bluuebunny/crossref_metadata_2025 huggingface dataset:
Forages underseeded in barley for residue management for potatoes
Authors: Holmstrom D. A. , Kunelius H. T. , Ivany J. A.
Published: April 2011

Producers have attempted to increase soil organic matter content in a 2-yr rotation of barley-potato by underseeding barley with forage grasses and legumes. A study beginning in 1996 was initiated to evaluate the effect of this practice on barley yields, root biomass, soil organic matter content, ease of post-harvest tillage as measured by a soil penetrometer and surface plant residue levels for the first year of a 2-yr rotation of barley-potato. Barley seeded alone, barley underseeded with berseem clover, barley underseeded with timothy/red clover, barley underseeded with timothy/red clover fall chisel plowed and barley underseeded with Italian ryegrass were evaluated with and without a fall application of glyphosate on a well-drained, fine sandy loam, Orthic Humo-Ferric Podzol soil. Barley yields were not affected by underseeding. Despite an increase in root biomass for some of the underseeded crops, soil organic matter content was not affected. Potato producers attempting to increase soil organic matter content in a 2-yr rotation of barley-potato by underseeding barley with a forage crop are advised to consider using annual forages such as berseem clover or other solutions such as residue management. Underseeding barley with red clover/timothy will require either a fall application of glyphosate or extra spring tillage to eliminate living plants. By underseeding barley, producers are incurring additional costs and eliminating the option of practising residue management, a soil conservation practice, unless they use glyphosate at an additional cost. Key words: Soil organic matter, glyphosate, root biomass, Italian ryegrass, red clover, berseem clover
The relationship between seedling and field resistance to two races of stem rust in Thatcher wheat
Authors: Knott D. R.
Published: April 2011

A set of 169 single descent lines from the cross Thatcher/LMPG-6 was used to study the inheritance of seedling resistance to six races of stem rust in Thatcher. The same lines were tested with two of the races in separate field nurseries. The results showed that at least some of the genes for seedling resistance had a significant, but limited, effect on field resistance. Additional genes conferred resistance only in adult plants in the field. Key words: Field resistance, stem rust, Thatcher wheat
Influence of photoperiod response on the expression of cold hardiness in wheat and barley
Authors: Mahfoozi S. , Limin A. E. , Hayes P. M. , Hucl P. , Fowler D. B.
Published: April 2011

Vernalization and photoperiod requirements regulate the timing of the vegetative/reproductive transition in plants. Cereals adapted to cold winter climates regulate this developmental transition mainly through vernalization requirements, which delay transition from the vegetative to the reproductive growth stage. Recent research indicates that vernalization requirements also influence the expression of low-temperature (LT) tolerance genes in cereals exposed to acclimating temperatures. The objective of the present study was to determine if LT tolerance expression was also developmentally regulated by photoperiod response. The nonhardy, short day (SD) sensitive, wheat (Triticum aestivum L. em Thell) cultivar AC Minto, the LT tolerant, highly SD sensitive barley (Hordeum vulgare L.) cultivar Dicktoo, and a barley selection with very low sensitivity to SD were subjected to 8-h (SD) and 20-h (LD) days at cold acclimating temperatures over a period of 98 d. Final leaf number (FLN) was used to measure photoperiod sensitivity and determine the vegetative/reproductive transition point. The LT tolerance of the less SD sensitive barley genotype was similar for LD and SD treatments. In contrast, a delay in the transition from the vegetative to the reproductive stage in AC Minto and Dicktoo grown under SD resulted in an increased level and/or longer retention of LT tolerance. These results support the hypothesis that not only the level, but also the duration of gene expression determines the degree of LT tolerance in cereals. Consequently, any factor that lengthens the vegetative stage, such as vernalization or photoperiod sensitivity, also increases the duration of expression of LT tolerance genes. Key words: Triticum aestivum L., Hordeum vulgare L., low-temperature tolerance, photoperiod, developmental regulation
Hi-Q summer rape
Authors: Stringam G. R. , Degenhardt D. F. , Thiagarajah M. R. , Bansal V. K.
Published: April 2011

Hi-Q is a canola quality Brassica napus cultivar adapted to the canola growing areas in western Canada. It has high seed yield, high oil and meal protein content, good lodging resistance, and excellent resistance to blackleg disease. It is superior in all these traits to the average of AC Excel, Defender and Legacy. Key words: Rape (summer), cultivar description, yield, blackleg resistant, lodging, resistant high quality
Reactions of western Canadian spring wheat and triticale varieties to Tilletia indica, the causal agent of Karnal bunt
Authors: Gaudet D. A. , Fuentes-Davila G. , De Pauw R. M. , Burnett P. A.
Published: April 2011

