bluuebunny/crossref_metadata_2025 huggingface dataset:
Current state of cold hardiness research on fruit crops
Authors: Palonen Pauliina , Buszard Deborah
Published: April 2011

This article gives an overview of the current state of cold hardiness research in fruit crops by reviewing the recently published studies on cold hardiness of both tree fruit and berry crops. Topics discussed include cold hardiness of fruit species, cultivars and different plant organs, biophysical and biochemical aspects of hardiness, evaluation of hardiness, as well as endogenous, cultural and environmental factors affecting cold hardiness in these species. Lack of cold hardiness is a major limiting factor for production of fruit crops in many regions of the world and improved cold hardiness one of the major objectives in numerous breeding programs and research projects. Screening cultivars or selections for cold hardiness is commonly done, and different methods applied to the evaluation of hardiness are discussed. The physical limit of deep supercooling may be a restricting factor for expanding the production of some fruit crops, such as Prunus species and pear. As for biochemical aspects, a relationship between carbohydrates and cold hardiness is most commonly found. Studies have also been made on different hardiness modifying cultural factors including rootstock, crop load, raised beds and application of growth regulators. The latter seems promising for some species. Cold hardiness is an extremely complex phenomenon and understanding different mechanisms involved is critical. Since hardiness is, however, primarily affected by genotype, developing cold-hardy fruit cultivars and effective screening methods for hardiness are essential. Finally, cultural practices may be improved to further enhance hardiness. Key words: Berries, cold hardiness, fruits, small fruits, stress, winter hardiness
Induced variability for C18 unsaturated fatty acids in Ethiopian mustard
Authors: Velasco L. , Fernández-Martínez J. M. , Haro A. De
Published: April 2011

The improvement of oil composition for C18 unsaturated fatty acids is one of the most important breeding objectives for the development of high-quality Ethiopian mustard oil. The objective of this research was to induce variability for fatty acid composition in this species using chemical mutagenesis. Seeds of line C-101 were treated with 1% ethylmethane sulfonate and the progenies of 8331 M2 plants were screened for fatty acid composition of the oil with near infrared reflectance spectroscopy followed by gas liquid chromatography on selected plants. Oleic and linoleic desaturation ratios (ODR and LDR, respectively) were used to detect putative mutants with altered levels of C18 unsaturated fatty acids. Seven of these mutants were isolated and M4 lines were developed. Six lines were characterized by low ODR, showing an increase in oleic acid and a reduction in linoleic acid. Three of these lines also showed reduced levels of linolenic acid. The other mutant line showed a decrease in both LDR and linolenic acid content. Since different enzyme systems seemed to be altered, a further oil improvement for C18 unsaturated fatty acids may be achieved through recombination among mutants. Key words: Brassica carinata Braun, C18 unsaturated fatty acids, mutagenesis
Regression model for predicting yield of hard red spring wheat grown on stubble in the semiarid prairie
Authors: Campbell C. A. , Selles F. , Zentner R. P. , McConkey B. G. , Brandt S. A. , McKenzie R. C.
Published: April 2011

Soil testing laboratories require predictive equations to make accurate fertilizer recommendations to cereal producers in the Canadian prairies. We used results from two 12-yr experiments (one studying snow management × fertilizer rates, and the other a tillage experiment), conducted on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan, to develop a regression model to estimate grain yield of hard red spring wheat (Triticum aestivum L.) grown on stubble. Stepwise regression, with backward elimination, was used to develop the relationship:Y = 1006 + 10.53 WU − 0.017 WU2 + 5.52 FN − 0.095 FN2 − 33.16 SN + 0.436 SN2 − (0.112 FN × SN) + (0.057 FN × WU) + (0.159 SN × WU) − 1.26 DD (R2 = 0.89, P = 0.001, n = 262)where Y = grain yield (kg ha−1), WU = estimated water use (mm), SN = soil test N (kg ha−1), FN = rate of fertilizer N (kg ha−1), and DD = degree days >5 °C (°C-days). Water use was available spring water in the 0- to 1.2-m depth plus 1 May to 31 July precipitation + irrigation, and SN was NO3-N in 0- to 0.6-m depth, measured in fall. We validated this model using data from two other experiments in the Brown soil zone and one in the Dark Brown soil zone in Saskatchewan, and an irrigation × N rate experiment in the Brown soil zone in southern Alberta. The results showed that this model will provide reasonable yield estimates for fine-, medium- and coarse-textured soils, when SN ≤ 55 kg ha−1, over a wide range of water use. We recommend that this equation be tested by colleagues who have appropriate data and be considered for use by soil testing laboratories in Saskatchewan, Alberta, Montana and the Dakotas. Key words: Multiple regression, soil test N, fertilizer N, water use, degree-days
AC Gemco azuki bean
Authors: Park S. J. , Anderson T. R.
Published: April 2011

AC Gemco, tested as A235, was developed from a landrace azuki bean [Vigna angularis (Willd.) Ohwi & Ohashi] "Martyn Bulk" by pure line selection. It is a medium to full-season-maturing cultvar in southwestern Ontario, and produces a high yield of large red seed. AC Gemco has about 12% more yield, larger seed, and matures about 4 d later than the landrace. Key words: Vigna angularis, azuki bean, red bean, cultivar description
Factors influencing grain N concentration of hard red spring wheat in the semiarid prairie
Authors: Campbell C. A. , Selles F. , Zentner R. P. , McConkey B. G. , McKenzie R. C. , Brandt S. A.
Published: April 2011

