bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary metabolites in the leaves and fruits of three pear cultivars during the growing season
Authors: Hudina Metka , Colarič Mateja , Štampar Franci
Published: April 2011

Primary metabolites (sugars and organic acids) in leaves and fruits of the pear cultivars Conference, Concorde and Williams were investigated during the growing season in Slovenia. Leaves were sampled 15 times from Apr. 25 to Oct. 22. Fruits were sampled seven times from Jun. 14 to Aug. 23. The contents of sugars (glucose, fructose, sucrose, and sorbitol) and organic acids (malic, citric, shikimic, and fumaric) in leaves and fruit were determined by high performance liquid chromatography (HPLC). Similar dynamic patterns were found in the glucose, fructose, sucrose and sorbitol in leaves and fruits of the genetically related cultivars Conference and Concorde. Leaf sugar was low at the beginning of the growing season when the leaves were not completely developed. Generally when sucrose increased in leaves it decreased in fruits. At the end of June the total sugar content in leaves reached its peak then rapidly decreased. At the same time, total sugar in fruits increased. From the beginning of August, total sugars in fruits increased regardless of the sugar content in leaves and likely due to decomposition of starch. After harvest, the contents of individual sugars (glucose, fructose, sucrose, and sorbitol) in the leaves decreased until the beginning of October when, just prior to leaf drop, they increased in all cultivars. Key words: Pyrus communis, sugars, organic acids
Trichoplusia ni growth and preference on broccoli and eight common agricultural weeds
Authors: Cameron Jennifer H. , Isman Murray B. , Upadhyaya Mahesh K.
Published: April 2011

Larval growth and feeding, and adult ovipositional preference of the cabbage looper, Trichoplusia ni Hübner, were investigated on broccoli (Brassica oleracea var. italica L.) and eight common agricultural weeds: cow cockle (Saponaria vaccaria L.), common groundsel (Senecio vulgaris L.), lamb’s-quarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), sheep sorrel (Rumex acetosella L.), shepherd’s purse (Capsella bursapastoris L.), stinkweed (Thlaspi arvense L.), and wild mustard (Sinapsis arvensis L.). Leaves from greenhouse grown plants were removed and fed to 1st instar larvae in a 7-d growth trial. Broccoli-fed larvae grew larger than those fed on cow cockle, redroot pigweed, sheep sorrel, stinkweed, and wild mustard. Only one insect of 64 survived for 7 d on stinkweed. In a leaf disc choice bioassay, 4th instar larvae showed a significant feeding preference for common groundsel over broccoli. Broccoli was preferred for oviposition over three of the weeds (common groundsel, lamb’s-quarters, and shepherd’s purse). Stinkweed showed promise as a dead-end trap species for this insect in broccoli, since more insects oviposited on stinkweed compared with broccoli yet larval survival on stinkweed was almost nil. Key words: Trichoplusia ni, broccoli, Thlaspi arvense, oviposition, feeding deterrence
Stevia rebaudiana (Bert.) Bertoni: Stages of plant development
Authors: Pedroza Carneiro José Walter
Published: April 2011

Vegetative and reproductive codes were developed to describe seeds under germination, normal seedlings, seedling growth, plant growth and branching, plant regrowth, flower buds, crop flowering (anthesis), developing seeds, seed dispersion, and senescent plants as V0, V1.i, V2.i, V3.i.k, V4.i.k, R1.i, R2.i, R3.i, R4.i and R5.i, respectively. The numerical code attached to both capital letters indicates the stage, and the lower case letters i or k indicate a number or a percentage. Key words: Natural sweetener, plant regrowth, anthesis, seed, seedling, transplant
Seeding date, row spacing, and weed effects on soybean isoflavone concentrations and other seed characteristics
Authors: Al-Tawaha A. M. , Seguin P.
Published: April 2011

Soybean [Glycine max (L.) Merr.] seeds contain isoflavones that may have positive impacts on human health. Field experiments were conducted in 2003/2004 in Québec, Canada to determine the effects of seeding date (late May and mid-June), row spacing (20-, 40- and 60-cm) and weeds (presence or absence) on soybean isoflavone concentrations and isoflavone yield. Total and individual isoflavone concentrations were determined by HPLC. Seed yield, and oil and crude protein (CP) concentrations were concurrently determined. Year, seeding date, and weeds affected total and individual isoflavone concentrations, while row spacing had no effect. Total isoflavone concentration was 84% greater in 2003 than 2004. Seeding in mid-June increased isoflavone concentration by 38%, compared with seed ing in May. The presence of weeds increased total isoflavone concentration by 9%. Year, row spacing, and weeds significantly affected seed yields. Seed yields were greatest in 2004, at 20- or 40-cm row spacing, and in the absence of weeds. Seeding date affected CP and oil concentrations. Greater CP concentration was observed with earlier seeding, the reverse was observed for oil. Weeds also affected CP and oil concentrations: higher CP and oil concentrations were observed in weedy and weed-free plots, respectively. Total isoflavone yield was affected by all factors evaluated. Isoflavone yield was greater in 2003 than 2004, with mid-June rather than late May seeding, when seeded at row spacing of 20- or 40- than 60-cm, and without weeds. Finally, negative correlations were observed between isoflavone concentrations and CP concentration and seed yield. It thus seems that certain agronomic practices may need to be tailored specifically to isoflavone production if concentrations in soybean are to be maximized. The negative correlations observed between isoflavone concentrations and other important seed characteristics warrant further research. Key words: Soybean, isoflavone, daidzein, genistein, glycitein, protein, oil, seed yield, weeds, row spacing, seeding date
The biology of Canadian weeds. 135. Lonicera japonica Thunb.
Authors: Larson Brendon M. H. , Catling Paul M. , Waldron Gerald E.
Published: April 2011

