bluuebunny/crossref_metadata_2025 huggingface dataset:
Competitiveness of Canada prairie spring wheats with wild oat (Avena fatua L.)
Authors: Kirkland K. J. , Hunter J. H.
Published: April 2011

Three spring wheat (Triticum aestivum L.) genotypes (Neepawa, a hard red spring, and HY320 and HY355 both Canada Prairie Spring wheats) were subjected to four levels of wild oat density at two locations over 4 yr to assess the effects of wild oat competition on biomass production, culm formation and yield. Wheat biomass and culm production were reduced at all wild oat density levels in each of the three cultivars. There were no significant differences among cultivars. In general, yields of all cultivars were reduced as wild oat density levels increased. Actual yield reductions at comparable wild oat densities tended to be greater at Regina than at Scott. There was a significant cultivar-by-density interaction for yield with yield reductions in HY320 > HY355 > Neepawa. Key words: Triticum aestivum, wheat (spring), wild oat density, competition, plant biomass, culms
The biology of Canadian weeds. 99. Matricaria perforata Mérat (Asteraceae)
Authors: Woo S. L. , Harms V. L. , Thomas A. G. , Peschken D. P. , Bowes G. G. , Douglas D. W. , McClay A. S.
Published: April 2011

Scentless chamomile, Matricaria perforata Mérat, (=M. maritima var. agrestis (Knaf) Wilmott), is an introduced weed having an annual to short-lived perennial life cycle. Two cytotype races are found in Canada with a distinctive geographic distribution. The tetraploid (2n = 36) is abundant in agricultural habitats of the Prairie region, whereas the diploid (2n = 18) is found mainly in ruderal habitats of the Atlantic region. Infestations are found in many annual and perennial crops, pastures, wasteland, lawns, gardens, roadsides, fence lines, and ditches. The plant reproduces entirely by seed, producing up to 1.8 million seeds m−2 in dense monospecific stands. A density of 25 annual plants m−2 can result in a 55% reduction in spring wheat yield under cool wet conditions. Shallow preseeding tillage in late autumn or early spring is an effective method of cultural control. Several herbicides are recommended for control of the weed in crop and noncrop areas. Scentless chamomile is considered a suitable candidate for biological control. Key words: Weed biology, scentless chamomile, Matricaria perforata, Matricaria inodora, Matricaria maritima var. agrestis, Tripleurosperum inodorum
Modelling the effects of potato seed-tuber age on plant establishment
Authors: Knowles N. Richard , Botar Gabor I.
Published: April 2011

Four physiological ages of potato (Solanum tuberosum L. 'Russet Burbank') seed-tubers were produced by varying the time of storage at 15 °C. Age was quantified as the accumulated degree-days (dd) above 4 °C over the 199-d storage interval, and plant emergence and establishment were then modelled in controlled environment studies. As age advanced, time to 50% sprout emergence decreased, reaching a minimum at 589 dd, and then increased with further aging. Apical dominance was also reduced, as evident from a linear increase in the number of sprouts per seedpiece with advancing age. Earlier emergence from older seed-tubers led to significantly more leaves, leaf area, and leaf and stem dry weights per plant compared with younger seed-tubers early in the study; however, this advantage in plant establishment was eventually lost as time progressed through 33 d, resulting in significant age by time interactions on each yield component. Unit leaf rate, and relative growth rates with respect to leaf area and plant dry weight, thus decreased linearly with advancing tuber age over the course of the study. Leaf area ratio of plants from older tubers was greater than that from younger tubers early in the study, but this difference decreased with time. Seed-tuber age affected LAR through altering the leaf weight ratio (efficiency of partitioning dry weight to leaves), not the specific leaf area. Yield component analysis showed that the number of leaves per stem and the leaf area per leaf accounted for 85 and 12% of the total variation in plant dry weight, respectively. Because plant establishment was clearly more advanced, there may be potential for utilizing aged Russet Burbank seed-tubers to improve grade and earliness and increase yield in areas with short growing seasons. Key words: Solanum tuberosum, seed-tuber age, vigor, potato
Earliness and duration of grain fill in winter wheat
Authors: Housley T. L. , Ohm H. W.
Published: April 2011

The duration of grain fill in wheat (Triticum aestivum L.) is one of the determinants of kernel weight. The purpose of this research was to investigate the genetic diversity for duration of grain fill in winter wheat. In one experiment the genetic diversity for duration of grain fill and the influence of temperature on heading, anthesis and duration were assessed in 175 cultivars and lines of diverse plant type and origin planted at the Purdue Agronomy Research Center. The effect of temperature on the rate and duration of grain fill was further assessed in two cultivars, Fundulea and Caldwell, over 4 yr. In a second experiment Fundulea and Caldwell were grown in the field under altered day length (12, normal, 17 h) to manipulate date of anthesis. Duration of grain fill in the 175 entries averaged 28 ± 0.9 d. Heading occurred on 17 different dates, anthesis on 13 different dates and grain maturity on 17 different dates. The average daily temperature (ADT) during grain fill ranged between 21.2 and 22.5 °C. Comparisons of the ADT through grain fill for Fundulea and Caldwell over 4 yr indicated a 0.83-d reduction in duration for each degree rise in ADT. Leaf area, plant height, and tiller number were similar for cultivars exposed to 17 h, 12 h, or normal day lengths. Anthesis was 5 d earlier and the ADT during grain fill was less (20–21 °C) in plants exposed for 17 h compared to those exposed for 12 h (22 °C). Weight of 1000 kernels was significantly higher in plants with early anthesis dates, but yield was not significantly changed by the day length treatments. There appeared to be genetic differences in temperature sensitivity during reproductive development which could be exploited in selecting cultivars suitable for early anthesis. The general similarity of duration for all experiments suggests that environmental constraints imposed by latitude and selection for yield, have led to a narrow germplasm base regarding duration of grain fill.Key words: Triticum aestivum, average daily temperature during grain fill, duration of grain fill, anthesis, heading
Maximum area, expansion rate and duration of summer rape leaves
Authors: Morrison M. J. , Stewart D. W. , McVetty P. B. E.
Published: April 2011

