Progress 09/01/09 to 08/31/13
Outputs
Target Audience: Organic field crop producers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Outreach for the project has occurred at multiple venues. We have an annual field day that has alternated between on-farm sites and research stations that host our organic variety trials. We also host a conference every winter where the previous years results are discussed and variety trial recommendations are handed out. We also regularly update our audience with the quarterly NC Organic Grain newsletter. Finally, the newest edition of the NC Organic Grain Production Guide was printed (2,000 copies) and is presented on our website, www.organicgrains.ncsu.edu What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Maize 1. Provide double-cross hybrids that can readily be produced and that are competitive in performance with current, non-organic hybrids. 2. Develop Ga1?s hybrids that will provide isolation from GMO pollen from neighboring fields. 3. Determine if Tcb1 hybrids can be developed as an alternative to (2). The source of Tcb1 traces to work done by Jerry Kermicle at the University of Wisconsin, who isolated the gene from teosinte. 4. Develop lines and hybrids based on newly-discovered dominant gametophytic factors isolated from Mexican racial accessions. Much of the accession identification was done by Jesus Sanchez, now at the University of Guadalajara. We have also demonstrated that the double crosses can be produced by using bulk increases of the component single crosses, which may be a real advantage to organic seed corn production. We have produced and tested many single-cross and topcross Ga1?s hybrids, including a commercially available one from Blue River. Although we have numerous Ga1?s lines, they share too much parentage to have adequate heterosis when crossed among themselves. So we are developing new lines using various combinations of our own lines, ex-PVP lines, some Ga1?s lines from Missouri (their 500-series lines), and two composites from Frank Kutka. Thus far, the most promising combinations appear to be NC and ex-PVP lines, but further testing is needed. Ultimately, Ga1?s hybrids will fail to be isolated from GMO pollen. We have ourselves released lines carrying Ga1-M, a promiscuous allele that, when present in either homozygous or heterozygous state, allows pollination from all sources, including Ga1?s. And we have shown that at least one ex-PVP line carries that allele. Sanchez at Guadalajara has shown that Ga1-M is at high frequency in Mexican landraces and hybrids, so it is likely to increase in frequency among US commercial breeding stocks over time (perhaps > 20 years). And that will ultimately end isolation using Ga1?s. For those reasons, we have attempted to substitute Tcb1 for Ga1?s. Tcb1 has the advantage of being dominant, while Ga1?s - for practical purposes - is effectively recessive, although the degree of Ga1's dominance/recessive-ness varies among materials and among environments. We have run the only yield trial ever run using Tcb1 stocks, and it was not encouraging. It may be that the teosinte source of Tcb1 causes the low yields that we observed via linkage drag. We are doing more backcrossing to try to eliminate any such source effects, but that takes time. As an alternative to Tcb1, we are using some newly discovered Dominant Gametophytic Factors (DGaFs) from Mexican landraces of maize. We verified that they work as advertised, isolated some families that have plants that are heterozygous/homozygous for various DGaFs and have begun a backcrossing program to incorporate these DGaFs into our leading lines. We also have a small-scale yield trial of DGaF topcrosses. Wheat We have conducted studies to identify effective screening methods for quantifying weed suppressive ability in field trials, test the allelopathic activity of locally adapted winter wheat lines from the North Carolina Official Variety Test (OVT) in controlled laboratory bioassays, determine the relative importance of allelopathy and competitive ability in determining weed suppressive in the field, and identified morphological traits and molecular markers associated with the competitive ability of winter wheat lines in North Carolina. In 2011 and 2012 we conducted a pilot study to identify efficient screening methods for quantifying weed suppressive ability in field trials. Measurements of Italian ryegrass seed head density during grain fill were strongly associated with the weed to crop biomass ratio, the generally accepted measure of weed suppressive ability. Visual ratings of weed biomass in the plots taken at all growth stages, especially during and after heading, were also strongly correlated with weed suppressive ability. Measurements from non-imaging spectrophotometers and overhead photographs taken from tillering to early dough development were unreliable estimates of end of season Italian ryegrass. A manuscript detailing our protocol development was recently published in Weed Science (Worthington et al. 2013) and a review