bluuebunny/crossref_metadata_2025 huggingface dataset:
Spring frost damage to placental tissues in lowbush blueberry flower buds
Authors: Randall A. , Eaton Olson and Leonard J.
Published: April 2011

Closed flower buds and flowers at full bloom of Vaccinium angustifolium Ait. were collected from the field and histologically examined after severe spring frosts. Prior to anthesis, blackened ovarian placentae in closed buds were the only damaged tissues evident; placental damage may interfere with both seed and fruit set. Undetected frost damaged placentae may contribute to losses in commercial yield. Key words: Vaccinium, frost damage, placenta
Identification of allelopathic compounds from rice (Oryza sativa L.) straw and their biological activity
Authors: Chung I. M. , Ahn J. K. , Yun S. J.
Published: April 2011

Experiments were conducted to identify allelochemicals from rice (Oryza sativa L.) straw extracts of four rice cultivars (Gin shun, Kasawala mundara, Philippine 2 and Juma 10), and to test their biological activity on barnyard grass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi). High performance liquid chromatography (HPLC) analysis showed that the concentration and composition of allelopathic compounds depended on the cultivar. Among the compounds identified were p-hydroxybenzoic acid at 6.87 mg g–1 in Gin shun, p-coumaric acid at 0.34 mg g–1 in Kasawala mundara, ferulic acid at 0.05 mg g–1 in Philippine 2, and p-hydroxybenzoic acid at 6.34 mg g–1 in Juma 10. Preliminary identification by HPLC analysis resulted in peaks with retention times near those of standards, including p-hydroxybenzoic acid m/z = 138). This was confirmed with electron impact/mass spectra. In a bioassay with nine known allelochemicals and their mixtures, p-hydroxybenzoic acid (10–3 M) showed the greatest inhibitory effect on barnyard grass seed germination, seedling length, and dry weight. This suggests that this compound may be a key factor in rice allelopathy on barnyard grass. Key words: Allelopathic compound, rice, barnyard grass, bioassay
Tillage intensity and crop rotation affect weed community dynamics in a winter wheat cropping system
Authors: Blackshaw R. E. , Larney F. J. , Lindwall C. W. , Watson P. R. , Derksen D. A.
Published: April 2011

Development of improved weed manage ment systems requires more knowledge on how various weed species respond to changing agronomic practices. A long-term study was conducted to determine weed population responses to various tillage intensities and crop rotations in a winter wheat (Triticum aestivum L.) dominated cropping system. Weed density and species composition differed with tillage, rotation, year, and date of sampling within years. Weed community dynamics were most affected by year-to-year differences in environmental conditions, followed by crop rotation, and then tillage intensity. Russian thistle (Salsola iberica Sennen & Pau) and kochia [Kochia scoparia (L.) Schrad.] densities increased in years of low rainfall and above average temperatures. Winter annual weeds such as downy brome (Bromus tectorum L.) and flixweed [Descurainia sophia (L.) Webb ex Prantl], as well as the perennial weed dandelion (Taraxacum officinale Weber in Wiggers), increased in years where higher than average rainfall was received in fall or early spring. Continuous winter wheat facilitated a dense downy brome infestation to develop over time. Trifluralin is not efficacious on stinkweed (Thlaspi arvense L.) or Canada thistle [Cirsium arvense (L.) Scop.] and its use in canola resulted in an increase in these species in a winter wheat-canola rotation. Total weed densities were often greater in zero tillage than in either minimum or conventional tillage. Russian thistle, downy brome, kochia, and redroot pigweed (Amaranthus retroflexus L.) were associated with zero tillage while wild buckwheat (Polygonum convolvulus L.), lamb’s-quarters (Chenopodium album L.), flixweed, and wild mustard (Sinapis arvensis L.) were associated with conventional tillage. Perennials such as dandelion and perennial sowthistle (Sonchus arvensis L.) were associated with zero tillage but Canada thistle was associated with conventional tillage. Information will be utilized to implement more effective weed management programs in winter wheat production systems. Key words: Conservation tillage, fallow, multivariate analyses, weed populations, weed shifts, zero tillage
W98616, a white-seeded spring wheat with increased preharvest sprouting
Authors: Hucl Pierre , Matus-Cádiz Maria
Published: April 2011

White-seeded spring wheat germplasm line W98616 was selected for improved levels of preharvest sprouting resistance. W98616 has levels of seed dormancy comparable to Columbus, a red-seeded sprouting-resistant cultivar. W98616 has similar test weight, kernel weight, maturity, plant height, grain protein, and kernel hardness, but is lower yielding and 2 d later heading relative to BW264, a hard white wheat cultivar. Key words: Triticum aestivum L., germplasm, white spring wheat, preharvest sprouting resistance
Mixture performance of phenotypically contrasting barley cultivars
Authors: C. Essah S. Y. , Stoskopf N. C.
Published: April 2011