The vegetative development phase in summer rape (Brassica napus) is characterized by the appearance and expansion of leaves. The objectives of this research were to examine the maximum individual leaf area (LAmax), leaf expansion rate (LAX) and leaf area duration (LAD) of individual leaves as influenced by leaf position and ambient air temperature. Westar summer rape was grown from seed to maturity in controlled environment chambers set at temperatures ranging from 10 to 25 °C. Plants representing each stage of leaf development were selected at random from the population for leaf area determination. Logistic equations were used to relate the area of individual leaves to Growing Degree Days (GDD). Polynomial regression equations were used to fit curves describing the relationship between LAmax, LAX, LAD and leaf position or air temperature. As the air temperature increased the LAmax increased. LAX increased to a maximum which occurred when LAmax was at its maximum. There were no significant differences for LAX among air temperatures ranging from 13.5 to 22 °C. Mean LAX was 0.21 cm2 GDD−1. There were no significant differences in LAD due to leaf position or air temperature. Mean LAD was 140.1 GDD.Key words: Leaf area, leaf expansion rate, leaf area duration, Brassica napus
Variation in spike harvest index among diverse genotypes of spring wheat and triticale
Authors: Hucl P. , Graf R. J.
Published: April 2011

Genotypes of spring wheat and triticale exhibited significant differences in spike harvest index (SPHI). SPHI averaged 78% over genotypes and experiments. Genotype SPHI differed by up to 13% units. SPHI, however, was not correlated with either plot harvest index, or grain yield.Key words: Spike harvest index, genotypic differences, spring wheat, Triticum aestivum L.
Seed yields of canola and volunteer barley as influenced by their relative times of emergence
Authors: O’Donovan J. T.
Published: April 2011

A model based on the rectangular hyperbola was used to describe the effects of population density and relative time of emergence of volunteer barley (Hordeum vulgare L. ’Klondike’) on seed yield of both canola (Brassica campestris L. ’Tobin’) and volunteer barley. At a given density of volunteer barley, canola seed yield decreased, while volunteer barley seed yield increased, the earlier the volunteer barley emerged relative to the canola. The results suggest that it is more critical to control early emerging volunteer barley plants (and possibly other weeds) since they have a greater effect on canola yield and can contribute significantly more seed to the soil than later emerging plants.Key words: Relative time of emergence, volunteer barley density, canola, rectangular hyperbola
Relationships between cover performance and date of fall-seeding where winter rye was broadcast into a standing potato crop
Authors: Edwards Linnell M. , Sadler John M.
Published: April 2011

Winter rye was broadcast into a potato crop just after topkilling with the object of avoiding post-harvest delays in establishing a winter ground cover. Rye treatments were interseeded (i) at intervals of 1 d for up to 10 d before potato digging, without post-harvest tillage and (ii) just after digging and preparatory seedbed tillage as a comparative standard. Generally, cover performance of rye, measured as plant count, tiller count or dry mass of plants showed significant (P < 0.05) increase with decreasing days to potato digging up to 3 or 4 d before digging. There was no sacrifice of rye cover using this inter-seeding approach compared with traditional post-(potato) harvest seeding in a prepared seedbed. Seeding 3–4 d before potato harvest is recommended on the basis of superior fall plant count, spring tiller count and shoot dry mass, and winter survival indices on either of these days.Key words: Cover crops, winter rye, winter survival, companion cropping
Evaluation of some characteristics of Chinese steamed buns prepared from Canadian wheat flours
Authors: Kruger J. E. , Morgan B. , Preston K. R. , Matsuo R. R.
Published: April 2011

A laboratory procedure for preparing and evaluating end-product characteristics of Chinese steamed buns from Canadian wheat flours is described. A blend of 60% Canada Western Red Winter (80% patent) and 40% Canada Western Soft White Spring (straight grade) wheat flours was evaluated and subsequently used as the control flour. Buns were prepared by a straight dough procedure using only flour, yeast and water. Evaluation of bun quality included measurement of volume with a loaf volumeter, symmetry by the width-to-height ratio, physical measurements of hardness, cohesiveness and gumminess with the Instron Universal Testing Machine, and color (L*, a*, b*) of crust and crumb using the HunterLab Labscan II Colorimeter. Buns prepared from different classes of Canadian wheats were evaluated. Both Canada Western Red Winter and Canada Western Red Spring wheat flours produced steamed buns which were similar to the control, whereas those made from a non-blended Canada Western Soft White wheat flour produced a less appealing product.Key words: Wheat, steamed buns, test-baking, flour, quality evaluation
Yield and water use of paired-row versus equidistant-row seeded spring wheat in a semiarid environment
Authors: Cutforth H. W. , Selles F.
Published: April 2011

