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

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.

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

HortScience ◽

10.21273/hortsci.47.12.1826 ◽

2012 ◽

Vol 47 (12) ◽

pp. 1826-1831 ◽

Cited By ~ 21

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).

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EFFECTS OF THIDIAZURON (TDZ) ON FRUITING OF TEMPERATE TREE FRUITS

Revista Brasileira de Fruticultura ◽

10.1590/s0100-29452001000300012 ◽

2001 ◽

Vol 23 (3) ◽

pp. 513-517 ◽

Cited By ~ 3

Author(s):

JOSÉ LUÍS PETRI ◽

ENIO SCHUCK ◽

GABRIEL BERENHAUSER LEITE

Keyword(s):

Fruit Set ◽

Calcium Content ◽

Fruit Trees ◽

Fruit Shape ◽

Fruit Weight ◽

Kiwi Fruit ◽

Growing Seasons ◽

Deciduous Fruit ◽

Apple Cultivars ◽

Tree Fruits

Thidiazuron (TDZ) is a phenylurea like citokinin on cell division fruit growth and fruit shape in some deciduous fruit trees. The effects of TDZ applied during flowering on apple cultivars 'Gala' and 'Fuji" were evaluated during seven growing seasons with annual applications on the same trees. The effects on pear and kiwi fruit trees were also evaluated. Every year, TDZ significantly increased fruit set and fruit weight on apple trees. The seven-year average of the fruit set from TDZ at 10 mg.L-1 was 112.7% while the control was only 51.3%. TDZ did not affect the number of clusters. The fruit weight increased 7.0% and 18.3% when the trees were sprayed with TDZ at 10 mg.L-1 and 5 mg.L-1, respectively. TDZ also increased fruit yield per tree by 28.7% and 41.8% for the 10 mg.L-1 and 5 mg.L-1 treatments, respectively. TDZ reduced the seed number per fruit and the calcium content in the flesh fruit, but increased the fruit firmness. The fruit set increased significantly on pear cultivar Packm's Triumph treated with TDZ, and reduced the seed numbers per fruit. TDZ applied at 12.5 mg.L-1 increased fruit weight by 47,4% on "Monty" kiwi.

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Male meiosis in sweet cherry is constrained by the chilling and forcing phases of dormancy

Tree Physiology ◽

10.1093/treephys/tpaa063 ◽

2020 ◽

Author(s):

Erica Fadón ◽

Sara Herrera ◽

María Herrero ◽

Javier Rodrigo

Keyword(s):

Sweet Cherry ◽

Male Gametophyte ◽

Pollen Viability ◽

Fruit Trees ◽

Fruit Production ◽

Male Meiosis ◽

Growth Cycles ◽

Growing Degree Hours ◽

Initial Hypothesis ◽

Heat Requirements

Abstract Male meiosis in temperate fruit trees occurs in the anthers once a year, synchronized with the seasons. The alternation of dormant and growth cycles determines the optimum moment for the male gametophyte formation, a process sensitive to both cold and warm temperatures. This ensures pollen viability and subsequent reproduction success that guarantee fruit production. In this work, we explore how male meiosis is framed by seasonality in sweet cherry. For this purpose, the dormant phases, male meiosis and blooming dates were established in four cultivars with different flowering dates and chilling requirements over 7 years. The chilling and heat requirements for each cultivar were empirically estimated, and chilling and heat temperatures were quantified according to the Dynamic and Growing Degree Hours (GDH) models, respectively. Endodormancy was overcome approximately a fortnight earlier during the colder winters than during the milder winters. Against our initial hypothesis, these differences were not clearly reflected in the time of male meiosis. The period between chilling fulfillment and meiosis lasted several weeks, during which a high amount of GDH accumulated. Results showed that male meiosis is conditioned by endodormancy but especially by warm temperatures, during the forcing period. This differs from what has been described in other related species and creates a framework for further studies to understand the strategies of synchronizing dormancy with seasons.

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Concepts for understanding fruit trees

10.1079/9781800620865.0000 ◽

2022 ◽

Keyword(s):

Fruit Trees ◽

Tree Physiology ◽

Numerous Species ◽

Temperate Deciduous ◽

Deciduous Fruit

Abstract This book presents a clear set of integrative concepts for understanding the overall physiology and growth of temperate deciduous fruit trees. The emphasis is on overarching principles rather than detailed descriptions of tree physiology or difference among numerous species of fruit trees. Although the focus is on deciduous fruit trees, many aspects apply to evergreen fruit trees and trees that grow naturally in unmanaged situations.

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Understanding the long-term storage sink.

10.1079/9781800620865.0010 ◽

2022 ◽

pp. 92-95

Author(s):

T. M. DeJong

Keyword(s):

Fruit Trees ◽

Phloem Tissue ◽

Storage Tissue ◽

Long Term Storage ◽

Diurnal Patterns ◽

Temperate Deciduous ◽

Deciduous Fruit ◽

Xylem Tissue ◽

Term Storage

Abstract Similar to short-term starch storage in the chloroplasts of the leaves that serves to buffer growth of organs from carbohydrate shortages due to diurnal patterns of photosynthesis related to daily patterns of light and darkness, trees also have long-term storage capacity to enable them to supply the minimal respiratory needs of tissues during the winter and resume growth in the spring when trees are still leafless. This long-term storage of carbohydrates and some minerals occurs primarily in the phloem and xylem tissue of the branches, trunk and roots. While active phloem tissue has higher concentrations of stored carbohydrates than xylem tissue, the mass of active xylem storage tissue is many times the mass of the active phloem tissue. Thus, xylem tissue comprises the largest storage compartment of temperate deciduous fruit trees. This chapter deals with understanding the long-term storage sink in fruit trees.

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

Climatic Change ◽

10.1007/s10584-020-02862-8 ◽

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.

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Epidemiological Relations of the Pseudomonad Pathogens of Deciduous Fruit Trees

Annual Review of Phytopathology ◽

10.1146/annurev.py.04.090166.001451 ◽

1966 ◽

Vol 4 (1) ◽

pp. 291-310 ◽

Cited By ~ 42

Author(s):

J E Crosse

Keyword(s):

Fruit Trees ◽

Deciduous Fruit

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Evaluation of N-P-K-Ca-Mg dynamics in plum (Prunus salicina Lindl.) var. Horvin under nursery conditions

Revista Colombiana de Ciencias Hortícolas ◽

10.17584/rcch.2020v14i3.11941 ◽

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

Keyword(s):

Fruit Trees ◽

Vegetative Development ◽

Vital Part ◽

Foliar N ◽

Early Stages ◽

Prunus Salicina ◽

Tropical Highlands ◽

Deciduous Fruit ◽

Successful Establishment ◽

Nutritional Balance

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.

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CHR: An Integrated Software Tool for chilling requirements

10.21203/rs.3.rs-34169/v1 ◽

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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