bluuebunny/crossref_metadata_2025 huggingface dataset:
DISTANCE FROM POLLEN SOURCE AND YIELDS OF MALE STERILE SUNFLOWER AND SORGHUM
Authors: ROBINSON ROBERT G.
Published: March 2010

Efficient production of hybrid sunflower (Helianthus annuus L.) and sorghum (Sorghum bicolor (L.) Moench) seed requires a minimum but adequate proportion of the land for pollinator rows and that the male sterile and pollinator rows accommodate production machinery. The objective of this research was to determine the effect of distance from pollen source on male sterile seed yield and if presently used ratios of male sterile to pollinator rows could be increased without reduction in seed yield of the male sterile parent from the land area occupied by both parents. Seed was harvested from male sterile rows located from 1 (76 cm) to 40 (30 m) rows from the pollen source. Correlations and regression analyses showed that yield per row declined linearly with distance from the pollinator rows. However, yield of the male sterile parent per hectare of area occupied by both parents was increased by including up to at least six male sterile and two pollinator rows per strip. Male sterile to pollinator row ratios of 12:1 for sunflower and 7:1 for grain sorghum did not differ significantly from the commonly used 3:1 ratio in yield of male sterile parent per hectare of area occupied by both parents.Key words: Helianthus annuus L., Sorghum bicolor (L.) Moench, hybrid seed production, plant breeding
EVALUATION OF PLANT TISSUE CRITERIA FOR PREDICTING MANGANESE DEFICIENCY IN OATS
Authors: KARAMANOS R. E. , KRUGER G. A. , HENRY J. L.
Published: March 2010

The Mn status of oat (Avena sativa L. ’Harmon’) plants grown on an organic soil in a field study was assessed using three plant criteria: whole plant samples when the first node of stem is visible at the base of shoot (FEEKES 6), whole plant samples when the sheath of the last leaf was completely extended and the ear was swollen but not yet visible (FEEKES 10), and just the flag leaf at FEEKES 10. The critical Mn levels corresponding to a 10% yield reduction were 16, 9 and 10 μg∙g−1 dry matter, respectively. Of these, the level of Mn in the whole plant at FEEKES 10 was the most accurate plant indicator of grain yield. However, correction of Mn deficiency by foliar application of Mn at FEEKES 10 was not as satisfactory as at FEEKES 6.Key words: Mn deficiency, oats (Avena sativa L.), organic soils, plant analysis, critical deficiency levels
EVALUATION OF FACTORS AFFECTING YIELD REDUCTION IN MATURE ALFALFA (Medicago sativa L.)
Authors: JONES E. R. , SWAIN R. H. , BELL K. W. , CARROLL R. B.
Published: March 2010

Alfalfa (Medicago sativa L.) stand longevity continues to be a problem even though progressive management practices are followed. The following parameters were evaluated on mature alfalfa stands to determine what factors were responsible for stand thinning: forage production, stand density, foliar and crown-root diseases, root and crown tissue weights, and total nonstructural carbohydrate levels. Foliar diseases did not affect stand density; however, three of five anthracnose-resistant cultivars had denser stands than susceptible parents. Fusarium infection was quite high but did not appear to be related to stand density. Individual root weight, root mass, and total nonstructural carbohydrates were not good indicators of stand density.Key words: Alfalfa stand longevity, foliar diseases, crown and root rot, root and crown tissue weight, total nonstructural carbohydrates, forage production
A FIELD TEST FOR ASSESSING THE WINTER HARDINESS OF ALFALFA IN NORTHWESTERN CANADA
Authors: McKENZIE J. S. , McLEAN G. E.
Published: March 2010

A procedure is described for separating differences in winter hardiness among alfalfa (Medicago sativa L.) cultivars under field conditions. The procedure depends upon two factors associated with winterkill in northern Alberta during the 1977–1978 winter, namely, low food reserves in the crowns resulting from improper cutting management plus cold stress due to lack of snow in early winter. To induce these conditions we recommend that year-old plants be clipped in mid-June, late July and early September and that snow be removed once from the plot during early winter on the first day that air temperatures below −30 °C are forecasted. Natural snow fall can protect the plot for the remainder of the winter. If soil temperatures do not drop close to the range of the LT50 of the control cultivars, snow cover may be removed again provided air temperatures are below −30 °C. Cultivar rankings for winter hardiness following severe stress induced by snow removal were significantly correlated (r = 0.944**) with the mean survival observed at five locations following natural winter stresses in this region. Although additional work is warranted, the induced stress procedure has real merit in screening winter-hardy genotypes in the field and in assessing management techniques to reduce the effects of stressful winter environments on alfalfa production in northwestern Canada.Key words: Alfalfa, winter hardiness, field test, snow removal, frequent clipping
INFLUENCE DES CULTIVARS ET DES STADES DE CROISSANCE SUR LE RENDEMENT EN MATIERE SECHE ET LA COMPOSITION CHIMIQUE DE FOURRAGES D’AVOINE IMMATURE
Authors: GERVAIS PAUL
Published: March 2010

The forage yields and the detailed chemical composition of six cultivars of oats harvested at the vegetative stage (three cuttings during the growing season to simulate grazing) and at the heading and dough stages (one cutting for silage) were established over a period of 3 yr. No significant difference in the dry matter yields of the cultivars was found within any of the three stages of growth. Highly significant increases in the yields, however, were recorded with advance in maturity from 4210 kg/ha at the vegetative stage to 6754 kg at heading and 9219 kg at dough stage. Likewise, the percent dry matter increased progressively from 12% to 19% to 33% for the same stages. In general, the organic and mineral compositions of the cultivars did not vary significantly within any stage of growth, but were influenced by the age of the tissues. The total digestible nutrient, the crude protein, the cell contents and the mineral elements Ca, P, K, Mg, Na, Zn and Fe decreased while the nitrogen-free extract, the cell walls, the lignin and the hemicellulose increased from the vegetative to the dough stage. The other constituents exhibited a less defined pattern or remained relatively stable from one stage to another.Key words: Yields, chemical composition, stages of growth, cultivars, forage oats
EFFECTS OF N, P, K, B AND LIME ON STRAWBERRY YIELDS
Authors: CUTCLIFFE J. A. , BLATT C. R.
Published: March 2010

