© 2006 Plant Management Network.
Quality of Farmer-Saved Wheat Seed is Variable in the Southern Great Plains
Jeffrey T. Edwards and Eugene G. Krenzer, Jr. (retired), 368 Ag. Hall, Department of Plant and Soil Sciences, Oklahoma State University, Stillwater 74078
Corresponding author: Jeffrey T. Edwards. email@example.com
Edwards, J. T., and Krenzer, E. G., Jr. 2006. Quality of farmer-saved wheat seed is variable in the southern Great Plains. Online. Crop Management doi:10.1094/CM-2006-0531-01-RS.
Profitable wheat (Triticum aestivum) production in the southern Great Plains is highly dependent on low input costs, as weather conditions are frequently not conducive for high yield. Many producers save seed from their own production for sowing the following year to reduce production costs, and some choose to purchase bin-run seed of unknown variety, although this practice has become much less common due to stricter enforcement of seed quality and protection laws. These seed sources are seldom tested for purity or germination; therefore, a three-year experiment was conducted in central Oklahoma to evaluate the purity and fecundity of farmer-saved seed sources as compared to commercially-available certified seed sources. Differences in forage and grain yield were observed among certified seed sources of the same variety, and whether or not a forage or grain yield advantage was associated with certified as compared to farmer-saved seed often depended on which certified source was used for the comparison. Certified seed sources generally contained less foreign material, fewer weed seeds, and had higher field germination percentage than farmer-saved seed. Overall, this experiment demonstrates that if farmers use quality control measures similar to those required for certified seed, farmer-saved wheat seed can produce forage and grain yield comparable to that of certified seed.
Wheat Production in the Southern Great Plains
Southern Great Plains’ agriculture is dominated by continuous hard red winter wheat (Triticum aestivum) production and approximately 50% of wheat acreage in this region is sown with the intention of using the crop for both pasture and grain production (i.e., dual purpose) (2). Dual-purpose management techniques, high temperatures, and inadequate moisture during grain fill frequently limit wheat grain yield in this area, leading the region’s wheat producers to look for ways to reduce input costs. Two popular methods of reducing production costs are to save wheat seed from year to year or to purchase uncleaned, bin-run wheat seed of unknown variety.
Planting bin-run wheat seed of unknown variety was a once a popular practice among growers when the primary interest was to produce forage for cattle grazing. The thought among these producers was that since grain production was not the primary objective, any weed seed present would only benefit forage production. However, off-site movement of weed populations has led to contamination of harvested wheat (i.e., dockage) and reduced wheat milling and baking quality. Further, stricter enforcement of state seed laws has led to decreased sale of bin-run seed of unknown variety.
Farmers who save their own wheat seed may or may not have it cleaned and typically do not test for germination or vigor prior to planting. This often leads to poor stand establishment and incorrect drill calibration (7). Furthermore, farmer-saved wheat seed does not go through the same quality-control standards as certified seed, so varietal mixing and contamination that can occur during planting, harvest, and storage is commonplace. This lack of quality control has led to the conception among growers that the purity of a wheat variety will "run out" if seed is saved for numerous years in a row.
We hypothesized that poor quality of farmer-saved seed would reduce yield potential in Oklahoma and that most producers would benefit from purchasing certified seed, as experiments conducted in other areas of the U.S. have produced this result (6). To test this hypothesis we set forth with the objective of evaluating the quality of farmer-saved seed in Oklahoma in terms of forage production, grain yield, varietal purity, and weed-seed contamination.
Testing Farmer-Saved and Certified Seed
Farmer-saved seed samples of wheat varieties commonly grown in Oklahoma were collected from farms in August of 2002. Varieties included 2174, Custer, Jagger, Karl 92, TAM 110, Thunderbolt, and bin-run samples of unknown variety. Certified seed of each variety was purchased from local vendors. Seed mass was measured by weighing a 100-seed sub-sample from each wheat sample. Weed seed contamination level was assessed by removing, identifying, and counting weed seed and inert material. Weed seed were not reintroduced to the wheat samples after purity analysis. Variety purity analysis was performed through visual analysis of conspicuous qualitative traits and tallying conforming and nonconforming spike numbers at crop maturity.