A field study was carried out to determine the effects of seed row configuration on days to maturity, water use and grain yield of spring wheat (Triticum aestivum L. ’Leader’) grown in a semiarid environment. From 1986 to 1989, Leader spring wheat was seeded at Swift Current, Saskatchewan in north-south equidistant-rows (25-cm row spacing) and paired-rows (two rows 10 cm apart with 50 cm between the centre of each paired row). Seed and fertilizer were applied at recommended rates for the Brown soil zone. There were no significant differences (P > 0.10) in grain yield, water use or days to maturity between equidistant-row and paired-row seeding. The data suggest that under the environmental conditions of the Brown soil zone paired-row seeding may have no agronomic advantage over equidistant-row seeding.Key words: Paired-row seeding, water use, grain yield, spring wheat
A transplant plug technique for production of alfalfa (Medicago sativa L.) plants from somatic embryos
Authors: McElroy A. R. , Brown D. C. W.
Published: April 2011

A transplant plug technique was developed that uses in vitro somatic embryogenesis techniques to mass-multiply alfalfa plants in a form suitable for direct transplanting. The plug contains potting media covered with an agar nutrient cap. Plants develop from embryos placed on the cap and then establish in the potting media.Key words: Hybrid alfalfa, Medicago sativa L., tissue culture, transplant plug, somatic embryogenesis
Effects of tillage systems and crop rotations on root and foliar diseases of wheat, flax, and peas in Saskatchewan
Authors: Bailey K. L. , Mortensen K. , Lafond G. P.
Published: April 2011

The dynamics of root and foliar diseases were studied in spring and winter wheat, peas, and flax and under zero, minimum, and conventional tillage at Indian Head, Saskatchewan, from 1987 to 1990. No disease was observed on flax during the 4 yr. Year-to-year variation was more important than tillage systems in explaining the incidence of bacterial leaf spot and foot rot of peas. Tan spot and septoria leaf blotch were the most important foliar diseases of wheat. Disease ratings (0–9) of the leaf spots were greater on winter wheat (average 2.2) than on spring wheat (average 1.9) and also greater on spring wheat following a cereal (average 2.0) than following peas or summer fallow (average 1.7). Hot and dry weather did not enhance development of foliar diseases, and no consistent effects of tillage on leaf disease ratings were observed. However, take-all and common root rot were affected by crop management. Incidence of take-all was greater on winter wheat (8%) than on spring wheat (1%) and also greater on winter wheat under conventional (11%) than minimum (8%) or zero tillage (6%). Severity of common root rot of spring wheat was greater following either spring (24%) or winter wheat (25%) than peas (22%) and summer fallow (15%). The severity of common root rot varied from year to year. In 3 of the 4 years, minimum-till and zero-till reduced the severity of the disease.Key words: Zero till, minimum till, conventional till, crop rotation, disease, spring wheat, winter wheat
Selection for resistance to the root-lesion nematode in alfalfa
Authors: Christie B. R. , Townshend J. L.
Published: April 2011

A study was conducted to evaluate response of alfalfa (Medicago sativa L.) to selection for resistance to the root-lesion nematode (Pratylenchus penetrans (Cobb) Filipjev and Sch.-Stek.) under growth-room facilities. Six hundred plants of the cultivar Vernal were inoculated with root-lesion nematodes. Counts were made 13–14 wk later of the number of nematodes g−1 root. Selections were made for relatively low counts (resistant) and high counts (susceptible). Selections were self-pollinated, and the S1 progeny of nine plants (five resistant and four susceptible) were evaluated. The S1 progenies from both types of selections had similar counts. The S2 progenies of resistant S1 parents, however, had lower counts than those of susceptible parents. The F1 crosses generally reacted as expected on the basis of the S2 parents. Results of this study suggest that progress can be made in breeding for resistance to the root-lesion nematode in alfalfa.Key words: Nematode, Pratylenchus penetrans, alfalfa, selection
Zero vs. conventional tillage and their effects on crop yield and soil moisture
Authors: Brandt S. A.
Published: April 2011

A study comparing zero tillage (ZT) with conventional tillage (CT) crop production in two rotations; fallow–oilseed–wheat, and oilseed–wheat–wheat, was conducted during 1979–1990. In 36 comparisons of ZT with CT over three rotation phases and 12 yr, ZT increased spring soil moisture in nine cases and resulted in no decreases; increased yield in nine cases while decreasing yield in three; and increased moisture use efficiency in six cases with two decreases. Increases in spring soil moisture were not related to precipitation during the non-growing season but may have been influenced by weeds. Increased spring soil moisture with ZT occurred more frequently on fallow than on stubble, presumably because precipitation was greater. Yield increases with ZT generally occurred where spring soil moisture was increased and weeds were adequately controlled. Yield decreases with ZT were normally associated with poor weed control, but in one case poor seed placement with ZT reduced yield. Throughout the study, inadequate weed control with ZT was a major factor limiting responses. Implications of these results on future research required to improve adoption of this important soil–conserving practice are discussed.Key words: Zero tillage, wheat, canola, flax, available moisture, weeds
Forage corn dry-matter yields and N uptake as affected by previous legumes and N fertilizer
Authors: Paré Théophile , Chalifour François-P. , Bourassa Josée , Antoun Hani
Published: April 2011