The reactions of 47 Canadian wheat and triticale cultivars to Tilletia indica Mitra, the causal agent of Karnal Bunt (KB), were evaluated in the field at Centro de Investigaciones Agricolas del Noroeste (CIANO), Yaqui Valley, Mexico, during 1998 and 1999. The majority of lines and cultivars flowered during January and February, which coincided with the onset of cooler temperatures and high relative humidity required for optimum infection by the fungus. Canada Western Amber Durum (CWAD) and triticale were resistant, ranging from 0 to 6% infection. Canada Western Red Spring (CWRS) wheats were also generally resistant, but the cultivars Roblin, BW90 and Laura, and the experimental line Roblin*2/BW 553, were susceptible, ranging from 11 to 28% in treatments with the highest infection levels. Canada Western Extra Strong (CWES) wheats varied in reaction from moderately resistant to susceptible, ranging from 1 to 15% infection. Canada Prairie Spring (CPS) wheats were generally susceptible, exhibiting infection levels ranging from 5 to 31% infection in the most severely infected treatments. Canada Western Soft White Spring (CWSWS) wheats were uniformly susceptible; the highest recorded infection level among Canadian wheats was observed on AC Reed (38%) during 1999. The susceptibility of CPS and CWSWS cultivars may represent an increased risk to the establishment of KB if the fungus were to become introduced into western Canada. Key words: Karnal bunt, wheat, disease resistance, disease susceptibility
Feasibility of applying all nitrogen and phosphorus requirements at planting of no-till winter wheat
Authors: Lafond G. P. , Gan Y. T. , Johnston A. M. , Domitruk D. , Stevenson F. C. , Head W. K.
Published: April 2011

The recent advances in no-till seeding technology are providing new N management options for crop production on the prairies. The objectives of this study were to evaluate the potential interaction between P and N fertilizer on winter wheat production in a one-pass seeding and fertilizing system and to determine the feasibility of side-banding all N requirements using urea or anhydrous ammonia at planting as compared with the current practice of broadcasting ammonium nitrate early in the spring. Three forms of N fertilizer (urea, anhydrous ammonia, ammonium nitrate), three rates of N (50, 75 and 100 kg ha–1) and three rates of P (0, 9 and 17 kg P ha–1) were investigated. Urea and anhydrous ammonia were applied during the seeding operation, whereas ammonium nitrate was broadcast the following spring. Applying P fertilizer to the side and below the seed at planting with rates > 9 kg Pha–1 increased grain yield in 3 out of 6 site-years when ammonium nitrate was broadcast early in the spring. The positive yield response to P corresponded to soil test levels of 24 kg P ha–1. With soil test levels greater than 34 kg P ha–1, grain yield response to P fertilizer was not observed. When urea was banded at planting, together with P fertilizer, the yield increases with the increased P rates was shown only in 1 out of 6 site-years. At 5 of th e 6 site-years, grain protein concentration was not affected by P fertilizer; while for 1 site-year, the high rate of P fertilization decreased grain protein concentration. Responses of total grain N and P yields to P fertilization were parallel to the corresponding responses of P fertilization to grain yield, and were rarely associated with N or P concentrations in the grain. Applying N fertilizer at rates of 50 to 100 kg N ha–1 increased winter wheat grain yields by 3 to 8% in 3 out of 6 site-years. The high N rates increased grain protein concentrations in all 6 site-years. Grain protein concentration was 6% greater with N fertilizer applied as ammonium nitrate in early spring than when banding urea or anhydrous ammonia at planting. More consistent improvements in grain yield and grain protein concentration were obtained when the N fertilizer was applied as ammonium nitrate in the spring. Further research is required to determine the benefits of applying some of the crop’s N fertilizer requirements at planting, to reduce the risks of N stresses when the spring application is delayed because of adverse weather or soil conditions. Key words: Ammonium nitrate, anhydrous ammonia, grain yield, nitrogen timing, phosphorus, protein, urea
Effect of Penicillium bilaii inoculation and phosphorus fertilisation on root and shoot parameters of field-grown pea
Authors: Vessey J. Kevin , Heisinger Krista G
Published: April 2011

The mechanisms underlying the stimulating effect of Penicillium bilaii inoculation on the growth of crop plants are not clear. The effect of P. bilaii inoculation on root morphology [dry weight (DW), length and specific root length) and other root and shoot parameters of pea were investigated at two field sites in western Canada in 1996. Pea (Pisum sativum L.) was grown at three levels of P fertilization (0, 6.4 and 19.3 kg ha–1) at Ellerslie, AB, and Outlook, SK. Shoot dry matter, P concentrations, P content and nodulation were also measured in pea plants harvested at the seven- to nine-node stage. Soil cores were used to sample roots. Although plants were responsive to P fertiliser at both sites, P. bilaii inoculation affected pea growth at the Ellerslie site only. At this site, P. bilaii inoculation increased root length by 48%, specific root length (m g–1 root DW) by 21%, root DW by 13%, and shoot P concentration by 13% in treatments that received no P fertiliser. We suggest that the stimulating effect of P. bilaii inoculation on crop P nutrition is partly explained by increases in root absorptive capacity in the presence of the fungus. However, this effect was only significant under P-limited conditions. Key words: Microbial inoculants, Pisum sativum, Penicillium bilaii, phosphorus, root length, root morphology
Crop yield and soil nutrient status on 14 organic farms in the eastern portion of the northern Great Plains
Authors: Entz M. H. , Guilford R. , Gulden R.
Published: April 2011

Cropping records from 13 organic farms in the eastern Canadian prairies and one in North Dakota (1991 to 1996) were surveyed to determine crop rotation pattern, yields and soil nutrient status. Major crops included cereal grains, forages, and green manure legumes. Organic grain and forage yields averaged from one-half to almost double conventional yields. Soil N, K and S levels on organic farms were generally sufficient; however, levels of available soil P were deficient in several instances. Key words: Crop rotation, weeds, forages, green manure crops
The importance of early season phosphorus nutrition
Authors: Grant C. A. , Flaten D. N. , Tomasiewicz D. J. , Sheppard S. C.
Published: April 2011