Japanese honeysuckle (Lonicera japonica Thunb.) is a twining semi-evergreen vine native to Japan, Korea and eastern China. Over the past 150 yr it has been introduced as an ornamental and become established in temperate and tropical regions worldwide. It was first discovered in Canada in 1976 in southwestern Ontario woodlands and has since been found growing without cultivation in 15 localities. While L. japonica does not occur very frequently in southern Ontario, climate change models suggest that it may become more abundant in this region. Its predominance elsewhere derives from morphological and physiological characteristics that allow it to be particularly successful in the edge habitats of fragmented landscapes. Through extensive vegetative propagation and competitive ability it occupies space which may otherwise host a diverse native flora. The plant has many uses in Asian medicine and is a popular ornamental, but has been prohibited in some regions due to its displacement of other species. A combination of cutting and foliar application of glyphosate has proven to be an effective control method in some circumstances. Planting of L. japonica should be discouraged and horticulturalists should consider alternative attractive vines. The spread of L. japonica should be monitored in Ontario and control of newly established populations should be considered to avoid costly large scale control in the future. Key words: Invasive species, Lonicera japonica, weed biology, climate change
Copper fertilizer practices in Manitoba
Authors: Goh T. B. , Karamanos R. E.
Published: April 2011

Soil testing criteria for copper (Cu) in Manitoba were established in the mid-1980s and were primarily based on growth chamber studies for a range of crop species. A multitude of Cu products and fertilizer placement methods are practiced with insufficient research in support of them. Hence, we attempted to develop agronomic and economic Cu fertilizer management practices for soils of Manitoba through a series of experiments for crop species at two locations with DTPA-extractable Cu levels of 0.12 and 0.25 mg kg-1 soil, respectively. These experiments involved broadcast and incorporation of CuSO4·5H2O (25% Cu), CuEDTA (7% Cu), and a low (<1%) and a high (>60%) water solubility Cu oxysulphate (12.5 and 12% Cu, respectively). Four rates of side-banded liquid CuEDTA (0, 0.28, 0.56 or 1.12 kg Cu ha-1) or seedrow-placed granular products (0, 1.12, 2.24 and 4.48 kg ha-1) as above, were either superimposed or were compared directly with broadcast and incorporation of the same rates. This study confirmed that DTPA extractable Cu levels of less 0.2 mg kg-1 soil are deficient, whereas DTPA-extractable Cu levels of greater than 0.2, but less than 0.4 mg kg-1 are marginal. Broadcast and incorporation of CuSO4·5H2O at rates as low as 2 kg Cu ha-1 or side banding of 0.28 to 0.56 kg Cu ha-1 of liquid CuEDTA provide maximum economic grain yield increases in soils with either deficient or marginal Cu levels. Seedrow applied granular Cu products may provide a maximum agronomic and economic yield increase only in soils with marginal soil Cu levels. Low solubility Cu products do not correct Cu deficiency, whereas CuEDTA, although agronomically equal to CuSO4·5H2O and high solubility oxysulphates, may have a disadvantage due to its high cost. Key words: Deficient, marginal, sulphate, oxysulphate, chelate, seedrow, side band, broadcast
Water use of some recent bread and durum wheat cultivars in western Canada
Authors: Wang H. , McCaig T. N. , DePauw R. M. , Clarke J. M. , Lemke R.
Published: April 2011

Recently developed cultivars of Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) and Canada Western Amber Durum (CWAD) (Triticum turgidum L. var durum) produced significantly more grain than older cultivars. This production was attributed to higher harvest indices and better water use efficiency. Durum cultivars and CWRS AC Intrepid and AC Barrie extracted relatively more soil water below 55 cm, which may be advantageous in minimizing leaching and related to drought tolerance during grain-filling. Key words: Hexaploid wheat, durum, water use, soil water
White mulch and a south facing position favour strawberry growth and quality in high latitude tunnel cultivation
Authors: Karhu S. T. , Puranen R. , Aflatuni A.
Published: April 2011

Polyethylene mulches with black or white surface were compared in seven strawberry (Fragaria × ananassa Duch.) genotypes in a 2-yr experiment. The plants were covered by an unheated walk-in tunnel at the beginning of the first harvest season. The effects of a south-west versus north-east position of plants within the double-row beds were also studied. Soil temperatures were higher under black mulch, especially mid-day temperatures on the bed surface in the southward position. White mulch favoured root and crown growth in the first year, and the southwest position increased plant growth in both years. With black mulch, lower carbohydrate reserves were observed after transplanting, and a decreased chlorophyll content of leaves was detected in the second year. Mulch colour did not affect yield quantity. The first-year harvest was advanced with black mulch, but in the second year, the harvest season was earliest on the south side of beds with white mulch. Black mulch decreased fruit size in the first year and the concentration of fruit soluble solids in both years. The results suggest that in northern latitudes white mulch improves strawberry plant growth and fruit quality over that obtained using black mulch, but enhanced yield is not to be expected when a double-row tunnel cultivation system is used. Key words: Fragaria × ananassa, mulch, plasticulture, polyethylene, strawberry, tunnel
Agassiz field pea
Authors: Bing Deng-Jin , Beauchesne Don , Sloan Al , Conner Robert , Gan Yantai , Vera Cecil , McLaren Debbie , Gehl David , Warkentin Tom , Chang Kan-Fa
Published: April 2011

