scholarly journals Freeze Tolerance of `Braeburn' Apple Shoots

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 775A-775
Author(s):  
D.O. Ketchie ◽  
R. Kammereck
Keyword(s):  
Shoot Growth ◽  
Freeze Tolerance ◽  
Normal Leaf ◽  
Apple Trees ◽  
Cold Temperatures ◽  
Freeze Resistance ◽  
Freeze Dried ◽  
Dta Analysis ◽  
Artificial Freezing ◽  
Freeze Test

Differential thermal analysis (DTA) and tetrazolium triphenyl chloride (TTC) were done on shoots of 4-year-old `Braeburn' apple trees for 3 years. The trees acclimated slowly in autumn. If cold temperatures last long enough in winter, shoots will acclimate as low as –40C. Shoots are sensitive to warm temperatures and deacclimated rapidly. An attempt to run a controlled test on freeze resistance of `Braeburn' did not respond to DTA. Moisture samples indicated trees were freeze dried. Different sets of trees were rehydrated and showed an exotherm pattern. Exotherms could be seen after 3 days at 26C, 14 days at 10C, and 21 days at 4C. Another controlled freeze test was performed on 1-year-old `Braeburn' trees. Trees were acclimated outdoors. An exotherm pattern could be seen upon DTA analysis. After artificial freezing, DTA and TTC tests showed pith killed at –24C, primarily xylem at –28C, and all tissue at –35C. After freezing, trees were placed in a greenhouse and warmed over 2 months. Upon dissection, we found xylem produced before freezing was dead, but a large amount of new xylem was generated. Trees appeared to have normal leaf and shoot growth for about a month, but eventually wilted and died. Dissection of these showed the same results as the first set dissected. New xylem evidently was not enough to carry the growth of the trees.

Herbicide Effects on Weed Control and Shoot Growth of Young Apple (Malus sylvestris) and Peach (Prunus persica) Trees

1994 ◽  
Vol 8 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Chester L. Foy ◽  
Susan B. Harrison ◽  
Harold L. Witt
Keyword(s):  
Shoot Growth ◽  
Field Experiments ◽  
Prunus Persica ◽  
Weed Species ◽  
Apple Trees ◽  
Herbicide Treatments ◽  
One Year ◽  
Broadleaf Species ◽  
Old Trees ◽  
Peach Trees

Field experiments were conducted at two locations in Virginia to evaluate the following herbicides: alachlor, diphenamid, diuron, metolachlor, napropamide, norflurazon, oryzalin, oxyfluorfen, paraquat, pendimethalin, and simazine. One experiment involved newly-transplanted apple trees; the others, three in apple and one in peach trees, involved one-year-old trees. Treatments were applied in the spring (mid-April to early-May). Control of annual weed species was excellent with several treatments. A broader spectrum of weeds was controlled in several instances when the preemergence herbicides were used in combinations. Perennial species, particularly broadleaf species and johnsongrass, were released when annual species were suppressed by the herbicides. A rye cover crop in nontreated plots suppressed the growth of weeds. New shoot growth of newly-transplanted apple trees was increased with 3 of 20 herbicide treatments and scion circumference was increased with 11 of 20 herbicide treatments compared to the nontreated control. Growth of one-year-old apple trees was not affected. Scion circumference of one-year-old peach trees was increased with 25 of 33 herbicide treatments.

scholarly journals Cold hardiness of peach flowers at different phenological stages

2018 ◽  
Vol 45 (No. 3) ◽  
pp. 119-124
Author(s):  
László Szalay ◽  
Imre Gergő Gyökös ◽  
Zsuzsanna Békefi
Keyword(s):  
Cold Hardiness ◽  
Freeze Tolerance ◽  
Phenological Stages ◽  
Climate Chamber ◽  
Cold Damage ◽  
Artificial Freezing ◽  
Delayed Development ◽  
Phenological Phases ◽  
Generative Organs