A review of studies conducted in a range of plant species indicated the importance of an adequate supply of P during early crop growth and outlined plant adaptations for accessing early season P. Potential implications of the requirement for early season P in the development of management practices to optimize P supply for crop production were also discussed. Phosphorus plays a critical role in energy reactions in the plant. Deficits can influence essentially all energy requiring processes in plant metabolism. Phosphorus stress early in the growing season can restrict crop growth, which can carry through to reduce final crop yield. Deficiencies during early growth generally have a greater negative influence on crop productivity than P restrictions imposed later in growth. Plants respond to P deficiencies by adaptations that increase the likelihood of producing some viable seed. The adaptations increase the ability of the plant to access and accumulate P and include modification of rhizosphere pH, diversion of resources to root production, increased root proliferation in high-P regions, and formation of associations with vesicular arbuscular mycorrhizae. Plants differ in strategies adopted and in efficiency of P absorption.

Effective nutrient management for optimal crop production must ensure that P is supplied to the crop in adequate amounts early in the growing season. It is important that we develop methods to accurately predict the early season P supply from the soil, in order to avoid either over-fertilization or crop deficiencies. Practices to provide adequate P early in plant growth include placement of P fertilizer in or near the seed-row and maintenance of adequate concentrations of plant-available P in the soil through a long-term nutrient management strategy. Other possible management practices could include enhancement of seed concentrations of P, manipulation of tillage system and crop sequence, improved activity of mycorrhizae and other microbiological agents such as Penicillium bilaii to increase phytoavailability of soil P, or genetic selection of crops with an enhanced ability for early season uptake of P from both soil and fertilizer sources. As plants differ in relative abilities to access P from the soil and fertilizer applications, nutrient management must be tailored to the specific crop, in order to optimize P supply and crop productivity. By restricting fertilizer applications to situations where P supply is limiting to crop production and by use of effective P management practices, we can optimize the economic of fertilizer use while avoiding negative impacts on environmental quality. Key words: Crop, fertilizer, placement, nutrient, management
Response of four common bean cultivars to granular inoculant in a short-season dryland production system
Authors: Nleya T. , Walley F. , Vandenberg A.
Published: April 2011

Common bean (Phaseolus vulgaris L.) is considered to be a poor N fixer relative to other legumes. However, considerable genotypic variability between cultivars is known to exist. Determining the importance of the host genotype to the symbiotic process will assist breeders in developing bean cultivars with improved N2 fixing capacity. Field experiments were conducted at two locations in Saskatchewan for two seasons to assess the N2 fixation rates of four common bean cultivars differing in growth habit and maturity. Beans were inoculated using a granular inoculant applied in the seedrow or in a sideband, or not inoculated at all. Inoculation resulted in greater nodule dry mass, shoot dry mass, seed yield and amount of N derived from atmosphere as compared with the uninoculated control. The response to inoculant application was cultivar specific, with N derived from the atmosphere ranging from a low of 51% (CDC Camino) to a high of 78% (CDC Pinnacle). The cultivars responded similarly to inoculant placement. The sideband treatment was associated with a delay in maturity. This may limit the suitability of this treatment where early maturity of the crop is critical. Key words: Phaseolus vulgaris, common bean, Rhizobium, N2 fixation, inoculation
Phenological development in two-row spring barley when grown in a long-day (Alberta, Canada) and a short-day (Western Australia, Australia) environment
Authors: Paynter B. H. , Juskiw P. E. , Helm J. H.
Published: April 2011

Phenological development in eight cultivars of two-row, spring barley (Hordeum vulgare L.) was examined when sown at two dates of seeding in two diverse environments. These environments were a short-day environment at Northam, Western Australia, Australia, in 1997 and a long-day environment at Lacombe, Alberta, Canada, in 1998. The Australian and Canadian barley cultivars used had different combinations of basic vegetative phase and daylength sensitivity. Barley grown at Lacombe reached each stage of phenological development in less time than at Northam. Most noticeable was a shorter duration of the period between seedling emergence to double ridge and between double ridge and awn emergence. At Northam, nearly 20% of the barley’s life cycle was spent on vegetative growth, just over 40% on ear/stem growth and close to 40% on grain filling. At Lacombe, barley spent nearly 55% of its life cycle filling grain and only 10% on vegetative growth and 35% on ear/stem growth. Later seeding accelerated all stages of development at Northam but only those stages until awn emergence at Lacombe. Late-sown barley at Lacombe took longer to reach physiological maturity. The relative contribution of each phase of crop growth was unaffected by date of seeding. Based on the time to awn emergence, Franklin was a very late flowering cultivar in both environments; Fitzgerald, Gairdner and Manley were late flowering; AC Oxbow and Harrington were mid-flowering; and Stirling was early flowering. Skiff was late flowering at North am but early flowering at Lacombe. Key words: barley (spring), phenological development, daylength sensitivity, basic vegetative phase
Influence of nitrogen fertilization on yield, hollow stem incidence and sap nitrate concentration in broccoli
Authors: Bélec C. , Villeneuve S. , Coulombe J. , Tremblay N.
Published: April 2011