Plots were sown September 17 and 25 at Chickasha (97.95°W, 34.04°N) and Perkins (97.03°W, 35.98°N), OK and October 4 and 8 at Stillwater (97.05°W, 36.07°N) and Lahoma (98.09°W, 36.39°N), OK, respectively. Plots were nine 6-inch rows wide by 20 ft long and seed were sown at 60 lb/acre into a conventionally-tilled seedbed using a cone planter. The experimental unit was seed source and the experimental design was a randomized complete block with four replications.
Weeds were managed according to Oklahoma State University extension recommendations (5). Wheat emergence was measured by counting the number of emerged wheat plants in two 1-yard samples from each plot and expressing as a percentage of the number of seed sown per linear yard as calculated from seeding rate and seed mass data. Forage production was measured at Perkins and Chickasha at approximately 11 weeks after planting by hand-clipping forage to the soil surface in two 1-yd by one-row samples in each plot, drying, and weighing. Portions of plots not harvested were then mowed to an approximate 2.5-inch height. Grain was harvested from each plot using a small-plot combine and grain yield was adjusted to a 12% moisture base.
Farmer-saved and certified samples of Jagger hard red winter wheat and bin-run samples of unknown variety were collected in the fall of 2003. Plots were sown September 12 and 25 at Lahoma and Perkins, OK and October 27 at Stillwater, OK. Planting techniques, crop management and research methodology were analogous to those used in 2002, with the exception that all samples were inspected for foreign material and weed seed content prior to seeding.
Farmer-saved and certified samples of Jagger hard red winter wheat were collected in the fall of 2004 and sown September 17 at Perkins and October 5 at Lahoma. Planting techniques, crop management and research methodology were analogous to those used in 2003. Data were analyzed using the mixed procedure of SAS V 9.1 (SAS institute, Inc., Cary, NC) and means were separated using Fischer’s protected LSD at the 0.05 significance level.
Results Generally Favored Certified Seed
Results from each year of the experiment indicate that the source from which certified seed was obtained and the location of the experiment were important factors in determining whether or not a forage or grain yield advantage was realized when using certified seed instead of farmer-saved seed (Tables 1, 2, and 3). In 2002/2003 at the Chickasha location, for example, there were differences in grain yield between the two certified samples of Jagger and whether or not a grain-yield increase was associated with planting certified seed depended on which certified sample was used for the comparison (Table 1). Similar trends were observed for fall forage yield at Perkins in 2003/2004 and grain yield at Lahoma in 2004/2005 (Tables 2 and 3). Differences in yield potential among seed of the same variety obtained from different environments were also observed by Quinby et al. (4) and underscore the need of testing more than one certified seed source when making farmer-saved vs. certified seed comparisons.
Table 1. Grain (bu/acre) and forage (dry lb/acre) yield produced by hard red winter wheat sources in Oklahoma in 2002-2003.
Table 2. Grain (bu/acre) and forage (dry lb/acre) yield produced by Jagger hard red winter wheat sources in Oklahoma in 2003-2004.
Table 3. Grain (bu/acre) and forage (dry lb/acre) yield produced by Jagger hard red winter wheat sources in Oklahoma in 2004-2005.
While the results are not always clear-cut, they do weigh in favor of certified seed, as farmer-saved and bin-run samples were generally only as good as certified samples and seldom out-performed certified seed sources. In fact, in terms of grain yield, 9 out of 19 farmer-saved samples were inferior to the best certified seed source at one or more location and 10 out of 19 samples were inferior in terms of fall forage production in 2002/2003. However, in 2003/2004 only 3 of 27 farmer-saved samples were inferior for grain production and 4 out of 17 were inferior in 2004/2005.
