STUDIES ON THE CHILLING REQUIREMENTS AND TOTAL GROWING DEGREE HOURS OF THE MAIN TURKISH HAZELNUT VARIETIES

1997 ◽  
pp. 185-190 ◽  
Author(s):  
A.B. Küden ◽  
C. Çakirmelikoglu ◽  
A. Kaya
Keyword(s):  
Chilling Requirements ◽  
Growing Degree Hours

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 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 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.

PEACH CULTIVARS IN FLORIDA AND THEIR CHILLING REQUIREMENTS

1990 ◽  
pp. 191-198 ◽  
Author(s):  
R.H. Sharpe ◽  
W.B. Sherman ◽  
J.D. Martsolf
Keyword(s):  
Chilling Requirements

scholarly journals Predicted global warming and Douglas-fir chilling requirements

1990 ◽  
Vol 47 (4) ◽  
pp. 325-330 ◽  
Author(s):  
DD McCreary ◽  
DP Lavender ◽  
RK Hermann
Keyword(s):  
Global Warming ◽  
Douglas Fir ◽  
Chilling Requirements

scholarly journals Identification of reference genes for RT-qPCR analysis in peach genotypes with contrasting chilling requirements

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
N. Marini ◽  
C.B. Bevilacqua ◽  
M.V. Büttow ◽  
M.C.B. Raseira ◽  
S. Bonow
Keyword(s):  
Reference Genes ◽  
Qpcr Analysis ◽  
Chilling Requirements

Season, sowing date, and row cover influences the production of cool season vegetables in movable high tunnels

2020 ◽  
Vol 100 (5) ◽  
pp. 528-536
Author(s):  
David A. Baumbauer ◽  
Macdonald H. Burgess
Keyword(s):  
Sowing Date ◽  
Fresh Weight ◽  
Cool Season ◽  
High Tunnel ◽  
Leafy Greens ◽  
Air Temperatures ◽  
Seeding Date ◽  
Northern Latitudes ◽  
Growing Degree Hours ◽  
High Tunnels

Moveable high tunnels offer the possibility of increasing the number of crops harvested from a given piece of ground in northern latitudes where there is a short growing season. In an effort to expand crop scheduling options, three leafy greens and three root vegetables were grown in the spring in a movable high tunnel, and in the fall were sown outside and the tunnel was moved over the crops in late September. The effects of seeding date and addition of row cover were further explored on fresh weight and days to harvest. Using row cover within the high tunnel increased growing degree hours (GDH) by an average of 29% in the spring and 17% in the fall over a high tunnel without row cover. Soil degree hours (SDH) in the high tunnel with row cover increased an average of 9% in the spring and 12% in the fall over the high tunnel without row cover. The addition of row cover increased yield of leafy greens and turnip by an average of 35% in spring 2018 when the outside air temperature was considerably below average. Early-seeded fall leafy greens out-yielded late-seeded by 52% due to the ability to make a second harvest. Using row cover within the high tunnel increased GDH and SDH during both spring and fall seasons and increased the yield of cool season vegetables when outside air temperatures were considerably below average.

scholarly journals CHR: An Integrated Software Tool for chilling requirements

2020 ◽  
Author(s):  
Chen Chen ◽  
Wanyu Xu ◽  
Ningning Gou ◽  
Lasu Bai ◽  
Lin Wang ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Software Tool ◽  
Fruit Trees ◽  
Cold Weather ◽  
Chilling Requirements ◽  
Deciduous Fruit ◽  
Heat Requirement ◽  
Integrated Software ◽  
User Friendly ◽  
Analyze Data

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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