bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sweetclover cultivars and management practices on following weed infestations and wheat yield
Authors: Moyer J. R. , Blackshaw R. E. , Huang H. C.
Published: April 2011

There is a renewed interest, especially among organic growers, in using either white sweetclover (Melilotus alba Desr.) or yellow sweetclover [M. officinalis (L.) Lam.] as cover crops. Sweetclover cultivars and tillage practices have changed since these crops were widely used as cover crops in the first half of the 20th century. Experiments were initiated in 1999, 2000, and 2002 to compare the effect of high- and low-coumarin cultivars and crop termination methods on weed suppression, available soil N, moisture conservation and following crop yield. Weed suppression was usually more effective when sweetclover residues were left on the surface than when removed as hay. Sweetclover termination at 70% bloom was often more effective in suppressing weeds than termination at the bud stage. In the summer and fall after termination, surface residues of Yukon, a high-coumarin and drought-tolerant cultivar, reduced lamb’s-quarters (Chenopodium album L.) density by > 80% compared with the no sweetclover check and essentially eliminated flixweed [Descurainia Sophia (L). Webb]. In the following spring, Yukon reduced kochia [Kochia scoparia (L.) Schrad.] density by > 80% and wild oat (Avena fatua L.) biomass by > 30% compared with the no sweetclover check. There was no difference in available N for a following crop between treatments with surface residue and cultivated fallow. Available soil moisture was about 10 mm less after the highest yielding sweetclover cultivars than after cultivated fallow, but subsequent wheat yield was not reduced. Maximum wheat yields were obtained after Yukon and Arctic sweetclover were grown as cover crops. It may be possible for organic growers to manage weeds with sweetclover in a reduced tillage system that leaves most of the plant residues on the soil surface. Key words: Cover crop, weed suppression, allelopathy, nitrogen, soil moisture
Identification of potential detoxification enzyme genes in Leptinotarsa decemlineata (Say) and study of their expression in insects reared on different plants
Authors: Zhang Jianhua , Pelletier Yvan , Goyer Claudia
Published: April 2011

Insects have evolved remarkable abilities to metabolize plant allelochemicals colonizing host plants otherwise toxic to them. These abilities largely rely on detoxification enzymes such as cytochromes P450 (P450), glutathione S-transferases (GST) and esterases. To identify the potential detoxification enzyme genes in Leptinotarsa decemlineata (Say), 44 expressed sequence tags (ESTs) including the ESTs of 38 P450, three GSTs and three esterases were generated using a degenerate rapid amplification of cDNA ends (RACE). The putative P450s were placed into 10 subfamilies representing five families. The gene expression was studied using a low-density reverse Northern array. The results showed that CYP4BN13v1 was up-regulated after the beetles transferred from potato to tomato, pepper or eggplant. The expression of CYP4Q11 was up-regulated in the beetles transferred to eggplants. In contrast, the expression of CYP9Z14v1 and CYP4BN13v1 was down-regulated after the beetles transferred to eggplant or flowering tobacco, respectively. This indicates that only a few P450 genes from the insect were induced or suppressed by different rearing plants. Although the function of these P450 enzymes in the metabolism of allelochemicals was not determined here, the result implies that the insect may use different oxidative metabolic pathways when they feed on different host plants. Key words: Cytochrome P450, glutathione S-transferase, esterase, gene expression, host plant
Kayak orchardgrass
Authors: Acharya S. N. , Friebel D. R. , Castonguay Y.
Published: April 2011

Kayak is a high yielding early maturing orchardgrass (Dactylis glomerata L.) cultivar with good level of winterhardiness suited for silage and hay production in western Canada including interior British Columbia. The population was developed at the Agriculture and Agri-Food Canada (AAFC) Research Centre, Lethbridge, AB. In BC and Western Forage Trials (WFTests), Kayak yielded 4% better than the check cultivar Kay under both rain fed and irrigated conditions. Kayak orchardgrass produces 10% more seed yield than Kay while its seed size is slightly smaller than Kay. Key words: Orchardgrass, Dactylis glomerata, high forage yield, winterhardy
Effect of natural light on surface temperature and lycopene content of vine ripened tomato fruit
Authors: Helyes L. , Lugasi A. , Pék Z.
Published: April 2011

Indeterminate round type tomato (Lycopersicon esculentum Mill.) grown on a supporting trellace system in the field was used to determine the correlation between light exposure and the surface temperature and lycopene content of tomato fruit. The positive correlation between solar radiation and surface temperature was stronger (R2 = 0.87) on non-shaded (NS) than on shaded (SF) (R2 >= 0.79) tomato fruits. There was strong negative correlation (R2 = 0.95) between surface temperature and lycopene content of tomato fruits. Increasing solar radiation and temperature explained the lower content of lycopene content and therefore the loss of nutritional quality of the non-shaded tomato fruits. Key words: Tomato, fruit surface temperature, lycopene
CO444 corn inbred line
Authors: Reid L. M. , McDiarmid G. , Zhu X.
Published: April 2011