of breeding methods for improving weed suppression through allelopathy and competitive ability was published in the Journal of Chemical Ecology (Worthington and Reberg-Horton 2013). We found significant variation in the allelopathic activity of winter wheat lines from the 2011 OVT in a controlled laboratory bioassay. However, allelopathic lines were not found to have superior weed suppressive ability to non-allelopathic lines of similar height in replicated field trials in 2012 and 2013. The role of morphological traits conferring competitive ability to wheat lines appears far more important than allelopathy in determining weed suppression outcomes in the field. Elite lines adapted to North Carolina growing conditions varied widely in their weed suppressive ability. We have identified commercially available cultivars with high yield potential in conventional and organic trials with promising weed suppressive ability. Morphological traits including erect growth habit and vigor during tillering, height throughout the growing season, and early heading date were generally associated with superior weed suppressive ability. Short vernalization alleles (vrn A1 and vrn B1) were also associated with enhanced weed suppression. Manuscripts describing these findings will be submitted to Crop Science this fall. A new study focused on identifying QTLs for weed suppressive ability in a biparental cross between weakly and strongly weed suppressive cultivars will be planted this fall. Soybean We tested multiple methods of measuring soybean canopies to predict their weed competitive ability. Directly measuring competitive ability is extremely expensive as it involves growing the crop in competition with weeds and then separating crop and weed biomass to assess the outcome. Fortunately, one of the techniques, overhead image analysis of the soybean canopy combined with pixel counting software, was sufficiently predictive to allow it to serve as an indirect measure of competitive ability (publication, Place et al 2011a). We utilized this approach to screen 45 entries chosen to represent as wide a range in growth patterns as possible (publications, Place et al. 2011b and Place et al. 2011c). Heritable variation in competitive ability is present in soybean and now the next step is to screen more genotypes from the national soybean germplasm collection. Our first screening of the national collection was conducted in 2012 and was repeated in 2013. The level of variation amongst 2012 entries was substantially higher than in our first trials suggested an even greater potential to improve this trait for organic production. Peanuts Seedling diseases continue to be the greatest barrier to organic production of large in-shell peanuts. Sixty to seventy percent of emerging seedlings die in the first two weeks. We have developed greenhouse screening protocols for the major disease organisms and are continuing to screen our collection for resistant lines. We created a genetically diverse cross population by bulking seed of our most disease resistant crosses, then growing the population for three generations without seed treatment, fungicides or insecticides. We have harvested these peanuts to serve as the seed for the next generation in a mass selection (“evolutionary breeding”) program. Evolutionary breeding harnesses natural selection for crop improvement and is arguably best suited for low input environments like organic farms. After harvest each year, we screen the peanuts to insure that only ones with sufficient size and quality are used as seed the next year.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Place, G.T., S.C. Reberg-Horton, and T.E. Carter. 2011. Screening tactics for identifying competitive soybean genotypes. Communications in Soil Science and Plant Analysis 42:2654-2665.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Place, G.T., S.C. Reberg-Horton, D.A. Dickey and T.E. Carter. 2011. Identifying soybean traits of interest for weed competition. Crop Science 51:2642-2654.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Place, GT, SC Reberg-Horton, TE Carter, AN Smith. 2011. Effects of soybean seed size on weed competition. Agronomy Journal 103:175-181.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
4. Sanchez, J., J.M. Padilla, L. De la Cruz, J. Ron, J.Holland, M. Krakowsky, and M. Goodman. 2011. Use of gametophytic isolating mechanisms for maize. Plant Breeding News 29:1.14. Available at http://www.fao.org/ag/agp/agpc/doc/services/pbn/pbn-230.htm#a114
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Worthington, M.L. and S.C. Reberg-Horton. 2013. Breeding cereal crops for enhanced weed suppression: optimizing allelopathy and competitive ability. Journal of Chemical Ecology 39:213-231.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Worthington, M.L., S.C. Reberg-Horton, D. Jordan, and J.P. Murphy. 2013. A comparison of methods for evaluating the suppressive ability of winter wheat cultivars against Italian ryegrass (Lolium perenne). Weed Science 61:491-4999.