There is lack of information on the yield and yield component performance of same-row and alternate-row mixtures (SRM and ARM) of widely contrasting barley (Hordeum vulgare L.) phenotypes. Therefore, four phenotypically contrasting spring barley cultivars, each selected to represent a unique combination of spike type (two-row or six-row), height (short or tall) and days to maturity (early or late) were used in 1991 and 1992 in field experiments at the Elora Research Station in Ontario, Canada, with the objective of determining whether a yield and/or yield-component advantage could be associated with same-row or alternate-row mixtures of barley cultivars. The four cultivars chosen for the study were each grown as monocrops, and in all six possible binary (two-cultivar) mixture combinations as same-row or alternate-row mixtures, in a randomized complete block design. A 13% yield increase of early, short:late, tall SRM over the midcomponent (weighted mean of the components grown in monocrop) yield in 1991, and 14% yield increase of early, tall:late, tall SRM over the midcomponent yield in 1992 was observed. Between the 2 yr, cultivars in ARM produced similar or significantly greater yields than the monocrop yields, except in 1991, when the late, short cultivar in ARM with early, tall cultivar produced significantly lower yields than in monocrop. The spike number m–2 was similar for all mixtures and their midcomponents, except in 1992, when early, short:late, short in ARM produced 7.0% more spikes than the midcomponent. The results of this study indicate a possible yield advantage of phenotypically contrasting barley mixtures compared to monocrops, with early, short:late, tall and early, tall:late, tall in same-row mixtures having the best combining abilities. Key words: Barley, phenotypes; mixture, same row; mixture, alternate-row; maturity; height
Bacillus cereus UW85 inoculation effects on growth, nodulation, and N accumulation in grain legumes: Field studies
Authors: John Bullied W. , Buss Terry J. , Kevin Vessey J.
Published: April 2011

Bacillus cereus strain UW85 was assessed for growth-promotion effects on soybean and common bean in the presence and absence of rhizobial inoculation at two field sites in Manitoba in 1994. Growth promotions due to B. cereus UW85 occurred for soybean only, and only at one site. Promotions in plant emergence in soybean were apparent at 60 d after planting (DAP), but stimulations in shoot dry weight (DW), N concentration, and N content were not apparent until 90 DAP. At maturity (120 DAP), inoculation with UW85 resulted in stimulation of seed yield by 9% and seed N content by 14%. However, stimulation in growth and N parameters by UW85 treatment was proportionally greater in the absence of B. japonicum inoculation than in the presence of the rhizobial inoculant. These observations, in combination with the observations that nitrogenase activity was not stimulated by UW85 treatment, clearly indicate that the UW85-mediated stimulation of growth and N accumulation of soybean is via a generalized stimulation of plant growth, and not via a stimulation in the soybean-B. japonicum symbiosis per se. Overall, our study indicates that inoculation with UW85 has the potential of increasing soybean production in western Canada, but these effects are site specific and are not seen in common bean. Key words: Bacillus cereus UW85, common bean, Glycine max, growth-promotion, Phaseolus vulgaris, soybean
Impact of lamb’s-quarters, common ragweed and green foxtail on yield of corn and soybean in Ontario
Authors: Weaver S. E.
Published: April 2011

Field studies were conducted in Harrow, Ontario, from 1990 to 1993 to quantify the relationship between yield of field corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] and density of lamb’s-quarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), and green foxtail [Setaria viridis (L.) Beauv.]. Experiments were conducted separately for each weed and crop combination. Weeds emerged at the same time as or within a week of the crop. Coefficients of the rectangular hyperbolic damage function were estimated for each year and pooled over years. In both crops, lamb’s-quarters was the most competitive of the three weed species, and green foxtail was the least competitive at low densities. Maximum yield loss at high weed density varied with weed species in field corn, but not in soybean. The estimated competition coefficients of the damage function have been incorporated in a decision support system for integrated weed management in Ontario. Key words: Weed interference, yield loss
Effect of plant age and cottony snow mold on winter survival of forage grasses
Authors: Hwang S. F. , Gaudet D. A. , Turnbull G. D. , Chang K. F. , Howard R. J. , Najda H.
Published: April 2011

The low temperature basidiomycete (LTB, syn. Copribus psychromorbidus Traquair), the causal agent of cottony snow mold, is a major constraint to forage grass survival and productivity in the parkland region of the Canadian prairies under prolonged snow cover (e.g., 160 d). Studies were conducted to establish the level of the snow mold resistance in seven grass species commonly grown in western Canada and to identify the seeding dates that permit grass plants to develop maximum levels of resistance to snow mold. Following attack by the LTB fungus, considerable variation in winter survival and forage yield was observed among the grass species. Smooth brome and meadow brome were most resistant, followed by timothy and creeping red fescue. Tall fescue and orchardgrass were the most susceptible. Controlled-environment and field studies demonstrated that orchardgrass seeded in late spring resulted in greater winter survival and dry matter yield than when seeded in July or August, both in snow mold inoculated and noninoculated treatments. Additional mortality and dry matter yield loss were linked to snow mold injury. These results demonstrated that snow mold injury could reduce winter survival and yield in first-year forage grasses, especially in orchardgrass, and early seeding could reduce the impact of winter stresses. Key words: Grass, orchardgrass, timothy, smooth bromegrass, meadow bromegrass, creeping red fescue
Sweet corn (Zea mays) cultivar tolerance to primisulfuron
Authors: O’Sullivan J. , Sikkema P. H.
Published: April 2011