At the colder peach production regions it is important to know the cold hardiness of peach cultivars at different phenological stages of flowering. In our experiment, artificial freezing tests were conducted in a climate chamber in five selected years between the period of 2007 and 2016 to determine the freeze tolerance of generative organs of three peach cultivars (‘Venus’, ‘Redhaven’, ‘Piroska’) at different phenological stages of bloom. Based on the results of the laboratory freezing tests LT<sub>50</sub> values were calculated. Our results showed that LT<sub>50</sub> values of examined peach cultivars in swelled bud stage averaged over five years were between –6.8 and –11.2°C according to cultivar, and as phenological phases progressed, cold hardiness of generative organs decreased. At the end of bloom LT<sub>50</sub> values varied between –1.7 and –4.1°C. Cultivar ‘Piroska’ had the highest freeze tolerance and cultivar ‘Venus’ showed the lowest in each year studied. This study shows that trees with delayed development are more prone to cold damage to flowers.  

RELATIVE AND ABSOLUTE ELECTROLYTIC CONDUCTANCE TESTS FOR FROST HARDINESS OF APPLE VARIETIES

1960 ◽  
Vol 40 (4) ◽  
pp. 630-637 ◽  
Author(s):  
J. Wilner
Keyword(s):  
Frost Resistance ◽  
Laboratory Method ◽  
Frost Hardiness ◽  
Apple Trees ◽  
Electrolytic Conductance ◽  
Laboratory Methods ◽  
Total Conductance ◽  
Average Survival ◽  
Artificial Freezing ◽  
Frost Injuries

A laboratory method for testing frost hardiness of apple trees is described. Results demonstrated that diffused electrolytes from pre-hardened twigs provided a reliable means of testing their hardiness. There was a definite association between increased diffusion of electrolytes from hardened tissues and increased injury of twigs. This association was found useful in establishing both the relative degrees of hardiness of three named varieties of apples, Antonovka, McIntosh and Northern Spy, and the absolute values for the ultimate frost resistance of their tissues. Thus, although the total conductance of electrolytes of the three varieties was about the same before the artificial freezing treatments, ranging from 900 to 1000 micromhos, the average survival and the conductance of diffused electrolytes were as follows: hardy Antonovka 71 per cent and 296 micromhos; less hardy McIntosh 53 per cent and 445 micromhos; and least hardy Northern Spy 23 per cent and 611 micromhos. Results also established quantitative values for the ultimate frost hardiness of apple trees, namely: no appreciable injury when the conductance from hardened tissues of twigs was within 200 to 250 micromhos or less. Conductance of electrolytes above 350 to 450 micromhos generally signified total killing; whereas intermediary readings indicated partial injury to twigs.The method used also permitted a study of the effects of several factors considered of vital importance in: (a) developing frost resistance of overwintering plants such as seasonal maturity, cold hardening and dehardening of tissues, and (b) causing excessive frost injuries such as increasing intensities and rates of freezing temperatures. The validity of the used laboratory methods is discussed.

scholarly journals COMPARATIVE STUDIES ON NEWLY DEVISED AND CONVENTIONAL METHODS OF GRAFTING IN ONE-YEAR-OLD `FUJI' APPLE TREES/ M.2 /MALUS PRUN1FOLIA SEEDLINGS.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 691b-691
Author(s):  
Yong-Koc Kim ◽  
Yong-Suk Kim
Keyword(s):  
Comparative Studies ◽  
Shoot Growth ◽  
Growing Season ◽  
Complete Healing ◽  
Apple Trees ◽  
Tree Form ◽  
Xylem Tissue ◽  
Fuji Apple ◽  
Conventional Methods ◽  
One Year

Experiments were carried out to evaluate some newly devised and conventional methods of grafting using `Fuji' apple trees on M.26/M. prunifolia rootstocks. Out of various methods of grafting, the modified inverted-veneer grafting and the inverted bark grafting showed a complete healing of the grafting union leaving no part of xylem tissue exposed in the air. However, owing to the longer period of growth for the trees grafted by the modified inverted-veneer grafting than the inverted bark grafting during the period of one growing season, the modified inverted-veneer gave slightly better shoot growth than the inverted bark grafting. It was clear that the former two methods were superior to the all other grafting methods, i.e., whip-and-tongue grafting, modified veneer grafting, inverted-veneer grafting, bark grafting, and chip budding in the grafting union healing, shoot growth, and tree form performance.