Agassiz is a semi-leafless and powdery mildew resistant field pea (Pisum sativum L.) cultivar with yellow cotyledons, high seed yielding ability, good lodging resistance, round seed shape and medium seed size. It is adapted to field pea growing regions in western Canada. Key words: Field pea, Pisum sativum, cultivar description, yellow cotyledons
Common bunt resistance gene Bt10 located on wheat chromosome 6D
Authors: Menzies J. G. , Knox R. E. , Popovic Z. , Procunier J. D.
Published: April 2011

Knowledge of the chromosomal location of disease resistance genes assists in their identification and classification. The determination of the chromosomal location in wheat of the common bunt (Tilletia tritici and T. laevis) resistance gene Bt10 was the goal of this study. Doubled haploid lines were developed from a cross between bunt susceptible Glenlea and bunt resistant AC Taber carrying Bt10. The doubled haploid lines were inoculated with T. tritici race T19, grown in a growth room and rated for bunt near maturity. A series of 50 wheat microsatellite markers were tested on DNA of the individual lines. The population segregated 1:1 for bunt reaction with clear separation between resistant and susceptible classes. A trait related DNA polymorphism generated by gwm469 located in chromosome 6D fit a 1:1 segregation. Combined segregation of bunt resistance and the gwm469 polymorphism differed significantly from a 1:1: 1:1 ratio with a preponderance of parental types confirming linkage of gwm469 with Bt10. The map distance between gwm469 and Bt10was estimated at 19.3 cM by MAPMAKER. The microsatellite markers wmc749, barc54 and cfd0033, located on chromosome 6D, also were significantly associated with the bunt resistance and gwm469. In total, six markers previously located to chromosome 6D were in the linkage group with the Bt10 common bunt resistance. The linkage of these markers with each other and Bt10 indicated that Bt10 is located on the short arm of chromosome 6D. Key words: Tilletia tritici, Tilletia laevis, Triticum aestivum, wheat, microsatellite, doubled haploid
Antioxidant capacity in June-bearing and day-neutral strawberry
Authors: Khanizadeh Shahrokh , Ehsani-Moghaddam Behrouz , Levasseur Audrey
Published: April 2011

The present study was carried out to estimate the crude, hydrophilic and lipophilic antioxidant content of known and new advanced selections among June-bearing and day-neutral genotypes using Trolox equivalent antioxidant capacity method. Crude, hydrophilic and lipophilic extractions were prepared using 25 g of frozen fruits from each sample. In June-bearing strawberries, significant differences were observed among crude, hydrophilic and lipophilic antioxidant values of different selected genotypes. Mean of crude, hydrophilic and lipophilic antioxidants in June-bearings were estimated to be 20.4, 13.4 and 0.5 μmol TE g-1 FW, respectively, which were higher than those of the day-neutral genotypes (i.e., 13.2, 9.4 and 0.3 μmol TE g-1 FW). The present study revealed the importance of genetic background for determining the antioxidant potential in selected June-bearing genotypes and the possibility of production of new strawberry cultivars with higher levels of antioxidant capacity through breeding programs. Key words: Hydrophilic, lipophilic, total antioxidants, strawberry breeding, TEAC, Trolox
Water use of pulse crops at various plant densities under fallow and stubble conditions in a semiarid environment
Authors: Gan Y. T. , Wang J. , Bing D. J. , Miller P. R. , McDonald C. L.
Published: April 2011

Understanding water use characteristics of crops is essential for optimizing crop productivity in semiarid environments. This study determined water use (WU), water use efficiency (WUE), and postharvest residual soil water (PHRSW) of dry pea (Pisum sativum L.) and desi and kabuli chickpea (Cicer arietinum L.) at four plant densities under fallow and stubble cropping systems in a semiarid environment. Crops were grown in southwest Saskatchewan from 1998 to 2000. Chickpea used 28% more water than dry pea, while kabuli chickpea used 14% more water than desi chickpea only when grown on fallow at one of the sites. Pulses grown on fallow used 66% more water than when grown on stubble, with largest difference (48%) in WU between the two cropping systems being in the 60- to 90-cm soil depths. Overall, dry pea had the greatest WUE (12.9 kg ha-1 mm-1), followed by desi chickpea (7.3 kg ha-1 mm-1) and kabuli chickpea (6.6 kg ha-1 mm-1). Water use efficiency increased with increasing plant density for all the pulses, with dry pea showing a stronger response than chickpea. The PHRSW below the 60-cm depth differed significantly among pulses. Dry pea left an average of 33 mm available water at harvest, the desi left 20 mm, and the kabuli 13 mm. A deeper rooting crop grown after dry pea may benefit more from water conservation in the soil profile than when grown after chickpea under semiarid environmental conditions. Key words: Cicer arietinum, Pisum sativum, water use efficiency, rooting depth
Node and branch development of chickpea in a semiarid environment
Authors: Gan Y. T. , Wang J. , Poppy L. B.
Published: April 2011