CO444 is a short season corn (Zea mays L.) inbred line with excellent combining ability and average to superior lodging resistance in hybrids. This inbred performed well as a parent with both stiff and non-stiff stalk inbreds. Excellent yields were achieved with the stiff stalk commercial inbred MBS1236 and the iodent commercial inbred LH176. In addition, when combined with the early inbred CL30, CO444 performed well in the very short season areas of Lethbridge and Vauxhall, Alberta. Key words: Corn, maize, Zea mays, cultivar description
Yield and quality response of autumn-planted sunflower (Helianthus annuus L.) to sowing dates and planting patterns
Authors: Saleem M. F. , Ma B. L. , Malik M. A. , Cheema M. A. , Wahid M. A.
Published: April 2011

Sowing time and sowing methods are often used to overcome environmental constraints on crop production. Information on the effect of these agronomic techniques on sunflower (Helianthus annuus L.) oil quality is, however, scarce. A field study was conducted to evaluate the effect of sowing dates and planting patterns, and their interaction, on seed yield and oil quality of hybrid sunflower. Sunflower hybrid Hysun-33 was sown at four dates beginning with the first week of August with fortnightly intervals under three planting patterns, viz., flat sowing (60 cm apart lines), ridge sowing (60 cm apart ridges) and bed sowing (90/30 cm) for 2 yr (2002 and 2003). The performance of the August sowing dates was significantly better with respect to yield and yield components than the September-sown crop. Among the three sowing dates in August, there was variable performance of the crop in the 2-yr study. On average, the sowing of sunflower from mid-August to the last week of August yielded better than early August sowing dates. The evaluation of quality parameters revealed greater content of achene oil in the September-sown crop followed by the crop sown in the last week of August. Delayed sowing lowered oleic acid content, but increased stearic and linoleic acid levels. Planting pattern treatments affected head diameter, achenes per head, 1000-achene weight and achene yield. Conclusively, sunflower sown on ridges during the second fortnight of August encountered favourable environmental conditions and gave significantly higher economic yield. Key words: Helianthus annuus , plantingg eometry, plantingpatterns, quality, sowingdates, sunflower yield
Flag leaf physiological traits in two high-yielding Canada Western Red Spring wheat cultivars
Authors: Wang H. , McCaig T. N. , DePauw R. M. , Clarke J. M.
Published: April 2011

Because of the common negative correlation between grain yield and grain protein (nitrogen) concentration, it is difficult to improve yield in the Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) class, which characteristically possesses high quantity and quality of protein. Previous studies found that the increased yield of some new CWRS cultivars relative to old cultivars was mainly attributed to higher yield per spike and spike filling rate and more efficient carbohydrate and N partitioning to the grain. The objective of this study was to investigate if the yield increase of two new CWRS cultivars, AC Barrie (registered in 1996) and AC Elsa (registered in 1997), is associated with a change in photosynthetic rate or other physiological traits of flag leaves compared with two old cultivars, Neepawa (registered in 1969) and Marquis (introduced in 1909). No difference was found between new and old cultivars in flag leaf photosynthesis rate or nitrogen concentration. Both new cultivars tended to have lower specific leaf area (SLA) and higher N accumulation per leaf when flag leaves were young and more N remobilization during grain filling compared with old cultivars. Over the 2 yr, flag leaf N remobilizations of AC Elsa and AC Barrie averaged 69 and 32% higher than Marquis and 50 and 17% higher than Neepawa, respectively. The enhanced flag leaf N remobilization along with increased N remobilization from other organs of new cultivars shifted the undesirable negative relationship between grain yield and grain protein concentration. AC Elsa had greater total photosynthesis per flag leaf than other three cultivars due to its larger leaf area and longer green leaf duration. Further research is required to determine if low SLA, large flag leaf and long green leaf duration are effective selection criteria for high yielding CWRS cultivars. Key words: Flag leaf, photosynthesis, specific leaf area, nitrogen remobilization
Susceptibility of winter and spring triticales to fusarium head blight and deoxynivalenol accumulation
Authors: Veitch R. S. , Caldwell C. D. , Martin R. A. , Lada R. , Salmon D. , Anderson D. M. , MacDonald D.
Published: April 2011

