A Conductivity Method for Screening Populations of Eucalypts for Frost Damage and Frost Tolerance

1986 ◽  
Vol 34 (4) ◽  
pp. 377 ◽  
Author(s):  
CA Raymond ◽  
CE Harwood ◽  
JV Owen
Keyword(s):  
Leaf Disc ◽  
Leaf Tissue ◽  
Conductivity Measurement ◽  
Frost Damage ◽  
Field Trials ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Conductivity Method ◽  
Survival Status ◽  
Whole Plant

The assessment of frost tolerance of Eucalyptus leaf tissue by an electrical conductivity method is described. Leaf disc samples were exposed to freezing treatments in test tubes within a liquid cold bath with precise temperature control, and the conductivity of the disc leachate measured. Leaf discs were then frozen at -20°C to obtain an absolute conductivity for the tissue. A modified relative conductivity value (RC*) is presented together with calibration against visual observations of leaf damage for seedlings of E. regnans and E. delegatensis. RC* was found to be a reliable indicator of leaf survival status and the RC*-damage relationship was constant across provenances of both species. Provenance and family variation for frost tolerance were examined for both species and significant differences in tolerance levels were found for unhardened E. delegatensis and for hardened seedlings of both species at several test temperatures. Provenance rankings were identical to results from field trials reported in the literature. The effect of the period between frost treatment and conductivity measurement was assessed together with variation between leaves of the same plant and the effect of storage of cut leaves for 24 h prior to exposure to frosting treatments. The absence of any significant effects from storing leaves for 24 h indicates the potential of using the method to screen samples collected in the field. Problems of relating RC*, leaf damage and survival of the whole plant are discussed and the potential use of RC* as a simple screening technique for identifying frost-tolerant families and provenances is examined.

Screening eucalypts for frost tolerance in breeding programs

1992 ◽  
Vol 22 (9) ◽  
pp. 1271-1277 ◽  
Author(s):  
C.A. Raymond ◽  
J.V. Owen ◽  
K.G. Eldridge ◽  
C.E. Harwood
Keyword(s):  
Data Analysis ◽  
Genetic Selection ◽  
Leaf Tissue ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Alternative Methods ◽  
Small Samples ◽  
Leaf Discs ◽  
Relative Conductivity ◽  
Highly Correlated

Improvements in a laboratory technique and statistical methods for screening eucalypts for relative frost tolerance using small samples of leaf tissue are described. As a contribution to more efficient genetic selection in a breeding program, these methods aim to provide reliable estimates of relative frost tolerance for ranking genotypes and to allow partitioning of total variation into components due to provenances, families, and individuals. Examination of sampling strategies indicated that four leaf discs per seedling at three frosting temperatures and 10 seedlings per family provided highly reliable estimates of frost tolerance. Mean relative conductivity values were found to be highly correlated with mean leaf damage sustained by a seedling across the whole range of values. Alternative methods of data analysis are compared. Estimation of LD50 values (the temperature at which 50% of leaf discs would be killed) and calculation of percent survival of leaf discs were found to be less efficient means of data analysis than directly analysing relative conductivity values. The nature of genetic control of frost tolerance and the assumptions underlying such nondestructive screening techniques are examined.

scholarly journals Frost Tolerance of Eight Olive Cultivars

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 558-560 ◽  
Author(s):  
Diego Barranco ◽  
Natividad Ruiz ◽  
María Gómez-del Campo
Keyword(s):  
Leaf Tissue ◽  
Freezing Temperature ◽  
Frost Damage ◽  
Frost Tolerance ◽  
Field Resistance ◽  
Ion Leakage ◽  
Susceptible Cultivar ◽  
Olive Cultivars ◽  
The Relationship ◽  
Resistance Data

This study aims to determine the relationship between laboratory frost-resistance data for the leaves of eight olive cultivars and observed field resistance in the same genotypes undergoing natural frost damage. The lethal freezing temperature (LT50) for each cultivar was established by measuring the electrical conductivity (EC) of the medium into which solutes from damaged leaf tissue were leaked. The value obtained was then correlated with percentage frost shoot for the same eight cultivars damaged by natural frosts in a field test. A negative correlation was observed between the percentage frost shoot and leaf LT50 for all the cultivars under study. The most frost-hardy cultivars (`Cornicabra', `Arbequina', and `Picual') were those presenting the lowest percentage frost shoot and lowest LT50. Conversely, the most frost-susceptible cultivar (`Empeltre') displayed 100% frost shoot, together with one of the highest LT50 values (–9.5 °C). According to these results, lethal freezing temperature (LT50) calculated from leaf ion leakage at a range of freezing temperatures, seem to be a valid parameter for evaluating frost tolerance in olive cultivars.

