Commercial generations of Brassica napus cause greater yield loss in Triticum aestivum, than volunteer B. napus generations

2010 ◽  
Vol 90 (5) ◽  
pp. 777-783 ◽  
Author(s):  
N J Seerey ◽  
S J Shirtliffe
Keyword(s):  
Triticum Aestivum ◽  
Brassica Napus ◽  
Generational Differences ◽  
Yield Loss ◽  
Plant Density ◽  
Wheat Yield ◽  
Yield Losses ◽  
Large Area ◽  
Seedling Mortality ◽  
Brassica Napus L

Volunteer canola (Brassica napus L.) has become a common weed in producer fields, due to the large area cropped, and inherent harvest losses. Commonly grown B. napus varieties which segregate in subsequent generations to create volunteers with unknown competitive capabilities are developed by hybrid genetics. The objective of this study was to evaluate the effect of volunteer B. napus variety and generation on competition yield loss in hard red spring wheat (Triticum aestivum L.). Two hybrid and one open-pollinated B. napus varieties with three consecutive generations produced from each variety were grown at varying densities in a wheat stand over 5 site-years. Yield loss depended on the density of B. napus in relation to total plant density. Generational differences in B. napus seedlings resulted in differences in wheat yield losses. Brassica napus densities at maturity provided a more robust model of wheat yield loss, as there were differences in wheat yield losses due to the interaction of generation and variety of B. napus. Commercial seed generations were the most competitive plants, while volunteer generations were less competitive. The amount of yield loss caused by volunteer B. napus was highly variable. The availability of low-priced herbicides, and the competitive ability of volunteer B. napus may allow for economic thresholds concerning weed control to be surpassed at low densities of volunteer B. napus populations. Key words: Competition, hybrid, open-pollinated, volunteer weed, seedling mortality, mature density, seedling density, feral

Estimating yield losses in wheat resulting from infestation by doublegee (Emex australis)

1974 ◽  
Vol 14 (70) ◽  
pp. 656 ◽  
Author(s):  
DJ Gilbey
Keyword(s):  
Crop Yield ◽  
Field Trial ◽  
Yield Loss ◽  
Wheat Yield ◽  
Yield Reduction ◽  
Yield Losses ◽  
Seedling Mortality ◽  
Emex Australis ◽  
Percentage Yield

The effect of doublegee (Emex australis) density on wheat yield was studied in a field trial. Percentage yield reduction (y) was related to doublegee plants m-2 at 1 week (x1) and 8 weeks (x2) after seeding thus: y = 10.3 + 0.24 x1 r = 0.78*** y = 5.6 + 0.44 x2 r = 0.86*** showing that estimates of doublegee density could be used for forecasting crop yield losses before it is too late to spray. No further yield loss occurred when x1 was greater than 120 plants metre-2. Doublegee seedling mortality that occurred during the seven weeks between plant counts was strongly related to the initial counts (x1) thus: r = 0.88***.

Influence of Tartary Buckwheat (Fagopyrum tataricum) Density on Yield Loss of Barley (Hordeum vulgare) and wheat (Triticum aestivum)

Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 521-523 ◽  
Author(s):  
E. Ann de St. Remy ◽  
John T. O'Donovan ◽  
Alan K. W. Tong ◽  
P. Ashley O'Sullivan ◽  
M. Paul Sharma ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Yield Loss ◽  
Plant Density ◽  
Wheat Yield ◽  
Tartary Buckwheat ◽  
Yield Reduction ◽  
Regression Equations ◽  
Fagopyrum Tataricum ◽  
The Relationship

The relationship between Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn. ♯ FAGTA) plant density (x) and percent yield loss (ŷ) was expressed by the following linear regression equations for barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), respectively; ŷ = 0.63 + 2.75 √x and ŷ = 5.04 + 3.05 √x. Tartary buckwheat causes serious yield reduction in barley and wheat. A Tartary buckwheat density at 30 plants/m2 at emergence reduced barley yield by 16% and wheat yield by 22%.

Effects of delaying chemical fallowing in pasture rotations on pasture quality and wheat yield in the Victorian Wimmera

1989 ◽  
Vol 29 (1) ◽  
pp. 69 ◽  
Author(s):  
GJ O'Leary ◽  
RM Binns ◽  
TR Lewis
Keyword(s):  
Dry Matter ◽  
Yield Loss ◽  
Wheat Yield ◽  
Growth Period ◽  
Poor Quality ◽  
Yield Losses ◽  
The Third ◽  
Pasture Quality ◽  
Chemical Fallow ◽  
Conservation Method

The effects of delaying chemical fallowing in a pasture rotation on pasture quality and subsequent wheat yield were investigated at sites near Minyip and Charlton, Victoria, in 1983 and 1984. Three chemical fallows were commenced at different times and were compared with a conventionally cultivated fallow. The earliest chemical fallow was established, together with a conventional fallow, at the end of winter. The second chemical fallow commenced towards the end of the rapid spring growth period in mid-October (early hayfreezing), and the third in mid- November (late hayfreezing) on a grass-dominant pasture. The pasture in spring ranged from 51 to 72% digestible dry matter (DDM) but the quality declined to 42-50% DDM by the end of the fallow treatments in autumn at each site in both years. Weathering of the pasture over summer reduced it to roughage. In contrast to a conventional fallow, early hayfreezing of pasture reduced the yield of subsequent wheat crops at Minyip by 14% in 1984 and 26% in 1985. Late hayfreezing caused losses of around 35% in each year at Minyip. At Charlton yield losses were much lower with only 14% loss observed from late hayfreezing in 1985. Because the feed produced by hayfreezing was of very poor quality, hayfreezing cannot be recommended as a viable fodder conservation method as it could not adequately compensate for any yield loss.