Field experiments were conducted in 1987 and 1988 on a Rivière-du-Loup sandy gravelly loam (Ferro-Humic Podzol) at St-Anselme and on a Chaloupe silty loam (Orthic Humic Gleysol) at Deschambault in Eastern Quebec. In monoculture, or following a legume, corn (Zea mays L.) Pioneer 3979 was fertilized with 0, 50, 100 or 150 kg N ha−1, and faba bean (Vicia faba L.) Outlook and soybean (Glycine max [L.] Merr.) Maple Amber received 20 kg N ha−1 as NH4NO3. In 1987, the whole-plant dry-matter yields (DMY) of corn increased linearly with the supply of N at St-Anselme and Deschambault. The stover and whole-plant N uptake, also increased linearly with the N levels at both locations, but the supply of N had no effect on the ear N uptake. In 1988, at St-Anselme and at Deschambault, the ear, stover and whole-plant DMY of plants not receiving N and following faba bean were significantly higher than those in monoculture or following soybean and not fertilized with N; these differences between previous crops were more evident at St-Anselme than at Deschambault. At both locations, the DMY of the stover, ears and whole plants of corn were more responsive to the increased N levels following soybean or corn. At both locations, the N uptake of corn following faba bean did not increase with the N levels in contrast to corn following corn or soybean. The N-fertilizer replacement values (NFRV) for soybean (on the basis of corn DMY) were negligible or lower than 0 kg N ha−1 at both locations. At St-Anselme, the values for faba bean were higher than 150 kg N ha−1, but averaged 32 kg N ha−1 at Deschambault (DMY basis). On the basis of corn N uptake, the NFRV of faba bean ranged from 92 kg N ha−1 for ears and was higher than 150 kg N ha−1 for whole plants at St-Anselme, and varied from 37 kg N ha−1 for stover to 44 kg N ha−1 for ears at Deschambault.Key words: Previous crop, forage corn, soybean, faba bean, N-fertilizer replacement value
Probable origin of standard crested wheatgrass, Agropyron desertorum Fisch. ex Link, Schultes
Authors: Asay K. H. , Jensen K. B. , Hsiao C. , Dewey D. R.
Published: April 2011

The origin of Standard crested wheatgrass (Agropyron desertorum, Fisch. ex Link, Schultes) has been the subject of considerable speculation, and both amphiploidy and autoploidy have been proposed as evolutionary pathways. Amphiploids, derived from hybrids between Fairway crested wheatgrass (A. cristatum, L., Gaertner) and the narrow-spiked diploid (A. mongolicum Keng) were hybridized with A. desertorum. Objectives were to test the hypothesis that A. desertorum arose from hybrids between A. mongolicum and A. cristatum. Hybrids between A. mongolicum × A. cristatum amphiploids and A. desertorum were reasonably fertile. Meiotic relationships in the amphiploids and hybrids with A. desertorum were more or less typical of that found in autotetraploids. The data support the premise that the genomes of A. desertorum, A. cristatum, and A. mongolicum are basically homologous, although some structural differentiation is evident. Multivariate analyses, based on 31 morphological characters, failed to separate A. desertorum from the amphiploids. Our findings support the hypothesis that the ancestral germplasm of A. desertorum was derived from hybridization between A. mongolicum and A. cristatum followed by chromosome doubling. We further propose that A. fragile is an autotetraploid derivative of A. mongolicum and that variants of A. desertorum could be generated from hybrids between A. fragile and tetraploid A. cristatum.Key words: Cytogenetics, grass breeding, Agropyron mongolicum, Agropyron cristatum, phylogeny, taxonomy
Salt stress tolerance in native Alberta populations of slender wheatgrass and alpine bluegrass
Authors: Acharya S. N. , Darroch B. A. , Hermesh R. , Woosaree J.
Published: April 2011

Alpine bluegrass [Poa alpina L.] and slender wheatgrass [Elymus trachycaulus (Link.) Gould ex Shinners] accessions from alpine and subalpine regions of the Canadian Rocky Mountains and eastern foothills were tested for tolerance to salinity stress. Accessions with higher emergence (%) than salt-tolerant Orbit tall wheatgrass [Thinopyrum elongatum (Host) D. R. Dewey, comb, nov.], after 21 d in vermiculite saturated with a NaCl-salinized half-Hoagland solution (electrical conductivity 15 dS m−1) and nurtured in growth cabinets set to repeat 20/15 °C day (16-h)/night temperatures, were considered tolerant of salt-stress. This test identified 72 alpine bluegrass and 11 slender wheatgrass salt-tolerant accessions. Most of these accessions originated from two specific sites near the Alberta-British Columbia border. Slender wheatgrass accessions tolerant to NaCl were also tolerant to the other salts commonly found in Alberta soils. In slender wheatgrass, the ability to emerge in a salinized nutrient solution had moderate heritability (61–68%), suggesting the possibility of genetic improvement through selection.Key words: Salt tolerance, selection, heritability, alpine bluegrass, slender wheatgrass
Pollinisation croisée et production de quatre cultivars de fraisier, Fragaria × ananassa
Authors: Colbert S. , Oliveira D. de
Published: April 2011

Comparisons were made to determine the cross-pollination potential of four strawberry cultivars. The weight per fertilized ovule of self-pollinated strawberries was compared to that from cross-pollination. Results indicated in 1986–1987 that the weight of strawberries was influenced by cross pollination. In 1986, the primary strawberries obtained by the crossing of Bounty × Glooscap had an average achene weight superior to that of the control. We also noticed the same observation for the secondary strawberries by the crossing of Honeoye × Bounty in 1986 and Redcoat × Honeoye in 1987.Key words: Strawberry, cross pollination, production, xenia
Boron nutrition and the composition of glucosinolates and soluble nitrogen compounds in two broccoli (Brassica oleracea var. italica) cultivars
Authors: Shelp B. J. , Shattuck V. I. , McLellan D. , Liu L.
Published: April 2011