Experiments were conducted to investigate the effects of applications of N, P, K, B and dolomitic limestone on yields of strawberry (Fragaria × ananassa Duch ’Redcoat’). Yields were increased by applied N and P, but were not affected by added potassium or boron. Second crop yields were increased by a greater extent than first crop yields by both N and P. First crop yields were increased by a pre-planting application of dolomitic limestone on a sandy loam soil with initial pH of 4.9. Leaf tissue concentrations at full bloom of 1.4–3.2% N, 0.17 to 0.34% P, 0.7 to 1.6% K, and 26–57 ppm B appear to be in the sufficiency range for the cultivar Redcoat. The concentrations of these elements in strawberry leaf tissue were lower after harvest than at full bloom.Key words: Strawberry fertility, leaf tissue concentration
THE EFFECT OF SEED MATURITY, STORAGE ON THE SOIL SURFACE, AND BURIAL ON SEEDS OF Thlaspi arvense L.
Authors: HUME L.
Published: March 2010

The development and germination of immature stinkweed (Thlaspi arvense L.) seeds were investigated under greenhouse and field conditions. In the greenhouse test, there was nearly 100% germination of seeds with a maturity of 15–16 days after anthesis. Seeds from clipped plants buried at 8 cm for 2–5 wk were lighter in weight than either seeds from plants clipped and stored on the soil surface or seeds collected immediately after clipping. Storage conditions influenced both seed coat color and dormancy. Mature seeds from plants stored on the ground turned dark reddish brown, while those from plants stored under the soil turned black. Storage under either set of conditions decreased the dormancy of stinkweed seeds compared to the controls. The more mature seeds from the field-grown populations were more dormant than those from plants grown in the greenhouse, and had slower germination rates. Immature green seeds only 6 days past anthesis were capable of germinating and producing seedlings. It is suggested that for control of stinkweed plants, cultivation should be carried out within 6 days following anthesis of the first stinkweed flowers.Key words: Immature seeds, stinkweed, dormancy
CANADA THISTLE SUPPRESSION AND RAPESEED TOLERANCE WITH DICAMBA AND PICLORAM
Authors: O’SULLIVAN P. A. , KOSSATZ V. C.
Published: March 2010

Field experiments were conducted over a number of years to determine the effectiveness for Canada thistle (Cirsium arvense (L.) Scop.) control and tolerance of rapeseed (Brassica campestris L. and Brassica napus L.) to various rates of dicamba (0–140 g/ha) and picloram (0–110 g/ha). Dicamba at 70 g/ha and picloram at 20 g/ha provided about 60% and 50%, respectively, reduction in the dry weight of shoots of Canada thistle growing in Candle rapeseed. This degree of suppression did not result in increases in rapeseed yield over the untreated check. Flower formation in Canada thistle was prevented by all rates of dicamba and picloram tested. In tolerance experiments the yield of Candle rapeseed was not reduced with dicamba applied at rates up to 70 g/ha at the two-, four- or six-leaf stages, but yields were reduced at higher rates. Picloram applied at rates up to 70 g/ha did not reduce the yield of Candle rapeseed. Altex yields were reduced with 40 g/ha and higher rates and Regent yields were reduced with picloram applied at 70 g/ha at the six-leaf stage. The data indicate that dicamba at 70 g/ha and picloram at 20 g/ha may selectively suppress the growth of Canada thistle in rapeseed and reduce the spread of this weed through seed or vegetative means while maintaining some rapeseed yield from the treated areas of a field.Key words: Canada thistle control, canola, dicamba, picloram, rapeseed tolerance
MICMAC BARLEY
Authors: STERLING J. D. E. , JONES R. W. , WALTON R. , LANGILLE J. E. , DUPUIS B. , BUBAR J. S.
Published: March 2010

Micmac is a two-rowed, feed quality, spring barley (Hordeum vulgare L.) with high yield, early maturity, and good kernel and threshing characteristics. It is well adapted to Eastern Canada. Breeder seed of the cultivar is maintained by the Agriculture Canada Research Station, Charlottetown, Prince Edward Island.Key words: Hordeum vulgare L., spring barley, cultivar description
ARCOLA DURUM WHEAT
Authors: KNOTT D. R.
Published: March 2010

Areola is an early maturing durum wheat (Triticum turgidum L.) of medium height and strength of straw. It has yielded well in the Black soil zones of eastern Saskatchewan and Manitoba and has good pasta-making quality.Key words: Cultivar description, durum wheat, Triticum turgidum
CONTROL OF WILD OATS IN WHEAT WITH BARBAN, DICLOFOP METHYL, FLAMPROP METHYL AND DIFENZOQUAT
Authors: KIRKLAND K. J. , O’SULLIVAN P. A.
Published: March 2010

The efficacy of diclofop methyl, flamprop methyl, difenzoquat, and barban on wild oats (Avena fatua L.) in wheat (Triticum aestivum L.) was tested in the field at Scott and Lacombe from 1978 to 1982. The four herbicides were applied at recommended rates and growth stages. Diclofop methyl consistently caused the greatest reduction in wild oat culms and plant weights and resulted in the largest wheat yield increases. Diclofop methyl, flamprop methyl and difenzoquat consistently produced yield increases over the untreated control.Key words: Wild oats, wheat, barban, diclofop methyl, flamprop methyl, difenzoquat
HARROW JUBILEE CUCUMBER
Authors: NUTTALL V. W. , BONN W. G.
Published: March 2010

