Quality versus quantity: spring wheat seed size and seeding rate effects on Avena fatua interference, economic returns and economic thresholds

The development of competitive cropping systems could minimize the negative effects of wild oat competition on cereal grain yield, and in the process, help augment herbicide use. A 3-yr field experiment was conducted at Kalispell, MT, to investigate the effects of spring wheat seed size and seeding rate on wheat spike production, biomass, and grain yield under a range of wild oat densities. Wheat plant density, spikes, biomass, and yield all increased as seed size and seeding rates increased. Averaged across all other factors, the use of higher seeding rates and larger seed sizes improved yields by 12 and 18%, respectively. Accordingly, grain yield was more highly correlated with seed size than with seeding rate effects. However, the combined use of both tactics resulted in a more competitive cropping system, improving grain yields by 30%. Seeding rate effects were related to spike production, whereas seed size effects were related to biomass production. As such, plants derived from large seed appear to have greater vigor and are able to acquire a larger share of plant growth factors relative to plants derived from small seed.

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Effects of Spring Wheat Seed Size and Reduced Rates of Tralkoxydim on Wild Oat Control, Wheat Yield, and Economic Returns

Weed Technology ◽

10.1614/wt-05-152r.1 ◽

2006 ◽

Vol 20 (2) ◽

pp. 472-477 ◽

Cited By ~ 2

Author(s):

Qingwu Xue ◽

Robert N. Stougaard

Keyword(s):

Seed Size ◽

Spring Wheat ◽

Weed Management ◽

Wheat Yield ◽

Wild Oat ◽

Wheat Seed ◽

Economic Returns ◽

Size Classes ◽

Large Seed ◽

Combined Use

Spring wheat competitive ability has recently been demonstrated to co-vary with seed size. The objective of this study was to determine if spring wheat seed size would influence the effects of variable tralkoxydim rates on wild oat control, wheat yield, and economic returns. The factorial treatment arrangement consisted of three spring wheat seed size classes and five tralkoxydim rates. Wild oat density, panicles, and biomass decreased as spring wheat seed size and tralkoxydim rate increased, with the combined effect being additive. Wild oat variables decreased in a log-logistic manner as tralkoxydim rate increased during both years. However, tralkoxydim was less effective in 2000 than 2002, as indicated by the higher dosage required to reduce the wild oat variables by 50% (greaterI50values). In contrast, the effect of large seeded wheat in suppressing wild oat was more consistently expressed, with wild oat variables decreasing linearly as seed size increased. Wheat yield and economic returns increased exponentially as tralkoxydim rate increased. At the same time, wheat yield and economic returns were greater for wheat plants derived from large seed compared to those derived from small seed. Averaged over all other factors, adjusted gross returns of 578, 657, and 703 $/ha were realized for the small, medium, and large seed size classes, respectively. The combined use of large seeded wheat plus tralkoxydim applications provided greater wild oat control than did either single tactic. The use of large seeded wheat had a stabilizing effect that increased the consistency and durability of the weed management system while simultaneously improving economic returns.

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Spring wheat seed size and seeding rate affect wild oat demographics

Weed Science ◽

10.1614/0043-1745(2002)050[0312:swssas]2.0.co;2 ◽

2002 ◽

Vol 50 (3) ◽

pp. 312-320 ◽

Cited By ~ 21

Author(s):

Qingwu Xue ◽

Robert N. Stougaard

Keyword(s):

Seed Size ◽

Spring Wheat ◽

Wild Oat ◽

Wheat Seed ◽

Seeding Rate

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Seed-Mediated Gene Flow in Wheat: Seed Bank Longevity in Western Canada

Weed Science ◽

10.1614/ws-08-099.1 ◽

2009 ◽

Vol 57 (1) ◽

pp. 124-132 ◽

Cited By ~ 10

Author(s):

Ryan L. Nielson ◽

Marc A. McPherson ◽

John T. O'Donovan ◽

K. Neil Harker ◽

Rong-Cai Yang ◽

...

Keyword(s):

