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.

scholarly journals Chilling accumulation in fruit trees in Spain under climate change

2019 ◽  
Vol 19 (5) ◽  
pp. 1087-1103 ◽  
Author(s):  
Alfredo Rodríguez ◽  
David Pérez-López ◽  
Enrique Sánchez ◽  
Ana Centeno ◽  
Iñigo Gómara ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Fruit Trees ◽  
Calculation Model ◽  
Cold Temperatures ◽  
Tree Crops ◽  
Chilling Requirements ◽  
The Impact

Abstract. Growing trees are quite vulnerable to cold temperatures. To minimise the effect of these cold temperatures, they stop their growth over the coldest months of the year, a state called dormancy. In particular, endodormancy requires accumulating chilling temperatures to finish this sort of dormancy. The accumulation of cool temperatures according to specific rules is called chilling accumulation, and each tree species and variety has specific chilling requirements for correct plant development. Under global warming, it is expected that the fulfilment of the chilling requirements to break dormancy in fruit trees could be compromised. In this study, the impact of climate change on the chilling accumulation over peninsular Spain and the Balearic Islands was assessed. For this purpose, bias-adjusted results of 10 regional climate models (RCMs) under Representative Concentration Pathways (RCPs) 4.5 and 8.5 were used as inputs of four different models for calculating chilling accumulation, and the results for each model were individually compared for the 2021–2050 and 2071–2100 future periods under both RCPs. These results project a generalised reduction in chilling accumulation regardless of the RCP, future period or chilling calculation model used, with higher reductions for the 2071–2100 period and the RCP8.5 scenario. The projected winter chill decrease may threaten the viability of some tree crops and varieties in some areas where the crop is currently grown, but also shows scope for varieties with lower chilling requirements. The results are relevant for planning future tree plantations under climate change, supporting adaptation of spatial distribution of tree crops and varieties in Spain.

scholarly journals Chilling accumulation in temperate fruit trees in Spain under climate change

2019 ◽  
Author(s):  
Alfredo Rodríguez ◽  
David Pérez-López ◽  
Enrique Sánchez ◽  
Ana Centeno ◽  
Iñigo Gómara ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Regional Climate ◽  
Fruit Trees ◽  
Fruit Production ◽  
Cold Temperatures ◽  
Tree Crops ◽  
Chilling Requirements ◽  
The Impact ◽  
Far Future

Abstract. Temperate fruit trees account for almost half of the worldwide fruit production, with Spain one of the largest world producers. Growing trees are quite vulnerable to cold temperatures. To minimise the effect of these cold temperatures, they stop their growth over the coldest months of the year, a state called dormancy. In particular, endodormancy, i.e. a dormancy related to the plant's inner physiological factors, requires accumulating cool temperatures to finish dormancy (be broken). The accumulation of cool temperatures according to specific rules is called chilling accumulation, and the chilling accumulation required to break dormancy is different for each tree crop and variety. There are several methods to calculate the chilling accumulation, all of them based on temperature only. Under global warming, it is expected that the fulfilment of the chilling requirements to break dormancy in temperate fruit trees could be compromised. In this study, the impact of climate change on the chilling accumulation over Peninsular Spain and the Balearic Islands was assessed. For this, bias-adjusted results of 10 Regional Climate Models (RCMs) under Representative Concentration Pathways (RCPs) RCP4.5 and RCP8.5 were used as inputs of four different methods for calculating chilling accumulation, and the results were compared for the near and far future under both RCPs. These results project a generalised reduction in chilling accumulation regardless of the RCP, future period or chilling calculation method used, with higher reductions for the far future and the RCP8.5 scenario. The projected winter chill decrease may threaten the viability of some tree crops and varieties in some areas, but also shows scope for varieties with lower chilling requirements. The results are relevant for planning future tree plantations under climate change, supporting adaptation of spatial distribution of tree crops and varieties in Spain.