Comparing responses to phosphorus of field pea (Pisum sativum), canola (rape, Brassica napus) and spring wheat (Triticum aestivum)

2006 ◽  
Vol 46 (5) ◽  
pp. 645 ◽  
Author(s):  
M. D. A. Bolland ◽  
R. F. Brennan ◽  
P. F White
Keyword(s):  
Triticum Aestivum ◽  
Brassica Napus ◽  
Pisum Sativum ◽  
Spring Wheat ◽  
Maximum Yield ◽  
Triticum Aestivum L ◽  
Field Pea ◽  
Alkaline Soils ◽  
Brassica Napus L ◽  
Single Superphosphate

The phosphorus (P) requirements of spring wheat (Triticum aestivum L.) are well known for all soils in south-western Australia; but the P requirements of field pea (Pisum sativum L.) and canola (Brassica napus L.), which are grown in rotation with wheat on marginally acidic to alkaline soils in the region, are not known. In a glasshouse study, the P requirements of field pea and wheat were compared for 16 soils collected throughout the agricultural region. Ten of the 16 soils were also used to compare the P requirements of canola and wheat. The P was applied as powdered single superphosphate, and yield of dried shoots of 42-day-old plants was measured. The amount of P required to produce 90% of the maximum yield of dried shoots (PR90 values) was used to compare the P requirements of the species. To produce 90% of the maximum yield, field pea required less P than wheat in 5 soils, similar P in 2 soils, and more P in 9 soils. Canola required less P than wheat in all 10 soils. We conclude the P requirements of field pea or canola relative to wheat depend on a complex interaction between plant and soil, particularly for field pea relative to wheat. Per unit of applied P, the P concentration in dried shoots decreased in the order canola > wheat > field pea, indicating the order in which plant roots of the 3 species were able to access P from soil.

GROWTH OF BARLEY, BROMEGRASS AND ALFALFA IN THE GREENHOUSE IN SOIL CONTAINING RAPESEED AND WHEAT RESIDUES

1978 ◽  
Vol 58 (1) ◽  
pp. 241-248 ◽  
Author(s):  
J. WADDINGTON
Keyword(s):  
Triticum Aestivum ◽  
Brassica Napus ◽  
Hordeum Vulgare ◽  
Wheat Straw ◽  
Nitrogen Deficiency ◽  
Triticum Aestivum L ◽  
Bromus Inermis ◽  
Hordeum Vulgare L ◽  
Total Leaf Area ◽  
Brassica Napus L

Under greenhouse conditions, incorporating ground straw in the soil at rates between 2,240 and 8,970 kg/ha reduced the emergence of alfalfa (Medicago media Pers. cv. Beaver) significantly (P < 0.05) and bromegrass (Bromus inermis Leyss cv. Magna) slightly, but had no effect on barley (Hordeum vulgare L. cv. Conquest). Rape (Brassica napus L. cv. Target and B. campestris L. cv. Echo) straws were more damaging than wheat (Triticum aestivum L. cv. Manitou) straw. Symptoms of severe nitrogen deficiency appeared early in the growth of barley where straw had been added to the soil. The effect on tillering varied. In one experiment tillers were smaller, in one tillers were larger; but in both, total leaf area produced was much less where 8,970 kg/ha of straw had been added to the soil. Bromegrass showed the same effects but to a lesser degree, probably because of slower growth requiring a smaller supply of nitrogen. Alfalfa growth was apparently unaffected. There was no evidence that the straw of either rapeseed species was more deleterious than wheat straw to crop growth after emergence. It is concluded that straw incorporated in soil affected barley and bromegrass growth by reducing the availability of nitrogen.

EFFECT OF ROW SPACING AND SEEDING RATES ON SUMMER RAPE IN SOUTHERN MANITOBA

1990 ◽  
Vol 70 (1) ◽  
pp. 127-137 ◽  
Author(s):  
M. J. MORRISON ◽  
P. B. E. McVETTY ◽  
R. SCARTH
Keyword(s):  
Brassica Napus ◽  
Seed Quality ◽  
Plant Density ◽  
Chlorophyll Concentration ◽  
Plant Distribution ◽  
Row Spacing ◽  
Seeding Rate ◽  
Brassica Napus L ◽  
Plant Densities ◽  
Lower Plant

To determine the effects of varying plant densities on summer rape (Brassica napus L.), the cultivar Westar was seeded in 15- and 30-cm row spacings at seeding rates of 1.5, 3.0, 6.0, and 12.0 kg ha−1. Plants seeded in 15-cm rows yielded more per area, produced more pods per plant and lodged less than those in 30-cm rows. Higher yields were associated with a more even plant distribution and a lower degree of intra-row competition. There were no significant protein, oil and chlorophyll concentration differences between the row spacing treatments. The highest yields (kg ha−1) were achieved with the 1.5 and 3.0 kg ha−1 seeding rates. Summer rape compensated for lower plant densities with the production of more branch racemes. As seeding rate increased, competitive mortality increased, resulting in greater etiolation at bolting, and greater lodging at harvest. Seed oil and protein concentrations were not affected by seeding rate. However, seed chlorophyll concentration decreased with increased seeding rate.Key words: Brassica napus, plant density, seed quality, rape (summer)

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