Fusarium head blight (FHB), caused by the fungus Fusarium graminearum (Schwabe), is one of the most destructive diseases in cereals worldwide. It may severely reduce both grain yield and quality, with potential contamination from trichothecene mycotoxins such as deoxynivalenol (DON). Spring and winter triticales (X Triticosecale Wittmack) were evaluated in a multi site and year field study to determine their susceptibility to FHB and DON accumulation. Fusarium-damaged kernels (FDK) and DON levels were affected significantly by both cultivar and site-year. Triticales were generally more susceptible to FHB compared with winter and spring wheat checks, as indicated by the higher levels of FDK and DON levels. A significantly positive linear relationship was observed between FDK and DON levels in winter triticales. This relationship in spring triticales was not significant on the combined data, but at each site-year, the regression was strong. FDK can be a good predictor of DON levels when environmental conditions are similar. The Atlantic region would appear to be a very good location in Canada for screening for fusarium head blight resistance. Key words: Winter triticale, spring triticale, cultivar; fusarium head blight, fusarium head blight, fusarium-damaged kernels, deoxynivalenol
Performance of prohexadione-calcium on shoot growth and fruit quality of apple — Effect of spray surfactants
Authors: Cline J. A. , Embree C. G. , Hebb J. , Nichols D. S.
Published: April 2011

Vegetative growth control of apples (Malus × domestica Borkh.) is necessary to maintain a balance between growth and cropping. Pruning is a labour-intensive management practice to achieve this and intrinsically stimulates new growth. Prohexadione-calcium (PC) is a plant bio-regulator that effectively regulat es the shoot extension growth of apples and other tree fruits. Previous research has demonstrated that its efficacy can vary based on the use of spray surfactants and adjuvants. This study investigated the efficacy of two rates of Apogee™, the commercial form of PC, used in combination with the spray surfactants Sylgard 309 and LI 700, on extension shoot growth and yield parameters.

Experiments were conducted in Ontario on Empire and Nova Scotia on Royal Court™ Cortland apples. Treatments of 0, 75 or 125 mg L-1 PC, with and without either 0.5% (vol/vol.) LI 700 surfactant or 0.05% (vol/vol) Sylgard 309 surfactant were applied to Empire trees, and 75 or 125 mg L-1 PC, with or without 0.5% (vol/vol) LI 700, were applied to Royal Court™ trees. An untreated control treatment was also included for comparison purposes. A total of two sprays were applied to the Empire trees and a total of three sprays were applied to the Royal Court™ trees. PC significantly decreased the vegetative growth of Empire and Royal Court™ trees by approximately 18 to 44%, respectively, and the efficacy of PC was enhanced when combined with either Sylgard 309 or LI 700 surfactant. No additional benefit in vegetative growth control was gained when using Apogee™ at rates of 125 mg L-1 PC, relative to 75 mg L-1 PC. The rate of Apogee™ did not influence the number of fruit or yield per tree or mean fruit size of either cultivar. For Empire, LI 700 and Sylgard 309 significantly reduced the number of fruit per tree, resulting in lower yields and crop densities. In addition, higher mean fruit weights, and a greater distribution of fruit in the larger size categories were observed for LI 700. Fruit from Royal Court trees treated with the highest rate of Apogee™ had higher crop densities, poorer coloured fruit, and a higher percentage of fruit less than 60 mm in diameter. These data provide support for the use of alternative surfactants with Apogee™ other than those listed on the US and Canadian product labels. Key words: Apogee™, Empire, Cortland, Regalis, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate, surfactant
Breeding meadow bromegrass for forage characteristics under a line-source irrigation design
Authors: Jensen Kevin B , Waldron Blair L , Robins Joseph G , Monaco Thomas A , Peel Michael D
Published: April 2011

Production from less productive lands limited by irrigation can be increased if genetically improved pasture grasses are developed with increased dry matter production (DMY) and nutritional quality. In 2000, 18 half-sib families of meadow bromegrass were seeded in a modified strip-plot design with four replications and water levels (WL) applied as nonrandom strips ranging from 10.1 mm wk-1 at WL-5 to 36.8 mm wk-1 at WL-1. The objective was to estimate genetic variability and parameters as affected by irrigation level and harvest date for DMY, crude protein (CP), in vitro true digestibility (IVTD), neutral detergent fiber (NDF), and digestible neutral detergent fiber (dNDF). Low h2 estimates for DMY suggest that gains in total DMY from selection within these half-sib families (HSF) are not likely. Crude protein concentrations were more influenced by harvest date than WL. Heritability estimates were relatively high regardless of WL or harvest date for IVTD. The effect of WL on h2 estimates for NDF were less defined, suggesting that gains might be achieved faster if selection was done on forage harvested later in the growing season at less than optimum irrigation. Heritability estimates for dNDF were either small or associated with large standard errors. Key words: Heritability, irrigation rates, forage yield and quality, crude protein, neutral detergent fiber, in vitro true digestibility
A review of wheat cultivars grown in the Canadian prairies
Authors: McCallum Brent D , DePauw Ronald M
Published: April 2011

