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Predicting timing of downy brome (Bromus tectorum) seed production using growing degree days

  • Daniel A. Ball, Sandra M. Frost (a1) and Alix I. Gitelman (a2)


Downy brome in dryland winter wheat presents a major constraint to the adoption of reduced tillage cropping systems in the Pacific Northwest of the United States. Effective suppression of downy brome during fallow periods depletes seed in the soil and reduces infestations in subsequent winter wheat crops. Delayed tillage operations or delayed herbicide applications in the spring increase the risk for production of viable downy brome seed during fallow periods. In a series of studies, downy brome panicles were sequentially sampled at Pendleton, OR, and Pullman, WA, in 1996 and 1997, and at nine locations around the winter wheat growing region of the western United States in 1999 and 2001. Cumulative growing degree days (GDD) were calculated using local, daily maximum, and minimum air temperature data. A simple GDD model based on the formula GDD = (daily maximum temperature [C] + daily minimum temperature [C])/2, with a base temperature of 0 C and a starting point of January 1, was used to calculate cumulative GDD values for panicle sampling dates. Number of seed germinating per collected panicle was recorded in greenhouse germination tests. Estimations of degree days required for production of viable downy brome seed were made using nonlinear regression of germination on GDD. The GDD value at which viable seed can be found on plants (i.e., when seed germination > 0) was of interest. Estimates of the GDD values at which viable seed could be found in the three studies ranged from 582 GDD at Bozeman, MT, to 1,287 GDD at Stillwater, OK, with a group of GDD values for Pendleton and Pullman around 1,000. Variation in seed-set GDD among locations may be attributed to differing climatic conditions that control vernalization at the various locations or to differences in vernalization requirements among downy brome biotypes (or both).


Corresponding author

Corresponding author. Columbia Basin Agricultural Research Center, Oregon State University, P.O. Box 370, Pendleton, OR 97801;


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Ball, D. A. 1992. Weed seedbank response to tillage, herbicides, and crop rotation sequence. Weed Sci 40:654659.
Ball, D. A., Klepper, B., and Rydrych, D. J. 1995. Comparative above-ground development rates for several annual grass weeds and cereal grains. Weed Sci 43:410416.
Ball, D. A. and Mallory-Smith, C. 2000. Sulfonylurea herbicide resistance in downy brome. Pages 4142 in Proceedings of the Western Society of Weed Science. Reno, Nevada: Weed Science Society of America.
Blackshaw, R. E. 1994. Rotation affects downy brome in winter wheat. Weed Technol 8:728732.
Brooking, I. R. 1996. Temperature response of vernalization in wheat: a developmental analysis. Ann. Bot 78:507512.
Chouard, P. 1960. Vernalization and its relations to dormancy. Annu. Rev. Plant Physiol 11:191237.
Daugovish, O., Lyon, D. J., and Baltensperger, D. D. 1999. Cropping systems to control winter annual grasses in winter wheat (Triticum aestivum). Weed Technol 13:120126.
Deen, W., Hunt, L. A., and Swanton, C. J. 1998. Photothermal time describes common ragweed (Ambrosia artemisiifolia L.) phonological development and growth. Weed Sci 46:561568.
Devos, K. M., Moore, G., and Gale, M. D. 1995. Conservation of marker synteny during evolution. Euphytica 85:367372.
Dotray, P. A. and Young, F. L. 1993. Characterization of root and shoot development of jointed goatgrass (Aegilops cylindrica). Weed Sci 41:353361.
Fowler, D. B., Chauvin, L. P., Limin, A. E., and Sarhan, F. 1996. The regulatory role of vernalization in the expression of low-temperature-induced genes in wheat and rye. Theor. Appl. Genet 93:554559.
Gleichsner, J. A. and Appleby, A. P. 1996. Effects of vernalization on flowering in ripgut brome (Bromus diandrus). Weed Sci 44:5762.
Hay, R. K. M. and Ellis, R. P. 1998. The control of flowering in wheat and barley: what recent advances in molecular genetics can reveal. Ann. Bot 82:541554.
Hay, R. K. M. and Kirby, E. J. M. 1991. Convergence and synchrony—a review of the coordination of development in wheat. Aust. J. Agric. Res 42:661700.
Kato, K. and Yokoyama, H. 1992. Geographical variation in heading characters among wheat landraces, Triticum aestivum L., and its implication for their adaptability. Theor. Appl. Genet 84:259265.
Klepper, B., Belford, R. K., and Rickman, R. W. 1984. Root and shoot development in winter wheat. Agron. J 76:117122.
Klepper, B., Rickman, R. W., and Peterson, C. M. 1982. Quantitative characterization of vegetative development in small cereal grains. Agron. J 74:789792.
Klepper, B., Rickman, R. W., Zuzel, J. F., and Waldman, S. E. 1988. Use of growing degree-days to project sample dates for cereal crops. Agron. J 80:850852.
Mallory-Smith, C., Hendrickson, P., and Mueller-Warrant, G. 1999. Cross-resistance of primisulfuron-resistant downy brome to sulfosulfuron. Weed Sci 47:256257.
Manupeerapan, T., Davidson, J. L., Pearson, C. J., and Christian, K. R. 1992. Differences in flowering responses of wheat to temperature and photoperiod. Aust. J. Agric. Res 43:575584.
Pacific Northwest Weed Management Handbook. 2002. Corvallis, OR: Oregon State University. 420 p.
SAS Institute Inc. 1989. SAS/STAT User's Guide. Version 6, 4th ed., Volume 2. Cary, NC: Statistical Analysis Systems Institute. 846 p.
Slafer, C. A. and Rawson, H. M. 1995. Base and optimum temperatures vary with genotype and stage of development in wheat. Plant Cell Environ 18:671679.
Thill, D. C., Schirman, R. D., and Appleby, A. P. 1980. Influence of afterripening temperature and endogenous rhythms on downy brome (Bromus tectorum) germination. Weed Sci 28:321323.
Trione, E. J. and Metzger, R. J. 1970. Wheat and barley vernalization in a precise temperature gradient. Crop Sci 10:390392.
Walenta, D. L., Yenish, J. P., Young, F. L., and Ball, D. A. 2002. Vernalization response of plants grown from spikelets of spring and fall cohorts of jointed goatgrass. Weed Sci 50:461465.
Wilen, C. A., Holt, J. S., and McClosky, W. B. 1996. Predicting yellow nutsedge (Cyperus esculentus) emergence using degree-day models. Weed Sci 44:821829.
Yenish, J. P., Doll, J. D., and Buhler, D. D. 1992. Effects of tillage on vertical distribution and viability of weed seed in soil. Weed Sci 40:429433.


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Predicting timing of downy brome (Bromus tectorum) seed production using growing degree days

  • Daniel A. Ball, Sandra M. Frost (a1) and Alix I. Gitelman (a2)


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