Harrow Jubilee is a white-spine, gynoecious, F1 hybrid pickling cucumber (Cucumis sativus L.) developed for the processing trade. It is highly tolerant to angular leaf spot and cucumber mosaic virus and resistant to scab. The main features of Harrow Jubilee are good productivity, shape and color, and excellent fresh and salt-stock quality.Key words: Cultivar description, cucumber
EFFECT OF TRIFLURALIN AND METRIBUZIN ON FABA BEAN GROWTH, DEVELOPMENT, AND SYMBIOTIC NITROGEN FIXATION
Authors: BERTHOLET J. , CLARK K. W.
Published: March 2010

Field studies were conducted to determine if trifluralin [α,α,α-trifluro-2,6,-dinitro-N,N-dipropyl-p-toluidine] and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-a5-triazin-5(4H)one] affect the growth and nitrogen self sufficiency of faba bean (Vicia faba L.). Metribuzin applied at 0.42 kg/ha as a pre-plant incorporated treatment resulted in substantial crop injury in 1981. Compared to the inoculated control, overall reductions averaged over the entire growing season, in plant dry weight, nodule dry weight, nitrogenase activity, and yield due to metribuzin were 59, 85, 92, and 65%, respectively. In 1982 metribuzin at 0.4 kg/ha was not as phytotoxic. Averaged over the season, the reductions recorded in plant dry weight, nodule dry weight, nitrogenase activity, and yield were 25, 33, 49, and 9%, respectively. The differences in phytotoxicity in the 2 yr at the two sites were attributed to differences in soil organic matter, and both the degree and timing of rainfall. During both years trifluralin did not cause any significant reductions in the parameters investigated. Reductions in nodulation and nitrogen fixation as a result of metribuzin application were evident only when the crop was injured and the plants were under stress from herbicide application. Trifluralin at 1.1 kg/ha reduced the phytotoxicity caused by metribuzin when the two chemicals were tank mixed. In 1981 there was a 23% yield improvement with the tank mix compared to metribuzin applied alone. In 1982, non-significant decreases in phytotoxicity with the tank mix were evident for the parameters studied. This reduced phytotoxicity may be explained on the basis of lateral root inhibition attributable to the trifluralin in the tank mix as was evident in the growth room study. The tank mix of trifluralin and metribuzin at 1.1 and 0.4 kg/ha, respectively, caused a 56% reduction in total root length compared to the inoculated control one week after emergence. Conversely, the total root length of the plants receiving only the 0.4 kg/ha rate of metribuzin did not differ significantly from the control. This may allow for greater herbicide uptake in the plants treated with only metribuzin leading to a greater level of injury.Key words: Faba bean, growth, symbiotic nitrogen fixation, trifluralin, metribuzin
VERNALIZATION AND PHOTOPERIOD RESPONSE CHARACTERISTICS OF A RECIPROCAL SUBSTITUTION SERIES OF RESCUE AND CADET HARD RED SPRING WHEAT
Authors: MAJOR DAVID J. , WHELAN E. D. P.
Published: March 2010

A reciprocal substitution series between Rescue and Cadet hard red spring wheats was used to identify chromosomal differences for vernalization response, basic vegetative phase, and photoperiod sensitivity. A greenhouse technique was used to provide estimates of these variables. Genes affecting vernalization were found on chromosomes 2A, 5A and 5B. Chromosomes 2A and 5B also affected the length of the basic vegetative phase. A gene on chromosome 3B affected photoperiod sensitivity.Key words: Day length, Triticum aestivum L., basic vegetative phase
COOKING QUALITY OF FIELD PEA MATURED UNDER VARIOUS ENVIRONMENTAL CONDITIONS
Authors: GUBBELS G. H. , CHUBEY B. B. , ALI-KHAN S. T. , STAUVERS M.
Published: March 2010

The yellow-seeded field pea (Pisum sativum L. ’Century’) was grown in the field in a 4-yr study to determine the effect of maturation conditions on cooking quality. Treatments included different seeding dates and cutting of the vines at soil level at different stages of maturity. Separate observations were made on pea seeds from different locations on the vines. The results were related to weather conditions during maturation. Later seeding and cutting of vines before full maturity resulted in lower yield, lower 1000-seed weights and poorer cooking quality. Pod location at the top of the plant, abnormally warm, sunny weather during seed maturation and abnormally cool, cloudy weather with severe mildew infection during seed maturation also were associated with lower 1000-seed weights and poorer cooking quality.Key words: Field pea, cooking quality, maturation conditions
COLD HARDINESS IN Triticum AND Aegilops SPECIES
Authors: LIMIN A. E. , FOWLER D. B.
Published: March 2010

A total of 237 Triticum and Aegilops accessions were cold-acclimated and screened for cold hardiness. These included 90 A genome accessions (T. monococcum L. and T. beoticum Boiss.), 26 AG genome accessions of T. timopheevi (Zhuk.) Zhuk., 44 D genome accessions of Ae. squarrosa L., and 77 accessions made from 22 Aegilops species. The greatest degree of cold hardiness was found in the polyploid Aegilops species; particularly Ae. cylindrica Host (CD genome). One Ae. cylindrica accession was equal to the hardy winter wheat cultivar Norstar (T. aestivum L., ABD genome). Triticum timopheevi accessions possessed only poor levels of cold hardiness. Two of the diploid progenitor species of common wheat, T. monococcum and Ae. squarrosa, had poor to intermediate levels of cold hardiness. The D genome species was, on average, more hardy than the A genome species. Several polyploids have achieved a level of cold hardiness greater than that found in any of the diploid species. It is speculated that these hardiness levels have been achieved, in part, by the chance incorporation of hardy diploids in the original hybridization. However, the evolution of new genie forms or an integrated genetic system between the genomes of the polyploid was probably equally important to the development of highly cold hardy types. The utility of related species for the improvement of cold hardiness in common wheat is discussed.Key words: Triticum, Aegilops, cold hardiness, winter wheat, interspecific hybridization
GROWTH RESPONSES OF EARLY MATURING INBRED LINES OF CORN TO SUBOPTIMAL TEMPERATURES
Authors: MENKIR A. , LARTER E. N.
Published: March 2010