Wheat is Canada's largest crop with most of the production in the western Canadian prairie provinces of Manitoba, Saskatchewan and Alberta. Since wheat production started in western Canada, over 100 yr ago, market classes of hexaploid spring bread wheat (Triticum aestivum L.) were the dominant type of wheat, although production of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.)] has grown significantly over this period, and hexaploid winter wheat was grown on a relatively small portion of the wheat area. Within hexaploid wheat there has been diversification into a number of market classes based on different end-use quality criteria. The predominant spring bread wheat class has been the Canada Western Red Spring (CWRS) class. A few cultivars were grown extensively over a long period of time, such as the CWRS wheat Thatcher, which was the dominant cultivar from 1939 to 1968, and Kyle, which was the leading Canada Western Amber Durum (CWAD) cultivar from 1988 to 2004. Other cultivars dominated particular wheat classes for many years such as Glenlea, Canada Western Extra Strong (CWES) spring wheat and Norstar, Canada Western Red Winter (CWRW) wheat. The reasons for newer cultivars replacing older cultivars include improvements in grain yield, resistance to stem rust (Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.), leaf rust (Puccinia triticina Eriks.), and other diseases, resistance to wheat stem sawfly (Cephus cinctus Nort.), enhanced end-use quality, and other agronomic characteristics such as lodging resistance. Cultivars with improved pest resistance were often rapidly adopted, such as Thatcher and Selkirk, in response to the stem rust epidemics in the 1930s and 1950s, and Rescue and Lillian in response to wheat stem sawfly epidemics in the 1940s and 2000s. Improved grain yield led to the rapid increase of many cultivars including Marquis in the 1910s and 1920s, Neepawa, Wascana and Wakooma in the 1970s, AC Barrie in the 1990s, and Superb in the 2000s. Increased breeding efforts recently have led to many more highly adapted cultivars and subsequently more diverse wheat production. Wheat classes and cultivars in the prairies continue to improve and diversify to meet the challenges of the marketplace and the production concerns of wheat growers. Key words: Rust, fusarium head blight, cereal quality, protein
Effect of density and time of removal of volunteer canola (Brassica rapa L.) on yield loss of wheat (Triticum aestivum L.)
Authors: O'Donovan John T , Harker K. Neil , Dew Donald A
Published: April 2011

Field experiments were conducted at Lacombe, Alberta, in 1976, 1978, and 1979. Nonlinear regression analysis of the data indicated that initial slopes (% wheat yield loss at low canola densities) varied from 0.29% in 1979 to 2.44% in 1978. However, volunteer canola at densities of 47 (1976), 345 (1978), and 251 (1979) plants m-2 had little effect on wheat yield if the canola was removed at approximately 25 d or earlier after wheat emergence. Key words: Brassia rapa, volunteer canola density, time of weed removal
1-Methylcyclopropene treatment modifies postharvest behavior of Fantasia nectarines
Authors: DeEll Jennifer R , Murr Dennis P , Ehsani-Moghaddam Behrouz
Published: April 2011

The effects of 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, on the ripening and quality of Fantasia nectarines were examined. Fruit were harvested from two commercial orchards and subsequently exposed to 1 μL L-1 of 1-MCP for 24 h at 0°C. Following treatment, fruit were held at 0°C for 0, 2, or 4 wk, and then assessed for quality during a ripening period at 23°C. 1-MCP treatment improved postharvest firmness retention in nectarines after 0 and 2 wk at 0°C plus 4 days at 23°C. Soluble solids concentration (SSC) was lower in nectarines treated with 1 MCP and held for 0 or 4 wk at 0°C, compared with similar non-treated fruit. The peel ground color change from green to yellow was also delayed by 1-MCP. Nectarines treated with 1-MCP exhibited less CO2 and hydrophobic volatile production during 14 days at 23°C, compared with non-treated fruit. The overall inhibition of fruit ripening by 1-MCP appears transitory in Fantasia nectarines. Chilling injury was observed after 4 wk of storage at 0°C and 1-MCP-treated fruit had less visual chilling-related injury but greater chilling-induced flesh hardening. Further research is needed to determine the effects of 1-MCP on different chilling injury symptoms in nectarines. Key words: 1-MCP, fruit quality, ripening, storage, shelf-life, Prunus persica
COMPARATIVE RISK OF GROWING FOUR IRRIGATED CROPS IN SOUTHERN ALBERTA
Authors: RAO U. M. B. , MAJOR D. J. , CAREFOOT J. M.
Published: April 2011

