Spring wheat seed size and seeding rate effects on yield loss due to wild oat (Avena fatua) interference

Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Robert N. Stougaard ◽  
Qingwu Xue

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.

Weed Science ◽  
2002 ◽  
Vol 50 (3) ◽  
pp. 312-320 ◽  
Author(s):  
Qingwu Xue ◽  
Robert N. Stougaard

1980 ◽  
Vol 60 (4) ◽  
pp. 1141-1146 ◽  
Author(s):  
H. G. NASS

The use of harvest index as a selection criterion for grain yield in F2 populations of spring wheat (Triticum aestivum L.) grown at two population densities was investigated. Harvest index was useful in delineating yield differences between lines for both crosses. The F4 lines selected in F2 for a high harvest index yielded about 9% more per plot in 1978 than F4 lines having a low harvest index in F2. Generally, lines selected at the higher commercial seeding rate yielded more than lines selected at the lower plant density. In 1979, a heavy Fusarium infection reduced the mean grain yield of the F6 lines and suppressed any significant response to selection resulting from population density and harvest index in F2. While selection based on high harvest index at low population density can be used to select higher yielding plants it was not as effective as selection at high population density which more closely approximates commercial crop densities. Additional research is needed before the use of harvest index as a selection tool in wheat breeding programs can be recommended for use in Atlantic Canada.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1900
Author(s):  
Beata Feledyn-Szewczyk ◽  
Grażyna Cacak-Pietrzak ◽  
Leszek Lenc ◽  
Jarosław Stalenga

The selection of a proper variety is one of the main factors influencing the quantity and quality of cereal grain yield in organic agriculture. The aim of the study was to determine the suitability of 13 varieties of spring wheat for cultivation in organic farming according to their competitive potential against weeds, susceptibility to fungal diseases and grain yield. Due to the large share of cereals in organic farms both in Poland and in Europe, the research results could be applied by organic farming system farmers and advisors. High-yielding varieties in the organic system were: KWS Torridon, Kandela, Arabella, Zadra and Waluta. The KWS Torridon and Kandela varieties were resistant to fungal pathogens infestation, while Brawura, Izera, Korynta and Ostka Smolicka showed the highest infestation rate. Ethos variety yields were the lowest due to its low plant density, with a high weed infestation rate. The wheat yields proved to be significantly correlated with plant density and the thousand grain weight, but no significant negative effects of weed infestation and pathogen infestation were found. A synthesis of the three-year results showed that the varieties most useful for organic farming were: Arabella, KWS Torridon, Kandela, Katoda, Waluta and Zadra.


Crop Science ◽  
2006 ◽  
Vol 46 (2) ◽  
pp. 935-945 ◽  
Author(s):  
Fernando R. Guillen‐Portal ◽  
Robert N. Stougaard ◽  
Qingwu Xue ◽  
Kent M. Eskridge

2006 ◽  
Vol 20 (2) ◽  
pp. 472-477 ◽  
Author(s):  
Qingwu Xue ◽  
Robert N. Stougaard

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.


2005 ◽  
Vol 85 (4) ◽  
pp. 771-776 ◽  
Author(s):  
John T. O’Donovan ◽  
Robert E. Blackshaw ◽  
K. Neil Harker ◽  
George W. Clayton ◽  
Ross McKenzie

Field experiments were conducted at three locations in Alberta to determine the relative competitiveness with wild oat (Avena fatua L.) of three hard red spring (HRS) and three Canada prairie spring (CPS) wheat (Triticum aestivum L.) varieties and a semidwarf hull-less barley (Hordeum vulgare L.) (Falcon), and normal height general purpose barley (AC Lacombe). Crop variety significantly affected crop yield loss, wild oat shoot dry weight and wild oat seed yield (competitive indicators). AC Lacombe barley was consistently more competitive than Falcon barley or any of the wheat varieties, while the HRS wheat varieties were mainly more competitive than the CPS varieties. Falcon barley was generally similar in competitiveness to the CPS wheat varieties. Differences among varieties in crop plant density at establishment correlated significantly with the competitive indicators suggesting that this factor contributed to the differences in competitiveness among the varieties. Crop density tended to be higher with the more competitive AC Lacombe barley and HRS wheat varieties than with the less competitive Falcon barley and CPS wheat varieties. Variety and seeding rate did not interact significantly but intentionally increasing the seeding rate improved the competitiveness of all varieties. Key words: Hard red spring wheat, Canada prairie spring wheat, crop seeding rate, hull-less barley, semi-dwarf wheat and barley