Considerable genetic variability was observed among 32 inbred lines of corn (Zea mays L.) for emergence percentage, emergence index (rate), and seedling dry weight when evaluated under controlled low temperature regimes. Emergence percentage ranged from 45 to 100%, emergence indices from 14.7 to 18.7 days, and seedling dry weights from 0.19 to 1.19 g/plant. Simple correlation coefficients indicated a significant (P = 0.05) and positive association between emergence percentage and emergence index (rate). Neither of the two emergence parameters were significantly associated with seedling dry weights. Twelve inbreds selected for field evaluation based upon their performance under controlled low temperature environments, expressed marked differences with respect to emergence percentage, seedling growth, time to silk, and grain yields. The two best inbred lines tested under both environments were CK76 and CO255. Although the emergence traits as determined under controlled environmental conditions were not significantly correlated with those evaluated in the field, measurements of post-emergence seedling growth were significantly and positively associated between the two environments. Thus the use of a predetermined optimal ambient temperature regime can be used as a screening method to identify strains with potential vigor and cold tolerance under field conditions.Key words: Corn, cold tolerance, physiology
EFFECT OF WEED CONTROL AND A COMPANION CROP ON ALFALFA AND SAINFOIN ESTABLISHMENT, YIELDS AND NUTRIENT COMPOSITION
Authors: MOYER J. R.
Published: March 2010

Alfalfa and sainfoin were sown in 1978, 1979, and 1980 on irrigated land at the Lethbridge Research Station. The forages were established using herbicides for weed control, no weed control, or a barley companion crop. Weed control treatments were applied only during the establishment year (year 1). Alfalfa yields, averaged from the three seedings, were 360 and 200 g/m2 greater during year 1 and year 2, respectively, when diclofop plus 2,4-DB was applied than when the companion crop was grown and no weed control was used. Weed yields were greater in years 2 and 3 where alfalfa was established in competition with weeds or companion crops than where weeds were controlled. Alfalfa yields were similar for all treatments in years 3 and 4. Year 1 treatments in sainfoin produced yield differences similar to those described for alfalfa; however, sainfoin yields tended to be smaller and weed yields larger. Year 1 and year 2 forages with high weed contents have acceptable nutrient composition but may not be saleable as hay or silage or to the dehydration industry. The seeding of pure stands of alfalfa on irrigated land using herbicides for weed control produced sufficient high quality forage, in year 1, to make this practice a viable alternative to seeding with a companion crop.Key words: Alfalfa, sainfoin, 2,4-DB, diclofop, MCPB, fiber, protein
PRODUCTIVITY AND QUALITY OF PERENNIAL AND HYBRID RYEGRASS, ORCHARDGRASS AND REED CANARYGRASS GROWN IN THE LOWER MAINLAND OF BRITISH COLUMBIA
Authors: FAIREY N. A.
Published: March 2010

A study was conducted in the Lower Mainland of British Columbia to determine the yield and quality characteristics of four grass species. Two cultivars of perennial ryegrass (PR), hybrid ryegrass (HR), orchardgrass (OG), and reed canarygrass (RC) were grown under a four-cut management system for two production years with annual rates of N:P2O5:K2O of 300:200:200 kg/ha. Dry matter yields of PR, HR and RC over the two production years were similar but each produced significantly less than OG. However, both PR and HR equalled OG in the production of digestible dry matter. RC equalled HR in the production of digestible dry matter but produced significantly less than either PR or OG. In vitro dry matter digestibility was significantly different among species, averaging 67% for PR, 64% for HR, 63% for RC and 59% for OG. It fluctuated throughout the growing season in a similar pattern for each cultivar in each production year, HR being an exception in the second year because it remained at constant digestibility. PR and HR were especially productive in the spring and early summer whereas OG produced digestible dry matter more evenly over the growing season. RC was the least productive species in the fall. Nitrogen content was highest for RC, intermediate for PR and OG, and lowest for HR. The differences observed among these species, in terms of seasonal and annual productivity and quality characteristics, emphasize the need for carefully defining grass production requirements before selecting the species, cultivar, and management system to meet those requirements.Key words: Grasses, yield, quality, digestibility, nitrogen content, nutritive value
COMPARISON OF MAGNESIUM SULFATE AND THIS Mg CHELATE FOLIAR SPRAYS; RESPOSE OF Mg-DEFICIENT BEAUTIFUL ARCADE APPLE SEEDLINGS
Authors: WEBSTER D. H.
Published: March 2010

Magnesium sulfate, applied as foliar sprays at 0.2% Mg, was more effective than THIS Mg in correcting Mg deficiency of Beautiful Arcade seedlings grown in solution culture in the greenhouse. The foliar sprays of THIS Mg chelate (4% Mg) were applied at a dilution of 1:200 (0.02% Mg). Conductivity measurements suggest that absorption of Mg from THIS Mg will occur above 65% RH compared to the level of 80% RH required for absorption from magnesium sulfate.Key words: Apple, magnesium deficiency, foliar spray, Mg chelate, Mg sulfate, THIS Mg
TOLERANCE OF SPRING BARLEY TO TRIFLURALIN DEEP-INCORPORATED IN THE FALL OR SPRING
Authors: O’SULLIVAN P. A. , WEISS G. M. , FRIESEN D.
Published: March 2010