This study, spanning 2 yr at two different sites, compared the effects of nitrogen fertilization on broccoli yield and quality in relation to the influence of site and production season. This research also evaluated the potential use of measuring nitrate in petiole extracts to determine broccoli nitrogen requirements when making a second fertilizer application 5 wk after transplant. Treatments consisted of factorial combinations of three nitrogen fertilization rates at transplant (Nmin, 50-Nmin and 100-Nmin kg N ha–1, where Nmin was the soil nitrate concentration) and four nitrogen fertilization rates 5 wk after transplant (0, 50, 100 and 150 kg N ha–1). The marketable yield of broccoli increased with the rate of nitrogen application. Hollow stem incidence showed the same trend as yield, and was greatest when high levels of nitrogen were applied 5 wk after transplant. Interactions between the 5-wk nitrogen application and production year, as well as growing site were significant. The nitrate content of the sap was measured immediately before the 5-wk nitrogen application and 2 wk later. The nitrate concentration measured at 5 wk increased with transplant nitrogen, as did the concentration measured at 7 wk. Nitrate concentration at 7 wk increased curvilinearly with the 5-wk fertilizer application rates. Sap analysis provided clear evidence of the effect of nitrogen application rates, but Environment precluded determination of an absolute threshold of nitrate sufficiency in the sap. Key words: Brassica oleracea L. var. Italica, split application, quality, environment
Comparison of the performance of bromoxynil-resistant and susceptible near-isogenic populations of oilseed rape
Authors: Cuthbert Janice L. , McVetty Peter B. E. , Freyssinet Georges , Freyssinet Martine
Published: April 2011

Bromoxynil herbicide resistance is the newest type of broad-spectrum, non-selective herbicide resistance to be introduced into oilseed rape (Brassica napus L.). This herbicide resistance is conferred by a single transgene (the oxy gene), taken from a soil bacterium, which confers the ability to metabolize hydroxybenzonitrile herbicides such as bromoxynil. The level of resistance to bromoxynil herbicide in oilseed rape is high, but it is not known whether there are any performance changes associated with the oxy transgene or with the derived herbicide resistance. To determine if there are changes in performance related to the oxy transgene, or the derived herbicide resistance, two near-isogenic transgenic bromoxynil-resistant populations, with two different forms of the oxy gene, Westar 235 and Westar 237, were developed at the University of Manitoba, grown in the field in Manitoba for several years and evaluated for comparative performance. Westar 235 and Westar 237 near-isogenic populations, either sprayed with bromoxynil at 280 g a.i. ha–1 or left unsprayed, were compared with the non-transgenic near-isogenic population cultivar, Westar, in Winnipeg, Carman, and Portage la Prairie from 1994 to 1997. There were no consistent differences in the performance of the sprayed or unsprayed transgenic near-isogenic populations in comparison to Westar for any trait. The few significant and minimal differences that were found were evenly divided between positive effects and negative effects of the oxy gene and derived herbicide resistance. There were no significant effects of spraying bromoxynil herbicide detected in paired comparisons of Westar 235 and Westar 237 sprayed versus Westar 235 and Westar 237 unsprayed, respectively. The effects of the oxy transgenes and the effects of bromoxynil spraying of herbicide-resistant lines were negligible, indicating that there is little, if any biological cost associated with the bromoxynil resistance transgenes or related herbicide resistance. Key words: Transgenic oilseed rape, Brassica napus, biological cost
Effects of cultivar and environment on farinograph and Canadian short process mixing properties of Canada Western Red Spring wheat
Authors: Preston K. R. , Hucl P. , Townley-Smith T. F. , Dexter J. E. , Williams P. C. , Stevenson S. G.
Published: April 2011

Fourteen Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) cultivars grown at six Saskatchewan sites in 1995 were used to assess the impact of cultivar and environment on dough mixing properties. ANOVA showed that cultivar, environment and interactions thereof generally had highly significant effects on farinograph and Canadian short process (CSP) water absorption and mixing parameters. Most of the variance in farinograph and CSP absorption could be attributed to environment, while cultivar was the predominant contributor to farinograph dough development time and stability. Both cultivar and environment had a strong influence on CSP mixing time and mixing energy. Neither protein nor particle size index as covariate had a strong influence on the partitioning of variance. Strong significant relationships were evident among absorption parameters and among most mixing strength parameters. No strongly significant relationships were found between absorption and mixing strength parameters. Significant differences were evident among cultivar means and among station means for all parameters. The strong impact of environment on most mixing properties suggests that attention should be focused on the potential adverse impact on the uniformity of CWRS shipments due to the trend towards reduced blending among regions associated with the continued development of large high throughput primary elevators. Key words: Cultivar, environment, wheat, dough mixing properties
Re-analyzing historical records of winter injury in Finnish apple orchards
Authors: Lindén Leena
Published: April 2011