- Type:
Websites
Status:
Published
Year Published:
2009
Citation:
http://rafiusa.org/bopscoalition/
- Type:
Theses/Dissertations
Status:
Accepted
Year Published:
2013
Citation:
Worthington, M.L. Breeding Winter Wheat for Improved Powdery Mildew Resistance and Weed Suppressive Ability against Italian Ryegrass.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Maize 1. Provide double-cross hybrids that can readily be produced and that are competitive in performance with current, non-organic hybrids. 2. Develop Ga1 s hybrids that will provide isolation from GMO pollen from neighboring fields. 3. Determine if Tcb1 hybrids can be developed as an alternative to (2). The source of Tcb1 traces to work done by Jerry Kermicle at the University of Wisconsin, who isolated the gene from teosinte. 4. Develop lines and hybrids based on newly-discovered dominant gametophytic factors isolated from Mexican racial accessions. Much of the accession identification was done by Jesus Sanchez, now at the University of Guadalajara. We have also demonstrated that the double crosses can be produced by using bulk increases of the component single crosses, which may be a real advantage to organic seed corn production. We have produced and tested many single-cross and topcross Ga1 s hybrids, including a commercially available one from Blue River. Although we have numerous Ga1 s lines, they share too much parentage to have adequate heterosis when crossed among themselves. So we are developing new lines using various combinations of our own lines, ex-PVP lines, some Ga1 s lines from Missouri (their 500-series lines), and two composites from Frank Kutka. Thus far, the most promising combinations appear to be NC and ex-PVP lines, but further testing is needed. Ultimately, Ga1 s hybrids will fail to be isolated from GMO pollen. We have ourselves released lines carrying Ga1-M, a promiscuous allele that, when present in either homozygous or heterozygous state, allows pollination from all sources, including Ga1 s. And we have shown that at least one ex-PVP line carries that allele. Sanchez at Guadalajara has shown that Ga1-M is at high frequency in Mexican landraces and hybrids, so it is likely to increase in frequency among US commercial breeding stocks over time (perhaps > 20 years). And that will ultimately end isolation using Ga1 s. For those reasons, we are attempting to substitute Tcb1 for Ga1 s. Tcb1 has the advantage of being dominant, while Ga1 s - for practical purposes - is effectively recessive, although the degree of Ga1's dominance/recessive-ness varies among materials and among environments. We have run the only yield trial ever run using Tcb1 stocks, and it was not encouraging. It may be that the teosinte source of Tcb1 causes the low yields that we observed via linkage drag. We are doing more backcrossing to try to eliminate any such source effects, but that takes time. As an alternative to Tcb1, we are using some newly discovered Dominant Gametophytic Factors (DGaFs) from Mexican landraces of maize. We verified that they work as advertised, isolated some families that have plants that are heterozygous/homozygous for various DGaFs and have begun a backcrossing program to incorporate these DGaFs into our leading lines. We will also have a small-scale yield trial of DGaF topcrosses this summer. It remains to be seen if the various DGaFs are allelic to Tcb1 or Ga1. PARTICIPANTS: Carolina Organic Commodity and Livestock Conference. Rocky Mount, NC. January 12 and 13, 2012. 115 participants. Partners, Carolina Farm Stewardship Association and Rural Advancement Foundation International Organic Farm Advisory Board Meeting. March, 2012. 15 participants. Organic Grains Field Day, July 19, 2012. 75 participants. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Wheat We have conducted a study to identify effective screening methods for quantifying weed suppressive ability in field trials and tested the allelopathic activity of locally adapted winter wheat lines from the North Carolina Official Variety Test (OVT) in controlled laboratory bioassays. We are also conducting the second year of studies testing the relative importance of allelopathy and competitive ability in determining weed suppressive in the field and identifying morphological traits associated with the competitive ability of winter wheat lines in North Carolina. In 2011 and 2012 we conducted a pilot study to identify effective screening methods to quantify weed suppressive ability in field trials. Measurements of Italian ryegrass seed head density during grain fill were strongly associated with the weed to crop biomass ratio, the generally accepted measure of weed suppressive ability. Visual ratings of weed biomass in the plots taken at all growth stages, especially during and after heading, were also strongly correlated with weed suppressive ability. Measurements from non-imaging spectrophotometers and overhead photographs taken from tillering to early dough development were unreliable estimates of end of season Italian ryegrass. A manuscript describing this research is currently under review in Weed Science. Soybeans We tested multiple methods of measuring soybean canopies to predict their weed competitive ability (see publications). Directly measuring competitive ability is extremely expensive as it involves growing the crop in competition with weeds and then separating crop and weed biomass to assess the outcome. Fortunately, one of the techniques, overhead image analysis of the soybean canopy combined with pixel counting software, was sufficiently predictive to allow it to serve as an indirect measure of competitive ability. We utilized this approach to screen 45 entries chosen to represent as wide a range in growth patterns as possible. Heritable variation in competitive ability is present in soybean and now the next step is to screen more genotypes from the national soybean germplasm collection. Our first screening of the national collection was conducted in 2012 and will be repeated in 2013. The level of variation amongst 2012 entries was substantially higher than in our first trials. Peanuts Based on the germplasm screening using bioassays for seedling diseases, we have created a cross population of the accessions with the highest seedling disease resistance and of advanced lines from our peanut breeding program that are well adapted to the region. This population will be planted at two participating organic farms and one organic research site according to the production practices on each farm. We will harvest the peanuts from these farms to serve as the seed for the next generation in a mass selection (evolutionary breeding) program. Evolutionary breeding harnesses natural selection for crop improvement and is arguably best suited for low input environments like organic farms. After harvest each year, we will screen the peanuts to insure that only ones with sufficient size and quality are used as seed the next year.
Publications
- Sanchez, J., J.M. Padilla, L. De la Cruz, J. Ron, J.Holland, M. Krakowsky, and M. Goodman. 2011. Use of gametophytic isolating mechanisms for maize. Plant Breeding News 29:1.14. Available at http://www.fao.org/ag/agp/agpc/doc/services/pbn/pbn-230.htm#a114
- Worthington, M.L. and S.C. Reberg-Horton. 2013. Breeding cereal crops for enhanced weed suppression: optimizing allelopathy and competitive ability. Journal of Chemical Ecology. (Accepted)
- Place, G.T., S.C. Reberg-Horton, D.L. Jordan, T. G. Isleib and G.G. Wilkerson. 2012. Influence of Virginia market type genotype on peanut response to weed interference. Peanut Science 39:22-29.
- Place, G.T., S.C. Reberg-Horton, D.A. Dickey and T.E. Carter. 2011. Identifying soybean traits of interest for weed competition. Crop Science 51:2642-2654.
- Place, G.T., S.C. Reberg-Horton, and T.E. Carter. 2011. Screening tactics for identifying competitive soybean genotypes. Communications in Soil Science and Plant Analysis 42:2654-2665.