Field experiments were conducted in 1982 and 1983 to investigate the tolerance of barley (Hordeum vulgare L. ’Galt’) seeded 5 cm deep in a Ponoka loam soil treated with trifluralin. There were eight rates of application from 0 to 3 kg/ha applied in fall and spring and incorporated by means of a rototiller set to till to a depth of 10 cm. All data were analyzed by regression. Gas chromatographic analysis of extracts of soil samples collected in the spring following fall application of trifluralin (0.0–3.0 kg/ha) indicated that approximately 45% of the herbicide was lost regardless of rate applied. Fall application of trifluralin up to 3 kg/ha and spring application up to 1.1 kg/ha did not adversely affect the numbers of barley seedlings that emerged. Trifluralin treatments within the rate range 0.85–1.4 kg/ha caused severe early injury (delayed growth) to barley, the magnitude of which varied with the season and year of application. Fall application caused less injury than the respective spring application during both years. With fall or spring applications up to 1.3 kg/ha or 1.0 kg/ha, respectively, barley yields were not reduced compared to the untreated control. With fall application at 1.4 kg/ha barley yield was reduced in one of the two years. Rates in excess of 1.8 kg/ha caused significant yield reductions with all treatments. The data indicate that trifluralin could be used as a deep-incorporated fall or spring treatment at rates up to 1.3 or 1.0 kg/ha, respectively for weed control in barley in central Alberta. Fall application would improve the safety to the crop. Barley could also be seeded into soil where trifluralin (1.4 kg/ha) was applied as a fall treatment for weed control in rapeseed (Brassica campestris L. and Brassica napus L.), but some loss of yield could be expected.Key words: Trifluralin rate, soil incorporation, barley, tolerance
EFFECTS OF CULTIVAR RESISTANCE, LEAF WETNESS DURATION AND TEMPERATURE ON RATE OF DEVELOPMENT OF POTATO EARLY BLIGHT
Authors: HOLLEY J. D. , HALL R. , HOFSTRA G.
Published: March 2010

Regression models were developed from field observations over three seasons in Ontario, to relate apparent infection rate (Y) of early blight, caused by Alternaria solani Sorauer, on three potato cultivars, Kennebec, Chieftain, and Norchip, to leaf wetness duration (W) and air temperature (T). Among regression equations of the form Y = a + bW + cT + dWT or Y = a + bW, cultivar-specific equations accounted for more variability in Y than equations derived from all cultivars. In all-cultivar equations and cultivar-specific equations, W accounted for 85%–89% of the variability in Y. Therefore, cultivar resistance and the average daily duration of leaf wetness were identified as important factors determining apparent infection rate under field conditions. Temperature, either singly or in combination with leaf wetness, accounted for less than 10% of the variability in Y and was negatively correlated with Y and W. The product of temperature and wetness was highly correlated with Y but, under field conditions, an increase in temperature tended to decrease the duration of leaf wetness, and therefore the value of Y as well. It is suggested that cultivar resistance and duration of leaf wetness will be important factors to be considered in the prediction of apparent infection rate and in the development of a practical weather-timed spray program for early blight of potato.Key words: Alternaria solani, Solanum tuberosum, disease control, weather-timed spray
EFFECTS OF SEEDING TREATMENT AND SOIL MOISTURE CONTENT ON THE EMERGENCE OF LETTUCE
Authors: CHEVRIER G. E. , STEWART K. A.
Published: March 2010

Lettuce seeds (Lactuca sativa L. ’Boston Dark Green’) were sown by fluid drill and as dry seed into soils at 25%, 50%, 75% and 100% field capacity (FC). Fluid drilling reduced the time to initial emergence and 50% emergence at soil moisture levels between 50% and 100% FC. At 25% FC, neither seeding method performed well with fluid drilled seed being entrapped inside the carrier gel after it had dehydrated. After 2 wk, no significant difference in final percent emergence was noted between seeding treatments at any soil moisture level. In a second experiment, fluid drilled lettuce seeds emerged earlier and reached 50% emergence sooner than dry seed, germinated seed sown without gel and dry-seed in gel at 40%, 50% and 75% FC. Gel-seeded treatments were not significantly affected by soil moisture whereas the emergence of seeding treatments without gel application was markedly improved as soil moisture content increased. After 2 wk, the percent emergence of dry seeded lettuce at 40% FC was significantly lower than the other seeding treatments. No differences were noted among treatments at 50% FC whereas at 75% FC, the emergence of dry seed in gel was significantly reduced.Key words: Lettuce, fluid drilling
WILD OAT INTERFERENCE IN SUNFLOWER
Authors: CHUBB W. O. , FRIESEN G. H.
Published: March 2010

In field experiments, sunflower (Helianthus annuus L. ’Hybrid 894’) recovered from initial effects of wild oat (Avena fatua L.) interference and yielded normally if the weed was removed within 4 wk after crop emergence and the crop was kept relatively free of wild oats thereafter until harvest. In widely spaced plantings, wild oats growing between-the-rows competed just as vigorously as in-the-row infestations. Selective postemergence herbicides did not always provide sufficient control of wild oats to prevent significant losses in sunflower yield.Key words: Competition, interference, seed yield, oil content, herbicides, critical period
EFFECT OF SEEDING DATE, NITROGEN AND PHOSPHATE FERTILIZER ON GROWTH, YIELD AND QUALITY OF RAPESEED IN NORTHWEST ALBERTA
Authors: CHRISTENSEN J. V. , HENNIG A. M. F. , McKENZIE J. S. , LEGGE W. G. , DePAUW R. M. , SIEMENS B. , THOMAS J. B.
Published: March 2010