scholarly journals COR/LEA Proteins as Indicators of Frost Tolerance in Triticeae: A Comparison of Controlled versus Field Conditions

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 789
Author(s):  
Klára Kosová ◽  
Miroslav Klíma ◽  
Ilja Tom Prášil ◽  
Pavel Vítámvás
Keyword(s):  
Cold Acclimation ◽  
Field Experiments ◽  
Quantitative Relationship ◽  
Field Trials ◽  
Frost Tolerance ◽  
Late Embryogenesis Abundant ◽  
Field Conditions ◽  
Lea Proteins ◽  
Winter Cereals ◽  
Vernalisation Requirement

Low temperatures in the autumn induce enhanced expression/relative accumulation of several cold-inducible transcripts/proteins with protective functions from Late-embryogenesis-abundant (LEA) superfamily including dehydrins. Several studies dealing with plants grown under controlled conditions revealed a correlation (significant quantitative relationship) between dehydrin transcript/protein relative accumulation and plant frost tolerance. However, to apply these results in breeding, field experiments are necessary. The aim of the review is to provide a summary of the studies dealing with the relationships between plant acquired frost tolerance and COR/LEA transcripts/proteins relative accumulation in cereals grown in controlled and field conditions. The impacts of cold acclimation and vernalisation processes on the ability of winter-type Triticeae to accumulate COR/LEA proteins are discussed. The factors determining dehydrin relative accumulation under controlled cold acclimation treatments versus field trials during winter seasons are discussed. In conclusion, it can be stated that dehydrins could be used as suitable indicators of winter survival in field-grown winter cereals but only in plant prior to the fulfilment of vernalisation requirement.

scholarly journals Winter frost injury of buds on one-year-old grapevine shoots of Vitis vinifera cultivars and interspecific hybrids in Poland

2012 ◽  
Vol 24 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Jerzy Lisek
Keyword(s):  
Vitis Vinifera ◽  
Interspecific Hybrids ◽  
Frost Damage ◽  
Frost Tolerance ◽  
Table Grape ◽  
Plant Parts ◽  
Frost Injury ◽  
Vitis Labruscana ◽  
Significant Damage ◽  
One Year

Winter frost injury of buds on one-year-old grapevine shoots ofVitis viniferacultivars and interspecific hybrids in PolandFollowing the winter of 2009/2010, an assessment of frost damage was carried out on the vines of 40 wine cultivars and 32 table grape cultivars grown in central Poland (Skierniewice, latitude 51° 57' N, longitude 20° 08' E). The minimum winter temperature of -28.1°C was recorded on 26 January 2010. Cultivars were assigned to five classes of different frost tolerance, according to information on the percentage of frozen buds: very resistant (below 1.9%), resistant (2 - 24.9%), medium susceptible (25 - 74.9%), susceptible (75 - 95.9%) and very susceptible (above 96%). The numbers of wine and table cultivars in each class were as follows: very resistant - 5 (wine) and 3 (table), resistant - 2 and 5, medium susceptible - 15 and 10, susceptible - 13 and 9 and very susceptible - 5 and 5. The most tolerant were the ‘Alwood’, ‘Delaware’, ‘Fredonia’ and ‘Zilga’ interspecific hybrids of theVitis labruscanagroup; the ‘Aurore’, ‘Marechal Foch’ and ‘Leon Millot’ hybrids originating fromV. vinifera, V. rupestris, V. ripariaandV. lincecumiiand ‘Sibera’ originating fromV. viniferaandV. amurensis.More than 96% of buds froze on the vines of some interspecific hybrids (‘Arkadia’, ‘Fanny’, ‘Kodrianka’ and ‘Lilla’). ‘Ortega’, ‘Nektar’, ‘Cserszegi Fueszeres’, ‘Riesling’ and ‘Chasselas Dore’ from theV. viniferacultivars showed the best tolerance to frost damage (42.5-62% of frozen buds). The buds of theV. viniferacultivars ‘Acolon’, ‘Dakapo’ and ‘Favorit’ all froze. Plant parts covered with soil and snow were not exposed to significant damage, even in the case of susceptible cultivars.