Regression Analysis ◽

Gene Flow ◽

Seed Size ◽

Spring Wheat ◽

Seed Bank ◽

Seed Viability ◽

Wheat Crop ◽

Western Canada ◽

Viable Seed ◽

Wheat Seed

Development of genetically modified (GM) wheat has raised concerns about the movement and persistence of transgenes in agroecosystems and the ability of growers to segregate GM from conventional wheat. Wheat as a crop has been studied extensively but the population biology of volunteer wheat is not well characterized. Artificial seed bank studies were conducted in western Canada to provide baseline data on volunteer wheat seed persistence. Seed from two cultivars of Canadian western red spring wheat, ‘AC Splendor’ and ‘AC Superb’, were buried in mesh bags at three depths (0, 2, and 15 cm) in two different environments in the fall of 2003 and 2004. In addition, in 2004, ‘AC Superb’ seed were separated into small and large seed lots and buried with a medium seed lot to examine the influence of seed size on seed bank persistence. Seeds were withdrawn at intervals to assess seed germination and viability and regression analysis conducted on the viable seed at each sample period, after burial. Seed viability was variable within years and sites, and declined exponentially over time. In the spring, approximately 6 mo after initiation, viable seed ranged from 1 to 43%. With the exception of a single site and year, seeds on the soil surface persisted significantly longer than buried seeds and increasing burial depth accelerated loss of viability. The maximum viability of wheat seeds at 0, 2, and 15 cm depth in the spring following planting was 43, 7, and 2%, respectively. The extinction of viability for 99% (EX99) of the seed was estimated from regression analysis. The EX99values of seeds buried at 0, 2, and 15 cm ranged from 493 to 1,114, 319 to 654, and 175 to 352 d after planting (DAP), respectively, with the exception of one site in 2003 where burial depths were not different and all had an EX99value of 456 DAP. Seed size and cultivar did not significantly affect persistence, with the exception of one site in 2003 where the difference in EX99values was 20 DAP. The rapid loss of seed viability limits temporal gene flow via volunteers in years following a wheat crop. Results provide data on spring wheat biology to aid in Canadian environmental biosafety assessments of GM wheat and will be incorporated into a mechanistic model to predict wheat gene flow on the Canadian prairies.

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Seeding rate effects on organic rice growth, yield, and economic returns

Agronomy Journal ◽

10.1002/agj2.20304 ◽

2020 ◽

Vol 112 (5) ◽

pp. 4104-4119

Author(s):

Xiufen Li ◽

Fugen Dou ◽

Kenton B. Watkins ◽

Shu Wang ◽

Kun Chen ◽

...

Keyword(s):

Growth Yield ◽

Economic Returns ◽

Seeding Rate ◽

Organic Rice ◽

Rice Growth ◽

Rate Effects

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Seeding Rate Effects on Weed Control and Yield For Organic Soybean Production

Weed Technology ◽

10.1614/wt-08-134.1 ◽

2009 ◽

Vol 23 (4) ◽

pp. 497-502 ◽

Cited By ~ 33

Author(s):

George T. Place ◽

Samuel Chris Reberg-Horton ◽

Jim E. Dunphy ◽

Adam N. Smith

Keyword(s):

North Carolina ◽

Weed Control ◽

Weed Management ◽

Population Studies ◽

Row Spacing ◽

Economic Returns ◽

Seeding Rate ◽

Soybean Production ◽

Seed Technology ◽

Rate Effects

The organic grain sector is one of the fastest growing sectors of the organic market, but farmers in the mid-Atlantic cannot meet the organic grain demand, including the demand for organic soybean. Weed management is cited by farmers as the largest challenge to organic soybean production. Recent soybean population studies show that lower seeding rates for genetically modified organism soybean farmers provide maximum economic return due to high seed technology fees and inexpensive herbicides. Such economic analysis may not be appropriate for organic soybean producers due to the absence of seed technology fees, stronger weed pressures, and price premiums for organic soybean. Soybean seeding rates in North Carolina have traditionally been suggested at approximately 247,000 live seeds/ha, depending on planting conditions. Higher seeding rates may result in a more competitive soybean population and better economic returns for organic soybean producers. Experiments were conducted in 2006 and 2007 to investigate seeding rates of 185,000, 309,000, 432,000, and 556,000 live seeds/ha. All rates were planted on 76-cm row spacing in organic and conventional weed management systems. Increased soybean seeding rates reduced weed ratings at three of the five sites. Increased soybean seeding rates also resulted in higher yield at three of the four sites. Maximum economic returns for organic treatments were achieved with the highest seeding rate in all sites. Results suggest that seeding rates as high as 556,000 live seeds/ha may provide organic soybean producers with better weed control, higher yield, and increased profits.

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Seed Size and Seeding Rate Effects upon Stand Density and Yield of Alfalfa 1

Agronomy Journal ◽

10.2134/agronj1979.00021962007100010021x ◽

1979 ◽

Vol 71 (1) ◽

pp. 83-85 ◽

Cited By ~ 15

Author(s):

C. S. Cooper ◽

R. L. Ditterline ◽

L. E. Welty

Keyword(s):

Seed Size ◽

Stand Density ◽

Seeding Rate ◽

Rate Effects

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Seed size and seeding rate effects on canola emergence, development, yield and seed weight

Canadian Journal of Plant Science ◽

10.4141/cjps-2014-222 ◽

2015 ◽

Vol 95 (1) ◽

pp. 1-8 ◽

Cited By ~ 32

Author(s):

K. N. Harker ◽

J. T. O’Donovan ◽

E. G. Smith ◽

E. N. Johnson ◽

G. Peng ◽

...