The effects of boron (B) nutrition on the composition of glucosinolate and soluble nitrogen (amino acids, NO3−, NH4+) compounds, as well as the distribution of B, were investigated in two cultivars of broccoli (Brassica oleracea var. italica ’Baccus’ and ’Commander’). The plants were grown to commercial maturity in vermiculite under glasshouse conditions and supplied continuously with B levels ranging from 0 to 2.5 mg L−1 of nutrient solution. Visible symptoms and inflorescence characteristics confirmed that Commander was more tolerant to B deficiency than Baccus. Eight glucosinolates were identified by high performance liquid chromatography and mass spectrometric analysis including 4-hydroxy-3-indolylmethyl-glucosinolate and 4-methoxy-3-indolylmethyl-glucosinolate which have not previously been reported for broccoli. The predominant glucosinolates were 3-indolylmethyl-glucosinolate, 1-methyoxy-3-indolylmethyl-glucosinolate and 4-methylsulfinylbutyl-glucosinolate. Baccus, but not Commander, also had considerable 2-hydroxy-3-butenyl-glucosinolate. In response to induced B deficiency [tissue B concentrations from 9–18 μg (g DW)−1], the total glucosinolates increased by about threefold in the young leaves, but not in the florets. In both the young leaves and florets, there were increases (54–175%) in the proportion of indolyl-glucosinolates. In both cultivars, the pool sizes of the glucosinolate precursor amino acids (phenylalanine, tryptophan and methionine), and of NO3− and NH4+ were not markedly affected.Key words: Boron nutrition, Brassica, broccoli, cultivars, glucosinolates, nitrogen
Effects of fungicide sprays on foliar diseases, yield, and quality of spring wheat in Finland
Authors: Peltonen Jari , Karjalainen Reijo
Published: April 2011

The fungicide Tilt (propiconazole) applied to spring wheat between Zadoks growth stages 47 and 55 significantly decreased the severity of foliar diseases caused by Septoria nodorum and Erysiphe graminis and prolonged duration of green leaf area. There were, however, genotypic differences in response to fungicide applications. With some cultivars, application of Tilt increased grain yield, nitrogen uptake efficiency and protein quality, but with other cultivars there was no benefit from spraying. Also, in a good growing season (1986) Tilt significantly increased grain nitrogen uptake, grain yield, grain weight, and protein quality, but in a cold and wet year (1987) Tilt did not increase yield or quality of the cultivars tested.Key words: Triticum aestivum, Septoria nodorum, Erysiphe graminis, fungicide application, yield components, protein quality
A comparison of broadcast and drill methods for no-till seeding winter wheat
Authors: Collins B. A. , Fowler D. B.
Published: April 2011

No-till seeding into standing stubble of a previous crop is required to provide a trap for snow that protects overwintering wheat from low temperature extremes experienced in most of western Canada. In this production system, the optimum winter wheat seeding date often conflicts with spring crop harvest. Broadcast (aerial) seeding into an immature, standing spring crop would provide an opportunity to eliminate this conflict for limited resources during harvest. The objectives of this study were to determine the effect of broadcast seeding date and rate on winter wheat establishment, development, and productivity and to compare broadcast and conventional no-till winter wheat seeding methods in east-central Saskatchewan. Eight field trials were conducted over 2 yr. Seedlings from broadcast seeding had more prostrate growth habit and lower establishment levels than those produced with conventional seeding methods. Unlike conventional drill seeding, pre-seeding soil moisture was not an important factor in broadcast seed germination. When broadcast seeding rate was increased from 67 to 202 kg ha−1 there were increases of 167, 66, and 91% in plants m−2, spikes m−2 and grain yield, respectively. Highest broadcast seed yields were obtained with a seeding date of 15 August at seeding rates ranging from 164 to 202 kg ha−1. Maximum grain yields were higher for conventional drill than for broadcast seeding methods. A heavy reliance on post-seeding rainfall, high seeding rates and a greater risk of failure more than offset the advantages of speed, better opportunity for timely seeding and improved labor distribution with broadcast compared to drill seeding methods.Key words: No-till, winter wheat, broadcast seeding, seeding date, seeding rate, establishment, plant development, yield
Agronomic response of six-row barley cultivars to supplemental fertilization and late-season fungicide treatments
Authors: Jedel P. E. , Helm J. H.
Published: April 2011

Management practices such as the use of fertilizers and fungicides can have positive effects on grain yield and quality of cereals, especially where diseases are a concern. Six cultivars of six-row barley (Hordeum vulgare L.) were tested at two fertility levels (standard and high) with a late-season application of the foliar fungicide Tilt (propiconazole) to determine their agronomic responses to these management practices. In 1988, when yields were limited because of early season drought, only Leduc showed a positive yield response to the Tilt, even though it has the highest level of genetic resistance to scald and net blotch of the cultivars tested. In 1989, when yields were again limited by adverse environmental conditions, no response to Tilt was found. In 1990, when growing conditions during the season were excellent, Empress, Noble and Samson had positive responses to Tilt application. Tilt had no effect on grain protein, maturity, or harvest index; it slightly improved test weights and kernel weights and decreased percent thins; and it had variable effects on height, number of viable tillers m−2, and kernel number spike−1. Yield response to Tilt was not affected by fertility regime. High fertility (112 kg ha−1 N 37 kg ha−1 P) resulted in an overall increase in yield of 0.62 t ha−1 from the standard fertility treatment (84 kg ha−1 N 27 kg ha−1 P); decreased harvest index; delayed maturity in 1989 only; increased height, number of viable tillers m−2, and kernel number spike−1; increased protein content of the grain in 1988 only; and had no effect on test weight, kernel weight and percent thins. Because of the variability of response from year to year and cultivar to cultivar, the economic feasibility of Tilt application may be limited.Key words: Hordeum vulgare L., propiconazole, soil fertility, management
A recessive gene for white sepal colour in sweetclover, Melilotus alba L.
Authors: Goplen B. P.
Published: April 2011

