Document Type : Research Paper

Authors

1 Department of Horticulture, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran. E-mail: dehghansamani@sku.ac.ir

2 Department of Horticulture, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran. E-mail: mkhani7@sku.ac.ir

3 Corresponding Author, Department of Agriculture science, Technical and Vocational University (TVU), Tehran, Iran. E-mail: masoudfattahi@tvu.ac.ir

Abstract

Objective: Almonds are high in antioxidants, vitamin E, protein, and fiber. This nutrient-rich nut is an excellent addition to any diet since it is a versatile ingredient linked to several health benefits. The development of communications have led to a wider cultivation of temperate fruits, cultivars being selected and grown in different environmental conditions. This situation has increased the risks derived from the incomplete breaking of dormancy, and encouraged studies concerning the chilling and heat requirements of fruit cultivars for breaking dormancy and flowering. Estimating chilling and heat requirements of flower buds in fruit trees is important due to predicting flowering time for appropriate site selection to escape spring frost damage.
Methods: In order to investigate the chill and heat requirements of commercial almond cultivars, a factorial experiment was planned and implemented in a completely randomized design with 3 replications in Shahrekord university lab (in 2017). The first factor included commercial almond cultivars in five levels (Mamaei, Rabi, Sefid, Shahroud 7, and Shahroud 12) and the second factor included chilling in seven levels (100, 200, 300, 400, 500, 600, and 700 hours at 4-7 °C). As soon as dormancy was induced in the buds of each cultivar, 75 branches were prepared and transferred to a refrigerator with a temperature of 4 to 7 ° C to determine the chilling requirement. The samples were taken out of the refrigerator and placed in water and sucrose solution in the greenhouse environment, and the flowering status of flower buds was examined.
Results: The results illustrated that the chill and heat requirements of Sefid and Mamaei cultivars were lower than average requirements of all cultivars in this respect. Furthermore, these two cultivars had the lower chill and heat requirements than other cultivars. Also, Sefid cultivar needed 170 hours of chill requirements and 5886 growing degree hours’ heat and Mamaei cultivar needed 170 hours of chill and 7707 growing degree hours’ heat. Rabi cultivar had lower chill and heat requirements than the average of all cultivars, but in Shahroud 7 cultivar both of chill and heat requirements were high. Shahroud 7 cultivar needed to 220.5 hours of chill and 10958 of heat growth degree hours for blooming. On the other hand, Shahroud 12 cultivar was identified as a cultivar with high chilling requirements and low heat requirements.
Conclusion: The minus effects of the lack of chilling for breaking dormancy in temperate fruits, both in vegetative growth, and fruit-bearing have been proved. Chilling requirements of temperate fruit cultivars have to be fully satisfied, if dormancy breaking is to result in the desired vegetative growth, and if the fruit-bearing capacity is to be fulfilled. On the other hand, in case of low chilling requirements blooming happens too early and cold temperatures produce an important loss of yield by frost.

