Fruit & Nut Crop Chill Portions Requirements

Chill Portions Requirements, Calculated using the Dynamic Model

Compiled by Katherine Pope, Orchard Advisor, UC Cooperative Extension

Crop	Cultivar	Chill Portions
Almond	Desmayo Largueta¹	28
	Ferragnes¹	32
	Nonpareil^1,2	22-23

Apple	Golden Delicious³	50

Apricot	Bergeron^4,5	62-65
	Búlida^4,5	54-56
	Canino⁵	30-45
	Currot^4,6,5	34-40
	Dorada^4,5	56-58
	Goldrich⁶	62
	Murciana^4,5	56
	Orange Red^4,5,6	55-69
	Palsteyn⁵	32-37
	Rojo Pasion^4,5	48-51
	San Castrese⁶	55
	Selene^4,5	57

Cherry	Brooks⁷	37
	Burlat^3,7	48-53
	Cristobalina⁷	30
	Lapins³	35
	Marvin⁷	58
	New Star⁷	54
	Rainier³	45
	Ruby⁷	48
	Sam³	70
	Somerset⁷	48

Nectarine	Aprilglo³	12
	Fantasia⁸	42
	Flavortop⁸	41
	Mayglo³	18
	Sunlite⁸	33

Peach	Andross⁹	63
	Big Top⁹	63
	Earligrande³	12
	Flordaprince³	8
	Maravilha³	12
	O’Henry⁹	63
	Redhaven³	75

Pistachio	Kerman^2,10	54-58
	Mateur¹¹	36
	Peters^2,10	58-65
	Sirora¹²	60

Prune	Improved French¹⁰	55-60

Walnut	Chandler¹⁰	45-50
	Hartley¹³	54
	Payne¹⁴	38

Numbers next to cultivar name indicates information source.

1. Ramirez, L., K. X. Sagredo, et al. (2010). Prediction models for chilling and heat requirements to estimate full bloom of almond cultivars in the Central Valley of Chile. Acta Horticulturae 872: 107-112.
2. Pope, K., et al. (2014). Nut crop yield records show that budbreak-based chilling requirements may not reflect yield decline chill thresholds. International Journal of Biometeorology: 1-9.
3. Erez, A. (2000). Bud dormancy; phenomenon, problems and solutions in the tropics and subtropics. Temperate fruit crops in warm climates. A. Erez. Dordrecht, The Netherlands, Kluwer Academic Publishers: 17-48.
4. Ruiz, D., J. A. Campoy, et al. (2007). Chilling and heat requirements of apricot cultivars for flowering. Environmental and Experimental Botany 61: 254-263.
5. Campoy (2012) The fulfilment of chilling requirements and the adaptation of apricot (Prunus armeniaca L.) in warm winter climates: An approach in Murcia (Spain) and the Western Cape (South Africa)
6. Viti, R., L. Andreini, et al. (2010). Effect of climatic conditions on the overcoming of dormancy in apricot flower buds in two Mediterranean areas: Murcia (Spain) and Tuscany (Italy). Scientia Horticulturae. 124: 217-224.
7. Alburquerque, N., F. Garcia-Montiel, et al. (2008). Chilling and heat requirements of sweet cherry cultivars and the relationship between altitude and the probability of satisfying the chill requirements. Environmental and Experimental Botany 64: 162-170.
8. Linsley-Noakes, G. C. and P. Allan (1994). Comparison of two models for the prediction of rest completion in peaches. Scientia Horticulturae 59: 107-113.
9. Miranda (2013) Evaluation and fitting of models for determining peach phenological stages at a regional scale
10. Estimate based on chill accumulation in California’s Central Valley in the winter of 2013-2014, spring phenology and final yields.
11. Elloumi, O., M. Ghrab, et al. (2013). "Chilling accumulation effects on performance of pistachio trees cv. Mateur in dry and warm area climate." Scientia Horticulturae (Amsterdam) 159: 80-87.
12. Zhang, J. and C. Taylor (2011). "The Dynamic Model Provides the Best Description of the Chill Process on 'Sirora' Pistachio Trees in Australia." Hortscience 46(3): 420-425.
13. Luedeling, E., M. Zhang, et al. (2009). Validation of winter chill models using historic records of walnut phenology. Agricultural and Forest Meteorology 149: 1854-1864.
14. Luedeling, E., L. Guo, et al. (2013). "Differential responses of trees to temperature variation during the chilling and forcing phases." Agricultural and Forest Meteorology 181: 33-42.