2009 ◽  
Vol 89 (4) ◽  
pp. 763-773 ◽  
Author(s):  
W E May ◽  
S J Shirtliffe ◽  
D W McAndrew ◽  
C B Holzapfel ◽  
G P Lafond

Traditionally, farmers have delayed seeding to manage wild oat (Avena fatua L.) in tame oat (Avena sativa L.) crops, but this practice can adversely affect grain yield and quality. The objectives of this study were: (1) to evaluate the effectiveness of using high seeding rates with early-seeded oat to maintain grain yield and quality, and (2) to determine an optimum seeding rate to manage wild oat and maximize grain yield and quality. The factors of interest were wild oat density (low and high density), seeding date (early May, mid May, early June and mid June), and tame oat seeding rate (150, 250, 350 and 450 viable seeds m-2). The study was conducted at Indian Head and Saskatoon, SK, in 2002, 2003 and 2004, at Winnipeg, MB, in 2002, and at Morden, MB, in 2003 and 2004. Wild oat biomass, wild oat panicle density and wild oat seed in the harvested sample decreased as seeding rate increased, while tame oat biomass and grain yield increased. Wild oat density ranged between 0 and 100 plants m-2 with averages of 10 plants m-2 in the low density treatment and 27 plants m-2 in the high density treatment. At low seeding rates, grain yield decreased with increasing wild oat density. The difference in grain yield between the two wild oat densities decreased as the seeding rate increased. There was a curvilinear decrease in grain yield as seeding was delayed. A seeding date × seeding rate interaction was noted for test weight, plump seed, thin seed and groat yield. Seed quality improved as seeding rate increased for only the mid-June seeding date. Even though the mid-June test weight increased as the seeding rate increased it was always lower than the early May test weight at any seeding rate. The results from this study established that in the presence of wild oats, early seeding of tame oat is possible providing high seeding rates, 350 plants m-2 are used.Key words: Wild oat competition, wild oat density, wild oat biomass, grain yield, grain quality


2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Roberto Ruggeri ◽  
Riccardo Primi ◽  
Pier Paolo Danieli ◽  
Bruno Ronchi ◽  
Francesco Rossini

Experiments were conducted in open field to assess the effect of seeding season and density on the yield, the chemical composition and the accumulation of total tannins in grains of two chickpea (<em>Cicer arietinum</em> L.) cultivars (<em>Pascià</em> and <em>Sultano</em>). Environmental conditions and genetic factors considerably affected grain yield, nutrient and total tannins content of chickpea seeds, giving a considerable range in its qualitative characteristics. Results confirmed cultivar selection as a central factor when a late autumn-early winter sowing is performed. In effect, a more marked resistance to Ascochyta blight (AB) of <em>Sultano</em>, allowed better agronomic performances when favourable-to-AB climatic conditions occur. Winter sowing appeared to be the best choice in the Mediterranean environment when cultivating to maximise the grain yield (+19%). Spring sowing improved crude protein (+10%) and crude fibre (+8%) content, whereas it did not significantly affect the accumulation of anti-nutrients compounds such as total tannins. The most appropriate seeding rate was 70 seeds m–2, considering that plant density had relatively little effect on the parameters studied.


2018 ◽  
Vol 98 (6) ◽  
pp. 1331-1341 ◽  
Author(s):  
W.E. May ◽  
M.P. Dawson ◽  
C.L. Lyons

In the past, most sunflower research was conducted in tilled cropping systems and was based on wide row configurations established using precision planters. Little agronomic information is available for the no-till systems predominant in Saskatchewan, where crops are typically seeded in narrow rows using an air drill. Two studies were conducted in Saskatchewan to determine the optimum seeding and nitrogen (N) rates for short-season sunflowers in a no-till cropping system. The N rate study used 5 N rates (10, 30, 50, 70, and 90 kg N ha−1) with the hybrid 63A21. The seeding rate study used 7 seeding rates (37 000, 49 000, 61 000, 74 000, 86 000, 98 000, and 111 000 seeds ha−1) with two cultivars, AC Sierra (open pollinated) and 63A21 (hybrid). There was a linear yield increase as the N rate increased from 10 to 90 kg N ha−1. Based on the N rates tested in this study and current N fertilizer costs below $1 kg−1, sunflower yields and gross returns were most favorable at 90 kg N ha−1. Future N response research with a wider range of N rates is warranted to best determine the optimum N rate. The optimum seeding rate was between 98 000 and 111 000 seeds ha−1 for AC Sierra and between 74 000 and 86 000 seeds ha−1 for 63A21. The optimum plant density, approximately 70 000 to 75 000 plants ha−1, was similar for both cultivars. These results are higher than the current recommended seeding rates for wide-row precision planting systems in areas with a longer growing season.


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