scholarly journals Evaluation of Chilling and Heat Requirements in Japanese Apricot with Three Models

HortScience ◽  
2012 ◽  
Vol 47 (12) ◽  
pp. 1826-1831 ◽  
Author(s):  
Zhihong Gao ◽  
Weibing Zhuang ◽  
Liangju Wang ◽  
Jing Shao ◽  
Xiaoyan Luo ◽  
...  
Keyword(s):  
Dormancy Breaking ◽  
Japanese Apricot ◽  
Flowering Date ◽  
Fruit Species ◽  
Chilling Requirements ◽  
Low Correlation ◽  
Growing Degree Hours ◽  
Heat Requirements ◽  
Chill Portions ◽  
Very High

Estimating chilling requirements is crucial for identifying appropriate cultivars for a given site, for timing applications of dormancy-breaking chemical agents, and for predicting consequences of climate change. For temperate-zone fruit species such as japanese apricot, productivity is reduced when chilling requirements are not adequately satisfied. In our study, we obtained chilling and heat requirements for flowering of six japanese apricot cultivars, which spanned the range of flowering times in this species for three successive years. Different methods for determining chilling requirements were evaluated and compared, and correlations among chilling requirements, heat requirements, and flowering date were established. The dynamic model proved to be the best for determining the chilling requirements of japanese apricot. The results showed a range of chilling requirements ranging from 26.3 to 75.7 chill portions and a narrow range of heat requirements, from 1017.7 to 1697.3 growing degree-hours (GDH). A very high correlation (R = 0.9797) between flowering date and chilling requirements and a low correlation (R = 0.4298) between flowering date and heat requirements suggest that flowering date in japanese apricot is mainly a consequence of the chilling requirements of the different genotypes, whereas heat requirements contribute a limited effect to the variation in flowering dates. Chilling requirements and heat requirements were positively related with a low correlation coefficient (R = 0.4211).

scholarly journals Determination of Endodormancy Break in Almond Flower Buds by a Correlation Model Using the Average Temperature of Different Day Intervals and its Application to the Estimation of Chill and Heat Requirements and Blooming Date

2005 ◽  
Vol 130 (3) ◽  
pp. 308-318 ◽  
Author(s):  
J.M. Alonso ◽  
J.M. Ansón ◽  
M.T. Espiau ◽  
R. Socias i Company
Keyword(s):  
Correlation Coefficients ◽  
Climatic Conditions ◽  
Climatic Data ◽  
Average Temperature ◽  
Fruit Species ◽  
Chilling Requirements ◽  
Growing Degree Hours ◽  
Heat Requirements ◽  
Heat Requirement

Almond (Prunus amygdalus Batsch.) blooming date is determined by the temperatures during the dormancy period, from the onset of endodormancy to just before blooming. In this work we have developed a model, based on several years data, to estimate the mean transition date from endodormancy to ecodormancy in 44 almond cultivars covering the whole range of almond bloom, through the significance of correlation coefficients between the temperatures occurring during dormancy and the date of full bloom. The estimation of this date for each cultivar has allowed the calculation of its chill and heat requirements. It was found that most cultivars have chilling requirements between 400 and 600 chill units, whereas the span of heat requirements was wider, from 5500 to 9300 growing degree hours Celsius. Some cultivars show high chilling requirements and low heat requirements whereas others show opposite requirements. These differences confirm the wide almond adaptability to different climatic conditions and offer the possibility of being utilized in breeding programs. The good fit shown by the application of this model in the prediction of bloom time may sustain its application in chilling and heat requirement estimation in other fruit species if blooming dates and climatic data for several years are available.

scholarly journals Estimation of Chilling and Heat Requirements of Some Persian Walnut Cultivars and Genotypes

HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 697-701 ◽  
Author(s):  
Asadolah Aslani Aslamarz ◽  
Kourosh Vahdati ◽  
Majid Rahemi ◽  
Darab Hassani
Keyword(s):  
Juglans Regia ◽  
Persian Walnut ◽  
Chilling Requirements ◽  
Plastic Bags ◽  
Lateral Buds ◽  
Growing Degree Hours ◽  
Natural Photoperiod ◽  
Heat Requirements ◽  
One Year ◽  
Chilling Hours

