{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T08:17:28Z","timestamp":1778055448273,"version":"3.51.4"},"reference-count":70,"publisher":"American Society for Horticultural Science","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["horts"],"published-print":{"date-parts":[[2011,2]]},"abstract":"<jats:p>\n                    Response to chilling temperatures is a critical factor in the suitability of peach [\n                    <jats:italic>Prunus persica<\/jats:italic>\n                    (L.) Batsch] cultivars to moderate climates such as in the southeastern United States. Time of bloom depends on the innate chilling requirement of the cultivar as well as the timing and duration of cold and warm temperatures experienced by the buds. Most current chilling models have considered dormancy break a sequential process: after appropriate chilling is received, a fixed amount of heat accumulation will produce bloom. This research shows that as chilling exposure increases, the time and heat accumulation required for peach floral budbreak decreases in an exponential relationship. When chilling is ample, a sequential, two-part dormancy model is adequate to describe budbreak, and increased chilling has little effect on heat requirement. In lower-chilling situations relative to a particular cultivar, the curvilinear relationship between chilling and heat requirement results in more heat being required for budbreak. This relationship, in conjunction with the range of chilling requirement found among the buds on a tree, results in an extended, asymmetrical budbreak.\n                  <\/jats:p>","DOI":"10.21273\/hortsci.46.2.245","type":"journal-article","created":{"date-parts":[[2019,1,31]],"date-time":"2019-01-31T21:56:20Z","timestamp":1548971780000},"page":"245-252","source":"Crossref","is-referenced-by-count":75,"title":["Increasing Chilling Reduces Heat Requirement for Floral Budbreak in Peach"],"prefix":"10.21273","volume":"46","author":[{"given":"William R.","family":"Okie","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bryan","family":"Blackburn","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"9090","reference":[{"key":"B1","series-title":"Acta Hort.","first-page":"9","article-title":"Winter chill models in a mild subtropical area and effects of constant 6\u00b0C chilling on peach budbreak","volume":"409","author":"Allan,","year":"1995"},{"key":"B2","series-title":"Grana","first-page":"269","article-title":"A model to predict the beginning of pollen season","volume":"30","author":"Andersen,","year":"1991"},{"key":"B3","series-title":"Acta Hort.","first-page":"71","article-title":"Validation of chill unit and flower bud phenology models for \u2018Montmorency\u2019 sour cherry","volume":"184","author":"Anderson,","year":"1986"},{"key":"B4","series-title":"J. Appl. Ecol.","first-page":"951","article-title":"Thermal time, chill days and prediction of budburst in Picea sitchensis","volume":"20","author":"Cannell,","year":"1983"},{"key":"B5","article-title":"Chilling requirements for opening of buds on deciduous orchard trees and some other plants in California","author":"Chandler,","year":"1937"},{"key":"B6","series-title":"HortScience","first-page":"305","article-title":"Heat requirement for blooming and leafing in peach","volume":"36","author":"Citadin,","year":"2001"},{"key":"B7","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"579","article-title":"Effect of level and duration of high temperatures on rest in the peach","volume":"110","author":"Couvillon,","year":"1985a"},{"key":"B8","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"47","article-title":"Influence of prolonged exposure to chilling temperatures on bud break and heat requirement for bloom of several fruit species","volume":"110","author":"Couvillon,","year":"1985b"},{"key":"B9","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"23","article-title":"A characterization of the \u201cAfter-Rest\u201d period of flower buds of two peach cultivars of different chilling requirements","volume":"99","author":"Couvillon,","year":"1974"},{"key":"B10","series-title":"Acta Hort.","first-page":"183","article-title":"An apple tree dormancy model for sub-tropical conditions","volume":"276","author":"del