Yields of barley, spring wheat, oat, and maize grown at Lethbridge, Alberta from 1970 to 1985 were analyzed for their responses to weather variables. There was no relationship among the yields of the four crops and each was influenced most by a different weather variable. The best model relating weather to yield involved a multiple regression analysis with 15-d averages of weather variables as independent variables. Barley was adversely affected by high temperatures, wheat by high late-season precipitation, oat by high wind, and maize by high solar radiation at the time of early grain filling. Published estimates of prices and costs of production were used to determine the relative risk of growing these crops. It is possible to meet cost of cultivation in all the years with barley and oat crops.Key words: Yield-weather analysis, wheat (spring), oat, barley, corn
LODGING IN LENTIL AND ITS RELATIONSHIP WITH OTHER CHARACTERS
Authors: ERSKINE W. , GOODRICH W. J.
Published: April 2011

Lentil (Lens culinaris Med.) is normally harvested by hand in west Asia and north Africa, but research is needed on mechanizing its harvest to reduce input costs. Yield losses from a mechanized harvest increase with increased lodging. The genetic, environmental, and genotype × environmental variation in lodging was studied in 242 lines grown at three locations contrasting in rainfall in northern Syria and Lebanon. There was no lodging at the dry site where only 1.5 t ha−1 biomass was harvested. The lodging was considerable at the two wetter sites, where biological yields exceeded 3 t ha−1. The broad-sense heritability of lodging score across sites was 0.41 ± 0.05; clearly, some response to selection for standing ability based on plot values may be expected. In a separate experiment of 22 lines in one location hand-harvested biological, seed and straw yields were obtained and detailed morphological measurements were made to relate to lodging scores. Path coefficient analysis revealed the importance of stem thickness as a direct effect on lodging. Consequently, stem diameter may be useful as a criterion in single-plant selection for reduced lodging. As there was a low direct effect of hand-harvested seed and straw yield on lodging, selection for resistance to lodging will not have a major correlated effect on the genetic potential for seed and straw yield.Key words: Lentil, Lens culinaris, lodging, standing ability
EFFECTS OF TEMPERATURE ON RATE AND DURATION OF KERNEL DRY MATTER ACCUMULATION OF MAIZE
Authors: TOLLENAAR M. , BRUULSEMA T. W.
Published: April 2011

The response of rate and duration of kernel dry matter accumulation to temperatures in the range 10–25 °C was studied for two maize (Zea mays L.) hybrids grown under controlled-environment conditions. Kernel growth rates during the period of linear kernel growth increased linearly with temperature (b = 0.3 mg kernel−1 d−1 °C−1). Kernel dry weight at physiological maturity varied little among temperature treatments because the increase in kernel growth rate with increase in temperature was associated with a decline in the duration of kernel growth proportional to the increase in kernel growth rate.Key words: Zea mays L, period of linear kernel dry matter accumulation, controlled-environment conditions, kernel growth rate
SOURCE-SINK LIMITATIONS OF MAIZE GROWING IN AN OUTDOOR HYDROPONIC SYSTEM
Authors: WALKER G. K. , MILLER M. H. , TOLLENAAR M.
Published: April 2011

Experiments were conducted from 1983 to 1985 to test the hypothesis that rate of dry matter accumulation by maize (Zea mays L.) during grain filling can be enhanced by an increase in assimilate demand for grain filling (i.e., sink strength).The sink strength of maize plants grown in an outdoor hydroponic system was varied independently of the source strength by manipulating the plant spacing during the period in which final kernel number is established. The crop growth rate during grain filling, the dry matter of leaves, stems, ears and roots, and grain yield components were determined. In all 3 yr the crop growth rate during grain filling of plants that had been growing at a 20 000 plants ha−1 spacing for variable periods and were returned to the control density of 80 000 plants ha−1 at the start of the grain-filling period was lower than that of plants grown continuously at a spacing of 80 000 plants ha−1. In 1985, plants grown at 20 000 plants ha−1 from 3 wk preanthesis until 2 wk postanthesis and at 80 000 plants ha−1 thereafter had 50% more kernels per plant than the control plants. However, the net photosynthesis during grain filling was not increased; in fact it was somewhat lower. Final grain yield was not significantly different, mainly due to greater translocation from the stems to the grain in the spaced plants than in the controls. These studies indicate that maize growing in a nonlimiting below-ground environment is not sink limited. Hence adding sink capacity by maintaining kernel number while increasing plant density or by adding more kernels per plant would not appear to be a promising route for raising the yield potential.Key words: Sink strength, hydroponics, plant spacing, kernel number, yield components
THE EFFECT OF SIMULTANEOUS APPLICATION OF ETHEPHON OR 2,4-D ON THE ABSORPTION, TRANSLOCATION AND BIOCHEMICAL ACTION OF ASULAM IN BRACKEN FERN (Pteridium aquilinum (L.) Kuhn)
Authors: HINSHALWOOD A. M. , KIRKWOOD R. C.
Published: April 2011