A genetic analysis involving P, F1, F2 and F3 in sweetclover (Melilotus alba L.) revealed that the white sepal trait was controlled by a single recessive gene, designated ws. This trait is characterized by chlorophyll-deficient white sepals and several associated pleiotropic effects including: lighter green colour of stems and foliage and a general greenish-red colour of the entire plant, lax and wilted appearance of the white sepal racemes, reduced opening of the mature flower, and a much reduced fertility as measured by percent pod set. Because of these regressive effects associated with the white sepal trait, it has limited use as a plant marker.Key words: Melilotus alba, white sepal, chimera, pleiotropy
Heritability for yield, leaf:stem ratio and stevioside content estimated from a landrace cultivar of Stevia rebaudiana
Authors: Brandle J. E. , Rosa N.
Published: April 2011

Stevia rebaudiana (Bert.) Bertoni is a herbaceous perennial native to the highlands of Paraguay. A number of compounds in the leaf tissue have a potential food use as low-calorie sweeteners. The purpose of this work was to determine if sufficient genetic variability was present in a landrace cultivar of stevia to allow selection of lines with agronomic and chemical properties suitable to local production conditions. Leaf yield, leaf:stem ratio and stevioside concentration were all found to be highly heritable. Leaf-yield levels were comparable to those in other stevia-producing areas. Stevioside concentration was higher, probably as a result of production under long days. These initial results also show that improvement of stevia through selection is possible and that it has potential for production in southwestern Ontario.Key words: Response to selection, low-calorie sweetener
The tolerance of spring wheat and barley to post-emergence harrowing
Authors: Lafond Guy P. , Kattler Kevin H.
Published: April 2011

Use of herbicides in certain situations may not always be appropriate for controlling weeds because of cost or improper crop stage. Crops produced without the use of herbicides require alternative weed-control methods. A 12-yr study was conducted at Indian Head, Saskatchewan, under weed-free conditions to determine the tolerance of spring wheat and barley, with or without ammonium phosphate fertilizer placed with the seed, to post-emergence harrowing. Barley and spring wheat harrowed with diamond-toothed harrows as it was emerging, at the 1.5-leaf stage, or at the 2.5-leaf stage in the absence of weeds produced yields similar to those from a non-harrowed check when averaged across years and fertilizer treatments. Ammonium phosphate fertilizer placed with the seed significantly increased yields of both barley and spring wheat (averaged across years and harrowing treatments) but did not alter the tolerance of barley and spring wheat to post-emergent harrowing. This implies that a delay between seeding and harrowing due to rain or using a harrowing operation to break a surface crust should not result in yield losses for barley and spring wheat.Key words: Triticum aestivum L., Hordeum vulgare L., cultural control, organic production phosphorus
Effect of vegetation suppression on the establishment of sod-seeded alfalfa in the Aspen Parkland
Authors: Bowes G. G. , Zentner R. P.
Published: April 2011

Four trials were conducted on a heavily grazed bluegrass-dominated pasture located in east-central Saskatchewan to compare the establishment of alfalfa (Medicago media Pers. Drylander) and forage grasses with no suppression vs. suppression of the resident vegetation using either glyphosate or rotovation. Successful forage establishment was based on seedling count, herbage yield and an economic assessment using net present value. The test area had been cleared of mature aspen poplar (Populus tremuloides Michx.) and balsam poplar (Populus balsamifera L.) trees, treated with 2,4-D to control suckering and was subsequently invaded by native forbs and grasses, mainly bluegrasses. Alfalfa successfully established with or without suppression while smooth bromegrass (Bromus inermis Leyss. ’Carlton’) established only when a suppression treatment was applied. Forage yields, averaged over 4 yr and four trials, following sod-seeding and glyphosate at 2.5 kg ha−1 were 1973 and 612 kg ha−1 for alfalfa and bluegrass plus smooth bromegrass, compared to 1287 and 748 kg ha−1 for alfalfa and bluegrass plus smooth bromegrass, respectively, when there was no suppression of the resident vegetation. The low-cost, no-suppression sod-seeding treatment was as profitable as the sod-seeding treatment using glyphosate.Key words: Sod-seed, zero till, alfalfa, smooth bromegrass, economics, glyphosate
Interactions of zinc with banded and broadcast phosphorus fertilizer on the dry matter and seed yield of oilseed flax
Authors: Grant C. A. , Bailey L. D.
Published: April 2011