Prairie producers are now being rewarded with significant premiums for producing wheat (Triticum aestivum L.) of high protein concentration. We analyzed data from two 12-yr experiments conducted on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan, to determine and quantify factors influencing grain N concentration of hard red spring wheat grown on stubble land. Results of one of the 12-yr studies, a snow management × fertilizer N, zero-tillage experiment, showed that under hot, dry conditions, grain N concentration was very high and increased with moderate rates of fertilizer N (FN), then levelled off at higher rates of N. Under cool, wet conditions, grain N first decreased (due to N dilution by yield) then increased with further addition of FN. Under warm intermediate moisture conditions, grain N concentration increased at moderate rates in response to FN. Data for the two 12-yr experiments were pooled and multiple regression, with backward elimination, and stepwise selection used to develop the relationship:Grain N (g kg−1) = −7.63 + 0.05 WU − 0.000094 WU2 + 0.30 SN − 0.0022 SN2 − (0.0010 SN × WU) + (0.0017 FN × SN) + 0.0189 DD (R2 = 0.64, P = 0.001, n = 262)where WU = water use (mm), SN = soil test N (kg ha−1), FN = (kg ha−1), and DD = degree-days >5 °C (°C-days) from 1 May to 31 August. WU was available spring soil water in 0- to 1.2-m depth plus 1 May to 31 July precipitation, and SN was NO3-N in the 0- to 0.6-m depth, measured in the fall. We attempted to validate this model using data from a long-term crop rotation and a fertilizer trial experiment in the Brown soil zone, a tillage × rotation experiment in the Dark Brown soil zone in Saskatchewan, and an irrigation × N fertilizer experiment in the Brown soil zone of southern Alberta. Validation met with only modest success (R2 up to 0.70, P = 0.001). Generally, estimated grain N concentrations were lower than the measured values. Water use (negatively related) and temperature (DD) (positively related) were the most important factors influencing grain N, while FN and SN (positively related) were much less important. Because of the complexity of response in grain N to the aforementioned factors, and since farmers cannot predict weather conditions, fertilizer management to achieve high protein remains a challenge under dryland conditions. Key words: Soil test N, fertilizer N, available water, degree-days
Influence of irrigation, nitrogen and seed piece spacing on yields and tuber size distribution of seed potatoes
Authors: Waterer Doug
Published: April 2011

This study examined the influence of irrigation, soil nitrogen (N) levels and seed piece spacing on the yields and tuber size distribution of Norland, Russet Burbank and Shepody potatoes over three seasons at two sites in central Saskatchewan. The crops were grown under standard irrigated conditions or on dryland with in-row spacings of 15, 23 or 30 cm and total N levels of 200 or 300 kg ha−1 as either preplant or split applications. Irrigation greatly enhanced yields of all tuber size categories in the drier years but had less effect if seasonal precipitation reached or exceeded normal levels. Smaller size tubers formed a greater proportion of the total yield in crops exposed to drought stress. Norland was less affected by drought than the later-maturing cultivars. Yield responses to N were limited to situations where soil moisture was abundant or crop demand for nutrients was increased by close in-row spacings. Close in-row spacing increased total yields in some cases, while in others it resulted in a reduction in tuber size with little effect on overall yields. Yields for the cultivar Norland were less affected by seed piece spacing than yields for Russet Burbank or Shepody. Key words: Solanum tuberosum, drop seed, spacing, fertility
Cadmium accumulation in crops
Authors: Grant C. A. , Buckley W. T. , Bailey L. D. , Selles F.
Published: April 2011

Cadmium is a heavy metal present in soils from natural and anthropogenic sources. Plant uptake of Cd at levels present in the soil solution is dependent on a system that is largely metabolically mediated and competitive with the uptake system for Zn and possibly other metals. Much of the Cd taken up by plants is retained in the root, but a portion is translocated to the aerial portions of the plant and into the seed. The amount of Cd accumulated and translocated in plants varies with species and with cultivars within species. Soil, environmental and management factors impact on the amount of Cd accumulated in plants. Potential methods of reducing the accumulation of Cd in crops include reduction of Cd input to the soil system, site selection, management practices which decrease the concentration of Cd in the soil solution and its uptake and translocation by plants, and development and production of plant cultivars with the genetic tendency for low Cd uptake. Key words: Cadmium, fertilizers, genetics, uptake, tillage, rotation
AC Wilmot spring wheat
Authors: Nass H. G. , Johnston H. W. , Blatt C. R. , Atlin G. , Rodd A. V. , Walker D. W.
Published: April 2011

AC Wilmot is a spring feed wheat (Triticum aestivum L. em Thell.) with more grain yield than the check cultivars in Atlantic Canada. It is moderately resistant to powdery mildew. The reaction of AC Wilmot to leaf and glume blotch is similar to the check cultivars. AC Wilmot is slightly more susceptible to fusarium head blight than the check cultivars. AC Wilmot is suitable for production in Atlantic Canada. Key words: Triticum aestivum, wheat (spring), cultivar description
Reevaluation of row spacing/plant density of seeded pasture grasses for the semiarid prairie
Authors: Jefferson Paul G. , Kielly G. Andrew
Published: April 2011

