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United States Department of Agriculture

Agricultural Research Service

Title: Thermal Requirements for Barley Maturation and Leaf Development in Interioralaska

Author
item Sharratt, Brenton

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 9, 1999
Publication Date: N/A

Interpretive Summary: Spring barley (Hordeum vulgare L.) is well adapted to the cool and short growing season of interior Alaska, but little is known about the thermal requirements for development and maturation of barley in this region. Forcasting the development and maturation of barley will enable growers in interior Alaska to more effectively schedule the irrigation and harvest of their crop as well as make timely applications of herbicides during the early growing season. Barley development in Alaska can be predicted by knowing the temperature at which growth is initiated in the spring as well as knowing degree days required for the development of leaves and grain kernels. Air temperature and barley development were monitored over the course of six growing seasons at Fairbanks (65 deg N) and Delta Junction (64 deg N), Alaska. These data were used to assess the temperature threshold for barley growth. Our results indicated that barley growth occurs in the spring whenever daily air temperatures exceed 0 deg C. Growers can forecast herbicide applications based upon daily air temperatures since 75 growing degree days (C) are required between the appearance of successive leaves. In addition, growers can forecast when barley is ready to swath in the fall of the year from daily air temperatures since 1100 growing degree days (C) are required for barley kernels to mature.

Technical Abstract: Spring barley (Hordeum vulgare L.) is well adapted to the cool and short growing season of interior Alaska, but little is known about the thermal requirements for development and maturation of barley in this region. Air temperature and barley development were monitored over the course of six growing seasons at Fairbanks (65 deg N) and Delta Junction (64 deg N), Alaska. These data were used to assess the base temperature (Tb) in the growing degree day model using the least variable, x-intercept, and regression coefficient methods. These methods indicated a range in Tb from 0 to 1.5 deg C. At a Tb of 0 deg C, barley required nearly 1100 deg C days to mature. The phyllochron differed between early and late plantings and averaged 75 deg C days leaf**-1. Planting date appeared to influence the phyllochron in this study due to differences in day length rather than temperature at the time of seedling emergence.

Last Modified: 8/29/2014
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