Yield-limiting potential of Beet western yellows virus in Brassica napus

2007 ◽  
Vol 58 (8) ◽  
pp. 788 ◽  
Author(s):  
R. A. C. Jones ◽  
B. A. Coutts ◽  
J. Hawkes
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Field Experiments ◽  
Green Peach Aphid ◽  
Erucic Acid Content ◽  
Feeding Damage ◽  
Worst Case ◽  
Beet Western Yellows Virus ◽  
Yield Decline ◽  
Wide Range

Losses in seed yield and quality caused by infection with Beet western yellows virus (BWYV) alone or in combination with direct feeding damage by Myzus persicae (green peach aphid) were quantified in field experiments with Brassica napus (canola, oilseed rape) in the ‘grainbelt’ region of south-western Australia. Plants infected with BWYV and infested with M. persicae were introduced into plots early to provide infection sources and spread BWYV to B. napus plants. Insecticides were applied as seed dressings and/or foliar applications to generate a wide range of BWYV incidences in plots. Colonisation by vector aphids and spread of BWYV infection were recorded in the plots of the different treatments. At sites A (Medina) and B (Badgingarra) in 2001, foliar insecticide applications were applied differentially at first, but, later, ‘blanket’ insecticide sprays were applied to all plots to exclude any direct feeding damage by aphids. When BWYV infection at sites A and B reached 96% and 100% of plants, it decreased seed yield by up to 46% and 37%, respectively. Also, variation in BWYV incidence explained 95% (site A) and 96% (site B) of the variation in yield gaps, where for each 1% increase in virus incidence there was a yield decrease of 12 (site A) and 6 (site B) kg/ha. At both sites, this yield decline was entirely because fewer seeds formed on infected plants. At site B, BWYV infection significantly diminished oil content of seeds (up to 3%), but significantly increased individual seed weight (up to 11%) and erucic acid content (up to 44%); significant increases in seed protein content (up to 6–11%) were recorded at both sites. In field experiments at sites B and C (Avondale) in 2002, insecticides were applied as seed dressings or foliar sprays. At site B, when BWYV incidence reached 98%, the overall yield loss caused by BWYV and direct M. persicae feeding damage combined was 50%. At site C, when BWYV incidence reached 97%, the overall combined yield decline caused by BWYV and direct feeding damage was 46%. This research under Australian conditions shows that, when aphids spread it to B. napus plantings such that many plants become infected at an early growth stage, BWYV has substantial yield-limiting potential in B. napus crops. Although the results represent a worst case scenario, the losses were greater than those reported previously in Europe and are cause for concern for the Australian B. napus industry. When applied at 525 g a.i./100 kg of seed, imidacloprid seed dressing controlled insecticide-resistant M. persicae and effectively suppressed spread of BWYV for 2.5 months and increased seed yield by 84% at site B and 88% at site C. Therefore, provided that mixing the insecticide with seed is sufficiently thorough, dressing seed with imidacloprid before sowing provides good prospects for control of BWYV and M. persicae in B. napus crops.

Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.)

2014 ◽  
Vol 94 (8) ◽  
pp. 1461-1469 ◽  
Author(s):  
Yun Ren ◽  
Jianfang Zhu ◽  
Nazim Hussain ◽  
Shanlin Ma ◽  
Genru Ye ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Dry Matter ◽  
Field Experiments ◽  
Seedling Quality ◽  
Leaf Number ◽  
Green Leaf ◽  
Brassica Napus L ◽  
Seedling Age ◽  
Neck Diameter

Ren, Y., Zhu, J., Hussain, N., Ma, S., Ye, G., Zhang, D. and Hua, S. 2014. Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.). Can. J. Plant Sci. 94: 1461–1469. Seedling quality is an essential indicator for seed yield in canola, which is affected by many factors, including seedling age. Two field experiments were conducted to compare canola seedling quality and seed yield on 30-, 35-, 40-, 45-, 50-, 55-, and 60-d-old seedlings in 2011 and 2012. The relationship between seedling quality traits and seed yield of different seedling ages was also analyzed. Results revealed that the highest seed yield obtained from 40-d-old seedlings was attributed to more branches and siliques per plant. The negative effect of young seedlings (30-d-old) on seed yield was greater than that of old seedlings (60-d-old). The reduction rates in seed yield on the 30- and 60-d-old seedlings were 25.7 and 18.2%, respectively, compared with the 40-d-old seedlings. Increased root neck diameter, green leaf number, shoot, and root dry matter was the case on 40-d-old seedling transplanted plants compared with other ages. However, the increase was larger in the old seedlings than in the young seedlings. On average, the shoot and root dry weights of the 30-d-old seedlings were 1.9 and 1.7% of those in the 60-d-old seedlings. However, correlation analysis revealed that the seedlings with the highest shoot and root dry matter did not necessarily obtain the highest seed yield. Factor analysis suggested that the effects of root neck diameter and green leaf number on seed yield were more pronounced than those of shoot and root dry matter. Therefore, high seed yield in canola could be defined in terms of optimum green leaf numbers and branches per plant.