Emergence of certified samples was always greater than 80%, but field germination rates were often below 75% for farmer-saved sources and below 60% for bin-run samples (data not shown), yet there was not a consistent yield reduction associated with reduced germination. These data suggest that seeding rates used in this experiment, and those typically used in the southern Great Plains, are above that required to optimize yield.
Temporal and spatial variability of the data indicate that benefits of certified seed in terms of forage and grain yield are not clear-cut; nevertheless, other factors such as weed seed contamination and varietal contamination may be as or more important to wheat growers’ profitability. It is in these quality parameters that the certified seed sources often had an advantage over farmer-saved sources evaluated in this experiment. It was common for farmer-saved samples to contain greater than 10% of other varieties and in 2002/2003 there was one sample that was misidentified by variety. While varietal purity is of little importance for some wheat producers in the southern Great Plains, increased concentration on identity-preserved grains and variety-specific management might make this a greater priority in the future.
Many farmer-saved samples contained greater than 5% inert matter in addition to weed seed (Fig. 1). Common weed contaminants included jointed goatgrass (Aegilops cylindrical), cheat (Bromus secalinus), rescuegrass (Bromus catharticus), downy brome (Bromus tectorum), feral rye (Secale cereale), vetch (Vicia angustifolia), and wild oat (Avena spp.)(data not shown). These contaminants were generally present at low (less than 20 weed seed per pound) levels; however, a few samples contained greater than 2,400 cheat seeds per pound and up to 300 Italian ryegrass (Lolium multiflorum) seeds per pound. Weed seed were removed from all samples prior to sowing, which did not allow for measurement of wheat grain yield reduction associated with weed interference. Previous research, however, has indicated that Italian ryegrass infestations as low as 2 plants per ft2 can reduce grain yield by as much as 38% (1) and cheat infestations of 177 seed per ft2 can reduce wheat grain yield by 35% (3). Therefore, the levels of weed contamination in many of our samples indicate that if proper quality-control measures are not taken any savings in seed cost for farmers who are primarily concerned with grain production and save their own seed, might be more than offset by higher weed control costs and discounts for dockage at the elevator.
In summary, based on our data, it would be difficult to make the generalization that planting certified seed was superior to farmer-saved seed. It could be surmised, however, that increased cost was the only downside to planting certified seed, and this increase would have been much less than the additional production costs associated with weed control for contaminated farmer-saved or bin-run seed. Nevertheless, a producer who concentrates on variety purity and maintenance of weed-free seed sources is likely to have seed quality equal to certified sources. Farmer-saved samples that were farther removed in time from certified (i.e., the number of years seed had been planted and saved from the original certified source) generally had greater impurities and weed seed. This increased contamination was probably due to a lack of quality-control standards and the resulting degradation of seed sources. For this reason, growers wishing to save their own seed would likely benefit from sowing a small amount of certified seed each year from which seed could be saved for replanting.
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2. Hossain, I., Epplin, F. M., Horn, G. W., and Krenzer, E. G., Jr. 2004. Wheat production and management practices used by Oklahoma grain and livestock producers. B-818. Oklahoma Agric. Exp. Stn.
3. Koscelny, J. A., Peeper, T. F., Solie, J., and Solomon, S. G., Jr. 1990. Effect of wheat (Triticum aestivum) row spacing, seeding rate, and cultivar on yield loss from cheat (Bromus secalinus). Weed Tech. 4:487-492.
4. Quinby, J. R., Reitz, L. P., and Laude, H. H. 1962. Effect of source of seed on productivity of hard red winter wheat. Crop Sci. 2:201-203.
5. Royer, T. A., and Krenzer, E. G., Jr., eds. 2000. Wheat management in Oklahoma. E-831. Oklahoma State Univ. Div. of Agric. Sci. and Natural Resources.
6. Spilde, L. A., and Hafdahl, M. P. 1994. Quality durum seed planted in North Dakota. J. Prod. Agric. 7:352-355.
7. Stockton, R. D., Krenzer, E. G., Jr., Solie, J., and Payton, M. E. 1996. Stand establishment of winter wheat in Oklahoma: A survey. J. Prod. Agric. 9:571-575.