scholarly journals Timing of High Temperature Influences Chilling Negation in Dormant Apple Trees

1992 ◽  
Vol 117 (2) ◽  
pp. 271-273 ◽  
Author(s):  
Eric Young
Keyword(s):  
High Temperature ◽  
Shoot Growth ◽  
Extension Growth ◽  
Apple Trees ◽  
The Third ◽  
Root And Shoot Growth ◽  
Negative Effect ◽  
Chilling Period ◽  
Positive Effect

Budbreak and root and shoot extension growth of apple trees (Malus domestics Borkh. MM.111) were affected by exposure to 500 hours of higher temperatures (15, 20, or 30C) during the first, second, or third 500 hours of a 1500-hour, 5C chilling period. Exposure to 15C during the third 500 hours had a significantly positive effect on budbreak, 20C at this time had no effect, and all other treatments had a negative effect on budbreak and new root and shoot growth.

scholarly journals Uptake and Translocation of Fall- and Spring-applied Zinc in Bearing Apple Trees

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 519F-520
Author(s):  
Enrique Sanchez ◽  
Tim Righetti
Keyword(s):  
Zinc Chloride ◽  
Shoot Growth ◽  
Early Spring ◽  
Flower Buds ◽  
Apple Trees ◽  
Fallen Leaves ◽  
Almost All

A zinc timing study was carried out in `Jonagold'/EM26 trees using labeled zinc chloride (98.8 atom% Zn-68). In the fall, five spurs with strong flower buds on each of five trees were labeled with a micropipet with a solution of 1000 ppm Zn at the rate of 240 μg of Zn per leaf. Almost all the Zn-68 applied was recovered in the fallen leaves. Next spring, leaves and flowers clusters sampled from the treated spurs showed that only 3% of their total Zn was fertilizer-derived. A spring application was performed on five spurs and young terminal shoots of each of five trees. The developing leaves were labeled with 500 ppm Zn-68 solution at petal fall. Two weeks later, the entire spurs and the treated shoots were sampled. Zinc remained in the treated areas and it was not transported below or above the application zone. The study supports the contention that Zn is highly immobile in the tree and, if needed, it should be applied in early spring in order to promote rapid leaf and shoot growth. Fall applications of Zn-68 were absorbed but not transported from the treated leaves to the surrounding tissues. Therefore, Zn was not recycled for the next year's growth.

scholarly journals Low Oxygen Delays Budbreak of Apple Trees in Greenhouse and Prolongs Storage Life

HortScience ◽  
1991 ◽  
Vol 26 (7) ◽  
pp. 890-891
Author(s):  
Eric Young ◽  
S.M. Blankenship
Keyword(s):  
Malus Domestica ◽  
Shoot Growth ◽  
Storage Life ◽  
Low Oxygen ◽  
Apple Trees ◽  
Bud Development ◽  
Oxygen Levels ◽  
Ambient Oxygen

Three percent oxygen significantly delayed and reduced budbreak of fully chilled apple (Malus domestica Borkh.) trees in a greenhouse. When ambient oxygen levels were restored, budbreak occurred normally. Apple trees stored under 3% ± 1% oxygen at 6C for 35 weeks had no detectable bud development in storage. Budbreak and subsequent shoot growth were normal after the trees had been removed from storage.

scholarly journals Response of Micropropagated Apple Trees to Field Establishment Procedures

HortScience ◽  
1991 ◽  
Vol 26 (11) ◽  
pp. 1364-1365 ◽  
Author(s):  
Richard H. Zimmerman
Keyword(s):  
Cold Storage ◽  
Vegetative Growth ◽  
Shoot Growth ◽  
Cultural Practices ◽  
Growing Season ◽  
First Year ◽  
Sectional Area ◽  
Apple Trees ◽  
Cross Sectional ◽  
Terminal Shoot