Field experiments at four sites over 3 yr evaluated the effect of banded and broadcast application of fertilizer P, with and without application of Zn on dry matter yield at flowering, and seed yield of flax. Application of P fertilizer increased dry matter yield and seed yield on a number of soils even when crop growth and yield were restricted by extremely dry conditions. Banded P was more effective than broadcast or residual P in increasing flax yields. Increases in yield due to Zn application were infrequent and showed no definite relation to soil Zn or P. Increases in yields with Zn application generally occurred only where P had been broadcast that season or the year before, while decreases in yields with Zn occurred more frequently where P had been banded. The results showed that increases in flax yields in response to Zn application are most likely to occur where P fertilizer is broadcast at relatively high levels or on soils with a history of heavy P application. Key words: P placement, P, Zn, flax, yield, Zn-P interaction
Excised-leaf water status evaluation and associations in field-grown winter wheat
Authors: Haley S. D. , Quick J. S. , Morgan J. A.
Published: April 2011

Water status measurements of excised leaves have been proposed as screening criteria for drought resistance in cereal crops. This study was conducted to assess the utility of such measurements in a wheat breeding program, through evaluation of environment and genotype differences in excised-leaf water status and examination of associations with several other traits. Initial water content (IWC) and rate of water loss (RWL) of excised leaves, epicuticular wax content (EW), stomatal frequency (SF), flag leaf area (LA), plant height (HT), heading date (HD), grain yield (GY), and test weight (TW) were measured on 24 winter wheat (Triticum aestivum L.) genotypes grown near Fort Collins, CO, during 1986–1987 and 1987–1988 (F87 and F88, respectively: subirrigated environments) and near Bennett, CO, during 1987–1988 (B88: dryland environment). Differences among genotypes for IWC and RWL were significant for F87 and F88, and nonsignificant for B88. Combined analyses of variance showed significant differences among environments for IWC and RWL. Initial water content was less for B88 than for F87 and F88. Significant genotype × environment (G × E) effects for IWC and RWL suggested that selection for high IWC or low RWL in irrigated environments (F87 and F88) may not provide selections that respond similarly in dryland environments (B88). Correlations for B88 revealed only a small, positive correlation between IWC and GY (r = 0.49*). For F87 and F88, significant correlations were observed between IWC and SF (r = −0.57** and −0.78**), RWL and LA (r = 0.74** and 0.71**), RWL and HT (r = 0.63** and 0.57**), and RWL and HD (r = 0.71** and 0.57**). Neither IWC or RWL were correlated with EW in any environment. Correlations between RWL (subirrigated) and G Y and TW (dryland) suggested that selection for low RWL in irrigated environments could provide some GY or TW advantage in dryland environments, despite observed G × E interaction and lack of RWL differences under the dryland environment. Key words: Cuticular transpiration, Triticum aestivum L., leaf water loss, stomata, drought
Relationship of excised-leaf water loss and stomatal frequency in wheat
Authors: Wang H. , Clarke J. M.
Published: April 2011

Rate of water loss from excised leaves of wheat (Triticum spp.) is associated with adaptation to dry growing conditions, but the causes of observed genotypic differences are not well understood. This study was conducted to determine the relationship between stomatal characteristics and excised-leaf water status in tetraploid (Triticum turgidum L. var. durum) and hexaploid (Triticum aestivum L.) wheat genotypes. Samples were taken from field and growth-room experiments to measure stomatal frequency (SF) and size, leaf water content at excision (WC0) and 30 min after excision (WC30), rate of water loss (RWL) 30-120 min after excision, epidermal conductance (ge), and relative water content (RWC). SF was not correlated with RWL in the field experiments and was negatively correlated with WC0 and WC30 in tetraploids but not in hexaploids. In the growth-room experiment, SF was positively correlated with ge 50 and 30 min after excision for tetraploid and hexaploid genotypes, respectively. SF was correlated with RWL in tetraploids (r = 0.64*, n = 12) and hexaploids (r = 0.81**, n = 12). However, there were no significant correlations between stomatal characteristics and WC0, WC30 or RWC. These results indicate that SF is perhaps one of several factors influencing genotypic differences in excised-leaf water loss. The inconsistency of this relationship may be due to the influence of other traits affecting RWL. Key words: Leaf water loss, stomata, drought, Triticum aestivum L., T. turgidum L. var. durum
Effect of storage temperatures on Rhizobium meliloti survival in peat- and clay-based inoculants
Authors: Biederbeck V. O. , Geissler H. J.
Published: April 2011

Legume growers and extension agents require advice on optimum conditions under which inoculants may be stored without deterioration of rhizobia or the effectiveness of the inoculant. This study was conducted to determine effects of storage duration and temperature on survival of Rhizobium meliloti in two inoculant carriers, one with a peat base and the other with a clay base. Inoculant subsamples were placed in polyethylene bags, then packaged into plastic containers and stored in wooden boxes at either −23 °C (freezer), 4 °C (refrigerator), or room temperature (21–33 °C). Before and after storage for 0.5, 3, 6, 9, 12, 15 and 20 mo, samples were analyzed for surviving rhizobia by most probable number (MPN) plant-infection technique using plastic pouches with seedlings of alfalfa (Medicago sativa L. ’Algonquin’). These counts showed no significant reduction of rhizobial viability in either inoculant at any temperature over the 20-mo study. The surprising lack of population decreases was attributed partly to the wide span between the confidence limits of MPN estimates (at P = 0.05) and partly to the effectiveness of the protective packaging in preventing any desiccation or acidification of the inoculants. Throughout the experiment pH remained unchanged at 6.8 and 8.5 and moisture content at 12.3 and 3.0% in the peat-base and clay-base inoculants, respectively. Nodule color and size indicated that symbiotic effectiveness was not affected by storage temperature. Counts, when averaged across temperatures, showed rhizobial populations remained constant around 1.3 × 109 cells g−1 peat and 1.1 × 108 cells g−1 clay. Re-testing of R. meliloti inoculants stored for up to 10 yr at 4 °C, after earlier regulatory testing, showed no significant viability reductions in any product stored < 7 yr and in some products stored for as long as 10 yr. The results indicated that rhizobial populations could be maintained at levels much above the regulatory minimum MPN (103 seed−1), which would be of critical importance when forage legumes are grown under adverse soil conditions and inoculation is required. Key words: Rhizobium meliloti, inoculant storage, temperature effects, carrier effects, MPN plant-infection technique, inoculant quality control
Selection of alfalfa for a lower initial rate of digestion and corresponding changes in epidermal and mesophyll cell wall thickness
Authors: Goplen B. P. , Howarth R. E. , Lees G. L.
Published: April 2011