Previous research in the semiarid prairie at Swift Current, Saskatchewan, indicated that optimum row spacing for forage production was 60 or 90 cm for crested wheatgrass (Agropyron cristatum [L.] Gaertner) and Russian wild ryegrass (Psathyrostachys juncea [Fisch.] Nevski). However, recent research suggested that harvest method affects forage yield estimates from row spacing experiments. An experiment with three row spacings of mixtures of alfalfa (Medicago sativa L.) with crested wheatgrass and Russian wild ryegrass was harvested mechanically and by hand. Yield differences between methods of harvesting were affected by row spacing; larger differences were observed at 15 cm than at 60 cm spacing, particularly for Russian wild ryegrass. The highest hand-harvested forage yield estimates were observed in the narrowest row spacing. In a second experiment, plant density was evaluated for the same grasses using square grid spacings of 30, 45, 60, 75 and 90 cm. Decreasing plant density was associated with decreased hand-harvested forage yield in both species. In a third experiment, 60- and 90-cm row spacing resulted in more seed heads and lower leaf content than 30-cm row spacing. Leaf digestibility increased slightly with increased row spacing. These results suggest that 30-cm row spacing should be recommended to producers for sustainable pastures in the semiarid prairie region. Key words: Forage yield, forage quality, leaf:stem ratio, plot technique
Comparison of sodseeding versus slotseeding of alfalfa into established crested wheatgrass in southwestern Saskatchewan
Authors: Schellenberg M. P. , Waddington J.
Published: April 2011

Establishment of alfalfa seedlings in existing grass pastures (sodseeding) can increase forage productivity and quality. Nonselective herbicides are used to control the grass, thus freeing up limiting resources such as soil moisture for utilization by the alfalfa seedlings. Mechanical removal of a ribbon of grass sod to create a "slot" of bare soil for seeding was proposed as an alternative to herbicide methods. Experiments were started in each of the 3 yr 1992–1994 to compare the establishment of alfalfa (Medicago sativa L.) cv. Rangelander in established crested wheatgrass (Agropyron desertorum (Fisch.) Schult.) utilizing sodseeding or slotseeding. Prior to sodseeding, the existing vegetation was killed with glyphosate at 2.2 kg ai ha−1. For slotseeding, four widths (2.5, 5, 7, and 10 cm) of sod were removed to provide a slot in which seed was placed. In combination with the four slot widths, two widths (15 and 35 cm) of undercutting grass vegetation adjacent to the slot were examined. Sodseeding after a glyphosate treatment provided an environment with greater suppression of existing vegetation, and a seeding groove with characteristics resulting in greater productivity than with slotseeding using any slot width with undercutting. Key words: Sodseeding, slotseeding, alfalfa, Medicago sativa, crested wheatgrass, Agropyron desertorum
Repression of seed coat pigmentation in Ethiopian mustard
Authors: Getinet A. , Rakow G.
Published: April 2011

The inheritance of seed colour in Brassica carinata A. Braun was investigated in backcross and F2 generations derived from two crosses between the brown seeded cultivar S-67 and two, true breeding, yellow seeded lines, PGRC/E 21164 and PGRC/E 21224 of the Plant Gene Resources Centre of Ethiopia. F1 seed was identical in colour to self-pollinated seed borne on the respective brown and yellow seeded parents indicating maternal control of seed colour in B. carinata. F1 plants of reciprocal crosses produced yellow seed that was somewhat darker than that of the yellow-seeded parent indicating incomplete dominance of yellow over brown. Backcross F1 plants, derived from the backcross to the brown parent, segregated brown and light yellow-brown/yellow seeded plants in a 1:1 ratio, while backcrosses to both yellow seeded parents produced only light yellow-brown/yellow seeded plants. The F2 generation segregated brown and light yellow-brown/yellow seeded plants in a 1:3 ratio. These results are in contrast to seed colour inheritance pattern observed in other Brassica species, where brown seed colour was fully or partially dominant over yellow. The apparent dominance of the absence of a gene product in yellow seed over its presence in brown seed, was explained by the presence of a dominant repressor gene (Rp) in yellow seed which inhibits the expression of seed coat pigment synthesis genes. The repressor gene is absent in brown seeded plants. The significance of this finding in relation to the development of yellow seeded lines in other Brassica species is discussed. Key words: Brassica carinata, seed colour inheritance, repressor
AC Alma barley
Authors: Choo T. M. , Martin R. A. , Ho K. M. , Atlin G. , Walton R. , Blatt R. , Rodd V.
Published: April 2011

AC Alma is a six-row, spring feed barley (Hordeum vulgare L.) cultivar developed by the Eastern Canada Barley Breeding Group, Agriculture and Agri-Food Canada. It has high yield and excellent lodging resistance. AC Alma performed well across Eastern Canada. Key words: Barley, Hordeum vulgare L., cultivar description, high yield, lodging resistance
Weathering losses of forage species on the fescue grassland in southwestern Alberta
Authors: Willms W. D. , King J. , Dormaar J. F.
Published: April 2011