Nine sweet corn cultivars were evaluated to identify cultivar sensitivity to primisulfuron in four field studies, conducted over a 2-yr period. Response to primisulfuron varied, depending on cultivar and application dose. DelMonte 2038 was highly sensitive to primisulfuron resulting in very severe injury and, in most cases, the death of all plants at both locations, each year. At Exeter in 1998 and 1999, injury was slight with no plant height or yield reductions on other cultivars. At Simcoe in 1998 and 1999, five other cultivars showed visual injury of 10% or greater at 50 g ha–1 of primisulfuron. However, in most cases, this did not result in a significant plant height or yield reduction. SS Jubilee Bt showed a yield reduction but only in 1998 at Simcoe. Three cultivars, CNS 710, GH 2690 and Reveille, were classified as fully tolerant to field applications of primisulfuron at 25 g ai ha–1 with little or no risk of injury. Key words: Sensitivity, herbicide injury, cultivars, primisulfuron, Zea mays
Leaf development of eight grass species following grazing
Authors: Lardner H. A. , Wright S. B. M. , Cohen R. D. H.
Published: April 2011

Grazing by herbivores affects grass species both morphologically and physiologically. A study was conducted on an irrigated pasture near Outlook, Saskatchewan, Canada during the summer of 1991 to determine leaf regrowth after grazing of reed canarygrass (Phalaris arundinacea L.), slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners subsp. trachycaulus], intermediate wheatgrass [Thinopyrum intermedium (Host) Barkw. & D.R. Dewey subsp. intermedium], orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus beibersteinii Roem. & Schult.), smooth bromegrass (Bromus inermis Leyss.), tall fescue [Festuca arundinacea (Schreb.) Wimm.] and timothy (Phleum pratense L.) in order to evaluate the suitability of these species for grazing. All eight species were mob-grazed by sheep at a stocking density of 30 animals ha-1. Physiological stage of leaf development was determined at 7, 14 and 21 d following defoliation. Smooth bromegrass and timothy consistently produced the greatest number of leaves for all regrowth periods. Tall fescue produced the least number of leaves at all time periods. Fifty-five percent of slender wheatgrass tillers and 19% of intermediate wheatgrass tillers were reproductive 21 d after defoliation. Based on leaf regrowth after grazing measured by leaf appearance, the grasses were ranked into three groupings – meadow bromegrass, smooth bromegrass and reed canarygrass ranked highest; intermediate wheatgrass, slender wheatgrass and orchardgrass ranked intermediate; and timothy and tall fescue ranked lowest. Key words: Leaf, regrowth, grass, grazing
Reactions of field pea varieties to three isolates of Uromyces fabae
Authors: Xue A. G. , Warkentin T. D.
Published: April 2011

Reactions of 93 field pea varieties to three isolates of Uromyces fabae (Pers.) de Bary (Uf-1, Uf-2, and Uf-3) were measured as leaf area with symptoms (LAS) under controlled environmental conditions. Significant differences ( P < 0.05) were observed from pea varieties and rust isolates, and variety ×isolate interaction. Of these varieties, Tara and Century were mo st resistant (LAS <2%) to both Uf-1 and Uf-3 isolates; Victoria and Topper were most resistant to Uf-2 only; and Titan, Tipu, Emerald, and Yellowhead were most resistant to Uf-3 only. The remaining varieties had LAS of 2-67% for Uf-1, 2-86% for Uf-2, and 2 -45% for Uf-3, and were considered susceptible to the respective isolates. Over the average of 93 varieties, Uf-3 had LAS of 8.6% and was considered a less virulent isolate compared to Uf-1 (16.2%) and Uf-2 (15.2%). It is suggested that several different pathogenic isolates are required to test pea lines for rust resistance. A growth room inoculation and assessment method was developed in this study and can be used for evaluating pea lines for susceptibility to U. fabae.
Yield and water use efficiency of pulses seeded directly into standing stubble in the semiarid Canadian Prairie
Authors: Cutforth H. W. , McConkey B. G. , Ulrich D. , Miller P. R. , Angadi S. V.
Published: April 2011

In semiarid climates, appropriate management of the previous crop stubble in combination with seeding method is important to improve growing conditions for the subsequent crop. To determine the effects of standing stubble of various heights on the microclimate and on the growth and yield of pulse crops, we seeded desi chickpea (Cicer arietinum L. “Cheston”), field pea (Pisum sativum L. “Grande”), and lentil (Lens culinaris L. “Laird”) directly into cultivated, short (15 to 18 cm), and tall (25 to 36 cm) spring wheat (Triticum aestivum L.) stubble. Standing stubble changed the microclimate near the soil surface by reducing soil temperatures, solar radiation, wind speed, and potential evapotranspiration throughout the life cycle of these crops. Microclimate effects were much more pronounced for tall versus short stubble. The three pulses responded similarly to increasing stubble height. Vine length increased as stubble height increased, but the plants did not stand more erect. However, there was a tendency for plant height to increase as stubble height increased. Tall and short stubble increased the overall average grain yield by 13 and 4% compared to cultivated stubble. Crop water use was not affected by stubble height so the increased grain production was due to increased water use efficiency. Tall and short stubble increased the overall average water use efficiency by 16 and 8% compared to cultivated stubble. Key words: Stubble height, pulse, microclimate, evapotranspiration, yield
Growth, photosynthesis and productivity of greenhouse tomato cultivated in open or closed rockwool systems
Authors: Hao X. , Papadopoulos A. P.
Published: April 2011