Real-Laborde,","year":"1990"},{"key":"B11","series-title":"HortScience","first-page":"347","article-title":"Problems in standardizing methods for evaluating the chilling requirements for the breaking of dormancy in buds of woody plants","volume":"38","author":"Dennis","year":"2003"},{"key":"B12","series-title":"Acta Hort.","first-page":"165","article-title":"The dynamic model for rest completion in peach buds","volume":"276","author":"Erez,","year":"1990"},{"key":"B13","series-title":"J. Amer. Hort. Sci.","first-page":"227","article-title":"Chilling accumulation and rest of sour cherry flower buds","volume":"110","author":"Felker,","year":"1985"},{"key":"B14","series-title":"J. Theor. Biol.","first-page":"309","article-title":"The temperature dependence of dormancy breaking in plants: Computer simulation of processes studied under controlled temperatures","volume":"126","author":"Fishman,","year":"1987"},{"key":"B15","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"333","article-title":"Peach floral bud break and abscisic acid content as affected by mist, light, and temperature treatments during rest","volume":"106","author":"Freeman,","year":"1981"},{"key":"B16","series-title":"Sci. Hort.","first-page":"371","article-title":"Effect of artificial chilling on the depth of endodormancy and vegetative and flower budbreak of peach and nectarine cultivars using excised shoots","volume":"108","author":"Gariglio,","year":"2006"},{"key":"B17","series-title":"For. Ecol. Mgt.","first-page":"798","article-title":"Modeling the effects of winter environment on dormancy release of Douglas-fir","volume":"259","author":"Harrington,","year":"2010"},{"key":"B18","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"107","article-title":"Seasonal variation in intensity of bud dormancy in apple cultivars and related Malus species","volume":"116","author":"Hauagge,","year":"1991"},{"key":"B19","series-title":"Plant Mol. Biol.","first-page":"157","article-title":"Gene expression of DAM5 and DAM6 is suppressed by chilling temperatures and inversely correlated with bud break rate","volume":"73","author":"Jimenez,","year":"2010"},{"key":"B20","series-title":"Ann. Bot. (Lond.)","first-page":"1013","article-title":"Apple fruit bud development and growth; Analysis and an empirical model","volume":"38","author":"Landsberg,","year":"1974"},{"key":"B21","series-title":"Tree Physiol.","first-page":"1165","article-title":"Models of the spring phenology of boreal and temperate trees: Is there something missing?","volume":"26","author":"Linkosalo,","year":"2006"},{"key":"B22","series-title":"J. S. Afr. Soc. Hort. Sci.","first-page":"19","article-title":"Estimating daily positive Utah chill units from maximum and minimum temperatures","volume":"5","author":"Linsley-Noakes,","year":"1995"},{"key":"B23","series-title":"J. Hort. Sci. Biotechnol.","first-page":"602","article-title":"Chill unit models for the sweet cherry cvs Stella, Sunburst and Summit","volume":"75","author":"Mahmood,","year":"2000"},{"key":"B24","article-title":"Handbook of peach and nectarine varieties","author":"Okie,","year":"1998"},{"key":"B25","series-title":"J. Jpn. Soc. Hort. Sci.","first-page":"519","article-title":"Relationships between chilling and heat requirement for flowering in ornamental peaches","volume":"73","author":"Pawsut,","year":"2004"},{"key":"B26","series-title":"Can. J. Bot.","first-page":"656","article-title":"Dormancy in peach (Prunus persica) flower buds. V. Anatomy of bud development in relation to phenological stage","volume":"80","author":"Reinoso,","year":"2002"},{"key":"B27","series-title":"Acta Hort.","first-page":"95","article-title":"The Omnidata biophenometer (TA45-P): A chill unit and growing degree hour accumulator","volume":"184","author":"Richardson,","year":"1986"},{"key":"B28","series-title":"HortScience","first-page":"331","article-title":"A method for estimating the completion of rest for \u2018Redhaven\u2019 and \u2018Elberta\u2019 peach trees","volume":"9","author":"Richardson,","year":"1974"},{"key":"B29","series-title":"Proc. Amer. Soc. Hort. Sci.","first-page":"239","article-title":"The effect of varying temperature regimes on degree-days to bloom in the Elberta