Rough fescue grasslands are readily damaged by heavy grazing pressure in the summer but tolerate grazing in winter. The grasslands have physical and nutritive properties that make them suitable for winter grazing by cattle thereby reducing the cost of winter feeding while preserving the integrity of the grasslands. However, their forage value declines during winter through the degradation of biomass yield and quality. This study took place at the Agriculture and Agri-Food Canada, Range Research Substation located on the Porcupine Hills in southwest Alberta. The objectives of this study were to determine the dynamics of litter biomass for important forage species over winter, to examine the role of leaf position in the plant on biomass loss from leaves, and to determine the associated changes in crude protein, phosphorus, and acid detergent fibre of the leaves, and carbon and nitrogen. Leaves of Parry oat grass (Danthonia parryi Scribn.), Idaho fescue (F. idahoensis Elmer), and rough fescue (F. campestris Rydb.) were sampled at monthly intervals from August to March over 3 yr to determine weight and chemical composition. Decomposition of these species, together with smooth aster (Aster laevis L.), was also tested for decomposition in the litter mass using nylon bags. Degradation of standing litter was most rapid in late summer and tended to decline toward stability by December. Biomass losses in leaves from August to March were similar (P > 0.05) among grass species. Over-winter losses in the litter mass tended to be greatest for smooth aster. Changes in the mineral and fibre concentrations of the herbage were typical of the trends expected for the period, that included late senescence and weathering, and followed closely the losses of biomass for the period. Forage decomposition is an important ecological process in mineral cycling and affects the quantity and quality of forage available for delayed grazing. Key words: Standing litter, buried litter, biomass, forage quality, winter, Parry oat grass, Idaho fescue, rough fescue, smooth aster
Rapid detection of rusty grain beetles (Coleoptera: Cucujidae) from wheat samples passing through a mechanical dockage tester
Authors: Demianyk C. J. , White N. D. G. , Jayas D. S.
Published: April 2011

A dockage tester (Carter dockage tester, Hart-Carter Co., Minneapolis, MN) was set up to clean wheat in accordance to Canadian grain industry guidelines and several running conditions. Under all conditions, 84–91% of adults and 57–81% of larvae of the rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae) were recovered from infested 1-kg samples in the aspirator discharge pan. All immature insects implanted in the germ of wheat kernels remained within the kernels, and were found within the bulk of the cleaned whole wheat. It is therefore possible to monitor the aspirator discharge pan of cleaned wheat samples for rapid detection of most free-living C. ferrugineus to limit infested grain from entering primary elevators. Key words: Cryptolestes, detection, dockage tester, Insecta, rusty grain beetle, wheat
AC Elsa hard red spring wheat
Authors: Clarke J. M. , DePauw R. M. , McCaig T. N. , Fernandez M. R. , Knox R. E. , McLeod J. G.
Published: April 2011

AC Elsa, hard red spring wheat (Triticum aestivum L.), is adapted to the Canadian Prairies. It combines high grain yield with high grain protein concentration in a short strawed background. It has improved resistance to leaf spots compared with the check cultivars, and resistance to prevalent races of leaf rust, stem rust, loose smut, and common bunt. AC Elsa is eligible for grades of Canada Western Red Spring wheat. Key words: Triticum aestivum L., red spring wheat, cultivar description, yield, protein, disease resistance
Implications of late fall and early spring 2,4-D applications on subsequent canola production on Black, Dark Brown and Gray Wooded Soil
Authors: Kirkland K. J.
Published: April 2011

Late fall or early spring application of 2,4-D to control winter annual weeds prior to canola has not been recommended as the herbicidal effects on canola growth and development on varying soil types are not well defined. 2,4-D was applied to Black, Dark Brown and Gray Wooded soils located in west-central and northwest Saskatchewan. Applications were made in the fall and early spring prior to planting Brassica napus L. and Brassica rapa L. canola from 1992 to 1994 at the recommended (0.42 kg ha−1) and twice the recommended rate. The rate of 2,4-D applied had no effect on canola plant population, pods per plant, yield, green seed, chlorophyll, kernel or test weight. Application of 2,4-D in the fall had no effect on any variable while spring application reduced plant stands and increased green content but had no effect on pod production, yield or chlorophyll content. Late fall application of 2,4-D prior to canola in rotation should be recognized as a valuable addition to weed management in canola, particularly when direct seeding is practised. Key words: Canola, 2,4-D, soil residual, injury
AC Endure red clover
Authors: Christie B. R. , Choo T. M. , Papadopoulos Y. A. , Lewis J. , Michaud R.
Published: April 2011

AC Endure red clover (Trifolium pratense L.) is a diploid cultivar of the double-cut type developed by mass selection at the Crop and Livestock Research Centre, Agriculture and Agri-Food Canada, Charlottetown, PEI. It is earlier flowering than Florex or Marino, and higher in forage yield, especially in the second and third harvest years. Key words: Red clover, Trifolium pratense L., cultivar description
Sensitivity of processing sweet corn (Zea mays) cultivars to nicosulfuron/rimsulfuron
Authors: O'Sullivan J. , Bouw W. J.
Published: April 2011

Sixteen processing sweet corn cultivars were evaluated to characterize cultivar sensitivity to nicosulfuron/rimsulfuron in field studies, conducted over a two-year period. Response to nicosulfuron/rimsulfuron varied widely, depending on cultivar and application rate. Delmonte 2038 was highly sensitive of nicosulfuron/rimsulfuron, resulting in the death of all plants. Nine cultivars showed moderate visual injury, but this did not always result in a significant yield reduction. Six cultivars were characterized as fully tolerant to field applications at rates of 25 g a.i. ha−1. These cultivars were Reveille, CNS 710, Krispy-King, Reward, More and GH 2628. Key words: Sensitivity, herbicide injury, cultivars, nicosulfuron, rimsulfuron, Zea mays
Alternative weed management strategies in conservation tillage systems for white beans (Phaseolus vulgaris L.)
Authors: Hooker David C. , Vyn Tony J. , Swanton Clarence J.
Published: April 2011

