Progress 09/01/09 to 08/31/12
Outputs
OUTPUTS: Multiple presentations were made to scientific peers at venues ranging from International through State levels on aspects of non-preference- type host plant resistance in the management of the wheat stem sawfly through the duration of this project. These covered basic research on the heritable non-preference in the plants, target insect host plant selection, and the potential implementation to address management issues. Many presentations were invited by grower organizations spanning State through National audiences, in addition to those made by research peers. Typically these included the results of a multi-year series of experiments conducted at State Experiment Station Research Centers and on grower farms in Montana (including a number of field-scale experiments). Rigorous analysis of the effectiveness of various strategies of exploiting non-preference was presented. Collectively these are summarized by year: Autumn 2009 - 3 National, 1 Regional, and 3 State; 2010 - 2 International Invitations, 1 National Symposium, 1 National Presentation, 3 Regional, 12 State; 2011 - 2 International Invitations, 1 National, 2 Regional, 10 State; 2012 - 2 International Invitations, a hosted International Symposium on Wheat Sawfly with 23 speakers included 6 presentations on aspects of this project, plus 1 National, 2 Regional, 6 State). Key to addressing one of the hypotheses of this project included experiments exploring various blend mixtures of containing antixenosis- and antibiosis-type host plant resistance as well as other deployment strategies. Antixenosis or non-preference was also used in preliminary efforts researching perimeter trap crops of attractive solid-stem resistant cultivars planted as a narrow border encircling the crop area of an unattractive variety. The specific results of the laboratory and field deployment experiments were presented at many State and Regional wheat grower meetings, as well as several National meetings. In 2012, this topic was requested as a conceptual presentation internationally at the 8th Argentine Entomology Congress, primarily due to the nature of the relative invulnerability of wheat stem sawfly to more conventional agricultural management strategies. Over the course of this project there were 11 local State-level television or radio interviews that explained antixenosis and its potential role in wheat stem sawfly management. The spring wheat variety 'DuClair' - PI660981 was registered in 2011 and has multiple loci conferring host plant resistance. An application has been filed for U.S. PVP for this variety. Finally, there is an on-line video describing blending wheat breeding with research on insect behavior and entomological exploration of host plant resistance. It is located at https://vimeo.com/48637779. There are two modules describing the concept of wheat stem sawfly antixenosis and its potential applications to management of this pest that are incorporated in the senior-level Integrated Pest Management course taught at Montana State University by the lead project director (Weaver). PARTICIPANTS: David Weaver (P.I.) led entomology and chemical ecology. Jamie Sherman (co-P.I.) led molecular genetics. Luther Talbert (co-P.I.) led plant breeding. The Arthur M. Post Farm near Bozeman and the Northern Ag Research Center in Havre, MT played a critical role in field experimentation. Wheat growers across four counties supported the research efforts and the planting of large scale experiments. In addition, concepts based on this project were incorporated in undergraduate teaching, graduate research education, and postdoctoral experiences in entomology, plant breeding, molecular techniques and customer outreach. TARGET AUDIENCES: Target audiences include wheat growers, plant genetics and insect behavioral and semiochemical researchers, community-level chemical ecologists and members of the wheat industry. Several workshops on discriminating antibiosis and antixenosis were held during the project, primarily at the request of County Extension personnel, targeting interested growers. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
We have developed a better understanding of the relative roles of quantitative trait loci located on chromosome 2D and 5A in non-preference of ovipositing wheat stem sawflies and how they can be utilized. We are now using marker-assisted selection to genetically map the attributes of non-preferred varieties in the laboratory. These traits include attractive plant volatile compounds and a newly discovered pattern in plant morphology. The identification of novel QTL and associated genetic indicators used in marker-assisted selection of antixenotic wheat varieties is most readily validated using hill plot field arrays. These maximize efficiency in characterizing wheat stem sawfly behavior and oviposition choices. The end result is the best combination of rapid marker-assisted selection coupled to the most efficient way to accurately perform the necessary field validation. This represents a significant step forward in our ability to develop and screen for wheat stem sawfly resistance. We have also rigorously evaluated how to best use the combination of antixenotic and antibiotic host plant resistance, especially when attractive antibiotic cultivars are included. A series of blend ratios were planted at multiple sites for several years. Despite being able to demonstrate that greater infestation occurred in the attractive antibiotic lines, we saw no evidence of a consistent significant increase in overall yield. The results simply do not compare to earlier experiments using a small proportion of single attractive antibiotic variety as a trap around the periphery of a large area of unattractive wheat. We have greatly increased grower awareness of the relationship between preference and antibiosis in management of wheat stem sawfly. We have illustrated a need for better quality, higher-yielding unattractive lines and there is now several better yielding varieties that have non-preference. Yield can still be optimized by combining antibiotic and antixenotic varieties, but probably only by perimeter trapping, which is well suited to crop rotation to non-host plants or to a fallow year following the crop. The commercial seed industry has embraced the concept of non-preference. Language to specifically address such varieties at the time of their approval for market release has been adopted. Grower adoption of optimal deployment of antixenosis and antibiosis is slow. Inhibition is due to limited experimental replication and economic data regarding the value of the effort, which is perceived as in efficient at planting. This is surprising since an additional step of swathing prior to combine harvest to prevent loss of stems to lodging is common and is an added direct dollar cost. This might well be avoided by the use by the more widespread adoption of perimeter traps.
