Author
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Takeda, Fumiomi |
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Submitted to: Blackberry and their Hybrids
Publication Type: Book / Chapter Publication Acceptance Date: 6/2/2017 Publication Date: 11/6/2017 Citation: Takeda, F. 2017. Climatic requirements. In: Hall, H. and Funt, R., editors. Blackberry and their Hybrids. Boston, MA:CABI. p. 35-48. Interpretive Summary: Technical Abstract: The article reviews the effects on several environment factors on the above-ground parts of a blackberry plant, including seasonal changes, the climatic requirements of blackberry plants, and the effects of light and temperature on plant survival and fruit quality. Weather and, to a large extent, temperature determines where blackberries can be grown. High temperatures in the summer, usually associated with high solar radiation, contribute to stress-related plant responses such as poor pollination and white drupe malformation. In winter and spring, unseasonably low temperatures can kill canes, damage flower buds, and open flowers. Practical low-temperature limits for blackberries is about -18 degrees celsius in mid-winter for eastern thornless blackberries and only -11 degrees celsius for trailing blackberries. In the spring, temperatures less than -3 degrees celsius during bloom can injure flowers and buds. In the Midwest, the use of the rotating cross-arm trellis system (RCA) and winter blanket have helped to mitigate the effect of severe winter temperatures in these regions where partial to full crop losses have been reported to occur three out of four years. Until recently, little has been known about spring temperatures at which injury occurs in blackberry flowers and buds. Our laboratory has used a frost chamber which mimics overnight radiative freezing. An infrared thermography was used to record exothermic events and to monitor the spread of ice formation in blackberry plants. The study revealed that flowers and buds froze over a narrow range of temperatures, and ice formation occurred among flowers and buds almost simultaneously. Maturing fruit of some blackberries are prone to develop a disorder called "white drupe" when the fruit is exposed to high solar radiation. Shading of fruit by positioning fruit on the north side of the row and with over-head fabric significantly reduced white drupe formation. Several cultural techniques are now available to mitigate extreme temperatures and high light intensity to improve plant survival, productivity, and fruit quality. These new production techniques have enabled the blackberry industry to expand northward and southward, and fruit to be harvested over a much longer season. |