scholarly journals Productivity definition of the chilling requirement reveals underestimation of the impact of climate change on winter chill accumulation

2018 ◽  
Author(s):  
José Antonio Campoy ◽  
Rebecca Darbyshire ◽  
Elisabeth Dirlewanger ◽  
José Quero-García ◽  
Bénédicte Wenden
Keyword(s):  
Climate Change ◽  
Sweet Cherry ◽  
Fruit Trees ◽  
Climate Projections ◽  
Negative Consequences ◽  
Traditional Methods ◽  
Productivity Level ◽  
Mild Winter ◽  
Winter Chill ◽  
The Impact

AbstractEvaluation of chilling requirements (CR) of cultivars of temperate fruit trees provides key information to assess regional suitability, according to winter chill, for both industry expansion and ongoing profitability as climate change continues. Traditional methods for calculating CR use climate controlled chambers and define CR using a fixed budburst percentage, usually close to 50% (CR-50%), without considering the productivity level associated to this percentage. This CR-50% definition may underestimate the real CR of tree crops for optimal productivity. This underestimation is particularly important to consider as winter chill accumulation is declining in many regions due to climate change. In this work we used sweet cherry to analyse the traditional method for calculating CR in many Rosaceae species (CR-50%) and compared the results with more a restrictive, productivity focused method, with CR defined with a 90% bud break level (90%, CRm-90%) close to the optimal budburst which assures productivity. Climate projections of winter chill suitability across Europe using CR-50% and CRm-90% were calculated. Regional suitability landscape was highly dependent on the method used to define CR and differences were found for a wide area of the European geography, both cold and mild winter areas. Our results suggest a need to use an optimal budburst level for the assessment of CR for sweet cherry. The use of traditional methods to determine CR can result in an underestimation of productivity CR with negative consequences for the fruit industry, particularly as climate change advances.

scholarly journals Revisiting climate change effects on winter chill in mountain oases of northern Oman

2020 ◽  
Vol 162 (3) ◽  
pp. 1399-1417
Author(s):  
Andreas Buerkert ◽  
Eduardo Fernandez ◽  
Beke Tietjen ◽  
Eike Luedeling
Keyword(s):  
Climate Change ◽  
Fruit Trees ◽  
High Elevation ◽  
Weather Data ◽  
Climate Change Effects ◽  
Winter Chill ◽  
Deciduous Fruit ◽  
Projected Changes ◽  
Chilling Hours ◽  
Chill Portions

Abstract For centuries, traditional high-altitude oases in Oman have depended on the cultivation of deciduous fruit trees. This study explores the effects of climate change on winter chill (estimated as Chilling Hours—CH and Chill Portions—CP), a prerequisite to overcoming dormancy and initiating flowering, in three Omani oases. The results are compared with findings from an earlier study which reported a decrease in the numbers of CH in high-elevation oases by an average of 1.2–9.5 CH year−1 between 1983 and 2008. Location-specific weather data were obtained by merging 15 years of in situ recordings with 28 years of observations from an official weather station near the top of the investigated watershed. Between 1991 and 2018, scenarios of the past few decades show chill reductions by 75, 35 and 18% when estimated in CP at the oases of Masayrat ar Ruwajah (1030 m a.s.l.), Qasha’ (1640 m a.s.l.), and Al ‘Ayn (1900 m a.s.l.), respectively. Over the course of the twenty-first century, the lowest-elevation oasis at Masayrat ar Ruwajah is projected to lose virtually all winter chill, whereas, despite significant chill losses, conditions are expected to remain viable for some of the currently grown species in the higher-elevation oases. These projected changes will compromise the cultivation of temperate fruit trees in the near future, affecting the sustainability of Omani oases. Our methods support results from earlier work performed at these locations and provide an updated procedure for assessing climate change effects on temperature-dependent systems.

scholarly journals Assessment of Climate Change Impacts on Chilling and Forcing for the Main Fresh Fruit Regions in Portugal