The effects of seeding data and nitrogen and phosphate fertilizer on the agronomic characteristics of two rapeseed species (Brassica campestris L. and B. napus L.) were studied for a 6-yr period at two northwest Alberta locations. Seeding dates were established at weekly intervals from early May to mid-June. Two fertility levels were established; a control treatment in which no fertilizer was applied and a fertilizer treatment in which nitrogen and phosphorus were applied to meet the requirements of a 1680 kg∙ha−1 crop. Maximum yields were obtained most frequently with seeding periods of mid- to late May for B. campestris and mid-May for B. napus. Seeding date had little effect on plant density or seed quality. Nitrogen and phosphate fertilizer reduced plant densities but increased seed yield where nutrient deficiencies occurred.Key words: Brassica campestris L., B. napus L., seeding date, yield, quality
EFFECTS OF SEEDING AND HARVESTING DATES ON YIELD AND OIL QUALITY OF SUNFLOWER CULTIVARS
Authors: DEDIO W.
Published: March 2010

Several sunflower cultivars were seeded at approximately weekly intervals from early May to 20 June from 1978 to 1981. In another experiment the plots were harvested at different dates to study the effects on yield and oil quality. In general the yield was highest for all cultivars at the earliest seeding, with the late maturing cultivars performing the best. In late plantings, the yields were in general lower and early maturing cultivars performed better than the later ones. The cross-over point varied from year to year ranging from 16 May to 7 June except in 1981 when there was no cross-over. The oil content was similarly affected, declining more rapidly with delay in seeding in the later maturing hybrids than in the early hybrids. In the separate study on harvest dates, maximum oil content was reached when seed moisture content had declined to 45%. This occurred approximately 1 wk earlier in the early cultivars than in the late ones. Maximum linoleic acid level was reached approximately a week after the maximum oil content was obtained.Key words: Seeding date, sunflower, oil content, yield, linoleic acid, harvesting date
THE EFFECTS OF FUSARIUM WILT AND WEED CONTROL ON SURVIVAL OF BIRDSFOOT TREFOIL
Authors: MURPHY W. M. , GOTLIEB A. R. , DUGDALE D. T.
Published: March 2010

Birdsfoot trefoil (Lotus corniculatus L.) seed production is no longer profitable for Champlain Valley farmers, partly because the plants do not grow or persist as well as they did in the past due to a Fusarium wilt disease (Fusarium oxysporum). This study was done to determine the effects of chemical and cultural weed control on birdsfoot trefoil seedlings in a Champlain-Valley clay soil containing Fusarium oxysporum. In a greenhouse experiment, 2,4-DB was applied to birdsfoot trefoil seedlings growing on pasteurized potting mix inoculated with F. oxysporum. When applied at label rate in the second trifoliate-leaf stage, and 14 days later, 2,4-DB increased seedling mortality additively with death due to F. oxysporum. When 2,4-DB was applied 7 days after the second trifoliate-leaf stage, it did not influence seedling survival. Applying 2,4-DB reduced dry weights of tops and roots of surviving seedlings. A field experiment was done on a clay soil (Glossaquic Hapludalf) being used for birdsfoot trefoil seed production and known to contain F. oxysporum. Raised beds were included as a variable to determine effects of improved root-zone drainage. Weeds were controlled by clipping or with 2,4-DB/dalapon postemergent herbicides in two birdsfoot trefoil seeding rates of 16.8 and 3.4 kg seed∙ha−1. The herbicides did not influence seedling death rate. By May of the second year plant populations within a seeding rate were the same, regardless of weed control practice and seedbed preparation.Key words: Dalapon, Fusarium oxysporum, Lotus corniculatus L., 2,4-DB
ROOT PENETRATION AND SHOOT ELONGATION OF TALL WHEATGRASS AND BASIN WILDRYE IN RELATION TO SALINITY
Authors: ROUNDY BRUCE A.
Published: March 2010

Tall wheatgrass [Elytrigia pontica (Podp.) Holub Syn: Agropyron elongatum (Host) Beauv. ’Jose’] and basin wildrye [Leymus cinereus (Scribn. & Merr.) A. Love Syn: Elymus cinereus Scribn. and Merr. ’Magnar’] may have potential for increasing forage production once established on saline rangelands. The shoot and root elongation, osmotic adjustment, leaf water stress, and turgor at growth cessation of these grasses in response to drought and salinity were compared in a growth chamber experiment. Seedlings were grown in columns of soil initially saturated with solutions with an electrical conductivity of 1.0, 10, and 20 dS∙m−1 and allowed to grow until desiccated. The greater shoot elongation and root penetration of tall wheatgrass than basin wildrye at all soil salinities corresponds with the higher survival of tall wheatgrass than basin wildrye on a saline soil and on a nonsaline soil in central Nevada. As leaf water potential decreased, both species had similar or higher turgor maintenance in saline than nonsaline soil. But salinity decreased growth of both species, even when no water stress was apparent, and plant and soil water potentials in the saline and nonsaline columns were similar. This suggests that salt toxicity or nutritional imbalances due to accumulated ions, rather than water stress, depressed growth. Plant materials for revegetating saline, arid rangelands should be screened not only for seedling vigor and ability to tolerate or avoid water stress but also for tolerance to salinity.Key words: Drought, osmotic adjustment, turgor, ion toxicity, salt tolerance
ATRAZINE PERSISTENCE AND RESIDUE EFFECTS ON ROTATION CROPS
Authors: IVANY J. A. , SADLER J. M. , KIMBALL E. R. , McRAE K. B.
Published: March 2010