The effects of ethephon and 2,4-D on the absorption, translocation and biochemical action of asulam were examined in field- and pot-grown bracken (Pteridium aquilinum (L.) Kuhn). In pot plants, asulam was observed to translocate basipetally to the rhizome system, greater accumulation being evident in the buds and apices compared to the rhizome per se. Although 2,4-D increased absorption of 14C-asulam, neither 2,4-D nor ethephon significantly affected total basipetal translocation. Ethephon was found to reduce accumulation of 14C-asulam within the target meristematic tissues of the rhizome system; this may account for the reduction in bracken control with asulam (4.40 kg a.i. ha−1) + ethephon (0.33 kg a.i. ha−1) compared to asulam alone (65 and 81% control, respectively). September application of asulam (4.40 kg a.i. ha−1) significantly reduced frond density in the following season. The incorporation of 14C-leucine into protein, and the folate levels were reduced in buds and apices treated with asulam. Simultaneous application of 2,4-D (0.33 kg a.i. ha−1) had no significant effect on the activity of asulam (4.40 kg a.i. ha−1) with respect to frond density and the reduction of folate levels, although there was evidence of antagonism with respect to protein synthesis. Free folate levels in rhizome apices treated with asulam + ethephon were greater than in those treated with asulam alone.Key words: Bracken, asulam, absorption, translocation, biochemical action
THE BIOLOGY OF CANADIAN WEEDS.: 90. Abutilon theophrasti
Authors: WARWICK S. I. , BLACK L. D.
Published: April 2011

Abutilon theophrasti Medic. (velvetleaf) forms extensive weed infestations in all major maize and soybean growing areas of Ontario and Quebec. A review of the literature on the biology of the species is presented. Velvetleaf causes crop losses through competition, allelopathic effects and by hosting insect pests and pathogens of crops. Velvetleaf has a number of features which contribute to its success as a weed, including: the production of a large number of seeds that have high viability with prolonged dormancy and sporadic, continuous germination patterns; robust seedling vigor; and the ability to produce seed under competition. Because of sporadic germination patterns, control is difficult. Effective control measures include the application of pre-emergence and/or postemergence herbicides followed by cultivation and additional herbicide applications to control escapes and later flushes of germination. A triazine-resistant bio-type of velvetleaf has recently been reported from the northeastern United States.Key words: Velvetleaf, Abutilon theophrasti, weed biology
KG 40 SOYBEAN
Authors: BRADNER N. R. , SIMPSON R. D. , HADLOCK A. A.
Published: April 2011

KG 40 is an early-maturing soybean (Glycine max) cultivar which has similar maturity and 4% higher yield than the cultivar Maple Arrow. Its main advantage is its yield performance and a high degree of phytophthora tolerance.Key words: Glycine max, soybean cultivar
KG 60 SOYBEAN
Authors: BRADNER N. R. , SIMPSON R. D. , HADLOCK A. A.
Published: April 2011

KG 60 is a moderately early maturing soybean (Glycine max) cultivar which is 1 d later and 14% higher yielding than the cultivar Pioneer 0877. Its main advantage is its very high yield potential.Key words: Glycine max, soybean cultivar
PS 80 SOYBEAN
Authors: BRADNER N. R. , SIMPSON R. D. , HADLOCK A. A.
Published: April 2011

PS 80 is a Maturity Group I soybean (Glycine max) cultivar which is 2 d later in maturity and slightly higher yielding than the cultivar Pioneer 1677. Its main advantage is superior export seed quality.Key words: Glycine max, Soybean cultivar
HERITABILITY AND GAIN CALCULATIONS FOR SIX-YEAR HEIGHT OF COASTAL WESTERN WHITE PINE IN BRITISH COLUMBIA
Authors: BOWER R. C. , YEH F. C.
Published: April 2011