Two full spring season tomato crops (Lycopersicon esculentum Mill. “Trust”) were grown in an open rockwool system with standard rockwool feeding formulae (O-R; conventional method), and in closed rockwool systems with standard rockwool (C-R) or Nutrient Film Technique (C-NFT) feeding formulae (modified in 1997) in 1996 and 1997 to examine the feasibility of a fully closed rockwool production system with appropriate feeding formulae. The closed rockwool system with optimized feeding formulae achieved high marketable yield, similar to that of the open rockwool system. There were no differences in early plant growth, plant biomass or biomass partitioning, and in total fruit yield, size and grades except for the closed rockwool system with the standard rockwool feeding formulae (C-R), which had lower yield than C-NFT in the last month of harvest in 1996. The photosynthesis of old foliage was higher and the root systems at the end of the experiments were rated healthier in plants grown in the closed (C-R and C-NFT) systems than in plants grown in the open (O-R) system. Over 30% of water and fertilizer was saved with the closed systems in comparison to the conventional open system. These results demonstrated that closed rockwool systems with optimized nutrient feedings are economically and environmentally sound alternative methods for greenhouse tomato production in Ontario. Key words: Lycopersicon esculentum, tomato, yield, recycling, rockwool, greenhouse
CDC EMDR-4, CDC EMDR-9, and CDC EMDR-14 spring wheats
Authors: Hucl Pierre , Matus-Cádiz Maria
Published: April 2011

Early-maturing spring wheat germplasm lines CDC EMDR-4, CDC EMDR-9, and CDC EMDR-14 have high levels of seed dormancy. Their agronomic performance is comparable to that of the cultivar Columbus. These three lines had similar grain protein concentration and kernel hardness relative to the check cultivars, except CDC EMDR-4, which had a soft endosperm texture. Key words: Triticum aestivum L., germplasm, seed dormancy, pre-harvest sprouting resistance
Renegade BX summer oilseed rape
Authors: McVetty P. B. E. , Rimmer S. R. , Scarth R.
Published: April 2011

Renegade BX is the fifth cultivar in the Navigator® series of summer oilseed rape (Brassica napus L.) canola cultivars. These cultivars are resistant to Compas® herbicide, a mix of herbicides including the broadleaf herbicide bromoxynil. Renegade BX is 380 kg ha-1 (13.6%) higher yielding, 8 g kg-1 higher in oil concentration and equal in protein concentration to the means of the check cultivars Defender, AC Excel and Legacy. Renegade BX is moderately resistant to blackleg disease. Renegade BX is adapted to the long- and mid-season B. napus canola growing areas of western Canada. Key words: Oilseed rape (summer), bromoxynil resistance, Navigator®, Compas®
Root biomass and shoot to root ratios of perennial forage crops in eastern Canada
Authors: Bolinder M. A. , Angers D. A. , Bélanger G. , Michaud R. , Laverdière M. R.
Published: April 2011

Shoot to root ratios (S:R) at peak standing crop are commonly used to estimate the annual crop residue C inputs to the soil from the root biomass left in the soil at harvest. However, root biomass has often been neglected in field studies and estimates of S:R for many commonly grown forage species are not available. Our objective was to determine root biomass and S:R of seven perennial grass species and two perennial legume species under eastern Canadian soil and climatic conditions. Root biomass in three soil layers (0–15, 15–30 and 30–45 cm) was measured shortly after the second harvest in the first (1995) and second (1996) year of production. Two harvests of aboveground DM were taken each year. The total root biomass (0–45 cm) in the second year of production (average of 1437 g m-2) was twice that measured in the first year of production (average of 683 g m-2). This temporal variation was mainly explained by the increase of root biomass in the 0- to 15-cm layer. The proportion of total root biomass (0–45 cm) in the 0- to 15-cm layer increased from 54 to 71% while that in the 15- to 30-cm layer decreased from 37 to 21%; the proportion of roots in the 30- to 45-cm layer remained constant at about 10% in both years. The S:R of alfalfa for the 0- to 15-cm depth was significantly higher than that for most of the grasses. No significant difference in S:R was observed among grass species. Recognizing that S:R may vary with locations and climatic conditions, our results suggest that average S:R of about 1.30 (values ranged from 1.01 to 1.72) in the first production year and 0.60 (values ranged from 0.43 to 0.87) in the second production year could be used as a first approximation to estimate the amount of root biomass left in the soil to a depth of 45 cm from forage crops in eastern Canada. The S:R of forage crops, particularly grasses, were lower than those of annual crops such as small-grain cereals and corn. Key words: Forage, annual C inputs, soil organic matter, root biomass, shoot to root ratios
Red smudge infection modifies sprouting response in four wheat lines
Authors: Fox S. L. , Fernandez M. R. , DePauw R. M.
Published: April 2011

Infection of wheat (Triticum aestivum L.) spikes by Pyrenophora tritici-repentis (Died.) Drechs. (Ptr) causes kernel discolouration, reducing the commercial value of the grain. Preharvest sprouting in wheat causes loss of grain yield, grain functionality and value as seed. The objective of this research was to determine the effects of Ptr infection on the expression of preharvest sprouting response. Four genotypes representing a range of preharvest sprouting response were studied: RL4137 has very good sprouting resistance; SC8021V2, good; AC Karma, fair; and Genesis, poor. These genotypes were grown in a growth cabinet and their spikes were artificially inoculated with a conidial suspension of Ptr or water. Spikes were collected at physiologic maturity, threshed by hand and germinated on wetted filter paper at 10 or 20°C to obtain a percentage germination and a mean germination time. Healthy seeds were also germinated in a solution containing a crude extract of the fungus. At 20°C, sprouting-resistant genotypes showed a significant delay in germination compared to susceptible genotypes; however, differences were not significant at the lower temperature. Genesis germinated quickly at both temperatures. All genotypes except Genesis had reductions in sprouting resistance when infected by Ptr, but these effects were significant only at 20°C. When inoculated with Ptr and germinated at 20°C, AC Karma germinated as quickly as the water controls and gave a preharvest sprouting response similar to Genesis. However, SC8021V2 and RL4137 inoculated with Ptr retained 40 and 78%, respectively, of their mean germination time compared to the water controls. Germination of healthy seeds in a solution containing a crude extract of Ptr increased the percentage germination and shortened the mean germination time of all genotypes, but did not result in significant changes for any individual line. Key words: Triticum, Pyrenophora tritici-repentis, preharvest sprouting, smudge
Rough fescue (Festuca campestris Rydb.) response to heat injury
Authors: Bogen A. D. , Bork E. W. , Willms W. D.
Published: April 2011

