scholarly journals 424 A Comparison of Techniques Used for Determining Freezing Injury on Two Apple (Malus × domestica Borkh.) Cultivars: Liberty and RedMax

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 466C-466
Author(s):  
M.E. Garcia ◽  
Linda A. Boccuzzo

Hardiness testing of the wood of deciduous fruit trees has been conducted using a variety of techniques. In our studies, the objective was to determine an efficient method of determining freezing injury for apple (Malus × domestica Borkh.) wood. We tested 1-year old wood of two cultivars: Liberty and RedMax. The wood was tested over the course of 2 years (1998 and 1999). Collection began in the late fall and continued throughout the winter (until it was determined full hardiness had been achieved) and then again in the early spring. The wood was cut into 1-cm sections and frozen. The artificial freezing was conducted in an ethanol bath, with the temperature lowered at 5 °C/h. Samples were removed in 3-min intervals. After freezing, the wood was acclimated to 4 °C for 12 h. Three tests were conducted to determine the hardiness/injury to the tissues. The tests used were: discoloration, callus growth and vital staining (with 2,3,5-triphenyltetrazolium chloride). This was a split block design with samples collected randomly from each tree. Four replicates (12 trees) of each cultivar were tested. Results showed that the callus test predicted the same LT50 as the other two tests, discoloration and vital staining. Discoloration was not easy to differentiate and was the most time-consuming. The callus grown by the apple wood was easily formed and distinguished. The callus test does not require the tetrazolium stain; therefore, one less step was needed in comparison to the vital staining test. This reduced testing time by over 6 h.

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 486c-486
Author(s):  
Gregory L. Reighard ◽  
William C. Newall ◽  
Charles J. Graham

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.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 854B-854
Author(s):  
Pinghai Ding* ◽  
Leslie H. Fuchigami

Differential exothermal characteristics in relations to bud water content and dormant periods were dynamically investigated within the buds of apple, pear, peach, plum, Grape, persimmon, and black walnut from late autumn to early spring. Differential thermal analysis (DTA) indicated that bud cold hardiness and two exotherms, the high temperature exotherm (HTE) and low temperature exotherm (LTE), were different among species and dormant periods. According to whether buds have deep supercooling during the dormant winter period the species tested can be divided into two groups. The first group, without supercooling, includes the buds of apple and pear, in which LTE was undetectable. The second group, with supercooling, includes the buds of peach, plum, grape, persimmon, and black walnut, in which LTE was detectable. The second group can be further divided into peach and plum subgroup, and grape, persimmon, and black walnut subgroup. Both HTE and LTE can be detected in the buds of peach and plum subgroup, in which bud cold hardiness can be further divided into three different stages; whereas in the buds of grape, persimmon and black walnut subgroup only LTE can be detected, in which bud cold hardiness can be further divided into five stages according to the detection dynamics of HTE and LTE. Bud differential exothermal characteristics and deep supercooling dynamics are closely related to bud water content and cold hardiness stages. No detection of LTE in the buds of apple and pear and no detection of HTE in the buds of grape, persimmon and black walnut were both closely associated with bud water content.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 389D-389
Author(s):  
Pinghai Ding ◽  
Sanliang Gu

Exotherm characteristics of dormant apple, pear, peach, plum, grape, persimmon, and black walnut buds were investigated from late autumn to early spring. Differential thermal analysis indicated differences in the high-temperature exotherm (HTE) and low-temperature exotherm (LTE) among the fruit species and sampling dates. According to exotherm characteristics and cold hardiness, the species tested could be divided into two groups, those without LTE (apples and pear) and those with LTE (grape, persimmon, black walnut, peach, and plum). The later group with LTE could be further categorized into two sub-groups those possessing three stages of hardiness development (peach and plum group) and those with five stages of hardiness development (grape, persimmon, and black walnut). In peach and plum group HTE and no LTE could be detected in the first and last stages when bud water content was higher than 55%. The second stage both HTE and LTE could be detected when bud water content was between 40% and 50 %. In the grape, persimmon, and black walnut group the first stage with only HTE was from bud formation to deep supercooling initiation when bud water content was higher than 52%. The second stage with both HTE and LTE was when bud water content was between 40% and 48%. The third stage when only LTE could be detected and bud water content was usually lower than 40%. The fourth stage was from HTE reappearance to LTE disappearance before bud swell. The fifth stage was from LTE disappearance to when only HTE could be detected. No detection of LTE in the buds of apple and pear and no detection of HTE in the buds of grape, persimmon and black walnut were both closely associated with water status in the buds.


HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 563F-564
Author(s):  
Pinghai Ding ◽  
Sanliang Gu

Exotherm characteristics of dormant apple, pear, peach, plum, grape, persimmon, and black walnut buds were investigated from late autumn to early spring. Differential thermal analysis indicated differences in the high-temperature exotherm (HTE) and low-temperature exotherm (LTE) among the fruit species and sampling dates. According to exotherm characteristics and cold hardiness, the species tested could be divided into two groups, those without LTE (apples and pear) and those with LTE (grape, persimmon, black walnut, peach, and plum). The latter group with LTE could be further categorized into two subgroups, those possessing three stages of hardiness development (peach and plum group) and those with five stages of hardiness development (grape, persimmon, and black walnut). In the peach and plum group, HTE and no LTE could be detected in the first and last stages when bud water content was >55%. In the second stage, both HTE and LTE could be detected when bud water content was between 40% and 50%. In the grape, persimmon, and black walnut group, the first stage with only HTE was from bud formation to deep supercooling initiation when bud water content was >52%. The second stage with both HTE and LTE was when bud water content was between 40% and 48%. The third stage when only LTE could be detected and bud water content was usually <40%. The fourth stage was from HTE reappearance to LTE disappearance before bud swell. The fifth stage was from LTE disappearance to when only HTE could be detected. No detection of LTE in the buds of apple and pear and no detection of HTE in the buds of grape, persimmon, and black walnut were both closely associated with water status in the buds.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 512e-512
Author(s):  
A.M. Shirazi

Six different Japanese Maples (Acer palmatum) cultivars `Water Fall', `Burgundy Lace', `Crimson Queen', `Oshio-Beni', `SangoKaKu', and `Bloodgood' from Monrovia Nursery were planted in a randomized block design on 4 June 1997 at the The Morton Arboretum. Leaf heat tolerance was evaluated by measuring ion leakage of the leaf tissue at 25–60 °C in July, Aug., and Sept. 1997. The LT50 (the temperature at which 50% of the tissues were injured) of all the cultivars were higher in July (≈53 °C) and were lower in September (≈47 °C). Water content of the leaf tissues were higher in July compare to August and September and were not related to heat tolerance of most cultivars. Stem cold hardiness was performed by artificial freezing tests in Oct., Dec., and Feb. 1997/98. The Lowest Survival Temperature (LST) for the most hardy to least hardy cultivars in October and December were: `Burgundy Lace' (–15, –27 °C), `Bloodgood' (–18, –24 °C), `Oshio-Beni' (–15, –24 °C), `Crimson Queen' (–15, –18 °C), `Water Fall' (–9, –18 °C) and `SangoKaKu' (–9, –12 °C), respectively. Growth, dormancy development, spring budbreak and performance of these cultivars will be compared.


2017 ◽  
Vol 30 (4) ◽  
pp. 1040-1049 ◽  
Author(s):  
CAROLINA DELLA GIUSTINA ◽  
ROBERTA APARECIDA CARNEVALLI ◽  
MARCELO RIBEIRO ROMANO ◽  
DIEGO BARBOSA ALVES ANTONIO ◽  
CAMILA ECKSTEIN