Publications
- Buteler, M. and D. K. Weaver. 2012. Host selection by the wheat stem sawfly in winter wheat and the potential role of semiochemicals mediating oviposition preference. Entomologia Experimentalis et Applicata. 143: 138-147
- Beres, B. L., L. M. Dosdall, D. K. Weaver, D. M. Spaner and H. A. Carcamo. 2011. The biology and integrated management of wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae), and the need for continuing research. C. P. Alexander Review Series. Canadian Entomologist 143: 105-125.
- Peterson, R. K. D., M. Buteler, D. K. Weaver, T. B. Macedo, Z. Sun, O. G. Perez, and G. R. Pallipparambil. 2011. Parasitism and demography of wheat stem sawfly larvae, Cephus cinctus. BioControl 56: 831-839
- Beres, B. L., H. A Carcamo, D. K. Weaver, L. M. Dosdall, M. L. Evenden, B. D. Hill, R. H. McKenzie, R.-C. Yang and D. M. Spaner. 2011. Integrating the building blocks of agronomy and biocontrol into an IPM strategy for wheat stem sawfly. Prairie Soils and Crops 4: 54-65.
- Carcamo, H. A., D. K. Weaver, S. B. Meers, B. L. Beres and A. L. Mauduit. 2012. First record of Bracon lissogaster (Hymenoptera: Braconidae) in Canada - a potentially important parasitoid of Cephus cinctus (Hymenoptera: Cephidae) in the prairies. Biocontrol Science and Technology 22: 367-369.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: OUTPUTS: This project combines basic and applied research in entomology and plant genetics targeting management of the wheat stem sawfly. A large set of near-isogenic lines were grown in replicated plots at sawfly-infested sites in Loma and Amsterdam MT in the summer of 2011. This approach replicated what was undertaken in the summer of 2010. Both sites experienced very extensive sawfly stem cutting damage. The cutting data observed in the field verifies the existence of quantitative trait loci on chromosomes 2D and 5D that probably control sawfly oviposition, but more detailed analysis of the infestation data in the laboratory suggests that there may be differential expression of the non-preference trait in different parental wheat variety backgrounds. This is not as clear-cut as previously believed, but is not that atypical. It creates for a different scenario when approaching marker assisted selection because the presence of the marker provides insight, but a full field characterization of phenotypic expression is required via planting in the field and then dissection in the laboratory. This still represents a gain in efficiency, because it is not necessary to increase seed for the planting of lines lacking the potential marker, but will always require detailed processing of stems. Solid stem, sawfly attractive lines were planted in blends. Our results for the second year of this research illustrate two key points. One is that variability in stem solidness itself is problematic because the failures to produce a sufficiently solid stem results in the attractive line receiving many eggs that survive the relatively weak antibiosis. This results in a low level of success for this approach. If stem solidness was sufficient, the outcome was more positive. The data shows that stem solidness that is historically limited by cloudy weather during cold wet springs has a confounding influence on this approach. Multiple sets of blends combining attractive and unattractive wheat varieties were planted at several sites. The data clearly suggest that oviposition is greater in attractive lines with antibiosis within a blend, which was expected. However, yield data are not significantly different than that for a pure stand of solid stem wheat. This is a function of the innate yield of currently available unattractive varieties. In addition, the blends do not perform as well as perimeter traps of attractive solid stem antibiotic lines. This is a very useful finding for growers, indicating that the trap strategy is best. Additional screening also shows that there are several new, higher yielding unattractive lines, which could be tested in blends in the summer of 2012 The experiments were presented to wheat growers at a Field day in Havre. In addition, the experiments were described at four wheat grower organization meetings. PARTICIPANTS: David Weaver (P.I.) led entomology and chemical ecology. Jamie Sherman (co-P.I.) led molecular gentics. Luther Talbert (co-P.I.) led plant breeding. The Arthur M. Post Farm near Bozeman and the Northern Ag Research Center in Havre, MT played a critical role in field experimentation. TARGET AUDIENCES: Target audiences include wheat growers, plant genetics and insect behavior researchers, chemical ecologists and members of the wheat industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We have greatly increased grower awareness of the relationship between preference and antibiosis in management of wheat stem sawfly. We have illustrated a need for better quality higher yielding unattractive lines. Identification of more of these is critical. This can be facilitated by marker assisted selection, although field validation of phenotype is essential. Yield benefits are equal in importance to reduction in pest numbers. In this case, it is obvious that one criterion can be met in the absence of another. Implementation of coupled antibiosis and antixenosis will be achieved only through demonstrated increases in yield while reducing pest numbers.