A modified nylon bag technique, described in detail in this paper, appears to be an effective method of selecting for a lower initial rate of digestion (IRD) in alfalfa. Breeding for reduced IRD in alfalfa resulted in a 15% reduction in 4-h dry matter disappearance (DMD) after three cycles of selection (ultimate goal of 25–30 % reduction for a bloat-safe alfalfa). No further reduction in IRD occurred with a 4th cycle of selection. The IRD characteristic appears to be expressed at early stages of vegetative growth (pre-bud to early bud) and not at a more advanced stage of maturity (mid-bud to early bloom). The IRD characteristic also appears to be subject to environmental influence. Alfalfa plants selected for reduced IRD have consistently thicker cell walls compared to the unselected alfalfa check cv. Beaver. The advanced cycle 4 LIRD synthetic is being increased for subsequent pasture trials and assessment of bloat reduction. Key words: Nylon bag technique, cell rupture, pasture bloat, initial rate of digestion, cell wall thickness
Field evaluation following two cycles of backcross transfer of somatic embryogenesis to commercial alfalfa germplasm
Authors: Bowley S. R. , Kielly G. A. , Anandarajah K. , McKersie B. D. , Senaratna T.
Published: April 2011

For successful application of artificial seed technology to alfalfa (Medicago sativa L.), parental plants must possess the necessary genes for somatic embryogenesis and produce progeny having high commercial value. A backcross procedure was initiated to transfer the ability to form somatic embryos from genotype A70-34, a selection from the cultivar Rangelander, to multiple-pest-resistant alfalfa germplasm. The objectives of this study were to evaluate the growth characteristics and seed yield of the F1; BC1 and BC2 generations to determine if introgression with commercial germplasm had improved the agronomic features of the embryogenic germplasm. This study consisted of two field experiments, each conducted at two locations. One experiment evaluated herbage growth characteristics and herbage production at Elora and Woodstock, Ontario, and the other evaluated seed yield at Elora and Delhi, Ontario. Significant increases in fall regrowth height, leaflet length:width ratio, and seed yield were detected over the cycles of crossing. By the BC2, fall dormancy and leaflet length:width ratio were similar to those in commercial populations. Although improvements in seed yield were detected, the BC2 was inferior in seed yield compared with commercial germplasm, and further introgression and (or) conscious selection for improved seed yield will be required. Through a population backcross procedure, it appears possible to develop commercial alfalfa germplasm capable of in vitro manipulation. Key words: Alfalfa, Medicago sativa L., somatic embryogenesis, artificial seed, backcross
AC Tamor field pea
Authors: Ali-Khan S. T.
Published: April 2011

AC Tamor is a large-seeded field pea cultivar with yellow cotyledons and resistance to powdery mildew. In non-irrigated registration tests, AC Tamor produced 4% higher yield than the check cultivars, while under irrigation it averaged 16% higher than the checks. Its large seed, round and smooth seed shape, and good cooking quality make AC Tamor suitable for domestic and international food markets. Key words: Field pea, powdery mildew resistance, cultivar description
The effects of nitrogen, row spacing and seeding rate on the yield of flax under a zero-till production system
Authors: Lafond G. P.
Published: April 2011

The long-term sustainability of agriculture requires that soil degradation be addressed and that crop production systems that incorporate the benefits of surface residues and standing stubble through conservation tillage practices be evaluated critically. The objective was to study the effects of nitrogen, row spacing and seeding rate on the yield of flax (Linum usitatissimum L.) under zero-till production practices. Three row spacings, six seeding rates and two rates of nitrogen were investigated. The plots were directly seeded into barley stubble under a continuous cropping zero-till production system. When yield levels were > 1200 kg ha−1, yields were not significantly affected by row spacing, but when yield levels were < 1200 kg ha−1, the 20-cm row spacing was favored over the 10- or 30-cm spacings. Yields increased linearly with increase in seeding rate at all row spacings. There were no interactions observed between nitrogen, row spacing and seeding rate. The results of this study have important implications in terms of equipment design, cost for zero-till seeding equipment, and the opportunity to easily modify existing equipment for zero-till seeding. Key words: Plant establishment, plant height, zero till, yield
Effects of drought stress on the water relations in Brassica species
Authors: Good Allen G. , Maclagan James L.
Published: April 2011

The physiological responses of different species of Brassica to induced drought stress were studied by analysing the relationships between relative water content, leaf water potential and leaf osmotic potential during the onset of drought stress. These data indicate that while there was a decrease in leaf osmotic potential with the onset of drought stress, this did not result from a net increase in solutes. Therefore, these genotypes of Brassica do not appear able to osmoregulate under these drought conditions. Key words: Brassica, drought, osmoregulation, water stress