‘Murphy’ were the most freezing-tolerant. In conclusion, genotypic variability in frost tolerance of open highbush blueberry flowers was detected, which can be exploited in breeding for more frost-tolerant cultivars.

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Protecting Blueberries from Freezes in Florida

EDIS ◽

10.32473/edis-hs216-2004 ◽

1969 ◽

Vol 2004 (7) ◽

Author(s):

Paul M. Lyrene ◽

Jeffrey G. Williamson

Keyword(s):

Early Spring ◽

Cooperative Extension Service ◽

Late Winter ◽

Publication Date ◽

Highbush Blueberry ◽

University Of Florida ◽

Frost Injury ◽

Early Ripening ◽

Freeze Damage ◽

Southern Highbush

Blueberries bloom in late winter or early spring in Florida, making the flowers and young fruit highly susceptible to freeze and frost injury. Killing freezes can occur as late as mid to late March throughout much of Florida, long after the initiation of bloom, especially for early-ripening southern highbush blueberry cultivars. This publication describes conditions that often occur in commercial blueberry fields during and after bloom when the potential for freeze damage exists. Practices that growers can use to minimize freeze damage are also discussed. This document is HS968, one of a series of the Department of Horticultural Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date: May 2004. HS968/HS216: Protecting Blueberries from Freezes in Florida (ufl.edu)

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(236) Evaluation of Styrax japonicus for Time of Budbreak and Susceptibility to Spring Freeze Damage

HortScience ◽

10.21273/hortsci.40.4.1002b ◽

2005 ◽

Vol 40 (4) ◽

pp. 1002B-1002 ◽

Cited By ~ 1

Author(s):

Sandra Reed

Keyword(s):

United States ◽

Genetic Variability ◽

Weather Conditions ◽

The United States ◽

Early Spring ◽

Late Winter ◽

Ornamental Tree ◽

Good Consistency ◽

Spring Temperatures ◽

Freeze Damage

Japanesesnowbell(Styrax japonicus Sieb. & Zucc.) is an outstanding small ornamental tree that is underutilized in the United States. Many of the cultivars of this Asian native frequently suffer spring freeze damage, especially when grown in the areas of the country that routinely experience dramatic fluctuations in late winter and early spring temperatures. The objectives of this study were to determine if there was variability within S. japonicus for time of budbreak and if this variability could be used for selecting plants with reduced susceptibility to spring freeze damage. In 1998, 224 open-pollinated seedlings were planted in the field. Percent budbreak was evaluated weekly during a 6-week period in Spring 1999 and 2000. While weather conditions varied greatly between the 2 years, there was good consistency between mean budbreak ratings in 1999 and 2000. There was a 4-week difference between the earliest and latest plants to break dormancy. Based on the 1999 and 2000 data, 28 plants were selected and propagated. A replicated trial involving these selections and three cultivars was carried out in 2002, 2003, and 2004. All of the selections broke bud later and suffered less freeze damage than `Emerald Pagoda' and `Carillon', but many performed similarly to `Pink Chimes'. Variation in height, width, caliper, and canopy shape was observed among the selections. There is an opportunity to utilize the genetic variability in S. japonicus for developing cultivars with reduced susceptibility to spring freeze damage.

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Effect of Snow Removal on Typhula Blight Development at High Elevation Golf Courses in Colorado

Plant Health Progress ◽

10.1094/php-2013-0821-02-rs ◽

2013 ◽

Vol 14 (1) ◽

pp. 12 ◽

Cited By ~ 1

Author(s):

Tamla Blunt ◽

Tony Koski ◽

Ned Tisserat

Keyword(s):

Kentucky Bluegrass ◽

High Elevation ◽

Early Spring ◽

Disease Suppression ◽

Late Winter ◽

Putting Greens ◽

Freeze Avoidance ◽

Snow Removal ◽

Freeze Damage ◽

High Elevations

Golf course superintendents at high elevations in Colorado apply fungicides in late October before permanent snow cover to suppress Typhula blight development. Many remove snow from putting greens in late winter or early spring assuming this practice helps suppress Typhula blight late into the snow season. They also remove snow to prevent ice formation and freeze damage to turfgrass during snowmelt. However, the benefits of spring snow removal in disease suppression and freeze avoidance have not been demonstrated in Colorado. We compared Typhula blight severity and turfgrass health in Kentucky bluegrass and annual bluegrass fairways where snow was removed weekly from late October through mid-November, from early- to mid-March until the end of the snow period, or not removed. Fall snow removal did not reduce Typhula blight severity compared to no snow removal, but it did result in freeze damage to annual, but not Kentucky bluegrass. Spring snow removal had no effect on Typhula blight severity or freeze damage. Thus the practice of snow removal was of no apparent benefit in our studies. Accepted for publication 3 June 2013. Published 21 August 2013.