Keywords

نکونام، فاطمه؛ فتاحی‌مقدم، محمدرضا و زمانی، ذبیح‌اله (1397). ارزیابی نیاز سرمایی و حرارتی جوانه‌های گل در سه رقم تجاری زردآلو با استفاده از مدل‌های مختلف. مجله علوم باغبانی ایران، 49 (1)، 25-36.
References
Alonso, J., Anson, J., Espiau, M., & Sociasi, C. R. (2005). 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. Journal of the American Society for Horticultural Science, 130, 308-318.
Anderson, J. L., Richardson, E. A., & Kesner, C. D. (1985). Validation of chill unit and flower bud phenology models for 'Montmorency' sour cherry. Acta Horticulturae, 184, 71-78.
Ballester, J., Socias, I., Company, R., Arus, P., & Devicente M. C. (2001). Genetic mapping of a major gene delaying blooming time in almond. Plant Breeding, 120, 268-270.
Bassi, D., Barrolini, S., & Viti, R. (2006). Recent advances on environmental and physiological challenges in apricot growing. Acta Horticulturae, 717, 23-31.
Cesaraccio, C., Spano, D., Snyder, R. L., & Duce, P. (2004). Chilling and forcing model to predict bud-burst of crop and forest species. Agricultural and Forest Meteorology, 126, 1-113.
Citadin, I., Raseira, M. C. B., Herter, F. G., & Silva, J. B. (2001). Heat requirement for blooming and leafing in peach. HortScience, 36, 305-307.
Covert, M. M. (2011). The influence of chilling and heat accumulation on bloom timing, bloom length and crop yield in almonds (Prunus dulcis Mill). Master dissertation. under the supervision of Mary Pedersen. San Luis Obispo: California Polytechnic State University, Department of Horticulture and Crop Science. https://doi.org/10.15368/theses.2011.222.
Campoy, J. A., Ruiz, D., Cook, N. G., Allderman, L., & Egea, J. (2011). High temperatures and time to budbreak in low chill apricot ‘Palsteyn’. Towards a better understanding of chill and heat requirements fulfillment. Scientia Horticulturae, 129, 649-655.
Egea, J., Ortega, E., Martinez-Gomez, P., & Dicenta, F. (2003). Chilling and heat requirements of almond cultivars for flowering. Environmental and Experimental Botany, 50, 79-85.
Erez, A., Fishman, S., Linsley-Noakes, G. C., & Allan, P. (1989, September). The dynamic model for rest completion in peach buds. In Second International Symposium on Computer Modeling in Fruit Research and Orchard Management, 165-174. https://doi.org/10.17660/ActaHortic.1990.276.18.
Gilreath, P. R., & Buchanan, D. W. (1981). Rest prediction model for low-chilling ''Sungold'' nectarine. American Society for Horticultural Sciences, 106, 426-429.
Glozer, K., & Grant, J. A. (2005). Use of the Dynamic Model and Chill Portions to time chemical rest-breaking treatments. In ''Bing" sweet cherry. edited by Board, C. C. A. Novato: University of California Cooperative Extension.
Hadavand, N., Asna-Ashari, M., Imani, A., & Ershadi, A. (2021). Investigation and estimation of chill and heat requirements of flower buds of some promising almond genotypes and cultivars. Journal of Plant Process and Function, 45(10), 329-315.
Luedeling, E., Kunz, A., & Blanke, M. M. (2013). Identification of chilling and heat requirements of cherry trees- a statistical approach. International Journal of Biometeorology, 57(5), 679-689.
Maulión, E., Valentini, G. H., Kovalevski, L., Prunello, M., Monti, L. L., Daorden, M. E., Quaglino, M., & Cervign, G. D. L. C. (2014). Comparison of methods for estimation of chilling and heat requirements of nectarine and peach genotypes for flowering. Scientia Horticulturae, 177, 112-117.
Nekoonam, F., Fattahi Moghaddam, M., & Zamani, Z. (2018). Evaluation of chilling and heat requirements of flower buds in three commercial apricot cultivars by using different models. Iranian Journal of Horticultural Science, 49(1), 25-36. (In Persian).
Polito, V. S. (2009). Dormancy and flowering in tree-crop species. Davis: UC Davis Plant Sciences.
Rattigan, K., & Hill, S. J. (1988). Relationship between temperature and flowering in almond: effect of location. Australian Journal of Experimental Agriculture, 27, 905-908.
Richardson, E. A., Seeley, S. D., & Walker, D. R. (1974). A model for estimating the completion of rest for “Red haven” and “Alberta” Peach Trees. Horticultural Science, 9, 331-332.
Ruiz, D., Campoy, J. A., & Egea, J. (2007). Chilling and heat requirements of apricot cultivars for flowering. Environmental and Experimental Botany, 61, 254-263.
Saure, M. C. (1985). Dormancy Release in Deciduous Fruit Trees. In Horticultural Reviews. edited by Janick, J. New Jersey: John Wiley and Sons. https://doi.org/10.1002/9781118060735.ch6.
Scorza, R., & Okie, W. R. (1990). Peaches (Prunus persica L. Batsch). Acta Horticulturae, 290, 177-231.
Shaultout, A. D., & Unrath, C. R. (1983). Rest completion prediction model for Starkrimson Delicious apples. American Society for Horticultural Sciences, 108, 957-963.
Zhang, J., & Taylor, C. (2011). The dynamic model provides the best description of the chill process on ''Sirora'' pistachio trees in Australia. Horticultural Science, 46(3), 420-425.