Node development of a crop plant can be used as a reference in making crop management decisions such as timing foliar fungicide application. A study was conducted in southwest Saskatchewan in 2001 and 2002 to characterize the nodal development, branching, and thermal time requirements on the main stem (MS) and on the branches of chickpea (Cicer arietinum L.). Large (9.1–11.0 mm) and small (8.1–9.0 mm) diameter seeds were planted at early-, normal-, and late-seeding dates in each year, and the crop was grown with recommended agronomic practices. The MS nodes were numbered upwards from the plant base, with the 1st node being the one immediately above the hypocotyls. All branches were identified and named in correspondence with their positions on the MS. The total number of nodes produced on the MS was 20 in the dry year of 2001 and 24 in the wet year of 2002, and their appearance was a function of growing-degree-days (GDD). The rate of the branch development in 2001 was greater compared with 2002 due to higher temperatures during the vegetative growth period. On average, branches No. 1 and 2 required 40 to 50 GDD units to emerge from the MS, while the emergence of branches No. 5 and 6 required 80 to 120 GDD units. Nodes on the branches that were positioned on the upper stems required more GDD units to develop compared with nodes on the branches that were positioned at the bottom of the MS. To use node development as a reference for crop management decisions in chickpea, one should bear in mind that the GDD requirements vary with node and branch positions on the culm. Key words: Cicer arietinum, legume, plant architecture, foliar fungicide, morphology
Nitrogen utilization timeline of carrot over the growing season
Authors: Westerveld Sean M , McDonald Mary Ruth , McKeown Alan W
Published: April 2011

A timeline of nitrogen (N) dynamics of the carrot crop was developed based on studies on the effects of N application on carrot growth, N uptake and partitioning, and interactions with Alternaria [ALB; A. dauci (Kühn) Groves and Skolko] and Cercospora [CLB; C. carotae (Pass.) Solheim] leaf blight. Preplant-applied fertilizer N affects yield only when residual N in the top 60 cm of the soil profile is insufficient. The majority of the N required by the crop is taken up beyond 50 d after seeding (DAS). Carrots have a root system that extends to 150-cm depth and >50% of the fibrous root system occurs below 30-cm depth. It is likely that N below 30 cm depth is required beyond 50 DAS, since the majority of the fibrous roots are below 30 cm depth after that stage. There is insufficient time for sidedressed N to leach into the active root system beyond 50 DAS, unless its application is timed before irrigation or rain events. Regardless of the amount of residual N, preplant-applied N is essential for minimizing leaf blight severity. It is possible that leaf blight defences are conferred upon leaf emergence and may benefit from abundant N at this time. A preplant soil nitrate-N test from both the top 30 cm and the 30- to 60-cm depth could be useful for determining residual N levels and for adjusting N fertilizer application rates accordingly. Key words: Daucus carota, Alternaria leaf blight, Cercospora leaf blight, nitrogen uptake, rooting depth, fertilization
Fruit zone leaf removal influences vegetative, yield, disease, fruit composition, and wine sensory attributes of Vitis vinifera L. 'Optima' and 'Cabernet franc'
Authors: Staff S. L. , Percival D. C. , Sullivan J. A. , Fisher K. H.
Published: April 2011

The influence of fruit zone leaf removal treatments (0, 50, and 100%) on grapevine canopy structure, incidence of bunch rot (Botrytis cinerea Pers.:Fr.), yield components, fruit and wine composition and wine sensory attributes was studied on Vitis vinifera L. 'Optima' and 'Cabernet franc'. The 50 and 100% leaf removal reduced leaf layer number, percent interior leaves and percent interior clusters. Yield was reduced between 29 and 46%. Severity of bunch rot in Optima and incidence and severity for Cabernet franc were reduced by leaf removal. Leaf removal improved colour, aroma and palatability of both Optima and Cabernet franc wines. Key words: Botrytis cinerea, defoliation, canopy management
Factorial analysis of self-incompatibility in alfalfa
Authors: Campbell T. A. , He Y.
Published: April 2011

Self-incompatibility (seeds/pod and seeds/floret tripped) was evaluated in the growth chamber (27°C) using a 6 × 6 factorial arrangement. Parents represented a broad range of self-compatibility and were selected on the basis of stability of autogamous seed production in the greenhouse and growth chamber. Additive genetic variation appeared to be most important, indicating that a mass selection scheme such as recurrent phenotypic selection would be effective in increasing levels of self-incompatibility in at least some alfalfa populations. Narrow-sense heritability estimates for seeds/pod and seeds/floret tripped were 0.23 (SE = 0.09) and 0.28 (SE = 0.06), respectively. There is a direct relationship between autogamous seed production and pollen production, however, results of this experiment indicate that there may be considerable variation in pollen production, germination and vigor among self-incompatible clones. Increased seed set resulting from self-incompatible × self-incompatible crosses could be a function of greater gamete selection in the self-incompatible parents (due to deleterious genes), improved pollen germination, and hybrid vigor in pollen tube growth. Key words: Medicago sativa L., autogamy, allogamy, hybrid
Flax (Linum usitatissimum L.) responses to chilling and heat stress on flowering and seed yield
Authors: Gusta L. V. , O'Connor B. J. , Bhatty R. S.
Published: April 2011