Rough fescue (Festuca campestris Rydb.) is an ecologically and economically important native plant species within grasslands of southwest Alberta. This is also a region where wildfires have become prevalent over the last decade. While the risk of long-term damage from fire may be determined by the susceptibility of rough fescue to heat injury, understanding the additive stress imposed by defoliation may assist in the development of grazing strategies facilitating rangeland recovery. Three laboratory studies were conducted to assess rough fescue sensitivity to heat stress, including the added impact of subsequent defoliation. Results indicated that fescue tillers were capable of withstanding temperatures of 60°C, but only for short periods (e.g., 16 s or less). At lower temperatures, a distinct interaction between exposure time and temperature was evident, with shorter times at greater temperatures causing similar reductions in growth as long exposure times at low temperatures. Decreased plant vigour, as evidenced by lower tiller numbers, resulted from defoliation coinciding with active regrowth, reinforcing the notion that rough fescue is sensitive to defoliation following heat stress. The greatest detrimental impact occurred with relatively longer periods of deferment (8 weeks) until defoliation following exposure to heat treatment. These results have implications for the recovery and conservation of burned rough fescue rangeland. Key words: Defoliation, Festuca campestris Rydb., heat stress, mortality, tillers, water bath
AC Vision barley
Authors: Ho K. M. , Choo T. M. , Martin R. A. , Caldwell C. D. , Walker D. , Rodd V.
Published: April 2011

AC Vision is a six-rowed spring feed barley (Hordeum vulgare L.) cultivar bred at the Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, and evaluated by the Eastern Canada Barley Breeding Group. It was selected from a Sabina/OAC Kippen cross. It has high yield, improved straw strength and resistance to powdery mildew. AC Vision is suitable for growing in areas II and IV of Ontario and in the Maritime Region of Canada. Key words: Hordeum vulgare L., feed barley, high yield, powdery mildew resistance
Effects of row arrangement and plant density on yield and quality of early, small-vined processing tomatoes
Authors: Warner J. , Hao X. , Zhang T. Q.
Published: April 2011

Early processing tomato (Lycopersicon esculentum Mill.) cv. H9230 and N 1045 were field grown with three row arrangements and two plant population densities in 1999, 2000 and 2001 to investigate their effects on fruit yield, quality, and foliar and fruit diseases. An equidistant single row arrangement (75/75 cm) resulted in similar or higher yield compared with the two less-even twin row arrangements (60/90 cm and 40/110 cm) over the 3 yr. The equidistant single row arrangement (75/75 cm) and wide twin row arrangement (60/90 cm) had reduced foliar and fruit diseases in a wet year (2000). However, the incidence of blossom-end rot was greater in the equidistant single row arrangement in a dry year (2001). Increasing the plant density from 33 300 to 40 400 plants ha-1 by reducing the plant spacing within the row from 40 to 33 cm increased the yield by 3–5 t ha-1. Row arrangement or plant density did not affect fruit size or soluble solids. Fruit size and soluble solids of H9230 were consistently greater than those of N1045 in all 3 yr. For production of early, small-vined processing tomatoes in southwestern Ontario, an equidistant single row arrangement with a plant density of 40 000 plants ha-1 is suggested. Key words: Lycopersicon esculentum, tomato, processing, yield, soluble solids, blossom-end rot
Investigation of variations in NBS motifs in alfalfa (Medicago sativa), M. edgeworthii, and M. ruthenica
Authors: Campbell T. A.
Published: April 2011

Medicago edgeworthii Sirjaev and M. ruthenica (L.) Ledebour are allogamous, diploid (2n = 2x = 16) perennials from Asia, which have a remarkable ability to survive stress , but are genetically distant from cultivated alfalfa (M. sativa L., 2n = 4x = 32). In lieu of hybridization, potentially important genes from the Asian species could be transferred to alfalfa using transgenic techniques. Many plant disease resistance genes (R-genes) belong to the nucleotide binding site-leucine rich repeats (NBS-LRR) superfamily and have several highly conserved NBS region motifs, which can be used to identify them. Thus, genomic DNA of alfalfa and the two Asian species was primed with a degenerate forward P-loop primer paired with degenerate reverse primers designed for GLPLA, RNBS-C, or RNBS-D-non-Toll/Interleukin (RNBS-D-non-TIR) motifs. The P-Loop/GLPLA primer combination yielded the largest number of sequences without stop codons, and alfalfa had the greatest variation within the kinase and RNBS-C domains; however several kinase and RNBS-C sequences were unique to M. edgeworthii or M. ruthenica. Priming with the P-loop/RNBS-C primer pair resulted in some open reading frames, which apparently did not belong to the NBS-LRR superfamily. The only open reading frames for the P-loop/RNBS-D-non-TIR primer combination were for M. ruthenica. These non-TIR-type clones, and the only non-TIR-type clone from the P-loop/GLPLA PCR (alfalfa), had sequences that were markedly different from the TIR-type sequences. The RNBS-C region may be useful in identifying non-TIRtype R-gene analogs in future studies. Screening for unique R-gene analogs in genetically distant Medicago species may be a very effective way of isolating potential new R-genes for transfer to alfalfa. Key words: Alfalfa, disease resistance, kinase, Medicago edgeworthii, Medicago ruthenica, NBS-LRR, R-gene analog
Crop yields and wild oat control in northern Alberta cropping systems
Authors: Darwent A. L. , Drabble J. C. , O’Donovan J. T. , Soon Y. K. , Mills P. F. , Clayton G. W. , Rice W. A.
Published: April 2011