Frequent winter injury is a major problem in apple (Malus domestica Borkh.) production in northern areas. Discriminant and cluster analysis were used to determine the critical climatic factors associated with winter injury occurrences in south-western Finland over a 71-yr period, 1927 to 1998. Years with and without winter injury were best characterized by variables indicating mid-winter severity: the monthly mean, minimum, and maximum temperatures from January to March. Also, weather conditions during the preceding summer and fall contributed significantly to the discrimination between winter injury and no injury years. A decrease in growing degree days, drought in August, and a high level of precipitation in September were associated with winter-kill years, probably due to their impact on the annual cycle of vegetative growth. The hypothesis on the adverse effect of mild spells during early and mid-winter could not be verified by this study. Mid-winter frost resistance was confirmed as the most important winter hardiness characteristic in the semi-maritime climate of Finland. At high latitudes rootstocks and cultural practices should be chosen to ensure that trees acquire vegetative maturity even under adverse weather conditions. Key words: Malus domestica Borkh., winter injury, climate, variety, discriminant analysis, medoid clustering
Three-component barley mixtures: Ratio effects in replacement series
Authors: Juskiw P. E. , Helm J. H. , Burnett P. A.
Published: April 2011

Within a species, cultivar mixtures may offer yield and quality advantages if the cultivars have complementary abiotic and biotic stress tolerances. This study was conducted at Botha, Lacombe and Olds, Alberta, from 1992 to 1994 to determine the effect of relative seeding ratios on yield and other traits of 16 three-component barley (Hordeum vulgareL.) mixtures of Virden:Abee:Tukwa all grown at a standard seeding rate of 250 seeds m–2. Grain yields of these mixtures fell between the yields of the monocrops, with yields of the 20:40:40 and 50:30:20 mixtures being higher than expected based on the weighted mean yields of the monocrops. When stability of yield was measured using ranking or regression analyses, several mixtures had desirable combinations of high yields and good stability with the 20:40:40 and the 40:20:40 mixtures being identified using either method. Test weights, kernel weights, percent thins, protein contents, and disease levels of the mixtures were intermediate to the monocrops; while lodging levels were as low as the best monocrop. As the proportion of any one cultivar in the mixture increased, the traits it brought to the mixture also increased. These mixtures had no yield advantage over growing a high yielding monocrop. Key words: Barley, Hordeum vulgare L., mixtures, cultivar, yield, tolerance, stress
OAC ARTHUR soybean
Authors: Tanner J. W. , Rajcan I. , Luzzi B. M. , Gostovic P. , Montminy W. , Zilka J. , Hume D. J.
Published: April 2011

OAC Arthur is a 2650 crop heat unit soybean [Glycine max (L.) Merr.] cultivar, which significantly out yielded the check cultivars, has adequate stalk strength and superior seed protein concentration. Key words: Soybean, cultivar description
Effect of tillage and crop rotation on root and foliar diseases of wheat and pea in Saskatchewan from 1991 to 1998: Univariate and multivariate analyses
Authors: Bailey K. L. , Gossen B. D. , Lafond G. P. , Watson P. R. , Derksen D. A.
Published: April 2011

Disease severity and incidence of fungal species on wheat and pea were evaluated under zero, minimum, and conventional tillage in three rotations with increasing broad-leaved crop diversity from 1991 to 1998 at Indian Head, SK. The objective was to determine whether differences in crop rotation and crop residue at the soil surface would increase crop disease problems. Rotation and tillage had little impact on disease relative to the environment. Reduced tillage did not substantially increase disease severity from leaf spot diseases of wheat or on diseases of field pea. However, the relative importance of root pathogens of wheat was affected; under reduced tillage Bipolaris sorokiniana and Gaeumannomyces graminis decreased, but Fusarium spp. increased on wheat roots. These changes did not affect overall root severity or yield. Rotations had limited impact on wheat disease severity and the prevalence of fungal species, but wheat grown in diversified crop rotations using cereal, pea and flax had consistently higher yields than wheat following wheat. Growing wheat after summerfallow or pea reduced foliar diseases of wheat compared with wheat after wheat. Increased crop diversity in rotations reduced populations of B. sorokiniana, Septoria tritici, and Stagonospora nodorum in wheat leaves and roots, but growing wheat after flax increased the incidence of Fusariumspp. in wheat roots. Key words: Rotation, tillage, root rot, leaf spot, Triticum aestivum, Pisum sativum
Effect of seed damage and metalaxyl seed treatment on pythium seedling blight and seed yield of field pea
Authors: Hwang S. F. , Gossen B. D. , Chang K. F. , Turnbull G. D. , Howard R. J.
Published: April 2011

When cool, wet conditions persist after planting, Pythium spp. can be an important constraint to stand establishment in field pea. Laboratory studies and field trials were conducted over 3 yr to assess the impact and evaluate the interactions of Pythium spp., metalaxyl seed treatment and damage to seed on seedling establishment, root rot severity and seed yield of field pea. Seedling emergence, seedling size, and seed yield were reduced by inoculation with Pythium spp. and by mechanical damage to the seed. Fungicide seed treatment reduced the impact of seed damage, but did not always restore seedling emergence and seed yield to the same level as from undamaged seed. Undamaged seed treated with metalaxyl was not affected by inoculation with Pythium spp. Differences among cultivars, although often significant, were small relative to the effect of seed injury. Laboratory studies showed a negative linear relationship between inoculum concentration and emergence from untreated seed. They also showed that Pythium spp. had a similar impact on seedling emergence in cool (20/10°C day/night) and cold (12/6°C) soils. This study showed that planting fungicide-treated, high-quality field seed was an effective means of maximizing emergence and stand establishment for commercial field pea production. Key words: Pisum sativum, seed vigour, metalaxyl, Pythium, seed damage
The potential of legume-shrub mixtures for optimum forage production in southwestern Saskatchewan: A greenhouse study
Authors: Schellenberg M. P. , Banerjee M. R.
Published: April 2011