2021 ◽  
Vol 12 ◽  
Author(s):  
Helder Fraga ◽  
João A. Santos
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Radiative Forcing ◽  
Global Climate Model ◽  
Climate Change Impacts ◽  
Fruit Trees ◽  
Fruit Tree ◽  
Future Projections ◽  
Growing Degree Hours ◽  
The Future

Air temperature plays a major role in the growth cycle of fruit trees. Chilling and forcing are two of the main mechanisms that drive temperate fruit development, namely dormancy and active plant development. Given the strong sensitivity of these crops to air temperature and the foreseeable warming under future climates, it becomes imperative to analyze climate change impacts for fruit trees. The fruit sector in Portugal has risen significantly over the last decades, gaining increasing importance both internally and through exports. The present research assesses the impacts of climate change on the chilling and forcing for economically relevant fruit trees in Portugal, namely apples, oranges, pears, and plums. To assess temperate fruit chilling and forcing conditions, the chilling portions (CP) and growing degree-hours (GDH) were computed over Portugal, for the recent-past (1989–2005) and future (2021–2080) periods, following two anthropogenic radiative forcing scenarios (RCP4.5 and RCP8.5). Future climate data were obtained from four regional-global climate model pairs to account for model uncertainties. Bias-correction methodologies were also applied. A spatial analysis over the main regions with PDO “Protected Denomination of Origin” or PDI “Protected Geographical Indication” of origin of each fruit tree was performed. Future projections show a clear decrease in chilling for all regions and fruit types in Portugal. Nonetheless, given the current chilling values in Portugal and the relative importance of chilling accumulation for each fruit type, these changes are more significant for certain varieties of apples than for other types of fruit. Regarding forcing, the future projections highlight an increase in its values throughout the different fruit tree regions in Portugal, which should lead to earlier phenological timings. These changes may bring limitations to some of the most important Portuguese temperate fruit regions. The planning of suitable adaptation measures against these threats is critical to control the risk of exposure to climate change, thus warranting the future sustainability of the Portuguese fruit sector, which is currently of foremost relevance to the national food security and economy.

scholarly journals Fruit Tree-Based Agroforestry Systems for Smallholder Farmers in Northwest Vietnam—A Quantitative and Qualitative Assessment

Land ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 451
Author(s):  
Van Hung Do ◽  
Nguyen La ◽  
Rachmat Mulia ◽  
Göran Bergkvist ◽  
A. Sigrun Dahlin ◽  
...  
Keyword(s):  
Management Practices ◽  
Smallholder Farmers ◽  
Knowledge Exchange ◽  
Fruit Trees ◽  
Agroforestry Systems ◽  
Fruit Tree ◽  
Rapid Expansion ◽  
Qualitative Assessment ◽  
Forage Grass ◽  
High Investment

Rapid expansion of unsustainable farming practices in upland areas of Southeast Asia threatens food security and the environment. This study assessed alternative agroforestry systems for sustainable land management and livelihood improvement in northwest Vietnam. The performance of fruit tree-based agroforestry was compared with that of sole cropping, and farmers’ perspectives on agroforestry were documented. After seven years, longan (Dimocarpus longan Lour.)-maize-forage grass and son tra (Docynia indica (Wall.) Decne)-forage grass systems had generated 2.4- and 3.5-fold higher average annual income than sole maize and sole son tra, respectively. Sole longan gave no net profit, due to high investment costs. After some years, competition developed between the crop, grass, and tree components, e.g., for nitrogen, and the farmers interviewed reported a need to adapt management practices to optimise spacing and pruning. They also reported that agroforestry enhanced ecosystem services by controlling surface runoff and erosion, increasing soil fertility and improving resilience to extreme weather. Thus, agroforestry practices with fruit trees can be more profitable than sole-crop cultivation within a few years. Integration of seasonal and fast-growing perennial plants (e.g., grass) is essential to ensure quick returns. Wider adoption needs initial incentives or loans, knowledge exchange, and market links.

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