The effect of a 5 °C chilling treatment at the seedling stage on days to flower, yield and oil quality and quantity was determined for seven cultivars of flax (Linum usitatissimum L.). Three days of chilling delayed flowering in Dufferin, McGregor and NorLin, whereas 5 d of chilling delayed flowering in all cultivars except Andro and Noralta. Seven days of chilling reduced the seed yield of only McGregor, Norlin, NorMan and Vimy. The effect of a 40 °C heat stress at the flowering stage on yield and oil composition was determined for the same seven cultivars. A heat stress of 40 °C for 3 d reduced the seed yield of NorMan, whereas, a 5 d stress reduced the seed yield of all cultivars except McGregor and Noralta. The composition of the oil was not affected by the heat stress. These results suggest genetic variability exists among flax cultivars for tolerance to chilling and heat stresses. Controlled tests can be used to select superior stress tolerant genotypes. Key words: Flax, chilling, heat, flowering, yield
Determination of the growth potential of strawberry plants (Fragaria × ananassa Duch.) by morphological and nucleotide measurements in relation to chilling
Authors: Robert Fabien , Pétel Gilles , Risser Georgette , Gendraud Michel
Published: April 2011

Early strawberry fruit production requires that non-dormant strawberry plants be covered during winter. Two methods were used to study the breaking of dormancy of Elsanta strawberry plants following chilling at temperatures below 8 °C. First, a morphological test using the petiole lengths of plants transferred from a nursery to a growth chamber was used. Second, the nucleotide contents before and after incubation of samples in an adenosine solution were measured by bioluminescence. The results show that these two methods can reveal changes in the growth potential of strawberry plants, and, therefore, the release from dormancy. Key words: Dormancy, strawberry plant, nucleotide, growth potential, Fragaria
The effect of hull removal and pearling on Fusarium species and trichothecenes in hulless barley
Authors: Clear R. M. , Patrick S. K. , Nowicki T. , Gaba D. , Edney M. , Babb J. C.
Published: April 2011

Fourteen samples consisting of three cultivars of hulless barley (Hordeum vulgare L.), grown commercially in southern Manitoba in 1994, were examined for levels of Fusarium species and seven fusarium trichothecene mycotoxins: deoxynivalenol (DON), diacetoxyscirpenol, 15-acetyldeoxyni-valenol (15ADON), fusarenone-X, HT-2 toxin, neosolaniol and T-2 toxin. Four fractions from each sample were analysed. These consisted of kernels with the hulls still attached, kernels whose hulls had been removed at harvest, kernels that had been dehulled in the laboratory using a deawner, and kernels that had been pearled in the laboratory to 60% of their original weight. A composite sample of the hulls, obtained from the laboratory dehulling, was also tested. Mycotoxins were determined by gas chromatog-raphy-mass spectrometry. DON and 15ADON were the only trichothecenes detected in this study. The greatest numbers of propagules of Fusarium spp. and the highest concentrations of DON and 15ADON were found in the hulls. The average concentrations of F. graminearum Schwabe and DON in barley were reduced: 90 and 49%, respectively, as a consequence of laboratory dehulling; 95 and 59%, respectively, as a result of dehulling during harvest; and 99 and 86%, respectively, as a result of pearling. Results suggest that growing hulless cultivars shows promise for management of mycotoxin problems associated with FHB. Key words: Fusarium graminearum, Fusarium poae, Fusarium avenaceum, deoxynivalenol, 15-acetyldeoxynivalenol, fusarium head blight
Sowing date and photoperiod effects on leaf appearance in field-grown wheat
Authors: Hotsonyame G. K. , Hunt L. A.
Published: April 2011

Rate of leaf appearance is a characteristic that can impact on the rate of development of a crop canopy. For wheat (Triticum aestivum L.), it is generally thought to be constant within a sowing date, but to vary among sowing dates. Such variation has been variously attributed to differences in the rate of change of photoperiod, the absolute photoperiod, or the mean air temperature. This study was undertaken to provide further information on the photoperiod and temperature effects on rate of leaf appearance in wheat. Field studies were conducted at Elora, Ontario at five sowing dates under natural and extended (20 h) photoperiod conditions. Two genotypes each of spring and winter wheat were grown under 0 and 150 kg ha−1 nitrogen fertilization. The results indicated that variations in rate of leaf appearance were not due to rate of change in photoperiod or absolute photoperiod at emergence. The change in rate of leaf appearance during a growth cycle was constant when mean air temperature during growth varied in a narrow range (less than 10 °C), but varied when there were wider ranges (over 10 °C) of temperature variation. Rate of leaf appearance was lower for the September seeding, at which time temperatures were around 5 °C, but were quite similar for May, June, July and August seedings even though temperatures ranged from approximately 15 °C (May) to 23 °C (June). The results suggested that the leaf appearance rate–temperature response curve is curvilinear, as found in some growth room studies, and supported work indicating that the phyllochron would depend on the temperature at the time of measurement. Key words: Wheat, photoperiod, temperature, nitrogen, sowing date, leaf appearance rate
AC Gayed flue-cured tobacco
Authors: Brandle J. E. , Rogers W. D. , Ankersmit J. C. D.
Published: April 2011