Grazing in fall and early winter decreases the cost of beef production in southwe stern Saskatchewan. This grazing system can be improved by utilizing legume and native shrub species, which exhibit high nutritive value in the fall. To realize the system's full potential, a better understanding of optimum mixtures of legumes and shrubs is required. A greenhouse study was conducted to optimize mixtures of legumes and shrubs for economical pasture production. The first goal was to obtain better understanding of synergy from mixtures of legumes and native shrubs. The second goal was to estimate the changes in soil quality caused by growing legumes and shrubs in monocultures or mixtures. Legume species studied were: alfalfa (Medicago sativa L.) (Alf), purple prairie clover [Petalostemon purpureum (Vert.) Rydb] (Pr Cl) and American vetch (Vicia americana Muhl.) (Vetch); shrubs were: winterfat [Krascheninnkovia lanata (Pursh) Guldenstaedt] (Wf) and Gardner's saltbush [Atriplex gardneri (Moq.) D. Dietr.] (Sb). Treatments consisted of five monocultures, six mixtures and a control. Data on plant biomass, forage quality and soil quality parameters indicate that legume and shrub mixtures of Alf + Wf and/or Alf + Sb can potentially provide diversified forage sources, extended grazing periods and higher or similar yields with enhanced or similar forage quality than when grown separately. Key words: Legume, native shrub, forage production, forage quality, winterfat, saltbush
Field pea response to seeding depth and P fertilization
Authors: Johnston Adrian M. , Stevenson F. Craig
Published: April 2011

A study was conducted at Melfort, SK, in 1998 and 1999 to determine whether seeding depth and P fertilization affect field pea (Pisum sativum L.) seedling emergence and grain yield. Treatments included a factorial combination of three seeding depths (38 mm, 76 mm, and 114 mm) with and without 25 kg P2O5 ha–1 as monoammonium phosphate. While seedling density was not affected by seeding depth at 3 wk after planting, the deepest seeding depth produced significantly fewer seedlings than the two shallower depths at 5 wk post-seeding. A year-by-seeding-depth interaction was recorded for grain yield, with deep seeding (114 mm) reducing yield by 8.5% in 1998, while no significant differences were recorded due to depth in 1999. Side-banded phosphorus fertilizer applications reduced seedling emergence at 3 wk; however, no difference was recorded by 5 wk after seeding. At harvest, addition of P fertilizer significantly increased grain yields on this high P testing soil; however, this response was small, averaging 138 kg ha–1. Results of this trial indicate that while field peas can tolerate deep seeding there appears to be little benefit from seeding deeper than 76 mm. Key words: Field pea, seeding depth, P fertilizer
Mineral concentrations in soybean seed produced under high day and night temperature
Authors: Gibson L. R. , Mullen R. E.
Published: April 2011

Environmental stress during reproductive growth can alter the mineral composition of soybean [Glycine max (L.) Merr.] seed, which can affect nutritional value, functional quality, and seed quality. This study was conducted to determine the impact of different combinations of day and night temperatures during reproductive growth on the final mineral concentrations in soybean seed. Day/night temperatures of 30/20, 30/30, 35/20, and 35/30°C were imposed during flowering and pod set (R1 to R5), seed fill and maturation (R5 to R8), and during the entire reproductive growth period (R1 to R8). The soybean seed was harvested at maturity and analyzed for elemental concentration of P, K, Ca, Mg, Mn, Fe, B, Cu, Zn, Al, and Na. Calcium and Mn declined and Na increased as mean day temperature during R1-R5 increased from 30 to 35°C. Phosphorus, K, Ca, and Mg became more concentrated in the seed with increased temperature during R5 to R8. The concentration of several minerals was increased by temperature treatments during R1 to R8. The exceptions were Mg and Fe, which declined, and Mn and Al, which were unchanged. Phosphorus, K, Fe, Cu, and Zn concentrations were negatively correlated with seed size. Concentrations of these minerals in seed may be greater in soybean grown in high temperature environments that limit seed size. The changes in mineral concentrations resulting from high temperature may alter soybean nutritional quality and modify its end-use properties for oil processing and tofu production. Key words: Soybean, Glycine max, mineral composition, temperature
Seed pre-treatment using a derivative of 5-hydroxybenzimidazole (AMBIOL) pre-acclimates carrot seedlings to drought
Authors: Rajasekaran Lada R. , Blake Terence J.
Published: April 2011