White bean producers often perceive that increased herbicide inputs are required with the adoption of conservation tillage. Acceptance of conservation tillage systems for this crop would increase if effective weed management practices were assured. In 1991 and 1992, various weed management strategies were evaluated in white bean (Phaseolus vulgaris L.) grown with three tillage systems at two sites in southern Ontario. Experiments were newly established each year following corn harvested for grain. Primary tillage treatments were fall moldboard plowing, fall chisel plowing, and first-year no-till. Combinations of mechanical weeding, metobromuron [3–(4–bromophenyl)–1–methoxy–1–methylurea] herbicide broadcasted at two rates, and a band application of the herbicide were investigated in each tillage system. Timely rotary hoeing reduced weed numbers in moldboard plow and chisel plow treatments, but was not effective in no-till. Weeds were adequately controlled in all tillage systems with mechanical treatments following a herbicide either broadcasted at a reduced rate or banded over the crop row. Metobromuron broadcasted at the full recommended rate alone controlled weeds in no-till; in contrast, the degree of weed control was poor without mechanical cultivation in both moldboard and chisel plow systems. Integrating mechanical and chemical control methods was more beneficial in tilled systems. Overall weed populations were lower in first-year no-till than moldboard plow or chisel plow tillage systems. White bean producers who adopt conservation tillage under conditions similar to those investigated can be assured of effective weed management alternatives as well as bean yields equivalent to conventional tillage. Key words: Conservation tillage, weed management, rotary hoe, inter-row cultivation, Phaseolus vulgaris
Effect of tillage management on yield performance in barley
Authors: Therrien M. C. , Grant C. A.
Published: April 2011

A 3-yr study was conducted to assess the effect of tillage management on relative yield performance of selected cultivars of barley. The experiment was located on two differing textures of orthic black Chernozemic soils over 3 yr. Relative yields differed significantly between cultivars within tillage systems, and between tillage systems, sites and years. All interactions were also highly significant. This suggests that barley variety performance trials should be conducted under the same tillage management system across sites and years and that significant interactions should be identified and mitigated, wherever possible. Failure to do so could lead to misidentification of high yield-performance cultivars and subsequent loss of economic opportunities to producers. Key words: Barley, tillage, interactions, yield response
Economic thresholds for wild radish, wild oat, hemp-nettle and corn spurry in spring barley
Authors: Weaver S. E. , Ivany J. A.
Published: April 2011

The yield response of spring barley (Hordeum vulgare L. 'Morrison') to a range of densities of wild radish (Raphanus raphanistrum L.), wild oat (Avena fatua L.), hemp-nettle (Galeopsis tetrahit L.), and corn spurry (Spergula arvensis L.) was investigated in field experiments on Prince Edward Island from 1991 through 1994. Barley yield was modelled as a function of both barley and weed density. In the absence of weed competition, barley seed yield, number of main shoots, number of heads, and thousand-kernel weight varied significantly during the 4 yr of the study. Increasing densities of wild radish and wild oat reduced the number of barley heads primarily by interfering with tillering, but wild oat also reduced barley thousand-kernel weight. Hemp-nettle and corn-spurry at densities up to 200 plants m−2 had little effect on barley yield, except in a year of low barley yield potential. Estimated economic thresholds for wild radish, wild oat, hemp-nettle and corn spurry at a barley population of 250 plants m−2 were 37, 45, 122 and 297 plants m−2, respectively, assuming a weed-free yield of 4 t ha−1, a crop price of $100 t−1, and weed control costs of $30 ha−1. Key words: Avena fatua, Galeopsis tetrahit, Hordeum vulgare, Raphanus raphanistrum, Spergula arvensis, yield loss, weed interference, economic threshold
Growth and yield of doubled haploid lines of oilseed Brassica rapa
Authors: Dewan D. B. , Rakow G. , Downey R. K.
Published: April 2011

The production of doubled haploid (DH) lines of Brassica rapa could be an efficient procedure for the development of inbred parents for hybrid production. A total of 162 B. rapa DH lines were evaluated in field tests at Saskatoon, Canada, in single row, replicated tests and 10 DH lines were tested in four-row plot, multilocation, replicated tests. Seed of DH lines was produced by bud selfing in the greenhouse. Approximately one-fifth of all DH lines tested were chlorophyll deficient, presumably due to the expression of recessive alleles. Inbreeding depression was evident in low seed and biological yields, low number of seeds per pod and delayed flowering. Seed yield of DH lines was positively associated with the number of seeds per pod, early flowering and a long pod-filling period. One DH line was equal in yield to its donor population (DP), suggesting that dominance deviation was the genetic basis for high seed yield in this species. The consistent performance of DH lines over years and locations indicated that DH lines may be selected after 1 year of evaluation for combining ability testing. Higher yielding DH lines of B. rapa must be selected before they can be used as parents for hybrid development. Key words: Brassica rapa, doubled haploid, field evaluation
Rare wild plants of potential or current economic importance in Canada — a list of priorities
Authors: Catling P. M. , Porebski S.
Published: April 2011