AC Gayed is a flue-cured tobacco (Nicotiana tabacum) cultivar bred at the Pest Management Research Centre of Agriculture and Agri-Food Canada. It is a a black root rot (Chalara elegans) resistant, backcross derivative of Delgold (ST205/PB19//*5 Delgold) (Pandeya and White 1984). The resistance gene originated from Nicotiana debneyi. AC Gayed is adapted to the tobacco production areas of Ontario. It has similar grade index, but slightly lower yield than Delgold when grown in disease-free conditions. Key words: Nicotiana tabacum, black root rot resistance, backcross
Achiever soybean
Authors: Voldeng H. D. , Guillemette R. J. D. , Leonard D. A. , Cober E. R.
Published: April 2011

Achiever is a 2750 heat unit soybean (Glycine max [L.] Merr.) cultivar with good yield potential. Key words: Soybean, cultivar description
Mapping risk areas for resistance to ACCase inhibitor herbicides in Manitoba
Authors: Bourgeois Luc , Morrison Ian N.
Published: April 2011

Since 1976, seven acetyl coenzyme-A carboxylase (ACCase) inhibitors (referred to as Group 1 herbicides) have been registered in western Canada for wild oat (Avena fatua L.) and green foxtail (Setaria viridis L.) control. In 1990, Group 1 resistant wild oat populations were identified from fields in Manitoba which had been repeatedly sprayed with these products during the previous 10 yr. Since the occurrence of resistance is directly related to the frequency of herbicide use, the purpose of this study was to compile herbicide use histories on a province-wide basis using data included in the Manitoba Crop Insurance Corporation (MCIC) database. The database was used to determine the relative importance of Group 1 herbicide use in major crops compared with other products, and to identify individual townships at low, medium and high risk for developing Group 1 resistance. Low, medium and high risk townships were arbitrarily defined as those in which Group 1 products were used on less than 30%, on 30 to 50% and on more than 50% of the sprayed fields, respectively. From 1981 to 1993, Group 1 herbicide use increased from 15 to 50% of the sprayed area, and since 1990, these products have been used on one out of two sprayed fields on an annual basis, with the most intensive use in flax. In the early 1980s, fewer than 5% of the townships were at high risk. These were located near the towns of Swan River, Dauphin and Treherne, and the city of Winnipeg, which were the locations where Group 1 resistant wild oat and green foxtail were first identified. Between 1989 and 1993, more than 40% of the townships were considered to be at high risk. Should the trend toward increased use of Group 1 herbicides continue through the 1990s, the resistance problem will inevitably worsen. Key words: Herbicide use, selection, herbicide rotation
Production of rainfed and irrigated crops under different crop rotations and input levels in southwestern France
Authors: Debaeke P. , Hilaire A.
Published: April 2011

Crop production in southwestern France is primarily limited by water availability. This long-term research was conducted to evaluate the performance of 9 rainfed and irrigated crops grown under 10 crop rotations. Increasing levels of management inputs (e.g., water and fertilizer) were applied to barley (Hordeum polystichum L.), corn (Zea mays L.), faba bean (Vicia faba L.), pea (Pisum sativum L.), rapeseed [Brassica napus L. ssp. oleifera (Metzg.) Sinsk], wheat (Triticum aestivum L.), sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max. (L.) Merrill)], and sunflower (Helianthus annuusL.) from 1984 to 1992 on a deep silty clay loam. Two or three management alternatives were applied to each crop rotation during 9 yr; they were defined at the crop level by an expected grain yield and a consistent combination of crop management factors (planting date, crop density, N-P-K fertilization, irrigation, and pesticides). Under irrigated management, corn, sunflower and soybean responded markedly to increased levels of inputs while sorghum did not respond significantly. In summer crops (corn, sorghum, sunflower), the intensification of inputs was generally ineffective under non-irrigated conditions. In winter wheat, grain yield increased with input levels but differential responses were observed with crop rotation. Variability in yield from year-to-year was reduced with irrigation. We concluded that low-input rainfed and medium-input with limited irrigation are productive agronomic systems for deep soils in southwestern France. Key words: Input level, crop rotation, irrigation
Are there economic benefits of accessing forage in wolf plants of crested wheatgrass?
Authors: Romo J. T. , Tremblay M. E. , Barber D.
Published: April 2011

Wolf plants are common in many crested wheatgrass [Agropyron desertorum (Fischer ex Link) Schultes] pastures, and they represent an inefficient use of forage. The objective of this study was to determine costs and benefits of improving management to exploit the forage in wolf plants. Predictors of the forage left ungrazed in wolf plants (unused residual forage) and economic costs and benefits of improving management to make this forage available to grazing animals were determined using 40 site-years of data from southern and central Saskatchewan. Economic analyses were completed for management practices including: 1) no control of wolf plants, i.e. status quo grazing management; 2) no improvement in grazing management, but the forage is swathed and baled every 5, 10, or 15 yr; 3) burning at 5, 10, or 15-yr intervals, but grazing management is not changed, and; 4) swathing and baling hay once, followed by intensified grazing management involving cross-fencing of the pasture with a four-strand barbed wire or a single-strand electric fence. Unused residual forage in wolf plants averaged 417 kg ha−1 (SE = 7.5) and was correlated (R2 = 0.75, P ≤ 0.001) with total standing crop of wolf plants. On average about 41% of the total standing crop in wolf plants was unused residual forage. Density of wolf plants and dead standing crop were also significantly correlated (P ≤ 0.001) with unused residual forage in wolf plants; however, R2 values of 0.12 and 0.41 suggest that they are not actually strong predictors. Swathing and baling the crested wheatgrass every 5, 10 or 15 yr is economically feasible when unused residual forage in wolf plants averages about 200, 100 and 50 kg ha−1, respectively, whereas burning at the same intervals is profitable when unused residual forage exceeds about 400, 200 and 100 kg ha−1. Results of this research clearly show that substantial amounts of unused residual forage are present in pastures of crested wheatgrass that are dominated by wolf plants. Wolf plants are indicators of poor grazing management and potential economic loss. Management that encourages more uniform and complete use of this unused residual forage is economically beneficial in most situations. Key words: Agropyron desertorum (Fischer ex Link) Schultes, economic analysis, grazing management, pasture management, range improvements
Growth analysis of timothy grown with varying N nutrition
Authors: Bélanger G. , Richards J. E.
Published: April 2011