The possibility that AMBIOL, a derivative of 5-hydroxybenzimidazole, may promote drought acclimation of carrot seedlings was studied. Carrot seeds were pre-treated by soaking in AMBIOL solutions of 0, 0.1, 1 or 10 mg L–1 for 24 h and germinated. Fifteen-day-old seedlings were exposed to a 7-d drought by withholding water until soil moisture content declined to one-third of the initial values. Drought caused a significant reduction in xylem pressure potential, elongation growth, leaf area expansion, root growth and dry matter production. Membrane capacitance, net photosynthesis, stomatal conductance, transpiration and water use efficiency all declined in all plants under drought. However, seed pre-treatment using AMBIOL 0.1 and 10 mg L–1 completely alleviated the drought-induced reduction in shoot dry matter production. Seed preconditioning using AMBIOL 10 mg L–1 promoted dry matter production, which was 214% higher than in the untreated droughted plants and was even 26% higher than that of the untreated, unstressed controls. AMBIOL appeared to have induced drought acclimation through root adjustments that enhanced root growth, possibly supplying root-derived essential factors. Key words: Acclimation, antioxidant, carrot, drought, dry matter production, 5-hydroxybenzimidazole, growth, membrane capacitance
Pea and soybean performance in Newfoundland
Authors: Spaner D. , Todd A. G. , McKenzie D. B.
Published: April 2011

Newfoundland livestock farmers import all feed grain legumes. Our objective was to compare field pea (Pisum sativum L.) and soybean [Glycine max (L.) Merr.] nodule formation, plant growth, grain and protein yield potential in Newfoundland. Two-year experimental mean pea yield was high (≈0.3 t grain ha–1), although lodging was severe. Vision soybean yielded around 400 kg grain protein ha–1 when seeds were inoculated, even with soil temperatures below 20°C. Despite reasonable yield potentials, agronomic adaptation problems mitigate against the local production of all common feed grain legumes in the near future. Key words: Pisum sativum; Glycine max; lupins; faba beans; inoculant
The biology of Canadian weeds. 115. Conyza canadensis
Authors: Weaver Susan E.
Published: April 2011

Conyza canadensis (L.) Cronq. (Canada fleabane, horseweed, mare’s-tail) is a winter or summer annual, native to North America, and found in all provinces of Canada except Newfoundland. It is a weed of orchards, vineyards, roadsides, and arable fields where tillage has been reduced or eliminated. Most seedlings emerge from late August through October and form rosettes which overwinter. Large numbers of small, wind-dispersed seeds, ranging to over 200 000 seeds per plant, are produced in late summer. Populations of C. canadensis in more than ten countries have evolved resistance to herbicides such as paraquat, atrazine, chlorsulfuron or glyphosate. Several paraquat resistant populations were found in orchards in Essex Country, Ontario. It serves as a wild host of the tarni shed plant bug, and of aster yellows, a mycoplasma disease transmitted by the aster leaf hopper. Key words: Canada fleabane, ERICA, Conyza canadensis, Erigeron canadensis, horseweed
Response of pea to rhizobia inoculation and starter nitrogen in Alberta
Authors: McKenzie R. H. , Middleton A. B. , Solberg E. D. , DeMulder J. , Flore N. , Clayton G. W. , Bremer E.
Published: April 2011

The introduction of new semileafless cultivars has contributed to the rapid expansion of pea (Pisum sativum) on the Canadian prairies. To determine the response of four new semi-leafless cultivars to rhizobia inoculation and starter fertilizer N, 58 field trials were conducted from 1995 to 1998 over a wide geographic region of Alberta. However, due to possible cross-contamination in 1995 and 1996 between inoculated and uninoculated treatments, average inoculation responses were only determined for the 22 trials conducted in 1997 and 1998. Rhizobia inoculation increased seed yield in 9 of the 22 trials by an average of 14%. The frequency of an inoculation benefit was only slightly higher (45% vs. 38%) on land with no history of legumes (n = 11) than on land that had grown a legume crop (n = 8), but the magnitude of the inoculation benefit was appreciably greater (19 vs. 5%) on land with no history of legumes. A significant interaction of inoculation with pea cultivar was observedin 6 of 22 trials: Majoret pea was the most responsive cultivar to inoculation while Baroness pea was the least responsive. Application of N fertilizer (20, 40 or 60 kg N ha–1) increased pea yield in 24% of the 58 trials conducted by an average of 9%. When spring soil NO3-N to 30cm was less than 20 kg N ha–1, application of N fertilizer increased pea yield in 33% of the trials by an average of 11% (n = 12). The modest benefits of rhizobia inoculation or starter N fertilizer in most trials, despite appreciable deficits between spring soil NO3-N and accumulation of N by pea, was likely due to adequate nodulation of pea by indigenous rhizobia. Key words: Pisum sativum, nitrogen fertilizer, Rhizobium leguminosarum biovar viceae, rhizobia inoculation, seed protein
Identification of Canadian durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.] cultivars using AFLP and their STS markers
Authors: Soleimani V. D. , Baum B. R. , Johnson D. A.
Published: April 2011

We have developed two identification schemes for currently registered Canadian cultivars of durum wheat [Triticum turgidum L. subsp. durum (Desf) Husn.] based on cultivar-specific amplified restriction fragment polymorphism (AFLPJ) and their sequence tagged sites (STS) markers. Each identification key required seven markers. Transformation of AFLPs into STS markers was done in order to develop a PCR-based identification assay, which was cost effective and required minimal technical expertise. A cultivar diagnostic PCR assay was carried out for each STS primer pair. Five STS primers showed polymorphism among cultivars, but 60% of STS primers (7 out of 12) did not produce any polymorphism. The PCR products of the latter primers were digested with selected restriction enzymes resulting in restriction fragment polymorphism for two more loci. An STS-based identification key was generated for cultivar identification based on either the presence/absence of a DNA band or the presence/absence of a restriction enzyme recognition site after digestion of the PCR products with a restriction enzyme. DNA-based markers can be used as an efficient alternative to morphological traits for cultivar identification and finger printing at any stage of plant development. Moreover, an STS-based assay can be used with a minute amount of plant tissue such as fraction of a seed. Key words: Amplified restriction fragment polymorphism (AFLP), sequence tagged sites (STS), cloning, identification, durum wheat
Management of common scab of potato using planting and harvest dates
Authors: Waterer D.
Published: April 2011

