Isogenic analysis of glufosinate-ammonium tolerant and susceptible summer rape lines

1998 ◽  
Vol 78 (3) ◽  
pp. 401-408 ◽  
Author(s):  
A. Kumar ◽  
G. Rakow ◽  
R. K. Downey

The development of transgenic Brassica napus L., tolerant to non-selective broad-spectrum herbicides, such as glyphosate and glufosinate-ammonium, could provide canola growers with an efficient method of weed control. The objective of this study was to determine whether the phosphinothricin-acetyl transferase (pat) gene which imparts tolerance to glufosinate-ammonium, affects the growth, development, productivity, and seed quality of B. napus canola. Nineteen glufosinate-ammonium tolerant and susceptible isogenic pairs of the B. napus cv. Westar, derived from independent transformation events, were evaluated in two field trials in each of 2 yr in Saskatchewan. Tolerant lines of six isogenic pairs were similar in their agronomic performance and seed quality to their susceptible counterparts indicating that glufosinate-ammonium tolerant B. napus can be developed that is not negatively affected in yield and quality by the presence of the pat gene. Several tolerant lines exhibited delayed flowering and maturity, lower biomass and seed yields, and lower oil and protein contents indicating positional effects of the pat gene on performance. Tolerant lines carrying two inserts of the pat gene were more negatively affected in their growth and development than single insert tolerant lines. The results of this study indicate that it would be beneficial to generate a number of different transformants and select elite transgenic lines which are not affected in their performance by the presence of the pat gene for use in cultivar development. Key words: Brassica napus, glufosinate-ammonium tolerance, isogenic analysis

2012 ◽  
Vol 92 (1) ◽  
pp. 97-107
Author(s):  
Juliana J. Soroka ◽  
Larry F. Grenkow

Soroka, J. J. and L. F. Grenkow. 2012. When is fall feeding by flea beetles ( Phyllotreta spp., Coleoptera: Chrysomelidae) on canola ( Brassica napus L.) a problem? Can. J. Plant Sci. 92: 97–107. Two cultivars of Brassica napus canola were seeded in mid-May and early June in three field experiments in each of 3 yr near Saskatoon, Saskatchewan, to determine the effects of late-season flea beetle feeding on seed yields. In the first experiment, canola was sprayed with insecticide late in the summer to eliminate naturally-infesting flea beetles. In the second, 1×1×1.5 m screen cages were placed over early- and late-seeded canola at flowering and infested with flea beetles as canola matured. In the third investigation, sleeve cages were placed over individual plants and infested with 100 flea beetles. Flea beetles had no detrimental effects on early-seeded canola in any experiment, but did affect seed yields of late-seeded plots in some trials. Over two cultivars in 1 year, late-seeded plants in cube cages infested with about 350 flea beetles per plant when lower pods were turning from translucent to green in colour reduced yield by 241 kg ha−1 over control yields. Seed weights in these late-seeded plots were decreased from 2.68 g per 1000 seeds in uninfested cages to 2.44 g per 1000 seeds in infested cages. Populations of 100 flea beetles per plant in sleeve cages had no effect on harvest parameters in any seeding date or year.


1982 ◽  
Vol 62 (4) ◽  
pp. 989-993 ◽  
Author(s):  
P. A. O’SULLIVAN ◽  
V. C. KOSSATZ

Control of Canada thistle (Cirsium arvense L. Scop.) topgrowth and regrowth, and tolerance of rapeseed (Brassica campestris L. and Brassica napus L.) to 3,6-dichloropicolinic acid at 0.2–0.3 kg/ha were excellent in greenhouse and field trials. Rapeseed yields following postemergence treatment were increased in 12 of 17 trials conducted on infested farm fields.


