|Soper, Geoff - SEAGREEN RESEARCH|
Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 2003
Publication Date: July 1, 2003
Citation: Anderson, R.L., Soper, G. 2003. Review of volunteer wheat seedling emergence and seed longevity in soil. Weed Technology 17: 620-626. Interpretive Summary: Technological advances have enabled scientists to develop herbicide-resistant wheat cultivars. This development expands the possible arsenal of herbicides that can be used in wheat to control weeds. However, negative consequences, such as gene transfer among species, can occur. To help producers in planning production systems that include herbicide-resistant cultivars, we reviewed literature on volunteer wheat seedling emergence and seed longevity in soil for insight to guide management decisions. Volunteer wheat persists in soil longer than commonly perceived; seedlings were still emerging 16 months after harvest. The probability of volunteers infesting following wheat crops is high, especially when short-term rotations such as continuous wheat and wheat-fallow are used. A second characteristic of volunteer wheat ecology is extreme variability; it will be difficult to predict volunteer wheat densities in following years. Longer rotations comprised of a diversity of crops will enable producers to accrue the benefits of herbicide-resistant cultivars, yet still manage wheat volunteers and avoid transfer of herbicide resistance. But, short-term rotations will accentuate the negative consequences of gene transfer.
Technical Abstract: Herbicide-resistant cultivars will improve some aspects of weed management in wheat (Triticum aestivum), however, negative consequences such as gene transfer among species, increased weed resistance, or less effective volunteer control may result from their use. Therefore, we reviewed literature on volunteer wheat seedling emergence and seed longevity in soil for insight to guide management decisions with herbicide-resistant wheat. Data from classical burial studies suggested that wheat seeds were short-lived in soil, persisting less than one year. Yet, in field studies, volunteer wheat seedlings were still emerging 16 months after harvest; occasionally, seedlings have been observed two years after harvest. Volunteer wheat emergence was extremely variable; causes of variability are numerous, including cultivar genetics, environmental conditions, and production practices. This innate variability makes it difficult to predict volunteer wheat infestations in future years. Diverse cropping systems will enable producers to accrue the benefits of herbicide-resistant cultivars, yet still manage wheat volunteers, minimize gene flow by pollen, and avoid transfer of herbicide resistance. In regions where alternative crops are not viable, herbicide-resistant cultivars will expand the weed spectrum that can be controlled in wheat, but a key concern will be controlling volunteers and gene transfer in the next wheat crop.