Height growth for western white pine (Pinus monticola Dougl.) after five growing seasons (6 yr from seed) in the forest on Vancouver Island was assessed in a progeny test of 20 wind-pollinated families in two plantations: Northwest Bay (830 m) and Cassidy (20 m). Mean height differed at the 0.1% level of significance between plantations, with the better growth at Cassidy. Family mean heights differed at the 10, 1 and 5% levels of significance at Cassidy, Northwest Bay, and combined over plantations, respectively. Family-by-plantation interaction was nonsignificant. Pooled over plantations, the heritability estimates appropriate for mass and family selection were 0.36 ± 0.20 and 0.54 ± 0.28, respectively. The expected genetic gain estimates from multistage selection are used to provide preliminary guidelines for strategies which might be employed in the improvement of height growth of western white pine in coastal British Columbia.Key words: Western white pine, height, heritability, genetic gains
PLANT SPACING EFFECTS ON PHOTOSYNTHESIS AND TRANSPIRATION OF THE GREENHOUSE TOMATO
Authors: PAPADOPOULOS ATHANASIOS P. , ORMROD DOUGLAS P.
Published: April 2011

The effect of four equidistant spacings (23, 30, 38, 45 cm) applied to four-row plantings of greenhouse tomato (Lycopersicon esculentum Mill. ’CR-6’) on plant net photosynthesis (P) and transpiration (E) was studied. Closer spacing decreased the leaf-area-based net photosynthesis (Pa) of the lower leaves but had little effect on the Pa of the upper leaves. The exposed parts of a tomato plant could adjust their Pa rates upwards to compensate for the low Pa of their shaded parts. The leaf-weight-based net photosynthesis (Pw) increased with the decrease of plant spacing and it was higher in inside compared to outside plants. The differences between the Pa and Pw results were mostly attributable to the effect of light in increasing the specific leaf weight (SLW). The E rate of plants increased at the closest spacing and there was a higher leaf weight based transpiration (Ew) in inside than outside plants. The leaf area based transpiration (Ea) and stomatal resistance (Rw) were not affected appreciably by light (photosynthetic photon flux density) other than at very low levels (i.e. less than 100 μmol m−2 s−1) where there was a sharp increase in Rw and a corresponding decrease in Ea. The P of plants growing in an environment of gradually declining duration and intensity of solar irradiance declined with the aging of plants. There was no similar effect on E.Key words: Lycopersicon esculentum Mill, plant spacing, photosynthesis, transpiration, tomato
Effect of seeding date, rate and depth on winter wheat grown on conventional fallow in S.W. Saskatchewan
Authors: Campbell C. A. , Selles F. , Zentner R. P. , McLeod J. G. , Dyck F. B.
Published: April 2011

Winter wheat (Triticum aestivum L.) seeded on conventional fallow is considered to have a high risk of winterkill in the Brown soil zone of the Canadian Prairies, yet many producers in this area continue to use this approach. Although this system is subject to frequent winterkill, the alternative (seeding into standing stubble) is itself subject to frequent economic loss due to drought stress. A 4-yr study was carried out on a medium-textured, Orthic Brown Chernozem using Norstar winter wheat seeded into bare fallow land. Several seeding dates, depths and rates were tested to determine if alternate management strategies could be used to enhance the chances of overwinter survival thereby improving the incidence of successful production when this crop was grown on conventional fallow. Multiple regression was used to relate grain yields and plant counts (survival over winter) to the number of days before freeze-up when the crop was seeded and the other treatment factors. Results confirmed those reported in southern Alberta. For example, production was very variable and both plant survival and grain yields were mainly influenced by seeding date, with the optimum seeding period being the first 2 wk of September; yields decreased sharply on both sides of this period. However, seeding just prior to freeze-up gave higher yields than seeding 2 or 3 wk prior to freeze-up even though this latest seeded material did not geminate until spring. Depth of seeding influenced plant survival but had little influence on yield. The 5.0-cm depth was recommended as the best for fallow. Seeding rate influenced plant survival and yields more so than depth, but the influence was not large and none of the three treatments prevented severe winterkill when temperatures were extremely low. We recommended that a seeding rate of 60 kg ha−1 be chosen for fallow as is the case for stubble seeded wheat. Grain protein was not influenced by any treatment and was mainly a function of moisture deficit (year). In spite of the variability in production with this system of management, producers may still choose to grow winter wheat on conventional fallow since if winterkilling occurs they have the option of reseeding the area to spring wheat. Key words: Seeding date, seeding rate, seeding depth, yields, grain protein
Wheat Spike Temperature in Relation to Base Temperature for Grain Filling Duration
Authors: Pararajasingham S. , Hunt L. A.
Published: April 2011