The influences of planting and harvest dates on yields and grade-out due to tuber damage by common scab (Streptomyces spp.) were evaluated over three cropping seasons using two cultivars of potato (Solanum tuberosum) grown on land heavily infested with pathogenic Streptomyces species. Early planting and delaying the harvest enhanced yields in both cultivars, but also increased tuber grade-out due to excessive levels of scab. Delaying the harvest reduced marketable yields more than did early planting. The longer harvest was delayed after top-kill, the greater was the grade out due to scab. Increased losses to scab exceeded any increase in tuber yields obtained by delaying harvest. This study demonstrates that common scab of potato may be managed by minimizing the period the crop is in the ground, but that this method of disease management is achieved at the expense of yields. Early planting coupled with timely harvesting after kill-down of the tops appears to be an effective compromise between the objectives of maximizing yields while avoiding excessive grade-out due to common scab. Key words: Potato scab, Streptomyces scabies, Solanum tuberosum, agronomy
Stomatal variability of native warm-season grasses from the Nebraska Sandhills
Authors: Awada Tala , Moser Lowell E. , Schacht Walter H. , Reece Patrick E.
Published: April 2011

Soil moisture deficit is usually the major limiting factor for herbage production in the Sandhills of Nebraska. We examined inter-population and interspecific variability in stomatal characteristics and drought tolerance in sand bluestem (Andropogon hallii Vitman), little bluestem [Schizachyrium scoparium (Michx.) Nash], prairie sandreed [Calamovilfa longifolia (Hook) Scribn.], and switchgrass (Panicum virgatum L.). Ramets were collected during the dormant season across an aridity gradient from east to west (ranging from 560 mm to 340 mm average annual precipitation) in the Sandhills of Nebraska. Plants were grown in individual pots under greenhouse conditions. Once plants were well established, stomatal characteristics were determined and stomatal conductance (gs) was measured through a dry-down period of no watering. Populations did not differ in stomatal characteristics across the gradient, except for stomatal density on the adaxial leaf surface of prairie sandreed and the abaxial leaf surface of sand bluestem. Leaves of switchgrass and prairie sandreed were amphistomatic (stomata on both leaf surfaces), whereas leaves of little bluestem and sand bluestem were hypostomatic (stomata on the lower leaf surface). In the absence of drought, gs was 17 to 31% higher in little bluestem than in other species. Differences among species in gs were found mainly when watered and disappeared as the dry-down progressed. There was a positive relationship between stomatal density and gs in all species except prairie sandreed. Prairie sandreed maintained 35% of the initial relative water content of its leaves after 17 d of dry-down, compared to 23% for sand bluestem, 14% for switchgrass, and 9% for little bluestem. Variation in stomatal traits within species did not explain ecotypic adaptation to sites with a range of precipitation in the Nebraska Sandhills. Key words: Stomatal characteristics, water stress, warm season grasses, Nebraska Sandhills
Impact of high soil pH on potato yields and grade losses to common scab
Authors: Waterer D.
Published: April 2011

The influence of soil pH on yields and grade-out due to tuber damage by common scab (Streptomyces scabies) was evaluated over multiple cropping seasons for potato (Solanum tuberosum) grown on land heavily infested with S. scabies. Soils with a native pH of 8.0 were adjusted to pH 7.0 to 9.0 using elemental sulfur as an acidulant and calcitic lime as the liming agent. There was little change in total tuber yields over this pH range, but the incidence and severity of scab lesions declined as the pH increased above 8.5. Marketable yields after grade-out to scab were highest at pH 9.0. This study demonstrates that in alkaline soils losses due to potato common scab may be managed by adjusting the soil pH to a point unfavorable to the scab organism. The economics of this type of pH change and its impact on subsequent crops need to be considered. Key words: Common scab, Streptomyces scabies, Solanum tuberosum, liming
The biology of Canadian weeds. 116. Echium vulgare L.
Authors: Klemow Kenneth M. , Clements David R. , Threadgill Paul F. , Cavers Paul B.
Published: April 2011

Echium vulgare L., known as blueweed or viper’s bugloss, is a blue or purple flowered biennial or short-lived monocarpic perennial herb found in every province in Canada. A naturalized weed of European origin, E . vulgare grows in highly disturbed are as, typically in soils of limestone or dolomite parent material. It is not competitive with crops, but serves as an alternate host for fungal pathogens and contains hepatotoxic alkaloids detrimental to livestock when consumed in large amounts. E. vulgare is a noxious weed in Nova Scotia, Québec, Manitoba, Alberta and parts of British Columbia. Beneficial aspects include contributions to honey production and herbal medicine. Key words: Echium vulgare, blueweed, viper's bugloss, weed biology