ABSTRACT The benefits of integrating agricultural components into silvopastoral systems are widely known, but the limited knowledge about ecological processes in the establishment phase impedes the use of this technology. The objective of this study was to evaluate interactions between fruit tree species and the sward layer under canopies of trees in the establishment phase of silvopastoral systems in Mato Grosso, Brazil. The experiment was implemented in October 2013, with an evaluation period from January to July 2015. The systems were composed of eight fruit trees intercropped with Tifton 85 grass. A completely randomized block design was adopted, with two replications per area per treatment. We evaluated the agronomic performance of the fruit trees, the categories of the light environment, and the plant accumulation under the canopies. The acerola fruit trees of the variety Roxinha had higher Leaf area index (LAI) and Light interception (LI) values, showing a denser canopy with small porosity and the lowest light quality available to the plants beneath the canopy (lower red/far-red ratio), thereby decreasing plant accumulation under trees. The guava fruit trees showed higher growth rates than the other fruit trees, but lower LAI and LI values and a higher red/far-red ratio, allowing higher plant growth under the canopy. Cajá trees showed a similar behavior; however, this species is deciduous, which limits its potential use in integrated systems. Banana and coconut trees were highly dependent on irrigation during the dry season. The remaining species showed an adequate growth and potential to control plant species growth under their canopies.


2017 ◽  
Vol 39 (4) ◽  
Author(s):  
MATEUS DA SILVEIRA PASA ◽  
BRUNO CARRA ◽  
CARINA PEREIRA DA SILVA ◽  
MARLISE NARA CIOTTA ◽  
ALBERTO FONTANELLA BRIGHENTI ◽  
...  

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. Ethylene is associated with abscission of flowers and fruitlets. Then, the application of ethylene synthesis inhibitors, such as AVG, is a potential tool to increase fruit set of pears. The objective of this study was to evaluate the effect of AVG, sprayed at different rates and timings, on fruit set, yield and fruit quality of ‘Rocha’ pear. The study was performed in a commercial orchard located in the municipality of São Joaquim, SC, during the growing seasons of 2014/2015 and 2015/2016. Plant material consisted of ‘Rocha’ pear trees grafted on quince rootstock ‘BA29’. AVG was tested at different rates (60 mg L-1 and 80 mg L-1) and timings [full bloom, one week after full bloom (WAFB), and two WAFB), either alone or in combination. The experiment was arranged in a randomized block design, with at least five single-tree replications. The fruit set, number of fruit per tree, yield, estimated yield, fruit weight, return bloom, and fruit quality attributes were assessed. Fruit set and yield were consistently increased by single applications of AVG at 60 and 80 mg L-1 at both one and two weeks after full bloom, without negatively affecting fruit quality attributes and return bloom.


2020 ◽  
Vol 14 (3) ◽  
pp. 334-341
Author(s):  
Francisco Orduz-Ríos ◽  
Karen Victoria Suárez-Parra ◽  
Pablo Antonio Serrano-Cely ◽  
Pablo Cesar Serrano-Agudelo ◽  
Nicolás Forero-Pineda

Temperate fruit trees are a vital part of the economy of the Cundiboyacense highlands in Colombia. The nursery stage is important because it guarantees development at the final grow site. Little is known about the fertilization processes and nutritional dynamics of deciduous fruit trees in the early stages. This research aimed to evaluate the dynamics of N-P-K-Ca and Mg, along with SPAD units, in grafted plum (Prunus salicina) var. Horvin plants under the conditions of tropical highlands, which were evaluated at different growth points (cm), from grafting to transplant. The foliar N concentrations were the highest, followed by the K, P and Mg concentrations. Macronutrient concentrations in the first-stage of grafted nursery plants require nutritional balance for vegetative development and successful establishment at the definitive grow site.


2020 ◽  
Author(s):  
Chen Chen ◽  
Wanyu Xu ◽  
Ningning Gou ◽  
Lasu Bai ◽  
Lin Wang ◽  
...  

Abstract Background Bud dormancy in deciduous fruit trees enables plants to survive cold weather. The buds adopt dormant state and resume growth after satisfying the chilling requirements. Chilling requirements play a key role in flowering time. So far, several chilling models, including ≤ 7.2 °C model, the 0–7.2 °C model, Utah model, and Dynamic Model, have been developed; however, it is still time-consuming to determine the chilling requirements employing any model. This calls for efficient tools that can analyze data. Results In this study, we developed novel software Chilling and Heat Requirement (CHR), by flexibly integrating data conversions, model selection, calculations, statistical analysis, and plotting. Conclusion CHR is a tool for chilling requirements estimation, which will be very useful to researchers. It is very simple, easy, and user-friendly.


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