The objective of this work was to determine the chilling and heat requirements of Persian walnut cultivars and genotypes using excised twigs. The experiment was carried out from Nov. 2006 and 2007 to Mar. 2007 and 2008. One-year-old twigs were prepared from four cultivars and four domestic genotypes of Juglans regia L. After leaf fall, the twigs were taken and placed in plastic bags and kept at 4 ± 1 °C to stimulate 400 to 1500 chilling hours. After chilling, the excised twigs were transferred to the greenhouse with a natural photoperiod and a temperature from 18 to 27 °C. The evaluation of budbreak was made three times a week and the number of accumulated growing degree hours (°C) was determined until the buds reached the balloon or green tip stage. The chilling requirements were lowest (400 h) for catkins and highest (1000 h) for lateral buds. The Serr cultivar and ‘Z30’ genotype had the lowest chilling requirements (650 and 650 h). ‘Lara’, ‘Z63’, ‘Z53’, ‘Pedro’, and ‘Z67’ showed intermediate chilling requirements with values of 900, 900, 800, 750, and 750 h, respectively. Finally, ‘Hartley’ completed its dormancy after an accumulation of 1000 h, being the walnut cultivar with the highest chilling requirement in our study. As the final result, the cultivars and genotypes were classified into three groups based on their heat requirements: low requirement (‘Z30’ and ‘Serr’), medium requirement (‘Z53’, ‘Z67’, ‘Lara’, and ‘Pedro’), and high requirement (‘Hartley’ and ‘Z63’).

scholarly journals Blooming under Mediterranean Climate: Estimating Cultivar-Specific Chill and Heat Requirements of Almond and Apple Trees Using a Statistical Approach

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 760 ◽  
Author(s):  
Isabel Díez-Palet ◽  
Inmaculada Funes ◽  
Robert Savé ◽  
Carmen Biel ◽  
Felicidad de Herralde ◽  
...  
Keyword(s):  
Mediterranean Climate ◽  
Fruit Trees ◽  
Growing Degree Hours ◽  
Temperate Deciduous ◽  
Deciduous Fruit ◽  
Apple Cultivars ◽  
Heat Requirements ◽  
Pls Analysis ◽  
Temperature Records ◽  
Chill Portions

Climate change, and specifically global temperature increase, is expected to alter plant phenology. Temperate deciduous fruit trees have cultivar-specific chill and heat requirements to break dormancy and bloom. In this study, we aimed to estimate chill and heat requirements (in chill portions, CP, and growing degree hours, GDH, respectively) of 25 almond (30–36 years) and 12 apple (14–26 years) cultivars grown under a Mediterranean climate. The set included early and late blooming genotypes. Long-term phenological and temperature records were analyzed by means of partial least squares (PLS) regression. The main difference between early and late genotypes was chill requirement, ranging from 8.40 CP of early genotypes to 55.41 CP of extra-late genotypes. However, as chill requirements are quite easily attained by all almond cultivars in this study, year-to-year variations in actual blooming dates for each genotype are governed by variability of mean forcing temperatures. In contrast, different chill and heat combinations resulted in similar mean blooming dates for the studied apple cultivars. Mean temperature in both chilling and forcing phases determined their blooming time in the location studied. Overlaps and gaps between both phases were obtained. Despite some limitations, the PLS analysis has proven to be a useful tool to define both chilling and forcing phases. Nevertheless, since the delineation of these phases determine the total amount of CP and GDH, further efforts are needed to investigate the transition of these phases.

scholarly journals Temperate Fruit Trees under Climate Change: Challenges for Dormancy and Chilling Requirements in Warm Winter Regions

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 86
Author(s):  
Abdel-Moety Salama ◽  
Ahmed Ezzat ◽  
Hassan El-Ramady ◽  
Shamel M. Alam-Eldein ◽  
Sameh Okba ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Compounds ◽  
Fruit Trees ◽  
Fruit Tree ◽  
Limiting Factor ◽  
Dormancy Breaking ◽  
Warm Winter ◽  
Winter Chill ◽  
Chilling Requirements ◽  
The Tropics

Adequate chill is of great importance for successful production of deciduous fruit trees. However, temperate fruit trees grown under tropical and subtropical regions may face insufficient winter chill, which has a crucial role in dormancy and productivity. The objective of this review is to discuss the challenges for dormancy and chilling requirements of temperate fruit trees, especially in warm winter regions, under climate change conditions. After defining climate change and dormancy, the effects of climate change on various parameters of temperate fruit trees are described. Then, dormancy breaking chemicals and organic compounds, as well as some aspects of the mechanism of dormancy breaking, are demonstrated. After this, the relationships between dormancy and chilling requirements are delineated and challenging aspects of chilling requirements in climate change conditions and in warm winter environments are demonstrated. Experts have sought to develop models for estimating chilling requirements and dormancy breaking in order to improve the adaption of temperate fruit trees under tropical and subtropical environments. Some of these models and their uses are described in the final section of this review. In conclusion, global warming has led to chill deficit during winter, which may become a limiting factor in the near future for the growth of temperate fruit trees in the tropics and subtropics. With the increasing rate of climate change, improvements in some managing tools (e.g., discovering new, more effective dormancy breaking organic compounds; breeding new, climate-smart cultivars in order to solve problems associated with dormancy and chilling requirements; and improving dormancy and chilling forecasting models) have the potential to solve the challenges of dormancy and chilling requirements for temperate fruit tree production in warm winter fruit tree growing regions.