A priorization system based on dollar value of plant, degree of relationship to economic genotype, and rarity status was applied to rare plants in Canada. This resulted in priorization of 56 taxa, approximately 1% of wild plants of Canada. Most of these taxa are native species, but a few are infraspecific taxa, and some are introduced. Most of the priorized taxa are plants of the Carolinian region of extreme southern Ontario, which is part of the Mixedwood Plains Ecozone. The provinces with the highest numbers were Ontario with 38, British Columbia with 9, Quebec with 8 and Manitoba with 7. Crops, crop relatives and forages accounted for 38 of the taxa. Twelve were plants providing ingredients for commercial drug products or health foods. Nine were sources of wood. Five were plants used in landscape gardening, land reclamation or erosion control. Native berry producing plants, i.e. relatives of clonal crops for which Canada contains significant germplasm on a world scale, were the largest economic group with 18 taxa. Twenty-six of the priorized plants were herbs, 17 were shrubs and 13 were trees. The genera Amelanchier and Linum were the largest taxonomic groups, each with four taxa. The list and related geographic data can be used to orient monitoring and management, to select and acquire material for ex situ protection, and to select and priorize sites for in situ protection. Key words: Germplasm, protection, rare plants, crops, pharmaceuticals, ornamentals, medicinal plants
Water deficit stress effects on N2 fixation in cowpea inoculated with different Bradyrhizobium strains
Authors: Figueiredo M. V. B. , Burity H. A. , França F. P. de
Published: April 2011

The objectives of this experiment were to select strains of Bradyrhizobium sp. resistant to water stress, envisaging an increase in N2 fixation in cowpea (Vigna unguiculata [L.] Walp.), and to verify the plant's adaptive physiological responses to water stress. The experiment was carried out in greenhouse conditions using random complete blocks subdivided into plots adjusted to soil water potential levels of −6.0, −75.0, and −85.0 kPa, and subplots containing strains of Bradyrhizobium sp. (SEMIA 6145, 6086, 6002 and NFB 700), with four blocks. The soil was a Yellow Latosol with pH 6.3. The crop used was cowpea cv. IPA 204. Stress was applied continuously beginning 15 d after planting, by the control of water potential through a porous cup. Various parameters were evaluated every 7 days, until final harvest at 45 d. There was significant interaction between Bradyrhizobium strains and water stress. At the more negative ψm, plants inoculated with the SEMIA 6145 had higher LHb concentration, ureide-N, ψw and root dry matter, forming associations of greater symbiotic efficiency, while plants inoculated with SEMIA 6086 were not resistant to stress. LHb concentration apparently was not inhibited at ψw −1.0 MPa in cowpea. The Bradyrhizobium strains may have affected the metabolism of N assimilation and/or transport. Key words: Bradyrhizobium, N2 fixation, porous cup, Vigna unguiculata, water stress, Yellow Latosol
AC Vista hard white spring wheat
Authors: DePauw R. M. , McCaig T. N. , Knox R. E. , M.Clarke J. , Fernandez M. R. , McLeod J. G.
Published: April 2011

AC Vista is a hard white spring wheat (Triticum aestivum L.) with resistance to preharvest sprouting. It combines high grain yield and resistance to prevalent races of leaf rust, stem rust, common bunt, and loose smut except race T9 in a semidwarf photoperiod insensitive background. AC Vista has harder kernels and stronger gluten than AC Karma. It is eligible for grades of the Canada Prairie Spring (White) wheat class. Key words: Triticum aestivum L., cultivar description, white spring wheat, preharvest sprouting resistance, common bunt resistance, high grain yield
Tillage regime, row spacing, and seeding rate influence infestations of root maggots (Delia spp.) (Diptera: Anthomyiidae) in canola
Authors: Dosdall L. M. , Florence L. Z. , Conway P. M. , Cowle N. T.
Published: April 2011

Infestations of root maggots (Delia spp.) (Diptera: Anthomyiidae) were assessed in Brassica rapa L. and Brassica napus L. grown under conventional and zero tillage regimes, at three row spacings (10, 20 and 30 cm) and three seeding rates (5.0, 7.5 and 10.0 kg ha−1 or 120, 180 and 240 plants m−2). The studies were conducted during two growing seasons (1995 and 1996) at each of two sites in central Alberta. Root maggot infestations were assessed by determining the numbers of eggs laid per plant during the growing season and by larval feeding damage to canola taproots assessed at the end of the season. Seed yields of the treatment plots also were determined. Plants of B. rapa were significantly more susceptible to root maggot infestations than were plants of B. napus. Root maggot egg populations and root damage were generally greater with zero tillage than with conventional tillage. Plants grown at higher seeding rates (7.5 and 10.0 kg ha−1) usually had less root damage than plants grown at the lowest (5.0 kg ha−1) seeding rate, and canola grown at wider row spacings (20 and 30 cm) had less root damage and higher yields than canola grown at the narrowest spacing (10 cm). Response surface regression analyses determined that deposition of fewest root maggot eggs per plant, least root damage and maximum yields occurred at seeding rates ranging from 7 to 11 kg ha−1 and at row spacings ranging from 17 to 25 cm. Even though canola grown in zero tillage had greater root maggot infestations than canola grown in conventional tillage, higher yields still occurred with zero tillage. Zero tillage is therefore an appropriate agronomic practice in areas infested by high populations of root maggots. Sowing B. napus rather than B. rapa, increasing seeding rates and widening row spacings are also appropriate cultural control practices for reducing crop damage from these pests. Key words: Delia radicum, Delia floralis, tillage, cultural control, canola
Selection for nitrogen use efficiency and N concentration in timothy
Authors: Michaud R. , Bélanger G. , Brégard A. , Surprenant J.
Published: April 2011