Nitrogen fertilization increases yield of timothy (Phleum pratense L.) but little knowledge exists on the effect of N fertilization on the growth processes of field-grown timothy. The objective of this study was to analyze the growth of timothy fertilized with increasing rates of N in spring and summer and, in particular, to determine the relative importance of radiation interception and radiation-use efficiency in explaining the differences in shoot growth caused by N deficiency. In two separate experiments conducted in spring 1993 and summer 1994, shoot growth, leaf area development, radiation interception and radiation-use efficiency of timothy grown with four N rates (0, 70, 140 and 210 kg N ha−1 in 1993; 0, 60, 120 and 180 kg N ha−1 in 1994) were determined using weekly sampling. Maximum leaf photosynthesis was also measured. The maximum shoot growth and LAI were reached with 140 kg N ha−1 in the spring of 1993 and 120 kg N ha−1 in the summer of 1994. The rates of N fertilization required to produce these maximum values of shoot growth were those that resulted in shoot N concentration equal to or greater than the optimal N concentration. The concept of an optimum N concentration was therefore useful in identifying situations of N deficiencies. When no N was applied, the growth rates were 32 and 33% of the maximum growth rates in spring and summer, respectively. The impact of the N deficiency was greater on RUE than on cumulative intercepted PAR. When no N was applied, the RUE and cumulative intercepted PAR were respectively 45 and 61% of their maximum values in spring, and 52% and 80% of their maximum values in summer. A general and synthetic expression of the effect of crop N concentration on shoot growth was developed using the concept of an optimal N concentration. Key words: Phleum pratense L., timothy, growth, radiation, photosynthesis, nitrogen
Will low-glucosinolate cultivars of the mustards Brassica juncea and Sinapis alba be vulnerable to insect pests?
Authors: Bodnaryk Robert P.
Published: April 2011

Foliar concentrations of the predominant glucosinolates in the mustards B. juncea (allyl glucosinolate, sinigrin) and S. alba (p-hydroxybenzyl glucosinolate, sinalbin) were determined in lines that had been selected in breeding programs for low levels of glucosinolates in their seeds for the oilseed market. The glucosinolate concentrations found in the cotyledons and leaves of the selected lines were also low, often by three or more orders of magnitude, compared with the unselected parent. The flea beetle, Phyllotreta cruciferae Goeze, and the diamondback moth, Plutella xylostella (L.), (both crucifer specialists) fed at equal rates on B. juncea and its low-glucosinolate lines, indicating that these species are insensitive to sinigrin and suggesting that their pest status on low-glucosinolate lines of B. juncea will likely remain unchanged. By contrast, the bertha armyworm, Mamestra configurata Wlk. (a generalist) fed up to fivefold more on the leaves of low-glucosinolate lines, suggesting that its pest status on low-glucosinolate B. juncea is likely to worsen relative to the mustard B. juncea. Flea beetles, diamondback moth, and the bertha armyworm fed at equal rates on the mustard S. alba and a low-glucosinolate line indicating that the status of these pests on low-glucosinolate S. alba will unlikely be much different from the mustard S. alba.Lines of S. alba differing in their sinalbin concentration by 1000-fold had equal levels of antixenosis resistance in their cotyledons against flea beetles, leaving little doubt that this resistance is independent of glucosinolates. Flea beetle resistance was also detected in the cotyledons of a low-glucosinolate line of B. juncea. The resistance was not detected in the parental line or in another low-glucosinolate line and appears to have arisen fortuitously during crossing and selection. Since resistance occurs in a line with concentrations of sinigrin three or more orders of magnitude lower than non-resistant lines, this resistance is also unlikely to be glucosinolate based. The mustards S. alba and B. juncea are a useful source of cotyledon resistance against flea beetles that is compatible with the aims of oilseed breeding. Key words: Glucosinolate, Brassica juncea, Sinapis alba, Phyllotreta cruciferae, Plutella xylostella, Mamestra configurata, resistance, mustard, canola, insect
Early corn seedling growth response to acetic, propionic and butyric acids
Authors: Janovicek K. J. , Vyn T. J. , Voroney R. P. , Allen O. B.
Published: April 2011