peach","volume":"88","author":"Rom,","year":"1966"},{"key":"B30","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"537","article-title":"The effect of temperature and bud type on rest completion and the GDH\u00b0C requirement for budbreak in \u2018Redhaven\u2019 peach","volume":"111","author":"Scalabrelli,","year":"1986"},{"key":"B31","series-title":"Plant dormancy: Physiology, biochemistry and molecular biology","first-page":"361","article-title":"Modeling climatic regulation of bud dormancy","author":"Seeley,","year":"1996"},{"key":"B32","series-title":"Acta Hort.","first-page":"53","article-title":"Temperature characteristics of anthesis phenology of deciduous fruit trees","volume":"416","author":"Seeley,","year":"1996"},{"key":"B33","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"242","article-title":"The relationship of node position to bloom date, fruit size, and endosperm development of the peach, Prunus persica (L.) Batsch cv Sullivan's Elberta","volume":"100","author":"Spencer,","year":"1975"},{"key":"B34","series-title":"Proc. Amer. Soc. Hort. Sci.","first-page":"122","article-title":"Chilling requirements of peach varieties","volume":"56","author":"Weinberger,","year":"1950a"},{"key":"B35","series-title":"Proc. Amer. Soc. Hort. Sci.","first-page":"129","article-title":"Prolonged dormancy of peaches","volume":"56","author":"Weinberger,","year":"1950b"},{"key":"B1","series-title":"Acta Hort.","first-page":"9","article-title":"Winter chill models in a mild subtropical area and effects of constant 6\u00b0C chilling on peach budbreak","volume":"409","author":"Allan,","year":"1995"},{"key":"B2","series-title":"Grana","first-page":"269","article-title":"A model to predict the beginning of pollen season","volume":"30","author":"Andersen,","year":"1991"},{"key":"B3","series-title":"Acta Hort.","first-page":"71","article-title":"Validation of chill unit and flower bud phenology models for \u2018Montmorency\u2019 sour cherry","volume":"184","author":"Anderson,","year":"1986"},{"key":"B4","series-title":"J. Appl. Ecol.","first-page":"951","article-title":"Thermal time, chill days and prediction of budburst in Picea sitchensis","volume":"20","author":"Cannell,","year":"1983"},{"key":"B5","article-title":"Chilling requirements for opening of buds on deciduous orchard trees and some other plants in California","author":"Chandler,","year":"1937"},{"key":"B6","series-title":"HortScience","first-page":"305","article-title":"Heat requirement for blooming and leafing in peach","volume":"36","author":"Citadin,","year":"2001"},{"key":"B7","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"579","article-title":"Effect of level and duration of high temperatures on rest in the peach","volume":"110","author":"Couvillon,","year":"1985a"},{"key":"B8","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"47","article-title":"Influence of prolonged exposure to chilling temperatures on bud break and heat requirement for bloom of several fruit species","volume":"110","author":"Couvillon,","year":"1985b"},{"key":"B9","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"23","article-title":"A characterization of the \u201cAfter-Rest\u201d period of flower buds of two peach cultivars of different chilling requirements","volume":"99","author":"Couvillon,","year":"1974"},{"key":"B10","series-title":"Acta Hort.","first-page":"183","article-title":"An apple tree dormancy model for sub-tropical conditions","volume":"276","author":"del Real-Laborde,","year":"1990"},{"key":"B11","series-title":"HortScience","first-page":"347","article-title":"Problems in standardizing methods for evaluating the chilling requirements for the breaking of dormancy in buds of woody plants","volume":"38","author":"Dennis","year":"2003"},{"key":"B12","series-title":"Acta Hort.","first-page":"165","article-title":"The dynamic model for rest completion in peach buds","volume":"276","author":"Erez,","year":"1990"},{"key":"B13","series-title":"J. Amer. Hort. Sci.","first-page":"227","article-title":"Chilling accumulation and rest of sour cherry flower buds","volume":"110","author":"Felker,","year":"1985"},{"key":"B14","series-title":"J. Theor. Biol.","first-page":"309","article-title":"The temperature dependence of dormancy breaking in plants: Computer