- Place, GT, SC Reberg-Horton, TE Carter, AN Smith. 2011. Effects of soybean seed size on weed competition. Agronomy Journal 103:175-181.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: The double-cross corn hybrid that we are currently using, NC476.DKHBA1 x NC320.NC368 is reasonably competitive with current commercial hybrids (which are not available for organic use), and is resistant to the disease pressure found in the Southeast. We are both testing existing lines that might improve its performance and developing new lines that might also. Existing lines that look promising for substituting on the NC476.DKHBA1 side include 2 NC296 dervatives and two other lines, PHN47 and NC412. On the NC320.NC368 side, 2309-1 (a NC320 derivative) and LH132 show promise. We have identified 4 possible gametophytic double-crosses that promise isolation from GMOs, reasonable productivity, and at least adequate disease resistance. Three of the four involve an NC492-derived line which we are temporarily calling E015. Three also involve Frank Kutka derivatives that we call KN and KS: NC338.NC302 x KN.E015 KN.NC460 x KS.E015 NC302.NC354 x NC464.KS NC520.NC464 x E015.NC354 Based on previous results we continued screening for another season on a selection of over 500 soybean genotypes from the over 18,000 genotypes in the USDA soybean germplasm collection. In this year's expanded wheat study we will use this new screening method to test the weed suppressive ability of the entire 2012 NC Official Variety Test and several hard winter wheat lines being developed for organic production systems. Laboratory studies have suggested that some wheat varieties gain a competitive edge against weeds through allelopathy, the release of chemicals through roots that suppress the growth of neighboring plants. We have conducted a laboratory bioassay to test the allelopathic ability of all of the varieties in the Official Variety Test. Organic Breeding: Official Variety Testing in Organic Conditions Official variety testing (OVT) for organic conditions was conducted at three organic locations in Salisbury, Kinston, and Herford, NC for the wheat testing and in Goldsboro, Kinston, and Herford NC for soybean and corn testing. PARTICIPANTS: Participant work on this project is described in the previous report section. TARGET AUDIENCES: All official variety test results from the project have been issued to interested producers through the North Carolina Organic Grains newsletter. PROJECT MODIFICATIONS: The organic corn test had very few entries from southeastern states. The number of corn varieties available to growers without seed treatment and with no transgenics was limited to 19 entries with the majority coming from the Midwest. Of course, this lack of adapted varieties for the Southeast is one of the impetuses for this project. We capitalized on an opportunity to participate with a group of public corn breeders and smaller seed companies in the Midwest conducting a multi-regional test of available corn varieties for organic producers. This United States Testing Network (USTN) is led by the Practical Farmers of Iowa.
Impacts
Project outputs of this manner are still pending as we are only in the second year of a long term breeding effort. However, one tangible effort from our corn breeding efforts includes the double cross hybrid NC476.DKHBA1 x NC320.NC368 which is reasonably competitive with current commercial hybrids (which are not available for organic use), and is resistant to the disease pressure found in the Southeast.
Publications
- No publications reported this period
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: Organic Breeding for Peanuts Soil-borne damping-off diseases is one of the biggest obstacles facing organic peanut production in the Southeast. Conventional producers control these diseases by using seed treated with fungicides. But organic producers can't use seed treated with the usual products, and organic approved seed treatments have not proven to be highly effective. So we have embarked on finding sources of resistance to the various elements of the damping-off complex. We conducted assays this year to measure lines' reactions to CBR, Sclerotinia blight, and more recently white mold (southern stem rot, Sclerotium rolfsii). Each disease assay includes four reps of 49 genotypes from the peanut genotype core collection. Organic Breeding for Corn On the basis of very limited data, we identified the double cross hybrid DKHBA1.NC476 x NC320.NC368 as being potentially useful for organic corn farmers. NC320 x NC368 has consistently been a high yielding hybrid. NC476 is broad-leafed, reasonably high yielding and early. DKHBA1 is well-adapted, high yielding and early. We are making attempts to use Ga1-S as an isolating mechanism to alleviate the threat of GMO pollen in organic production fields. While we have an array of gametophytic inbreds available that yield well in hybrids (in contrast to most other groups attempting to utilize this concept), all of our own lines are rather closely related. We have