Field studies on Prince Edward Island (P.E.I.) loam to fine sandy loam soils from 1977 to 1980 determined the rate of breakdown of atrazine and soil residue effects on crops grown in rotation with silage corn (Zea mays L.). The rate of breakdown was rapid during the first 30 days after application with an estimated half-life of 23 days when averaged over rates and years. Timothy (Phleum pratense L.) and red clover (Trifolium pratense L.) were most sensitive to atrazine residues; yields of red clover were reduced significantly from the 1.13-kg/ha rate and of timothy after the 2.25-kg/ha rate. Yields of winter rye (Secale cereale L.) broadcast seeded in standing corn in August and barley (Hordeum vulgare L.) seeded the next spring were not affected, or reduced only slightly, by atrazine residues from initial applications of 1.13 kg/ha but showed significant yield losses at the 2.25- and 4.50-kg/ha rates. Alfalfa (Medicago sativa L.) seeded the next spring after atrazine use was tolerant of residues showing significant yield losses only at the 4.50-kg/ha rate. In this study, atrazine applied at 1.13 kg/ha in silage corn was sufficiently broken down to permit production of all crops studied except red clover.Key words: Atrazine, residue, clover (red), timothy, alfalfa, rye (winter), barley
DIFFERENTIAL TOLERANCE OF TWO BARLEY CULTIVARS TO METRIBUZIN
Authors: CALDWELL C. D. , O’SULLIVAN P. A.
Published: March 2010

In greenhouse and growth cabinet studies, two cultivars of barley (Hordeum vulgare L. ’Klondike’ and ’Summit’) were found to differ in their tolerance to postemergence applications of metribuzin. Klondike was more susceptible than Summit, although both displayed varying amounts of injury depending on environmental conditions. Klondike was most susceptible following herbicide application at the three-leaf stage; when soil was moist at application; and when application was followed by a period of cold (0 °C). For both cultivars, high relative humidity and increasing duration of a dark period following spraying increased the injury from metribuzin. Increasing the duration of a light period following spraying had the opposite effect. The magnitude of the light/dark regime response was greater for Klondike than for Summit.Key words: Barley cultivar tolerance, metribuzin, environmental factors
CARBOFURAN EFFECTS ON ESTABLISHMENT OF LEGUMES IN RELATION TO PLANT GROWTH, NITROGEN FIXATION, AND SOIL NEMATODES
Authors: BELANGER G. , WINCH J. E. , TOWNSHEND J. L.
Published: March 2010

Field experiments were conducted to determine the effects of carbofuran on the establishment and subsequent yields of sod-seeded legumes. The effects of carbofuran on plant growth, nodulation and nitrogen fixation of birdsfoot trefoil (Lotus corniculatus L.) in non-sterilized and sterilized soil were evaluated in growth cabinet experiments. In the field experiments carbofuran, applied immediately after seeding, had a positive effect on plant stand and seedling dry matter production of birdsfoot trefoil and alfalfa (Medicago sativa L. ssp. falcata L.) in the weeks following seeding. In the first production years of these field trials, there was a trend for the total and legume yields to be higher in the carbofuran plots than where carbofuran was not used. In either growth cabinet experiment, however, shoot growth was not affected by carbofuran but a reduction in the number of plants in the non-sterilized and carbofuran pots occurred. A toxic effect of carbofuran on seedlings may have been involved. No correlation between soil nematode numbers and plant stand or dry matter production was found in either field or growth cabinet experiments. In the growth cabinet experiments, carbofuran did not affect the number of nodules but improved nitrogen fixation in sterilized pots of exp. B. Carbofuran increased the dry weight of individual nodules in the sterilized pots of exp. A but a decrease was observed in exp. B. These effects of carbofuran on the dry weight of individual nodules and specific nodule activity were also observed in the nematode-free environment created by sterilization. In view of these responses in sterile soil, it was suggested that the effect of carbofuran was not as a nematicide but rather a positive physiological effect on the plant component of the plant-rhizobium system.Key words: Carbofuran, establishment, legumes, nitrogen fixation, nematodes
GROWTH OF FOUR GRASS SPECIES AS AFFECTED BY RATE OF NITROGEN APPLICATION AND YEAR OF ESTABLISHMENT ON TWO SOIL TYPES
Authors: SIMONS R. G. , GROSS A. T. H.
Published: March 2010

In an experiment to investigate the relationship between nitrogen fertilization and forage yield, four grass species, bromegrass (Bromus inermis Leyss.), intermediate wheatgrass (Agropyron intermedium (Host) Beauv.), crested wheatgrass (A. cristatum (L.) Gaertn.) and Russian wild ryegrass (Elymus junceus Fisch.), were sown in each of 3 yr on two soil types, a clay loam and a sandy loam. Five N treatments up to 252 kg N∙ha−1∙year−1 were imposed and data were collected for each of the 3 yr following the seeding year on each plot. There was considerable variation in the dry matter yields between seeding years and postseeding years. On the clay loam soil, the first year after seeding was generally the most productive whereas on the sandy loam the second harvest year produced the most. Intermediate wheatgrass was the most productive grass on the clay loam soil, crested wheatgrass on the sandy loam soil. Bromegrass produced well on both types while Russian wild ryegrass was the least productive on both soils. All species responded well to additional N. There was no advantage to split N application. The N content of forage was similar in all four species and on both soil types but was increased by fertilizer N.Key words: Bromegrass, wheatgrass, Russian wild ryegrass, nitrogen, forage yield, establishment year.
INSECT PESTS AND THE EVOLUTION OF DEFENSIVE GLANDULAR TRICHOMES IN ALFALFA
Authors: SMALL ERNEST
Published: March 2010