Corn (Zea mays L.) responses to crop rotation, tillage practice and/or plant residue placement may be due to differential production of acetic, propionic and butyric acids which are associated with the anaerobic decomposition of plant residues. To evaluate early corn growth response to acetic, propionic and butyric acids, a series of bioassays was conducted in which seeds of three commercially available corn hybrids, Pioneer 3737, Pioneer 3949 and Hyland 2260, were germinated and allowed to develop in solutions containing these acids alone or in combination at four concentrations (1.0 ×10−4 M, 1.0 × 10−3 M, 5.0 ×10−3 M, and 1.0 × 10−2 M) which were adjusted to two solution pH levels (4.5 and 7.5). None of the acids or acid mixtures tested affected seed germination. However, all three acids inhibited corn radicle growth. The magnitude of inhibition was butyric > propionic > acetic. Reducing solution pH tended to increase the degree of radicle growth inhibition. Particularly with propionic and butyric acids, the extent of radicle growth inhibition was affected by hybrid. Results indicated early corn growth inhibition associated with these acids is affected by acid type, acid concentration, solution pH and corn hybrid. Key words: Allelopathy, acetic, propionic, butyric, corn, hybrid response
Extract viscosity of winter rye: Variation with temperature and precipitation
Authors: Gan Y. T. , McLeod J. G. , Scoles G. J. , Campbell G. L.
Published: April 2011

Winter rye (Secale cereale L.) is well adapted to the Canadian prairies and rye grain with low extract viscosity (EV) may become an important component in animal diets. Information on how environmental factors affect EV is needed for facilitating the selection of low EV materials and production of low EV grain. Eleven winter rye genotypes were grown in thirteen environments on the Canadian prairies. The grain was studied to determine the effects of precipitation and growing degree-days on EV. The amount of precipitation that plants received 5 wk immediately after heading (P5wk) was closely associated with EV (r = −0.62 to −0.76). Growing degree-days accumulated in 5 wk after heading (GDD5wk) had a smaller but significant (P < 0.05) association to EV (r = 0.34 to 0.61). EV was not correlated with temperature or precipitation during the periods from planting to heading or the whole growing season. For all genotypes tested, EV decreased rapidly with increase of P5wk when P5wk was below 140 mm. When P5wk was greater than 140 mm, the response of EV to P5wk was reduced. Genotypes were significantly different in the response of EV to P5wk; the rate of change in EV with P5wk was greater for some genotypes than for others as indicated by regression slopes. For example, the genotype RT-150 had a regression slope five times greater than that of the genotype G-66S. Our study indicates that the critical growth stage when EV can be affected was after plant heading and that the amount of precipitation that plants receive during the period of 5 wk after heading can be used to predict the relative viscosity level for rye grown in different environments. Key words: Secale cereale, extract viscosity, pentosans, rainfall, degree-days, regression
Mixtures of Persian clover with Italian ryegrass or barley-Italian ryegrass for annual forage
Authors: Thompson Donald J. , Stout Darryl G.
Published: April 2011

In the interior of British Columbia, spring barley (Hordeum vulgare L.) and Italian ryegrass (Lolium multiflorum var. italicum Beck.) are intercropped with fertilizer N as a 1-yr break before reseeding irrigated alfalfa (Medicago sativa L.). Persian clover (Trifolium resupinatum L.) was seeded with barley and ryegrass or only ryegrass to determine its effect on seasonal yield and forage nutritive value. All species mixtures were grown with and without a total of 200 kg ha−1 of N to compare N2 fixation by Persian clover with N fertilizer. Averaged over 2 yr, adding Persian clover to barley-ryegrass provided a total yield that was 96% of that obtained by adding fertilizer N to barley-ryegrass. Second cut yield averaged 58% more with clover than with N. However, the grasses yielded more than the grasses with added clover in the third cut. Adding clover to ryegrass provided 94% of the total yield of adding N fertilizer. Persian clover was higher in crude protein and in vitro digestibility of dry matter than ryegrass, so adding clover tended to improve the nutritive value of mixtures. This was most obvious without N, where Persian clover accounted for more of the total forage produced. The study shows that Persian clover is a valuable addition to barley-ryegrass mixtures; it reduces fertilizer needs, improves mid-season yield and improves forage nutritive value. Key words: Persian clover, barley, Italian ryegrass, forage mixtures
Nitrogen contribution of field pea in annual cropping systems. 2. Total nitrogen benefit
Authors: Beckie H. J. , Brandt S. A. , Schoenau J. J. , Campbell C. A. , Henry J. L. , Janzen H. H.
Published: April 2011

The total nitrogen (N) benefit of field pea (Pisum sativum) to a succeeding non-legume crop was measured in a small plot experiment at Scott, Saskatchewan in the moist Dark Brown soil climatic zone, and in a small plot and landscape experiment near Melfort, Saskatchewan in the moist Black soil climatic zone from 1993 to 1995. The total N benefit was calculated as the difference in net N mineralized from soil plus N in the above- and below-ground crop residue between field pea and non-legume stubble-cropped plots over the growing season. Landscape slope position did not affect the total N benefit of field pea to a succeeding wheat crop, and preseeding tillage had an inconsistent effect on the total N benefit between years. The direct N benefit of field pea aboveground residue available to the succeeding crop in the landscape experiment was a minor component of the total N benefit, which averaged 25 kg N ha−1. The total N benefit was equivalent to the N residual effect, defined as the amount of fertilizer N required for a non-legume crop grown on non-legume stubble to achieve the same yield as that of the non-legume crop on field pea stubble. This confirms that the N residual effect of field pea to the succeeding non-legume crop was due to the N contribution; any non-N contribution to the N residual effect was effectively excluded. Key words: Pisum sativum, Triticum aestivum, Hordeum vulgare, Brassica rapa, Linum usitatissimum, total nitrogen benefit