Publications
- Buteler, M., D. K. Weaver, P. L. Bruckner, G. R. Carlson, J. E. Berg, P. F. Lamb. 2010. Identification of winter wheat cultivars suitable as trap crops for the wheat stem sawfly based on screening using agronomic traits and semiochemical production. Canadian Entomologist 142: 222-233.
- Blake, N. K., R. N. Stougaard, D. K. Weaver, J. D. Sherman, S. P. Lanning, Y. Naruoka, Q. Xue J. M. Martin and L. E. Talbert. 2011. Identification of a quantitative trait locus for resistance to the orange wheat blossom midge in spring wheat. Plant Breeding 130: 25-30.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: This project combines basic and applied research in entomology and plant genetics targeting management of the wheat stem sawfly. A set of 100 near-isogenic lines were grown in replicated plots at sawfly-infested sites in Havre MT and Amsterdam MT. Both sites received significant sawfly cutting. Preliminary analysis of cutting data confirms the existence of quantitative trait loci on chromosomes 2D and 5D controlling sawfly oviposition. In addition, the data allowed refining the position of the QTL on chromosome 2D which will provide direction for marker assisted selection. In addition to analysis of NIL, lines that varied for stem solidness and sawfly attraction were planted in blends at both locations. Preliminary analysis of cutting data suggested that the degree of control provided by solid stems varied between sites. At least one line with low attraction gave consistent low cutting values, further confirming the need to diversify and combine resistance sources. Volatile profiles from this line will be studied in detail. Preliminary outputs suggest variation in the amount of volatile attractants produced. Five sets of blends combining attractive and unattractive wheat varieties were conducted at the same sites. The data clearly suggest that oviposition is greater in attractive lines with antibiosis, which was expected. Detailed yield comparisons are underway. The experiments were shown to wheat growers at the Field day in Havre. In addition, the experiments were described at two other Field Days and presented at five wheat grower organization meetings. PARTICIPANTS: David Weaver (P.I.) led entomology and chemical ecology. Jamie Sherman (co-P.I.) led molecular gentics. Luther Talbert (co-P.I.) led plant breeding. The Northern Ag Research Center in Havre, MT played a critical role in field experimentation. TARGET AUDIENCES: Target audiences include wheat growers, plant genetics and insect behavior researchers, chemical ecologists and members of the wheat industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We have discovered that it is critical to characterize the relative contributions of attractive and unattractive varieties carefully. Yield can be influenced by parasitism, which we have shown can prevent losses due to the pest in earlier research. There were high levels of parasitism in these samples this year. We are evaluating whether this change in parasitism is due to the focus of the pests to attractive lines that also reduce the number of available hosts or if it is the result of overall increases in parasitism because of two years of favorable conditions. Results from the sawfly resistance studies were extended to a second insect pest, the orange wheat blossom midge. Following the approach we developed for the sawfly, we were able to identify a major quantitative trait locus for oviposition preference and derive near-isogenic lines for further agronomic testing.
Publications
- Blake, N. K., Stougaard, R. N., Weaver, D. K., Sherman, J. D., Lanning, S. P., Naruoka, Y., Xue, Q. Martin, J. M., and Talbert, L. E. 2011. Identification of a quantitative trait locus for resistance to Sitodiplosis mosellana (Gehin), the orange wheat blossom midge, in spring wheat. Plant Breeding (in press).
- Sherman, J. D., Weaver, D. K. Hofland, M. L., Buteler, M. Lanning, S. P., Naruoka, Y., Crutcher, F., Blake, N. K., Martin, J. M., Lamb, P. F., Carlson, G. R., and Talbert, L. E. 2010. Identification of novel QTL for sawfly resistance in wheat. Crop Science 50: 73-86.
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