Glandular trichomes can defend (Medicago species from herbivores in a variety of insect orders. Wild alfalfas with high concentrations of glandular trichomes occur in a restricted portion of the geographical range of the species (Medicago saliva L. sensu lato), especially in the Caucasus, Ukraine, and adjacent areas of the USSR. These observations suggest that this adaptation was developed to defend the alfalfa against insect pests with similar geographical distribution. That M. sativa plants with pods covered with glandular hairs tend to have larger, if fewer, seeds than plants with pods lacking the hairs also suggests an adaptation against herbivores. Because the glandular trichomes occur primarily on the ovaries and pods, the pests likely feed on seeds. After considering the biology and geography of the major Soviet insect pests of cultivated alfalfa, it was concluded that the most likely insects responsible for the localized evolution of pod glandularity are species of Tychius (Coleoptera: Curculionidae).Key words: Alfalfa, Medicago sativa L., seed chalcid, Brachophagus, Tychius, glandular trichomes, pest resistance (immunity)
THE BIOLOGY OF CANADIAN WEEDS.: 69. Potamogeton crispus L.
Authors: CATLING P. M. , DOBSON I.
Published: March 2010

A review is provided of information on the biology of curly-leaved pondweed (Potamogeton cripsus L.). This submersed aquatic behaves as a winter annual through the production of summer-dormant apices. These germinate in the fall giving rise to an overwintering plant with narrow, acute, flat-margined leaves. In spring, the winter foliage disintegrates and larger leaves with serrulate, undulate margins and round tips begin to develop. Fruit is produced and the development of dormant apices is completed mostly by late June, after which the plants begin to die and dormant apices sink to the bottom. An introduced species, curly-leaved pondweed had spread through much of the U.S. by 1950. It is now well established in southern Ontario and is one of the province’s major nuisance aquatics. It is also well established in Quebec, but is not a nuisance there and is not spreading (C. Hamel, pers. commun.). In contrast it is spreading rapidly in western Canada where it was first noticed only 20 yr ago. Curly pondweed has potential uses in waterfowl management and compositing. It thrives in alkaline, calcareous and polluted waters. The dormant apices are the most important mode of reproduction with up to 900 being produced by a single plant in 1 year. Where the plant is a problem in Ontario, mechanical harvesting techniques of control have been used effectively. Dominance of curly-leaved pondweed in some areas is probably a consequence of its unusual vegetative life cycle allowing competition avoidance, and its tolerance of polluted water.Key words: Potamogeton crispus, weed biology, Canada, distribution
BIOLOGY OF CANADIAN WEEDS.: 72. Apera spica-venti
Authors: WARWICK S. I. , BLACK L. D. , ZILKEY B. F.
Published: March 2010

Apera spica-venti (silky bentgrass), a major weed of winter cereals in Europe for many years, has recently become established as a weed of winter cereals in three counties in southern Ontario. A review of the literature on the biology of the species is presented. Occurring on light sandy loam soils which are under a rotational tobacco/winter-cereal cropping system, infestations of silky bentgrass may result in considerable crop losses, particularly in winter-wheat. Several features contribute to the successful establishment and spread of the species: a winter annual habit concordant with the phenologies of winter cereals; numerous, light seeds easily dispersed by wind and farm machinery; production and early shedding of seed prior to the harvest of crops in July; little postharvest dormancy and the ability to germinate under a wide-range of temperature and light conditions. Although not yet registered for use in Canada, the herbicides isoproturon and chlortoluron would seem to provide effective control. Various cultural practices, including crop rotation, delayed seeding, and increased cultivation combined with the use of appropriate herbicides appear to be the ideal combination for control of silky bentgrass.Key words: Bentgrass (silky), weed biology, windgrass, loose silky bent
WHEAT AND TRITICALE ROOT DEVELOPMENT AS AFFECTED BY TRIFLURALIN
Authors: OLSON B. M. , McKERCHER R. B.
Published: March 2010

A growth chamber study was conducted to investigate the effects of trifluralin on root morphology of wheat and triticale seedlings. Five spring wheat cultivars, five durum wheat cultivars and three triticale cultivars were grown for 15 days in soil treated with 0, 0.4 and 0.8 ppm trifluralin. Root damage from trifluralin in both wheat and triticale was greater at 0.8 ppm than 0.4 ppm. The 0.4 ppm rate of trifluralin reduced dry weight of Canuck, Hercules and Carman compared to the control; however, at 0.8 ppm, root dry weight of all cultivars was reduced compared to the control. Trifluralin injury symptoms included increased number of seminal roots, decreased seminal root extension, increased root diameter, and reduced root dry weight. As a group, the roots of spring wheat were injured more by trifluralin than the roots of either durum wheat or triticale. Differences in root damage amongst the cultivars was more apparent after the appearance of the second radicle root. A negative correlation was obtained between caryopsis lipid content (μg lipid per caryopsis) and root dry weight among the cultivars at the 0.8 ppm trifluralin rate.Key words: Trifluralin, wheat, triticale, root morphology, lipid
A MODIFIED AUGMENTED DESIGN (TYPE 2) FOR RECTANGULAR PLOTS
Authors: LIN CHUANG-SHENG , POUSHINSKY GREG
Published: March 2010

A modified augmented design (type 2) is presented for the situation where subplots are long and narrow (rectangular plots). The arrangement of the whole plots is the same as in the type 1 modified augmented design, but the subplots are laid out in rows within whole plots. The number of subplots per whole plot is 5, where the centre plot is the control plot. Twelve sets of data generated from three hypothetical fertility maps were used to investigate (i) the choice of adjustment method based on ANOVA of control plots and (ii) the estimated relative efficiencies of the methods. The results showed that the choice of adjustment method based on ANOVA is satisfactory and, although the estimates of relative efficiency differed from the population values, the ranking of the estimates and that of population values was nearly identical.Key words: Augmented design, non-replicated experiment, control of soil heterogeneity