OUTCROSSING IN RAPE AND MUSTARD UNDER SASKATCHEWAN PRAIRIE CONDITIONS

1987 ◽  
Vol 67 (1) ◽  
pp. 147-151 ◽  
Author(s):  
G. RAKOW ◽  
D. L. WOODS
Keyword(s):  
Brassica Napus ◽  
Erucic Acid ◽  
Acid Content ◽  
Seed Oil ◽  
Outcrossing Rate ◽  
Erucic Acid Content ◽  
Seed Color ◽  
Wide Range ◽  
Outcrossing Rates ◽  
The One

The interplant outcrossing rate was studied for one cultivar and four lines of rape (Brassica napus) and three cultivars of mustard (Brassica juncea) under field conditions at Saskatoon, Saskatchewan, in 1982, 1983 and 1984. Marker characters used for determining outcrossing rates were seed oil erucic acid content for rape and seed color for mustard. The average interplant outcrossing rate was 21.8% for rape and 18.7% for mustard. No significant differences in outcrossing rates among the one cultivar and the four lines of rape or the three cultivars of mustard were detected. A wide range in outcrossing rates between plants within cultivars and lines was observed for both species, but whether this variation was genetic or was environmentally induced could not be determined in these experiments. Some of the implications of this partial outcrossing on methods used for the breeding of these crops are discussed.Key words: Outcrossing, rape, mustard

Prognosis of boron deficiency in oilseed rape (Brassica napus) by plant analysis

1998 ◽  
Vol 49 (5) ◽  
pp. 867 ◽  
Author(s):  
Youzhang Wei ◽  
R. W. Bell ◽  
Yuai Yang ◽  
Zhengqian Ye ◽  
Ke Wang ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Seed Yield ◽  
Field Experiments ◽  
Seasonal Effects ◽  
East China ◽  
Yield Response ◽  
Boron Deficiency ◽  
Plant Analysis ◽  
Critical Range

In areas where soils are low in boron (B), the ability to predict B deficiency by plant analysis depends on the development of calibrated standards and offers the potential of preventing or minimising losses in seed yield. The present study aimed at establishing relationships between seed yield in winter oilseed rape (Brassica napus) and B concentrations in defined leaves during growth before fiowering and from them to determine critical values for the prognosis of B deficiency. Oilseed rape cv. Zheyouyou 2 was grown in 10 field experiments in Zhejiang province, south-east China, with B rates from 0 to 3· 3 kg/ha. At 4 of the sites, oilseed rape was resown in the following year to assess seasonal effects on critical concentrations. Experiments were conducted on the 3 main soil groups on which oilseed rape is grown in south-east China. The youngest open leaf (YOL) was selected as the sampling part because its B concentrations were strongly responsive to increasing B supply and well correlated with seed yield response. In this study, the best model of the relationship between YOL B concentration and yield was the Mitscherlich equation, which explained 68-89% of the variation in the data. The calculated critical range in the YOL at seedling stage was 20-25 mg B/kg and appeared to be valid in 2 seasons and on 3 soil types. The critical B range for prognosis of B deficiency was found to predict consistently those crops in farmers" fields that had low seed yield and low soil B, but needs to be evaluated in other growing environments especially those for spring rape.

Interrelationships Among Grain Yield and Related Traits of Candidate Restorer Lines of Brassica Napus L.

2021 ◽  
Vol 24 (1) ◽  
pp. 51-64
Author(s):  
AKM Aminul Islam ◽  
NK Chowdhury ◽  
FM Era ◽  
MG Rasul
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Coefficient Of Variation ◽  
Seed Weight ◽  
Agronomic Traits ◽  
Path Coefficient ◽  
Phenotypic Effect ◽  
Wide Range ◽  
Pod Length ◽  
Number Of Seeds