Keyword(s):

Seed Size ◽

Seed Weight ◽

Seed Quality ◽

Canola Seed ◽

Seeding Rate ◽

Brassica Napus L ◽

Linear Association ◽

Rate Effects ◽

Pod Development ◽

Direct Seeded

Harker, K. N., O’Donovan, J. T., Smith, E. G., Johnson, E. N., Peng, G., Willenborg, C. J., Gulden, R. H., Mohr, R., Gill, K. S. and Grenkow, L. A. 2015. Seed size and seeding rate effects on canola emergence, development, yield and seed weight. Can. J. Plant Sci. 95: 1–8. Canola (Brassica napus L.) is the most common dicotyledonous crop in Canada. Here we determine the effect of canola seed size and seeding rate on canola emergence, development, yield and seed weight. In 2013, direct-seeded experiments were conducted at nine western Canada locations. Four canola seed sizes (1000-seed weights ranging from 3.96 to 5.7 g) and one un-sized treatment (4.4 g average) were seeded at two rates (75 and 150 seeds m−2). Higher seeding rates led to higher canola emergence and stubble density at harvest. Higher seeding rates also increased early crop biomass, 1000-seed weights and seed oil content and reduced days to start of flowering and days to crop maturity. Seed size effects on canola emergence, yield or seed quality were not significant. Increasing seed size had a positive linear association with early canola biomass and 1000-seed weights, whereas, both days to flowering and days to the end of flowering had a negative linear association with seed size. Greater biomass from large seeds increases crop competition with weeds and also hastens flowering, shortens the flowering period and reduces the risk that canola will be exposed to high temperatures that can negatively impact flowering and pod development.

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Compensatory Mechanisms Associated with the Effect of Spring Wheat Seed Size on Wild Oat Competition

Crop Science ◽

10.2135/cropsci2005.08-0270 ◽

2006 ◽

Vol 46 (2) ◽

pp. 935-945 ◽

Cited By ~ 6

Author(s):

Fernando R. Guillen‐Portal ◽

Robert N. Stougaard ◽

Qingwu Xue ◽

Kent M. Eskridge

Keyword(s):

Seed Size ◽

Spring Wheat ◽

Wild Oat ◽

Wheat Seed ◽

Compensatory Mechanisms

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Winter wheat competition against jointed goatgrass (Aegilops cylindrica) as influenced by wheat plant height, seeding rate, and seed size

Weed Science ◽

10.1614/ws-04-006r ◽

2004 ◽

Vol 52 (6) ◽

pp. 996-1001 ◽

Cited By ~ 23

Author(s):

Joseph P. Yenish ◽

Frank L. Young

Keyword(s):

Winter Wheat ◽

Plant Height ◽

Seed Size ◽

Wheat Variety ◽

Wheat Yield ◽

Cultural Control ◽

Wheat Seed ◽

Seeding Rate ◽

Herbicide Resistant ◽

Jointed Goatgrass

Jointed goatgrass is a troublesome weed in winter wheat with selective control only possible with a herbicide-resistant crop. Even with herbicide-resistant wheat, cultural control is still an important part of jointed goatgrass management. A study was conducted in 1998 and 2000 to determine whether using larger sized seed of a tall wheat variety at an increased seeding rate would reduce the effect of jointed goatgrass on winter wheat. Wheat seed size, seeding rate, and variety height had no effect on jointed goatgrass plant density. Tall (∼130 cm) wheat reduced mature jointed goatgrass biomass 46 and 16% compared with short (∼100 cm) wheat in years 1 and 2 of the experiment, respectively. Spikelet biomass was also reduced approximately 70 and 30% in the same respective years. One thousand–spikelet weight of jointed goatgrass was reduced 37 and 7% in years 1 and 2, respectively, when grown in competition with taller compared with shorter wheat. Moreover, dockage was 80 and 30% less in years 1 and 2, respectively, when grown in competition with taller than shorter wheat. Mature jointed goatgrass height was similar regardless of the competitive wheat height. However, jointed goatgrass was as much as 18% taller than the short wheat and 15% shorter than the tall wheat. Seeding rate had the most consistent effect on wheat yield. Wheat seed yield was about 10% greater with 60 than 40 seed m−1of row when competing with jointed goatgrass. Results of this study indicate that growers could use a tall winter wheat variety to improve crop competition against jointed goatgrass. Results also indicate that plant breeders should consider plant height because herbicide-resistant varieties are developed for the integrated management of jointed goatgrass.

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