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Long-term changes in the frost-free season on the Canadian prairies

Canadian Journal of Plant Science ◽

10.4141/p03-169 ◽

2004 ◽

Vol 84 (4) ◽

pp. 1085-1091 ◽

Cited By ~ 17

Author(s):

Herb Cutforth ◽

EG (Ted) O’Brien ◽

Jason Tuchelt ◽

Rick Rickwood

Keyword(s):

Climate Change ◽

Early Spring ◽

Late Winter ◽

Past Century ◽

Canadian Prairies ◽

Spring Frost ◽

Growing Seasons ◽

Spring Frosts ◽

Agricultural Regions

The climate of the prairies has warmed over the past century, especially during late winter and early spring. Some regions of the prairies have warmed faster than others. Climate change has been documented to affect living systems in North America, such as promoting earlier phenological development and longer growing seasons. We examined weather records gathered at several long-term weather-recording sites across the agricultural regions of the Canadian prairies for evidence of trends in last spring frosts, first fall frosts, and frost-free durations. During the latter half of the 20th century, the trends were towards earlier last spring frost dates and towards longer frost-free seasons in the agricultural regions of the Canadian prairies. Across most of the prairies the trends towards later first fall frost dates were smaller and generally not significant. The largest changes have occurred in the central and northern agricultural regions of Alberta, whereas the least change occurred over much of southern Alberta and in southern Manitoba. Key words: Last spring and first fall frost dates, frost-free season, agroclimatic indices, climate change, Canadian prairies

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Genetic linkage mapping for molecular dissection of chilling requirement and budbreak in apricot (Prunus armeniaca L.)

Genome ◽

10.1139/g09-050 ◽

2009 ◽

Vol 52 (10) ◽

pp. 819-828 ◽

Cited By ~ 62

Author(s):

Bode A. Olukolu ◽

Taly Trainin ◽

Shenghua Fan ◽

Chittaranjan Kole ◽

Douglas G. Bielenberg ◽

...

Keyword(s):

Interval Mapping ◽

Early Spring ◽

Prunus Armeniaca ◽

Climatic Conditions ◽

High Density ◽

Late Winter ◽

Phenotypic Variance ◽

Chilling Requirement ◽

Density Maps ◽

Spring Frosts

Commercial production of apricot is severely affected by sensitivity to climatic conditions, an adaptive feature essential for cycling between vegetative or floral growth and dormancy. Yield losses are due to late winter or early spring frosts and inhibited vegetative or floral growth caused by unfulfilled chilling requirement (CR). Two apricot cultivars, Perfection and A.1740, were selected for high and low CR, respectively, to develop a mapping population of F1 individuals using a two-way pseudo-testcross mapping strategy. High-density male and female maps were constructed using, respectively, 655 and 592 markers (SSR and AFLP) spanning 550.6 and 454.9 cM with average marker intervals of 0.84 and 0.77 cM. CR was evaluated in two seasons on potted trees forced to break buds after cold treatments ranging from 100 to 900 h. A total of 12 putative CR quantitative trait loci (QTLs) were detected on six linkage groups using composite interval mapping and a simultaneous multiple regression fit. QTL main effects of additive and additive × additive interactions accounted for 58.5% ± 6.7% and 66.1% ± 5.8% of the total phenotypic variance in the Perfection and A.1740 maps, respectively. We report two apricot high-density maps and QTLs corresponding to map positions of differentially expressed transcripts and suggested candidate genes controlling CR.

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Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽

10.1071/sr9941355 ◽

1994 ◽

Vol 32 (6) ◽

pp. 1355 ◽

Cited By ~ 12

Author(s):

RB Garnsey

Keyword(s):

Soil Moisture ◽

Adult Development ◽

Survival Rates ◽

Soil Surface ◽

Early Spring ◽

Lumbricus Rubellus ◽

Late Winter ◽

Cocoon Production ◽

Density And Biomass ◽

Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

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TEMPERATURE RESISTANCE OF GOLDFISH MAINTAINED UNDER CONTROLLED PHOTOPERIODS

Canadian Journal of Zoology ◽

10.1139/z59-050 ◽

1959 ◽

Vol 37 (4) ◽

pp. 419-428 ◽

Cited By ~ 40

Author(s):

William S. Hoar ◽

G. Beth Robertson

Keyword(s):

Temperature Change ◽

Seasonal Variations ◽

Rapid Growth ◽

Endocrine System ◽

Early Spring ◽

Late Winter ◽

Thyroid Activity ◽

Temperature Resistance ◽

Sudden Temperature Change

Goldfish maintained under controlled photoperiods for 6 weeks or longer were relatively more resistant to a sudden elevation in temperature when the daily photoperiods had been long (16 hours) and relatively more resistant to sudden chilling when they had been short (8 hours). The magnitude of the effect varied with the season. Thyroid activity was slightly greater in fish maintained under the shorter photoperiods. The longer photoperiods stimulated more rapid growth of ovaries during late winter and early spring. The endocrine system is considered a link in the chain of events regulating seasonal variations in resistance to sudden temperature change.