A study was conducted on the Agriculture and Agri-Food Canada Research Farm, Beaverlodge, Alberta, to compare nine cropping systems in relation to productivity and wild oat (Avena fatua L.) control. The nine cropping systems consisted of three crop rotations and three levels of banded N fertilizer. Each cropping system had its own regime of tillage and weed control. One of the rotations consisted of mechanical fallow, along with canola ( Brassica rapa L.), barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), while the other two rotations consisted of the same annual crops, but with either flax (Linum usitatissimum L.) or red clover (Trifolium pratense L.) plowdown with partial fallow substituted for mechanical fallow. The three rates of banded N fertilizer were 0, 75 and 150% of recommended, based on soil tests and provincial recommendations. From 1991 to 1994, cropping systems with mechanical fallow and fall tillage after annual crops produced 24% higher total seed yields than cropping systems with no fall tillage after annual crops and either continuous annual crops or red clover plowdown. Increasing the rate of banded N fertilizer from 0 to 75% of recommended increased total crop seed yields but a further increase from 75 to 150% had no significant effect. Although cropping systems with mechanical fallow had an advantage over other cropping systems, the effect of crop sequencing and yearly weather conditions on total crop seed yields was greater than the effect of cropping systems. Wild oat populations varied greatly with year, but the ease of management was greater in cropping systems with the mechanical fallow than in other cropping systems. Wild oat density increased when diclofop or difenzoquat performed inadequately or when poor red clover establishment allowed populations to increase. Reductions in wild oat populations appeared to be largely due to the consistent effectiveness of sethoxydim. Key words: Crop rotation, mechanical fallow, N fertilizer, fall tillage, herbicides
Comparing Brassica oilseed crop productivity under contrasting N fertility regimes in the semiarid northern Great Plains
Authors: Miller P. R. , Angadi S. V. , Androsoff G. L. , McConkey B. G. , McDonald C. L. , Brandt S. A. , Cutforth H. W. , Entz M. H. , Volkmar K. M.
Published: April 2011

We compared the growth and yield of five Brassica spp. genotypes [two B.juncea (L.) Coss., two B. napus L. and one B. rapa L.] in 11 environments spanning two degrees of latitude and longitude in southern Saskatchewan in 1996–1998. All entries were managed with three levels of N fertility at each site. Plant height for the canola-quality B. juncea breeding line J904316 was 21% greater than the mean of the other genotypes, but shoot biomass did not differ for the same comparison. Cutlass Oriental mustard consistently yielded greatest across all environments while the yield of J904316 was highly variable among environments. The mean seed yield of Cutlass was 12% greater than the highest-yielding B. napus cultivar and 32% greater than the B. rapa cultivar, and had a greater harvest index. Earlier genotypes yielded greater than late-flowering and maturing genotypes within B. juncea and B. napus, but the earliest genotype, Maverick (B. rapa), yielded lower than all other genotypes. All Brassica spp. genotypes were responsive to N fertilization, and high total available N (average = 109, range = 91 to 131 kg N ha-1) was generally required to maximize seed yield, but not shoot biomass, under the conditions of this study. Pod density was the primary yield component influenced by N level. This study illustrates the potential adaptive advantage of B. juncea on the semiarid northern Great Plains. Key words: Brassica, canola, genotype, mustard, N fertility, semiarid, northern Great Plains
AC Metcalfe barley
Authors: Legge W. G. , Metcalfe D. R. , Haber S. , Harder D. E. , Noll J. S. , Tekauz A. , Thomas P. L.
Published: April 2011

AC Metcalfe is a two-row spring malting barley (Hordeum vulgare L.) cultivar widely adapted to western Canada with high yield, good agronomic traits, moderate disease resistance and excellent malting quality. Of note are its good resistance to loose smut and moderate resistance to Fusarium head blight. Key words: Malting barley, Hordeum vulgare L., cultivar description, yield, disease resistance, malting quality
Comparison of take-all disease incidence among wheat classes and other small grains under irrigation in Saskatchewan
Authors: Bailey K. L. , Irvine B.
Published: April 2011

The incidence of take-all disease was determined in several cultivars among three wheat classes (hard red spring wheat, Canada prairie spring wheat, and durum wheat), triticale, and barley grown under irrigation in Saskatchewan. There were few differences in disease incidence among cultivars within a crop type. However, there was more take-all in Canada prairie spring wheat cultivars than hard red spring wheat, durum wheat, and triticale; the lowest incidence of disease occurred on barley. Key words: Take-all, resistance, wheat, triticale, barley
The biology of Canadian weeds. 126. Amaranthus albus L., A. blitoides S. Watson and A. blitum L.
Authors: Costea and F. J. Tardif M.
Published: April 2011