Heritability of frost tolerance in white clover (Trifolium repens)

1990 ◽  
Vol 114 (2) ◽  
pp. 151-155 ◽  
Author(s):  
J. R. Caradus ◽  
A. C. Mackay ◽  
J. Van Den Bosch ◽  
S. Wewala ◽  
D. H. Greer
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Size Effects ◽  
Leaf Size ◽  
Frost Damage ◽  
Frost Tolerance ◽  
Method Of Calculation ◽  
Selection For ◽  
Heritability Estimates ◽  
High Selection

SUMMARYWhite clover genotypes selected for frost tolerance and susceptibility were pair-crossed in various combinations with unselected genotypes of Grasslands Huia. Progeny lines and parent genotypes were artificially frosted at −8°C and scored for percentage of leaves damaged. Progeny from crosses between frost-tolerant genotypes were less damaged by frost than progeny from crosses involving either susceptible genotypes or unselected Grasslands Huia genotypes. Heritability estimates for frost tolerance or susceptibility were high, ranging from 0·75 to 0·93, depending on method of calculation. Removal of leaf-size effects from scores of frost damage reduced heritability estimates to 0·54–0·73. It was concluded that, because heritability for frost tolerance was high, selection for this character and incorporation of frost tolerance into agronomically suitable but frost-sensitive cultivars by breeding would be successful.

scholarly journals A transgenic approach for controlling Lygus in cotton

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Anilkumar Gowda ◽  
Timothy J. Rydel ◽  
Andrew M. Wollacott ◽  
Robert S. Brown ◽  
Waseem Akbar ◽  
...  
Keyword(s):  
Insecticidal Activity ◽  
The United States ◽  
Field Trials ◽  
Transgenic Cotton ◽  
Economic Losses ◽  
Bt Cotton ◽  
Transgenic Event ◽  
Plant Feeding ◽  
Whole Plant ◽  
Further Development

Abstract Lygus species of plant-feeding insects have emerged as economically important pests of cotton in the United States. These species are not controlled by commercial Bacillus thuringiensis (Bt) cotton varieties resulting in economic losses and increased application of insecticide. Previously, a Bt crystal protein (Cry51Aa2) was reported with insecticidal activity against Lygus spp. However, transgenic cotton plants expressing this protein did not exhibit effective protection from Lygus feeding damage. Here we employ various optimization strategies, informed in part by protein crystallography and modelling, to identify limited amino-acid substitutions in Cry51Aa2 that increase insecticidal activity towards Lygus spp. by >200-fold. Transgenic cotton expressing the variant protein, Cry51Aa2.834_16, reduce populations of Lygus spp. up to 30-fold in whole-plant caged field trials. One transgenic event, designated MON88702, has been selected for further development of cotton varieties that could potentially reduce or eliminate insecticide application for control of Lygus and the associated environmental impacts.

Comparative study of leaf antioxidant activity as a possible mechanism for frost tolerance in ‘Hass’ and ‘Ettinger’ avocado cultivars

2019 ◽  
Vol 157 (04) ◽  
pp. 342-349
Author(s):  
A. Weil ◽  
C. Sofer-Arad ◽  
Y. Bar-Noy ◽  
O. Liran ◽  
L. Rubinovich
Keyword(s):  
Antioxidant Activity ◽  
Cell Damage ◽  
Frost Damage ◽  
Frost Tolerance ◽  
Persea Americana ◽  
Leaf Extracts ◽  
Major Drawback ◽  
Market Growth ◽  
Frost Stress ◽  
Phenolics Content

AbstractA major drawback of avocado (Persea americanaMill.) is susceptibility to frosts, which reduces yields and limits its geographic distribution and market growth. Whereas the frost-susceptible cultivar ‘Hass’ leads the global avocado market, cv. ‘Ettinger’, although commercially less important, is considered frost-tolerant. The mechanism behind the greater frost tolerance of ‘Ettinger’ has not yet been elucidated; therefore, the aim of the current study was to evaluate the differences between the frost responses of the two cultivars. The results showed that detached ‘Ettinger’ branches had greater tolerance than ‘Hass’ to controlled frost stress. Tissue browning caused by methyl viologen oxidative cell damage, superoxide accumulation in leaf discs following wounding and browning of cut surfaces in branches were much lower in ‘Ettinger’ than in ‘Hass’, suggesting greater antioxidant activity (AA) in the former. In leaf extracts, AA was significantly higher in ‘Ettinger’ than in ‘Hass’, but osmolarity was similar in the two cultivars. Total phenolics content was significantly higher in ‘Ettinger’ but addition of a protein mask did not significantly reduce AA in either cultivar. Interestingly, following the freezing treatment, AA increased in ‘Ettinger’ and remained almost unchanged in ‘Hass’, while osmolarity was unaffected in either cultivar. These results suggest that the greater frost-tolerance of ‘Ettinger’ than ‘Hass’ is due largely to its greater AA, which springs mainly from a non-enzymatic source, i.e. accumulation of phenolic compounds. Based on the current study, future applications may be developed to minimize frost damage in avocado orchards.