obtained some unrelated Ga1-S stocks from Frank Kutka and will be testing them in crosses with each other and with the Ga1-S crosses next summer. Organic Breeding for Soybeans Based on previous results we selected over 500 genotypes from the over 18,000 genotypes in the USDA soybean germplasm collection. Each soybean genotype was screened for early growth vigor. This screening process involves taking equivalent overhead digital images of each soybean genotype and processing the images with imaging software that enables us to quantify the leaf to ground ratio for the soybean genotype. A higher leaf to ground ratio is indicative of a more weed competitive soybean genotype. Additionally we measured the soybean canopy width, height, and overall vigor rating to select competitive genotypes. Organic Breeding for Wheat In October 2010 we planted an experiment designed to find a simple and effective method of estimating weed suppressive ability in plots overseeded with Italian ryegrass. Plots were overseeded with ryegrass at rates of 0, 50, 150, and 300 plants per square meter. We intend to test three methods of investigating weed suppressive ability in these plots: 1) visual ratings, 2) aerial photographs of the plots evaluated with Sigma Scan image analysis software (SPSS), and 3) multiband spectral signature data collected with a Crop Circle ACS-210 multiband sensor. At the end of the growing season (Zadoks 92) we will cut a twelve square foot swath of each plot with a forage harvester, separate the wheat and ryegrass biomass by hand, and determine the ratio of weed to wheat biomass in each plot. Each of the proposed proxy methods will then be tested for correlation with the end of season biomass ratios. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Official Variety Testing in Organic Conditions Official variety testing (OVT) for organic conditions was conducted at three organic locations. We teamed up with the North Carolina OVT group to create similar testing conditions. We also hope that these efforts may result in an eventual inclusion of variety testing in organic conditions as part of the normal NC OVT process. The organic wheat test received 38 entries from private seed companies and public breeders throughout the Southeast. The organic corn test had very few entries from southeastern states. The number of corn varieties available to growers without seed treatment and with no transgenics was limited to 11 entries. Of course, this lack of adapted varieties for the Southeast is one of the impetuses for this project. We capitalized on an opportunity to participate with a group of public corn breeders and smaller seed companies in the Midwest conducting a multi-regional test of available corn varieties for organic producers. We included 18 corn entries in our organic OVT to provide a Southeastern regional test site. The organic soybean test had the largest number of entries (48) for organic and non treated, non GMO soybean cultivars . Farmer outreach with the Rural Advancement Foundation International (RAFI) The focus of our work has been to reach out to farmers in the southeast and develop a system for soliciting their input and participation in our breeding work. Our first goal was to develop visibility and clear messaging of the project - to make it recognizable and understandable to farmers. To accomplish this goal RAFI developed a logo and website for the BOPS project. Our second goal was to identify and develop a network of organic grain farmers across the southeast. We have developed a database of over 500 organic farms across the southeast, which we have sent multiple mailings and email updates to. We have also made phone calls to many of the farmers on this list. We have been able to interact with a core group of 65 farmers from 11 different states on multiple occasions. Our third goal was to develop a system for soliciting input from farmers to influence the breeding work at NC State. To accomplish this goal this past year we developed an organic seed survey, which was mailed to our southeastern farmer network database. We also worked with NC State partners to host a webinar in January of 2010 to collect input from farmers and share what the breeders were working on. We have identified individual farmers who serve as opinion leaders in our area, and have begun to network with these farmers to identify their major concerns. We have made many visits to farmers in North Carolina and Virginia to learn about the challenges they face. We will create opportunities for discussion about the major issues identified by the farmer network, including: organic seed supply and distribution, traits needed to combat disease and pests, and concerns over GMO contamination. We will also work with NC State partners to host a session at the January 2011 Organic Grains Conference in North Carolina in which we bring together prominent members of the network, either in person or via webinar.
Publications
- No publications reported this period
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