Growth, flowering, and fruiting of micropropagated `Jonathan' apple trees (Malus domestica Borkh.) transferred in Spring 1983 to the field from either a nursery, cold storage, or greenhouse were compared. First-year shoot and trunk growth was greatest for trees transplanted from the nursery and least for trees that were held in the greenhouse before being transferred to the field. Trees pruned low (35 cm) at planting time had more terminal shoot growth and less trunk cross-sectional area after the first growing season than those pruned high (90 cm). The effect of preplanting cultural practices on vegetative growth diminished in the 2nd year and disappeared by the end of the 3rd year in the orchard. Flowering began in 1985 and was only slightly affected by preplanting cultural practices and pruning treatments. Fruiting was not affected by the treatments.

scholarly journals USE OF CRYOPROTECTANTS FOR FROST PROTECTION IN PEACHES

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 486c-486
Author(s):  
Gregory L. Reighard ◽  
William C. Newall ◽  
Charles J. Graham
Keyword(s):  
South Carolina ◽  
Shoot Growth ◽  
Fruit Trees ◽  
Fruit Tree ◽  
Freezing Injury ◽  
Vegetative Shoot ◽  
Flower Bud ◽  
Cold Temperatures ◽  
Red Color ◽  
Deciduous Fruit

Late spring freezes often result in significant flower bud kill in deciduous fruit trees. Some products have been marketed as frost protectant compounds which purportedly protect flower stigmas and ovaries from freezing injury and death. Two of these compounds, Frost Free and Frostgard, were tested at two locations in South Carolina over three years. Varieties `Junegold', `Loring', `Redhaven', and `Jefferson' were treated with Frost Free (FF) in years 1988-1990 and with Frostgard (FG) in 1990. Significant differences in fruit yield and vegetative growth occurred during this period, but no consistent trends were evident. In 1989, FF-treated `Redhaven' and `Jefferson' trees averaged 10.5 and 21.8 kg more fruit/tree than the controls. However, no lethal cold temperatures occurred during the bloom period. In 1990, FG-treated `Redhaven' trees averaged 8.0 kg more fruit/tree than the control trees. The fruit from FF-treated trees were lower in Brix, had less red color, and vegetative shoot growth was slightly greater than that of the FG and check trees. These data suggest that Frost Free may have plant growth regulator properties.

scholarly journals Cold hardiness of peach flowers at different phenological stages

2018 ◽  
Vol 45 (No. 3) ◽  
pp. 119-124
Author(s):  
Szalay László ◽  
Gyökös Imre Gergő ◽  
Békefi Zsuzsanna
Keyword(s):  
Cold Hardiness ◽  
Freeze Tolerance ◽  
Phenological Stages ◽  
Climate Chamber ◽  
Cold Damage ◽  
Artificial Freezing ◽  
Delayed Development ◽  
Phenological Phases ◽  
Generative Organs

At the colder peach production regions it is important to know the cold hardiness of peach cultivars at different phenological stages of flowering. In our experiment, artificial freezing tests were conducted in a climate chamber in five selected years between the period of 2007 and 2016 to determine the freeze tolerance of generative organs of three peach cultivars (‘Venus’, ‘Redhaven’, ‘Piroska’) at different phenological stages of bloom. Based on the results of the laboratory freezing tests LT<sub>50</sub> values were calculated. Our results showed that LT<sub>50</sub> values of examined peach cultivars in swelled bud stage averaged over five years were between –6.8 and –11.2°C according to cultivar, and as phenological phases progressed, cold hardiness of generative organs decreased. At the end of bloom LT<sub>50</sub> values varied between –1.7 and –4.1°C. Cultivar ‘Piroska’ had the highest freeze tolerance and cultivar ‘Venus’ showed the lowest in each year studied. This study shows that trees with delayed development are more prone to cold damage to flowers.

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