2001 ◽  
Vol 81 (4) ◽  
pp. 657-664 ◽  
Author(s):  
J. L. Cuthbert ◽  
P. B. E. McVetty

Unidirectional outcrossing rates were assessed between neighboring plots, rows (spaced 40, 80 and 120 cm apart) and plants of oilseed rape (Brassica napus L.) grown in simulated plant breeding field trials, using the transgenic dominant bromoxynil herbicide resistance gene as a marker. Bromoxynil susceptible (pollen recipient) plots, rows and plants were planted in the field and surrounded by bromoxynil-resistant plots, rows and plants, respectively. The field trials were conducted at Winnipeg, Carman, and Portage la Prairie, Manitoba, in 1996 and 1997. Seed produced on the susceptible plots and rows was harvested and then planted in the field the following year with all emerged seedlings sprayed at 750 g a.i. ha–1 bromoxynil to identify resistant individuals. Approximately 420 000 seedlings were screened in 1997 and 1998 with 23 816 resistant individuals identified, each resistant individual being the result of an outcrossing event. The overall mean plot-to-plot outcrossing rate was 4.0% (± 0.23). The overall mean row-to-row outcrossing rate was 9.5% (± 0.62) for the 40-cm row spacing, 5.6% (± 0.37) for the 80-cm row spacing and 3.9% (± 0.25) for the 120-cm row spacing. For the plant-to-plant trials, seed produced on the susceptible plants was harvested and then a sample was planted in the greenhouse with all emerged seedlings sprayed at 560 g a.i. ha–1 bromoxynil to identify resistant individuals. The overall mean plant-to-plant outcrossing rate was 21.0% (± 1.73). Outcrossing rates of this magnitude have significant implications for all oilseed rape breeding programs. Methods to minimize outcrossing are discussed. Key words: Brassica napus L., outcrossing rates, transgenic dominant bromoxynil resistance marker


1987 ◽  
Vol 67 (3) ◽  
pp. 675-684 ◽  
Author(s):  
G. C. BEAULIEU ◽  
D. J. HUME

In order to determine regions of adaptation of winter rapeseed (Brassica napus L.), field trials were planted at about 30 locations in Ontario in 1981 and 1982. Four cultivars were tested each year. Winter survival was poor in northern Ontario in both years, and along the north shore of Lake Erie in the first year. Over all sites, mean winter survival was 52%. At sites which did not completely winterkill, plant survival and yield averaged 70% and 2.38 t ha−1. Best winter rapeseed performance in Ontario occurred at well-drained sites with good winter snow cower and an absence of excessive flooding or cold temperatures in the spring. Cultivars did not differ in survival or yield in 1981–1982. The cultivar Jet Neuf had higher yields than the other cultivars in 1982–1983. There were differences in oil and protein content among the cultivars. The results suggest that winter rapeseed could become a viable crop in Ontario.Key words: Rapeseed (winter), Brassica napus, seed yield, winter survival, adaptation


1990 ◽  
Vol 70 (1) ◽  
pp. 127-137 ◽  
Author(s):  
M. J. MORRISON ◽  
P. B. E. McVETTY ◽  
R. SCARTH

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)


2017 ◽  
Vol 204 (2) ◽  
pp. 147-154 ◽  
Author(s):  
M. Rashid ◽  
J. G. Hampton ◽  
M. P. Rolston ◽  
K. M. Khan ◽  
D. J. Saville

2015 ◽  
Vol 35 (6) ◽  
Author(s):  
Humberto A. Gajardo ◽  
Benjamin Wittkop ◽  
Braulio Soto-Cerda ◽  
Erin E. Higgins ◽  
Isobel A. P. Parkin ◽  
...  

1979 ◽  
Vol 59 (4) ◽  
pp. 959-962 ◽  
Author(s):  
JOHN M. CLARKE

Field trials were conducted at Saskatoon in 1976, and at Swift Current in 1977, to investigate intra-plant variation in number of seeds per pod and seed weight in Brassica napus L. ’Tower’. Number of pods was greatest on the main raceme, least on the lowest branch. Seed number per pod was also highest on the main raceme, as was seed weight. In 1976, number of seeds per pod and seed weight were higher in pods from the lower half of the main raceme than from those on the upper half. A study of the trends in number of seeds per pod between the end of flowering and maturity revealed a general decline in number of seeds per pod and an increase in the number of aborted seeds at the lower branch positions. At the end of flowering, pods from all branch positions had equal numbers of developing seeds.


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