scholarly journals Effects of Phosphorus Additions on Growth, Mineral Nutrition, and Gas Exchange of Red Alder (Alnus rubra) Seedlings Grown in Outdoor Sandbeds

2002 ◽  
Vol 17 (4) ◽  
pp. 209-215 ◽  
Author(s):  
Kevin R. Brown
Keyword(s):  
Field Trials ◽  
Stem Volume ◽  
P Availability ◽  
Growth Responses ◽  
Red Alder ◽  
Whole Plant ◽  
Treatment Volume ◽  
P Rate ◽  
P Addition ◽  
P Supply

Abstract The growth of young red alder on Vancouver Island may increase with phosphorus (P) availability. In order to better interpret growth responses in field fertilization trials, this study examined the effects of P additions (10, 100, 200, or 400 kg P/ha) on the growth and nutrient uptake of red alder seedlings grown in outdoor sandbeds for one growing season. Height did not increase with P supply. Stem growth and whole-plant mass increased with P rate from 10 to 100 kg/ha, but did not increase further at greater rates of P addition. Stem volumes, averaged across the P100, P200 and P400 treatments, were 37% greater than in the P10 treatment. Volume and mass did not increase as foliar P concentrations exceeded 2.2 g P/kg. These responses were consistent with data from field trials. Reduced growth in the P10 treatment was not accompanied by significantly reduced foliar P concentrations. Increases in stem volume with P supply were associated with increases in the amount of branching and foliage borne on branches but not with shifts in allocation of dry matter from roots to shoots. West. J. Appl. For. 17(4):209–215.

Sounding sea ice thickness using a portable electromagnetic induction instrument

Geophysics ◽  
1991 ◽  
Vol 56 (12) ◽  
pp. 1992-1998 ◽  
Author(s):  
Austin Kovacs ◽  
Rexford M. Morey
Keyword(s):  
Sea Ice ◽  
Electromagnetic Induction ◽  
Direct Determination ◽  
Conductivity Measurement ◽  
Field Trials ◽  
The Arctic ◽  
Ice Thickness ◽  
Remote Measurement ◽  
Sea Ice Thickness ◽  
Processing Module

Field trials using a man‐portable, commercially available, electromagnetic induction (EMI) sounding instrument, with a plug‐in data processing module for the remote measurement of sea ice thickness, are discussed. The processing module was made to allow for the direct determination of sea ice thickness and to show the result in a numerical display. The processing module system was capable of estimating ice thickness within 10 percent of the the true ice value for ice from about 0.7 to 3.5 m thick, the thickest of undeformed ice in our study area. However, since seawater under the Arctic pack ice has relatively uniform conductivity (2.55 ± 0.05 S/m), a simplified method can be used for estimating sea ice thickness using just an EMI instrument. This technique uses only the EMI conductivity measurement, is easy to put into use, and does not rely on theoretically derived look‐up tables or phasor diagrams, which may not be accurate for the conditions of the area.

Studies on the Potential of Winged Bean as a Multipurpose Legume Cover Crop in Tropical Regions

1984 ◽  
Vol 20 (4) ◽  
pp. 297-301 ◽  
Author(s):  
Anjana Banerjee ◽  
D. K. Bagchi ◽  
L. K. Si
Keyword(s):  
Vegetative Growth ◽  
Cover Crop ◽  
Dry Matter ◽  
Field Trials ◽  
Winged Bean ◽  
Tropical Regions ◽  
Growing Period ◽  
Whole Plant ◽  
Legume Cover Crop ◽  
Cultivation Methods

SUMMARYThe potential of winged bean as a multipurpose legume cover crop was shown in field trials by its abundant vegetative growth throughout the growing period of two years. Protein contents of the dry matter of the whole plant, vegetable pods, seeds and tubers were in the range 22–34, 25–30, 32–38 and 16–19%, respectively. In a comparison of two cultivation methods, significantly higher yields were obtained from staked plants than from those grown without supports; protein contents, however, remained constant.

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