Improvement of N use efficiency of timothy (Phleum pratense L.) involves higher DM yield but, for feeding purposes, N concentration should also be considered. Differences in N use efficiency were found among 40 genotypes of timothy. The analysis of residues of the linear regression between N uptake and DM yield of all genotypes allowed for the selection of genotypes with both high N use efficiency and contrasted N concentrations. Key words: Phleum pratense L., timothy, genetic selection, nitrogen use efficiency
The biology of Canadian weeds. 110. Tragopogon dubius Scop., Tragopogon pratensis L., and Tragopogon porrifolius L.
Authors: Clements David R. , Upadhyaya Mahesh K. , Bos Shelley J.
Published: April 2011

Several types of salsify or goat's-beard, Tragopogon species (Asteraceae), are found in Canada as biennial or monocarpic perennial herbs with yellow or purple flowers. Introduced from Eurasia, T. pratensis and T. dubius have become established in all provinces in Canada except Newfoundland and the territories. Tragopogon porrifolius tends to be more local, but is also found in southern areas of most provinces. Tragopogon species hybridize readily, and the tetraploid species T. mirus and T. miscellus have resulted from crosses among the three diploid Tragopogon species in North America. Salsify species produce relatively large umbrella-like pappuses which promote long-distance dispersal. These species also invade rangeland, and are considered noxious weeds in some parts of Canada. Key words: Tragopogon dubius, Tragopogon pratensis, Tragopogon porrifolius, Tragopogon mirus, Tragopogon miscellus, salsify, goat's-beard, Asteraceae, Compositae, hybridization, weed biology
No-till alfalfa stand termination strategies: Alfalfa control and wheat and barley production
Authors: Bullied W. J. , Entz M. H. , Smith Jr. S. R.
Published: April 2011

Crop rotations involving perennial alfalfa (Medicago sativa L.) present the unique problem of terminating the alfalfa stand. Intensive tillage currently used to terminate alfalfa increases the risk of soil erosion and reduces many of the rotational benefits from alfalfa. Inadequate alfalfa termination results in severe competition to the following crop by surviving alfalfa plants. Field experiments were conducted in Manitoba between 1991 and 1993 with the following objectives: 1) to investigate no-till vs. tillage management systems for successful alfalfa termination, 2) to compare fall vs. spring alfalfa termination, 3) to compare the performance of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) seeded into alfalfa residue, and 4) to determine the relationship between alfalfa escapes and grain yield. Fall termination produced higher grain yields than spring termination, however this advantage was only achieved with the better termination treatments capable of lowering alfalfa regrowth below a critical level. The best herbicide treatment tested here was glyphosate at 1.78 kg a.i. ha−1. Successful treatments would have to reduce residual alfalfa basal crown area (a measure of alfalfa regrowth potential) after cereal grain harvest to below 2%. Alfalfa escapes reduced yield of following wheat and barley crops similarly (P > 0.05). When alfalfa termination treatment method allowed some regrowth, in-crop herbicide treatments significantly reduced alfalfa basal crown area. Results of this study indicate that it is feasible to terminate alfalfa with herbicides in the absence of tillage, however an overall cropping strategy, including adequate consideration of weeds present in alfalfa fields at time of termination, must be considered. Key words: Herbicides, competition, recropping, no-till, alfalfa regrowth, soil conservation, sustainable cropping
Meadow bromegrass response to coated and conventional urea fertilizers
Authors: Malhi S. S. , Heier K. , Zhang M. , Nyborg M.
Published: April 2011

In central Alberta, surface-broadcast urea is usually less effective in increasing grass forage yield than ammonium nitrate (AN) due to volatilization loss. A 2-yr field experiment was conducted in 1994 and 1995 on meadow bromegrass (Bromus bibersteinii Roem and Shult 'Regar') at Eckville, Alberta to compare a number of synthetic con-trolled-release urea fertilizers with conventional urea and AN fertilizers for their effect on dry matter yield (DMY), protein yield (PY), N-use efficiency (NUE) and percent N recovery (NR). The N fertilizers were applied at 100 kg N ha−1 in early June of 1994 and mid-April of 1995. The meadow bromegrass was harvested three times during the May to September growing season. In both years there was a significant forage yield response to applied N. In 1994, the DMY, PY, NUE and NR were similar for urea and AN, and most of the treated urea products were inferior to urea alone. This was most likely due to delayed application of N fertilizer until just before the start of summer rains. In 1995, urea had lower DMY (by 874 kg ha−1), PY (by 177 kg ha−1), NUE (by 8.8 kg DM kg−1 N ha−1) and NR (by 27.3%) than AN. Some of the coated urea products (e.g., Sh. 19, Sh. G) gave significantly greater DMY, PY, NUE and NR than urea alone, though still less than AN. These results suggest that under conditions when surface-applied urea is inferior to AN, its effectiveness can be improved by using Sh. 19 and Sh. G controlled-release urea fertilizers on grassland. The controlled-release fertilizers may be more expensive and therefore, additional cost must be considered as compared with AN before using on a commercial basis. Key words: Ammonium nitrate, bromegrass, controlled-release N fertilizers, forage yield, N recovery, urea
AC CALMONT common bean
Authors: Park S. J. , Tu J. C. , Rupert T.
Published: April 2011