Forty-three candidate restorer lines of Brassica napus were evaluated for 11 agronomic traits for genetic variability and interrelationships among yield traits to find out yield contributing traits. A wide range of variability and character association was observed among the lines. The line BNR-017 took the lowest time for first (26.67 days) and 100% flowering (41.00 days) whereas BNR-031 (74.33 days) and BNR-034 (74.00 days) matured earlier. The lines BNR-022 (1.07m) and BNR-026 (1.02m) were found with the shortest plant stature and all other lines were in average plant height of around 1.35m. The lines BNR-039, BNR-011, BNR-001, BNR-013 and BNR-014 were found the best performer for number of pods per plant, seeds per pod and seed yield per plant. Estimates of genotypic and phenotypic coefficient of variation were high (≥30%) for seed yield per plant (30.52 and 33.13, respectively). High broad sense heritability was recorded for 1000-seed weight (97.69%), days to ripening (97.12%), days to first flowering (96.80%), days to 100% flowering (95.50%) and pod length (92.74%). Significant and negative correlation was observed between seed yield per plant and number of seeds per pod, -0.217* and -0.192*, respectively both at genotypic and phenotypic level, while the highest positive and significant genotypic (0.786**) and phenotypic (0.795**) correlation were found with pod length. Path co-efficient analysis showed the highest positive and direct phenotypic effect of number of seeds per pod (1.221) on seed yield per plant while days to first flowering had the maximum negative direct effect (-0.039). The results of genotypic and phenotypic coefficient of variation, heritability and genetic advance in percent of mean, correlation co-efficient and path coefficient revealed that pods per plant, pod length, seeds per pod and 1000-seed weight could be used as selection criteria to increase seed yield in rapeseed. Ann. Bangladesh Agric. (2020) 24(1) : 51-64

Control of Beet western yellows virus in Brassica napus crops: infection resistance in Australian genotypes and effectiveness of imidacloprid seed dressing

2010 ◽  
Vol 61 (4) ◽  
pp. 321 ◽  
Author(s):  
B. A. Coutts ◽  
C. G. Webster ◽  
R. A. C. Jones
Keyword(s):  
Brassica Napus ◽  
Green Peach Aphid ◽  
Foliar Spray ◽  
Aphid Transmission ◽  
Feeding Preference ◽  
Breeding Lines ◽  
Beet Western Yellows Virus ◽  
Disease Management Strategy ◽  
Treated Seed ◽  
Infection Resistance

Eighteen Brassica napus (canola) genotypes were examined for their responses to infection with Beet western yellows virus (BWYV) and infestation by Myzus persicae (green peach aphid) in a field experiment and in a series of pot experiments under controlled-environment conditions. When exposed to infection with BWYV in the field, plants of cvv. Tranby and Trigold remained uninfected with BWYV. Only 2–5% of plants of cvv. Stubby and Banjo became infected, but infection incidence was 14–23% in cvv. Tanami and Jade, and reached 45–65% in 12 other commercial cultivars or advanced breeding lines of B. napus. Once plants became infected, the sensitivity rankings for most genotypes were 2–3: mild to moderate symptoms consisting of plant stunting and reddening of lower leaves. When plants of cvv. Tranby, Trigold, Stubby, and susceptible control cv. Pinnacle growing in pots were exposed to spread of BWYV by viruliferous winged M. persicae flying from an infested cv. Pinnacle plant infected with BWYV, similar numbers of aphids colonised each of the different cultivars. Thus, no aphid feeding preference was apparent among the different B. napus cultivars. However, all 18 plants of cv. Pinnacle became infected with BWYV, but only 1, 2, and 5 plants of cvv. Trigold, Tranby, and Stubby became infected, respectively. When 68 plants each of cvv. Tranby, Trigold, and Stubby were each inoculated with 1–10 viruliferous aphids/plant, only 1 of cv. Trigold, 3 of cv. Tranby, and 6 of cv. Stubby became infected with BWYV despite infection of 45 plants of cv. Pinnacle. This shows that cvv. Tranby, Trigold, and Stubby have resistance to infection with BWYV by aphid transmission. In 2 experiments when viruliferous M. persicae were placed on plants of B. napus grown from seed treated with imidacloprid (240 g a.i./100 kg seed), they infested 72% of plants grown from treated seed and transmitted BWYV to 62% of them regardless of the growth stage inoculated. Aphids colonised 100% of plants grown from untreated seed but 0% of plants sprayed with imidacloprid (2 g a.i./L water), and infection with BWYV was diminished markedly by the foliar spray. This suggests that insufficient insecticide adhered to most of the dressed seeds to kill the aphids and prevent BWYV transmission. B. napus cultivars found to have infection resistance to BWYV can be used in conjunction with imidacloprid seed dressings (if applied effectively) as components of an integrated disease management strategy for control of BWYV in B. napus crops.

scholarly journals Inheritance of Ear Resistance to European Corn Borer in Sweet Corn