Identification of QTLs controlling chilling and heat requirements for dormancy release and bud break in Japanese apricot (Prunus mume)

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Yuto Kitamura ◽  
Tsuyoshi Habu ◽  
Hisayo Yamane ◽  
Soichiro Nishiyama ◽  
Kei Kajita ◽  
...  
Keyword(s):  
Bud Break ◽  
Dormancy Release ◽  
Prunus Mume ◽  
Japanese Apricot ◽  
Heat Requirements

Relationship between temperature and flowering in almond: effect of location

1987 ◽  
Vol 27 (6) ◽  
pp. 905 ◽  
Author(s):  
K Rattigan ◽  
SJ Hill
Keyword(s):  
Continuous Function ◽  
Threshold Temperature ◽  
Chilling Requirement ◽  
Flowering Date ◽  
Hourly Temperature ◽  
Single Location ◽  
Growing Degree Hours ◽  
Chill Unit ◽  
Maximum Temperatures ◽  
Different Climates

A model for the prediction of flowering date in almond requires estimates of the chilling and heat sum requirements. We estimated hourly temperatures from daily minimum and maximum temperatures. A continuous function relating hourly temperature to rate of chilling was used to calculate daily chill unit accumulations. Heat sums were measured as growing-degree-hours: the linear accumulation of hourly temperatures above a threshold temperature. Our model was tested with estimates derived from data obtained at 1 French and 2 Australian locations. The results indicate that estimates derived from data at a single location can be successfully used for other locations with different climates. The accuracy of flowering date prediction generally improves as the number of locations and years of data on which it is based increase. The predictions for the cultivars Mission and Nonpareil were within 5 days of the observed dates in 73 and 88% respectively of the locations-years examined. We concluded that the chilling requirement in almond is (mean � s.e.) 284 � 33 chill units and 3 groups of cultivars can be identified with respect to heat sum requirement in the ranges 5300-6300; 6800-7700 and 8200-8900 degree hours above 4.5�C.

scholarly journals CHILLING REQUIREMENTS OF HAZELNUT CULTIVARS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1106f-1106
Author(s):  
Shawn A. Mehlenbacher
Keyword(s):  
Southern Italy ◽  
Corylus Avellana ◽  
Plant Parts ◽  
Chilling Requirements ◽  
Very High ◽  
Female Flowers

Chilling requirements of 44 genotypes of Corylus avellana L. were estimated by cutting shoots in the field at weekly intervals and forcing them in a warm greenhouse for four weeks. The chilling requirements of catkins, female flowers, and leaf buds were assumed to have been met when development occurred on more than half of the respective plant parts. Chilling requirements were lowest for catkins and highest for leaf buds, and ranged from <100 to 860 hours for catkins, 290-1550 hours for female flowers, and 365-1395 hours for leaf buds. The lowest chilling requirements were observed for the leading cultivars of Turkey and southern Italy. The yellow-leafed ornamental C. avellana var. aure a had very high chilling requirements for all plant parts.

Improving Ligand-Ranking of AutoDock Vina by Changing the Empirical Parameters

2021 ◽  
Author(s):  
T. Ngoc Han Pham ◽  
Trung Hai Nguyen ◽  
Nguyen Minh Tam ◽  
Thien Y Vu ◽  
Nhat Truong Pham ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ligand Binding ◽  
Success Rate ◽  
Binding Affinity ◽  
Correlation Coefficient ◽  
Autodock Vina ◽  
Docking Simulations ◽  
Low Correlation ◽  
Very High ◽  
Ligand Ranking

AutoDock Vina (Vina) achieved a very high docking-success rate, p ̂, but give a rather low correlation coefficient, R, for binding affinity with respect to experiments. This low correlation can be an obstacle for ranking of ligand-binding affinity, which is the main objective of docking simulations. In this context, we evaluated the dependence of Vina R coefficient upon its empirical parameters. R is affected more by changing the gauss2 and rotation than other terms. The docking-success rate p ̂ is sensitive to the alterations of the gauss1, gauss2, repulsion, and hydrogen bond parameters. Based on our benchmarks, parameter set1 has been suggested to be the most optimal. The testing study over 800 complexes indicated that the modified Vina provided higher correlation with experiment R_set1=0.556±0.025 compared with R_Default=0.493±0.028 obtained by the original Vina and R_(Vina 1.2)=0.503±0.029 by Vina version 1.2. Besides, the modified Vina can be also applied more widely, giving R≥0.500 for 32/48 targets, compared with the default package, giving R≥0.500 for 31/48 targets. In addition, validation calculations for 1036 complexes obtained from version 2019 of PDBbind refined structures showed that the set1 of parameters gave higher correlation coefficient (R_set1=0.621±0.016) than the default package (R_Default=0.552±0.018) and Vina version 1.2 (R_(Vina 1.2)=0.549±0.017). The version of Vina with set1 of parameters can be downloaded at https://github.com/sontungngo/mvina. The outcomes would enhance the ranking of ligand-binding affinity using Autodock Vina.

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