AC Calmont is a high-yielding dark red kidney bean (Phaseolus vulgaris L.) with medium-full season maturity in Ontario. Its main advantages are high yielding potential and disease resistance. Seed has acceptable cooking/canning quality. AC Calmont is resistant to alpha, alpha Brazil and delta races of anthracnose (Colletotrichum lindemuthianum) and is resistant to bean common mosaic virus races 1 and 15. Key words: Phaseolus vulgaris, dry bean, cultivar description
Effects of burial, stem portion and cultivar on the decomposition of canola straw
Authors: Blenis Peter V. , Chow Pak S. , Stringam Gary R.
Published: April 2011

Buried canola straw underwent 1.6 to 2 times as much decomposition as straw on the soil surface. Decomposition of Brassica napus L. was slightly less than that of B. rapa L. and cultivar effects were small in one year and insignificant in the other. Because treatment effects varied between stems and roots, plant portion likely should be considered in decomposition studies. Key words: canola, straw decomposition, burial, cultivars
Development of an identification scheme for Canadian registered oat cultivars using RAPDs
Authors: Guillin Eduardo , Baum Bernard R. , Mechanda Subbaiah
Published: April 2011

DNA fingerprints for all 53 oat cultivars registered in Canada were generated using random amplified polymorphic DNAs (RAPDs). Repeatability and reliability of the PCR-RAPD fingerprints were confirmed on up to 20 single seeds or seedlings, from breeders seed of five cultivars. An identification key was computer generated for the 53 cultivars. Twenty-nine potentially diagnostic bands were scored on the 53 cultivars to generate the key, but only 13 were found useful and sufficient by the computer generating key program. The identification scheme lends itself to be online. Further research is required to complete the scheme for routine cultivar identification and verification in Canada. The problems that need to be investigated are discussed. Key words: DNA fingerprinting, oat cultivars, RAPD, identification key
Fall cutting management affects yield and persistence of alfalfa in Atlantic Canada
Authors: Bélanger G. , Kunelius T. , McKenzie D. , Papadopoulos Y. , Thomas B. , McRae K. , Fillmore S. , Christie B.
Published: April 2011

The existing recommendation to avoid harvesting alfalfa during a critical fall rest period, based on calendar dates, is under review in Canada and adjacent areas of the United States. The effect on yield and persistence of four fall cutting management treatments (based on cumulative growing degree-days between harvests) was investigated for two cultivars of alfalfa (Medicago sativa L. 'Apica' and 'Oneida VR') at five sites in Atlantic Canada. The average seasonal DM yield for the five sites in the first production year was 1.6 to 2.3 t ha−1 greater with an additional harvest as compared with the two-harvest system (Truro, Nappan, Fredericton, and Charlottetown) and the one-harvest system in St. John's. Seasonal DM yield benefits were reduced over time; by the third production year, there was no increase in seasonal DM yield with an additional harvest. The seasonal DM yield increased with increasing the interval between the final harvest and the previous one. Taking an additional harvest resulted in higher winter plant mortality between the first and second production years in Truro and Nappan, and the third and fourth production years in St. John's. At the other two sites (Charlottetown and Fredericton), and for the first three production years in St. John's, winter plant mortality was unchanged with an additional harvest but regrowth potential in the following year was reduced. At the two sites that experienced a severe winter (Nappan and Truro), the cultivar Oneida VR was more adversely affected by the additional harvest than Apica. Our results indicate that in Atlantic Canada, taking an additional harvest increases the risk of winterkill. If an additional harvest is to be taken, increasing the interval between the final harvest and the previous one to at least 500 growing degree-days will decrease the risk of winterkill and might have a positive effect on next year's regrowth. Key words: Medicago sativa L., alfalfa, yield, persistence, harvest management, cultivar
Antioxidant response of soybean cotyledons (Glycine max) to ultraviolet irradiation
Authors: Kozak R. G. , Ricco R. A. , Gurni A. A. , Boveris A. D. , Puntarulo S.
Published: April 2011

After 24 h of UV-B + UV-C irradiation the homogenates of superficial layers of soybean cotyledons (Glycine max var. Hood) contained significantly more tocopherol (133%) and ascorbic acid (20%) than the control. However, UV-B irradiation alone did not affect the content of these antioxidants. Neither β-carotene nor thiol content was significantly affected after UV-B or UV-B + UV-C irradiation. Pigmentation of cotyledons from control and UV-B-exposed plants did not differ visibly, but cotyledons from plants exposed to UV-B + UV-C accumulated a red pigment in the epidermis 15 h after receiving the UV radiation. Spectral analysis indicated a substantial increase in absorbance between 250 and 340 nm after UV-B + UV-C exposure, compared with controls. Ethanolic extracts from UV-B + UV-C-irradiated cotyledons showed a significant peak at 532 nm at pH 10, which was not seen at pH 6. Successive changes in pH were accompanied by reversible changes in the spectra. TLC studies indicated that Rf values for the pigment were 0.75 and 0.63 in Forestal and formic solvents, respectively. By comparison with literature values, these results are consistent with the features of apigeninidin. The results suggest that UV-B irradiation and UV-C irradiation affect different mechanisms at the cellular level. Key words: Antioxidants, colored pigment induction, cotyledon, ultraviolet irradiation, UV-B + UV-C