A review of biological information is provided for three species of the genus Amaranthus: A. albus L., A. blitoides S. Watson and A. blitum L. The last species has been revised taxonomically and a new subspecies for Canada is presented-A. blitum subsp. emarginatus (Moq. ex Uline & Bray) Carretero, Munoz Garmendia & Pedrol. Amaranthus albus and A. blitoides are native to the U.S.A. and introduced to Canada. Both species are annual ruderal and agrestal weeds. During the past 100 yr the two species have spread across most provinces of Canada, but the greatest frequency and abundance have been recorded in Saskatchewan. Originating from Europe, Asia and North Africa, A. blitum was initially considered a non-persistent species. The present study shows that A. blitum especially, subsp. emarginatus, has continued to spread in Québec. The three species are alternate hosts to many insects, nematodes, viruses, bacteria and fungi that affect cultivated plants. In other areas (U.S.A., Europe and Asia), the three species have developed multiple resistance to triazine and acetolactate-synthase-inhibiting herbicides. Key words: Amaranthus albus, Amaranthus blitoides, Amaranthus blitum, weed biology, ecology, taxonomy, herbicide resistance
Levels of “phenoxy” herbicides in prairie rainfall during 2000–2001
Authors: Hill B. D. , Inaba D. J. , Byers S. D. , Grant C. A.
Published: April 2011

Rainfall was sampled at nine prairie locations and analyzed for lindane and 18 herbicides using a MSD-GC method. 2,4-D was detected in 75% of the 166 samples and in the highest amounts (total seasonal deposits of 18-261 µg m-2). The highest seasonal accumulations (131–429 µg m-2) of the four “phenoxy” herbicides, 2,4-D, bromoxynil, dicamba and MCPA, occurred in cultivated areas of southern Alberta despite the low rainfall in the region. The highest herbicide concentrations (5.7–26 µg L-1) usually occurred in small rainfalls and occasionally exceeded the Canadian aquatic life guidelines. It was concluded that with the possible exception of southern Alberta phenoxy herbicide levels in rainfall have not increased dramatically across western Canada in recent years and that injury to sensitive crops is unlikely. Key words: Phenoxy herbicides, 2,4-D, atmospheric deposition, Canadian prairies, rainfall
Yield potential and forage quality of annual forage legumes in southern Alberta and northeast Saskatchewan
Authors: Fraser J. , McCartney D. , Najda H. , Mir Z.
Published: April 2011

There is limited information on the adaptability of small and medium-seeded annual legumes in Western Canadian cropping systems. Pea (Pisum spp.), vetch (Vicia, Lathyrus spp.), medic (Medicago spp.), alfalfa (Medicago spp.), berseem clover (Trifolium alexandrinum L.), arrowleaf clover (T. vesiculosum L.), Persian clover (T. resupinatum L.), balansa clover [T. michelianum Savi. var. balansae (Boiss.) Azn.], rose clover (T. hirtum All.), crimson clover (T. incarnatum L.) and black lentil (Lens culinaris Medik.) were grown at Lethbridge and Brooks, Alberta, and at Melfort and Nipawin, Saskatchewan over a 2 or 3 yr period to assess their forage yield potential under irrigation and dryland conditions. Measurements included plant height, stand establishment, flowering date, forage yield and forage quality. Peas, winter and hairy vetch, and berseem clover were the top yielding species across locations (5452–6532 kg ha-1). Berseem clover, hairy vetch, winter vetch, Nitro alfalfa, and Persian clover yielded in excess of 9000 kg ha-1 under irrigation at Brooks. Hairy and winter vetches, Magnus pea, chickling vetch (Lathyrus sativus L.) and berseem clover yielded over 4300 kg ha-1 in dryland and rainfed locations at Lethbridge, Melfort and Nipawin. These entries had an upright growth habit, established quickly and were normally harvested twice. Crude protein concentration and yields were higher in legumes at irrigated locations in Alberta than rainfed locations in central Saskatchewan. Burr medic at the Brooks irrigated location produced the highest crude protein yield of 2495 kg ha-1. Berseem clover, Persian clover, Nitro alfalfa, hairy and winter vetches show promise as legumes in short term rotations, as green manures and intercrops for increasing forage quality in silage or late season grazing in Western Canada. Key words: Medicago, Trifolium, Vicia, Pisum, Lens, forage yield, forage quality
Photosynthetic responses of muskmelon (Cucumis melo L.) to photon flux density, leaf temperature and CO2 concentration
Authors: Chen N. , Gan Y. , Wang G.
Published: April 2011