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 450D-450
Author(s):  
Daniel F. Warnock ◽  
David W. Davis
Keyword(s):  
Combining Ability ◽  
European Corn Borer ◽  
Field Experiments ◽  
Rating Scale ◽  
Sweet Corn ◽  
Channel Length ◽  
Feeding Damage ◽  
Corn Borer ◽  
Wide Range ◽  
Feeding Resistance

European corn borer, Ostrinia nubilalis Hübner, is an economic pest of sweet corn. Consumer demand for high-quality, insect-free produce with minimal pesticide residue necessitates exploitation of various control options. Ear feeding resistance could reduce insecticide inputs. The inheritance of ear feeding resistance and silk channel length in the F1 derived from a diallel cross (Griffing's model I, method 2) of eight breeding stocks describing a wide range of feeding resistance was investigated in field experiments. Feeding damage, based on a 1 (no damage) to 9 (>10% ear damage) visual rating scale, and silk channel length of ears that had been manually infested at the ear tip with O. nubilalis were recorded. A significant (P ≤ 0.05) year by location interaction was found for ear feeding damage and silk channel length. Genotype ear feeding damage and silk channel length differences were significant (P ≤ 0.01) beyond genotype by environment (year and location) interactions. Mean feeding damage ranged from 2.5 (parents 1 × 7) to 8.8 (parent 2) and mean silk channel length ranged from 1.9 cm (parents 2 × 7) to 9.0 cm (parent 3). Ten of the 28 possible crosses (reciprocals combined) and 1 parent were classed as resistant (damage rating < 3.0). Eleven crosses, including all 7 involving parent 2, and 2 parents were susceptible (damage rating > 4.0). Pearson's correlation analysis indicated lower damage levels were weakly to moderately associated with increased silk channel length for both parents (r = –0.18) and progeny (r = –0.44). The general combining ability (GCA) component was significant (P ≤ 0.01) for ear feeding damage, suggesting additive effects control ear feeding damage. GCA and specific combining ability (SCA) effects did not account for silk channel length variability, suggesting strong environmental influences. Improved ear feeding resistance should be possible via recurrent selection with recombination.

Control of Winged Waterprimrose (Jussiaea decurrens) and Northern Jointvetch (Aeschynomene virginica) with Fungal Pathogens

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 497-501 ◽  
Author(s):  
C. D. Boyette ◽  
G. E. Templeton ◽  
R. J. Smith
Keyword(s):  
Oryza Sativa ◽  
Glycine Max ◽  
Fungal Pathogens ◽  
Liquid Culture ◽  
Field Experiments ◽  
Colletotrichum Gloeosporioides ◽  
Pathogenic Fungus ◽  
Field Tests ◽  
Wide Range ◽  
Growing Region

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

scholarly journals The Nitrogen-Fixing Bacteria—Effective Enhancers of Growth and Chemical Composition of Egyptian Henbane under Varied Mineral N Nutrition

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 921
Author(s):  
Rania M. A. Nassar ◽  
Engy A. Seleem ◽  
Gianluca Caruso ◽  
Agnieszka Sekara ◽  
Magdi T. Abdelhamid
Keyword(s):  
Seed Yield ◽  
Field Experiments ◽  
Tropane Alkaloids ◽  
Pharmaceutical Products ◽  
N Fertilizer ◽  
Recommended Dose ◽  
Mineral N ◽  
N Nutrition ◽  
N Dose ◽  
Egyptian Henbane

Egyptian henbane (Hyoscyamus muticus L.) plants are rich sources of alkaloids used in pharmaceutical products. Recently, rising efforts have been devoted to reducing mineral fertilizer supply, production cost, and environmental pollution via decreasing the doses of nitrogenous fertilizers and adopting biofertilizer farming systems. Two field experiments were conducted to examine the potential role of N fixing bacteria Azotobacter spp. and Azospirillum spp. on the growth, mineral status, tropane alkaloids, leaf anatomy, and seed yield of Egyptian henbane grown with different levels of mineral nitrogen fertilizer, i.e., 25%, 50%, and 100% of the recommended dose, equal to 30, 60, and 120 kg N ha−1. N fertilizer improved growth, mineral elements, tropane alkaloids, seed yield, and yield components of Egyptian henbane, which showed a gradually rising trend as the rate of N fertilizer increased. High doses of N fertilizer presumably elicited favorable changes in the anatomical structure of Egyptian henbane leaves. The application of 50% N dose plus N fixing bacteria affected Egyptian henbane trials similarly to 100% of recommended N dose. In conclusion, the N fixing bacteria proved to be a sustainable tool for a two-fold reduction in the recommended dose of mineral N fertilizer and the sustainable management of Egyptian henbane nutrition.

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