simulation of processes studied under controlled temperatures","volume":"126","author":"Fishman,","year":"1987"},{"key":"B15","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"333","article-title":"Peach floral bud break and abscisic acid content as affected by mist, light, and temperature treatments during rest","volume":"106","author":"Freeman,","year":"1981"},{"key":"B16","series-title":"Sci. Hort.","first-page":"371","article-title":"Effect of artificial chilling on the depth of endodormancy and vegetative and flower budbreak of peach and nectarine cultivars using excised shoots","volume":"108","author":"Gariglio,","year":"2006"},{"key":"B17","series-title":"For. Ecol. Mgt.","first-page":"798","article-title":"Modeling the effects of winter environment on dormancy release of Douglas-fir","volume":"259","author":"Harrington,","year":"2010"},{"key":"B18","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"107","article-title":"Seasonal variation in intensity of bud dormancy in apple cultivars and related Malus species","volume":"116","author":"Hauagge,","year":"1991"},{"key":"B19","series-title":"Plant Mol. Biol.","first-page":"157","article-title":"Gene expression of DAM5 and DAM6 is suppressed by chilling temperatures and inversely correlated with bud break rate","volume":"73","author":"Jimenez,","year":"2010"},{"key":"B20","series-title":"Ann. Bot. (Lond.)","first-page":"1013","article-title":"Apple fruit bud development and growth; Analysis and an empirical model","volume":"38","author":"Landsberg,","year":"1974"},{"key":"B21","series-title":"Tree Physiol.","first-page":"1165","article-title":"Models of the spring phenology of boreal and temperate trees: Is there something missing?","volume":"26","author":"Linkosalo,","year":"2006"},{"key":"B22","series-title":"J. S. Afr. Soc. Hort. Sci.","first-page":"19","article-title":"Estimating daily positive Utah chill units from maximum and minimum temperatures","volume":"5","author":"Linsley-Noakes,","year":"1995"},{"key":"B23","series-title":"J. Hort. Sci. Biotechnol.","first-page":"602","article-title":"Chill unit models for the sweet cherry cvs Stella, Sunburst and Summit","volume":"75","author":"Mahmood,","year":"2000"},{"key":"B24","article-title":"Handbook of peach and nectarine varieties","author":"Okie,","year":"1998"},{"key":"B25","series-title":"J. Jpn. Soc. Hort. Sci.","first-page":"519","article-title":"Relationships between chilling and heat requirement for flowering in ornamental peaches","volume":"73","author":"Pawsut,","year":"2004"},{"key":"B26","series-title":"Can. J. Bot.","first-page":"656","article-title":"Dormancy in peach (Prunus persica) flower buds. V. Anatomy of bud development in relation to phenological stage","volume":"80","author":"Reinoso,","year":"2002"},{"key":"B27","series-title":"Acta Hort.","first-page":"95","article-title":"The Omnidata biophenometer (TA45-P): A chill unit and growing degree hour accumulator","volume":"184","author":"Richardson,","year":"1986"},{"key":"B28","series-title":"HortScience","first-page":"331","article-title":"A method for estimating the completion of rest for \u2018Redhaven\u2019 and \u2018Elberta\u2019 peach trees","volume":"9","author":"Richardson,","year":"1974"},{"key":"B29","series-title":"Proc. Amer. Soc. Hort. Sci.","first-page":"239","article-title":"The effect of varying temperature regimes on degree-days to bloom in the Elberta peach","volume":"88","author":"Rom,","year":"1966"},{"key":"B30","series-title":"J. Amer. Soc. Hort. Sci.","first-page":"537","article-title":"The effect of temperature and bud type on rest completion and the GDH\u00b0C requirement for budbreak in \u2018Redhaven\u2019 peach","volume":"111","author":"Scalabrelli,","year":"1986"},{"key":"B31","series-title":"Plant dormancy: Physiology, biochemistry and molecular biology","first-page":"361","article-title":"Modeling climatic regulation of bud dormancy","author":"Seeley,","year":"1996"},{"key":"B32","series-title":"Acta Hort.","first-page":"53","article-title":"Temperature characteristics of anthesis phenology of deciduous fruit trees","volume":"416","author":"Seeley,","year":"1996"},{"key":"B33","series-title":"J. Amer. Soc. Hort. 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