Two cultivars (Huanghemi and Elizabeth) of muskmelon (Cucumis melo L.) were evaluated to determine the effect of photon flux density (PFD), leaf temperature, and CO,2 concentration on the net photosynthetic rate (Pn). The cultivars were evaluated under open field and solar-heated greenhouse conditions in northwest China. The Pn increased as the PFD increased, and then the rate of increase in Pn declined for Huanghemi and decreased for Elizabeth. Elizabeth registered 22 µmol m-2 s-1 for light compensation and 1127 µmol m-2 s-1 for light saturation, which, respectively, were 50 and 70% of those required by Huanghemi. The Pn increased with increasing leaf temperatures in the range of 9.8 to 50.8°C. The optimum temperature for photosynthesis was 35.3°C for muskmelon grown in open field, 2.4°C (7%) greater than that for muskmelon grown in the greenhouse. At optimal temperatures, the field-grown muskmelon had the Pn of 19.8 µmol m-2 s-1, 30% greater than that for the greenhouse-grown muskmelon. Both cultivars responded positively to CO2 concentrations of below the CO2 saturation points, whereas Huanghemi exhibited greater (51%) Pn and higher (49%) carboxylation efficiency than Elizabeth at optimal CO2 level. The two cultivars exhibited greater photosynthesis in open field than when grown in solar-heated greenhouses, while Elizabeth performed better than Huanghemi when light conditions were poor. Selective use of cultivars with low requirements for light and temperatures will enhance the photosynthesis and productivity of muskmelon grown in solar-heated greenhouses of northwest China. Key words: Light compensation, light saturation, photon flux density, transpiration
A protocol for spring milling wheat production in the Maritimes
Authors: Nass H. G. , Caldwell C. D. , Walker D. F. , Price M. , Sanderson J. B.
Published: April 2011

Maritime cereal producers have had difficulty in producing spring milling wheat (Triticum aestivum L.) crops of 13.5% grain protein with consistency. A 3-yr study was conducted from 1999 to 2001 to develop a nitrogen management protocol to produce spring milling wheat with 13.5% grain protein. Experiments were conducted at three locations: Harrington, Prince Edward Island; Hartland, New Brunswick; and Truro, Nova Scotia. Ten split nitrogen treatments were applied to four spring milling wheat cultivars, AC Walton, Glenlea, Grandin and SS Maestro. Generally, any split nitrogen application of 75 to 100 kg ha-1 or greater produced grain protein of 13.5%. However, 10 cultivars out of 36 cultivar × site combinations failed to reach the desired 13.5% grain protein at any nitrogen treatment. Moisture stress after flowering, excessive precipitation during early plant development and protein dilution due to high grain yield were some of the possible reasons why 13.5% grain protein was not obtained. Milling quality was enhanced with increasing amounts of applied nitrogen because as grain protein increased, water absorption, development time, dough stability and time to dough breakdown increased while mixing tolerance index and 20-minute drop decreased. There was little or no improvement in milling quality with nitrogen applications greater than 75 to 100 kg ha-1. Maritime grain producers can produce high-quality, high-yielding spring wheat with relatively low levels of nitrogen input; however, environmental factors may override management in determining the ultimate product quality. Key words: Spring wheat, Triticum aestivum, protein, milling quality, nitrogen
Effect of the Nicotiana debneyi black root rot resistance gene on the yield and quality characteristics of flue-cured tobacco in Ontario
Authors: Haji H. M. , Brammall R. A. , VanHooren D. L.
Published: April 2011

The effects of Nicotiana debneyi-derived resistance to black root rot disease were evaluated for yield, agronomic and quality traits by comparing the near isogenic cultivars AC Gayed (resistant) and Delgold (susceptible). Over 7 yr of trials the possession of resistance led to yields and economic returns that averaged 6 and 7% lower, respectively, than for the susceptible line. Key words: Flue-cured tobacco, Nicotiana tabaccum, Black Root Rot, Chalara elegans, Nicotiana debneyi, yield, quality
Tom, Russian wildrye
Authors: McLeod J. G. , Jefferson P. G. , Muri R. , Lawrence T.
Published: April 2011

Tom, a new diploid cultivar of Russian wildrye, Psathyrostachys juncea (Fisch.) Nevski, was developed by the Semiarid Prairie Agricultural Research Centre, Research Branch, Agriculture and Agri-Food Canada, Swift Current, SK. Tom is an eight-clone synthetic developed by recurrent selection for heavy seed weight and improved seedling emergence from deep planting. Tom represents a significant improvement in herbage yielding ability over the check cultivars Swift and Tetracan. Key words: Cultivar description, Russian wildrye, Psathyrostachys juncea (Fisch.) Nevski, seedling emergence, seed weight
Comparison of the effect of mur and nap cytoplasms on the performance of intercultivar summer rape hybrids
Authors: Riungu Teresio C. , McVetty Peter B. E.
Published: April 2011

The performance of six isogenic pairs of male fertility restored, hand-crossed, summer rape (Brassica napus L.) hybrids, in the mur and nap cytoplasms, were investigated in four Manitoba environments. Hybrids in both cytoplasms exhibited high-parent heterosis for seed yield, total dry matter (TDM) and, to a lesser degree, harvest index (HI). Negative high parent heterosis for days to flowering, days to maturity, oil concentration and protein concentration was observed. Combined over hybrids within cytoplasms, the mur and nap cytoplasmic hybrid groups differed in oil concentration in all environments, and in protein concentration in one of four environments. Similarly, the mur hybrid group was lower-yielding and had lower TDM, HI and oil concentration, but higher protein concentration than the nap hybrid group. Even though there are some biological costs associated with the mur cytoplasm, especially for oil concentration, it appears that the mur cytoplasmic male sterility (CMS) system has good potential for use in summer rape hybrid cultivar breeding and commercial hybrid seed production, since hybrids in the mur cytoplasm display heterosis for many traits in absolute terms. Key words: Biological cost, Brassica napus L., cytoplasmic male sterility, heterosis, hybrid