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Leaf spot and dry rot of lettuce caused by Xanthomonas vitians (Brown) Dowson

Australian Journal of Agricultural Research ◽

10.1071/ar9630778 ◽

1963 ◽

Vol 14 (6) ◽

pp. 778 ◽

Cited By ~ 4

Author(s):

DE Harrison

Keyword(s):

Leaf Spot ◽

Early Spring ◽

Late Winter ◽

Laboratory Studies ◽

Dry Rot ◽

Complete Destruction ◽

Western Victoria ◽

Valley Area ◽

North Western

During the late winter and early spring of 1960, and again to a lesser extent in 1961 and 1962, many lettuce crops in the Murray Valley area of north-western Victoria were seriously affected by a disease characterized by blackening, dry rotting, and collapse of the affected leaves. The incidence of disease varied from about 10% up to practically complete destruction of some plantings. A yellow bacterium was consistently isolated from affected plants and proved to be pathogenic to lettuce. Laboratory studies have shown that the organism agrees closely with the recorded description of Xanthomonas vitians (Brown) Dowson, which has not, apparently, been previously studied in Australia.

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Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

Bulletin of Entomological Research ◽

10.1017/s0007485314000315 ◽

2014 ◽

Vol 104 (5) ◽

pp. 576-585 ◽

Cited By ~ 29

Author(s):

C. Monzo ◽

J.A. Qureshi ◽

P.A. Stansly

Keyword(s):

Natural Enemy ◽

Early Spring ◽

Citrus Greening ◽

Asian Citrus Psyllid ◽

Late Winter ◽

Diaphorina Citri ◽

Citrus Groves ◽

Arthropod Fauna ◽

Predator Exclusion ◽

Insecticide Sprays

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of ‘huanglongbing’ (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.

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Phenological phases of pollination related to climate change

10.5194/egusphere-egu21-15034 ◽

2021 ◽

Author(s):

Samuel Monnier ◽

Michel Thibaudon ◽

Jean-Pierre Besancenot ◽

Charlotte Sindt ◽

Gilles Oliver

Keyword(s):

Climate Change ◽

Pollen Season ◽

Microscopic Analysis ◽

Allergic Diseases ◽

Early Spring ◽

Late Winter ◽

General Tendency ◽

New Production ◽

Start Date ◽

Generic Term

Knowledge:Rising CO2 levels and climate change may be resulting in some shift in the geographical range of certain plant species, as well as in increased rate of photosynthesis. Many plants respond accordingly with increased growth and reproduction and possibly greater pollen yields, that could affect allergic diseases among other things.The aim of this study is the evolution of aerobiological measurements in France for 25-30 years. This allows to follow the main phenological parameters in connection with the pollination and the ensuing allergy risk.Material and method:The RNSA (French Aerobiology Network) has pollen background-traps located in more than 60 towns throughout France. These traps are volumetric Hirst models making it possible to obtain impacted strips for microscopic analysis by trained operators. The main taxa studied here are birch, grasses and ragweed for a long period of more than 25 years over some cities of France.Results:Concerning birch but also other catkins or buds&#8217; trees pollinating in late winter or spring, it can be seen an overall advance of the pollen season start date until 2004 and then a progressive delay, the current date being nearly the same as it was 20 years ago, and an increasing trend in the quantities of pollen emitted.For grasses and ragweed, we only found a few minor changes in the start date but a longer duration of the pollen season.Discussion:As regards the trees, the start date of the new production of catkins or buds is never the 1st of January but depends on the species. For example, it is early July for birch. For breaking dormancy, flowering, and pollinating, the trees and other perennial species need a period of accumulation of cold degrees (Chilling) and later an accumulation of warm degrees (Forcing). With climate change these periods may be shorter or longer depending of the autumn and winter temperature. Therefore, a change in the annual temperature may have a direct effect on the vegetal physiology and hence on pollen release. It may also explain why the quantities of pollen produced are increasing.The Poaceae reserve, from one place to another and without any spatial structuring, very contrasted patterns which make it impossible to identify a general tendency. This is probably due to the great diversity of taxa grouped under the generic term Poaceae, which are clearly not equally sensitive to climate change.Conclusion:Trees with allergenic pollen blowing late winter or early spring pollinate since 2004 later and produce amounts of pollen constantly increasing. Grasses and ragweed have longer periods of pollination with either slightly higher or most often lower pollen production.

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