Estimates of the base temperature for grain filling duration of wheat (Triticum aestivum L.) differ between outdoor and indoor studies. This study was set up to determine whether this difference could be attributed to variation in spike-air temperature differentials. Spike and/or spikelet temperatures were determined in wheat grown outdoors as well as indoors. Spike temperature, measured with an infrared thermometer, of wheat grown outdoors with adequate water supply was 1.5 °C greater than air temperature while spikelet temperature measured with a thermocouple closely approximated air temperature. In indoor grown wheat, on the other hand, regardless of the magnitude of air temperature, spikelet temperature was found to be 3–4 °C above that of air when lights were on. Estimating the base temperature for grain filling duration with data from a previous indoor study, with compensation for the 3–4 °C increase in spikelet temperature, resulted in 8.8 °C base temperature for grain filling duration, comparable to that obtained in outdoor studies. Differences between outdoor and indoor studies may thus reflect spike-air temperature differentials. Estimation of the base temperature for grain filling with air temperature appears appropriate for outdoor studies. Key words: Triticum aestivum (L.), base temperature, grain filling duration, wheat
Response of barley yield and yield components to nitrogen rate under low and high input management systems
Authors: Zebarth B. J. , Sheard R. W.
Published: April 2011

Increasing rates of nitrogen (N) fertilization may increase disease and lodging in cereals. As a result, use of high-input management (HIM) systems, which use growth regulators to control lodging and fungicides to control disease, may allow a greater increase in yield due to N fertilization than occurs in conventional low input management (LIM) systems. The study was conducted to determine the influence of two management systems on the response of yield and yield components of barley (Hordeum vulgare L.) to N fertilization and to determine if use of a HIM system was cost-effective under southern Ontario growing conditions. Barley, cv. Leger, was grown at eight rates of N fertilization under either HIM or LIM systems in 10 environments in southern Ontario. The response of grain and straw yield to N rate was not significantly different between management systems; however, the maximum economic yield occurred at a significantly higher N rate under the HIM system (90 kg N ha−1) than under the LIM system (71 kg N ha−1). The number of heads m−2 was higher under the HIM system than under the LIM system whereas the reverse was true for grains head−1. Increased N rate resulted in increased 1000-grain weight under the HIM system but had little influence on 1000-grain weight under the LIM system. Over the duration of the study, the increased revenue obtained under the higher input management system was generally less than the cost of the added inputs used, emphasizing the need for threshold values which producers can use to determine when crop protection inputs are likely to be cost-effective. Key words: Fungicide, growth regulator, seeding rate, nitrogen, barley
The biology of Canadian weeds.: 96. Senecio jacobaea L.
Authors: Bain John F.
Published: April 2011

Senecio jacobaea L. (tansy ragwort) is a roadside and pasture weed which was introduced into Canada in the 1850s. It is established in cool, wet areas, most commonly on the east and west coasts. The species is important economically because the presence of pyrrolizidine alkaloids in the foliage makes it toxic and the poisoning of livestock has resulted. Individuals produce dimorphic achenes which possess different dormancy and dispersal characters and are therefore able to establish in a wider range of habitats. Vegetative reproduction is common especially after damage to the plant. Control of the weed is achieved either through the application of hormone-like herbicides or by biological means. The establishment of the biological control agent, cinnabar moth (Tyria jacobaeae L.), in populations has resulted in defoliation of individuals but has not resulted in effective control of the weed, except in eastern Canada. Key words: Tansy ragwort, Senecio jacobaea, biological control, pyrrolizidine alkaloids
Yield responses of oats and alfalfa to common hemp-nettle (Galeopsis tetrahit) interference
Authors: Légère Anne , Deschênes Jean-Marc
Published: April 2011

Effects of various densities of hemp-nettle (Galeopsis tetrahit L.) on yields of oats (Avena sativa L.) and first year alfalfa (Medicago sativa L.) were investigated in field experiments. In both crops, emergence of hemp-nettle seedlings occurred after plot establishment such that final densities were generally greater than initial densities. Hemp-nettle plants within a stand were distributed normally over no more than seven 15-cm height classes. Very few plants were found in the lower height classes. Weight distribution according to the same height classes showed that average to tall individuals produced a large proportion of the weed biomass. Oat yields decreased as hemp-nettle density increased. In the density range of 28–248 hemp-nettle plants m−2, oat grain yield losses varied between 12 and 50%. Alfalfa was cut according to either a two-cut regime, or a three-cut regime which included an early harvest. Alfalfa yields decreased with increase in hemp-nettle density regardless of cutting regime, whereas effects of cutting regime on alfalfa yield varied with year of experiment. In each regime, timing of first harvest determined the duration of hemp-nettle interference and may have affected the degree of carry-over effects to later harvests. Key words: Hemp-nettle, Galeopsis tetrahit, weed competition, weed interference, crop losses
PS 42 soybean
Authors: Bradner N. R. , Simpson R. D. , Hadlock A. A.
Published: April 2011

PS 42 is a Maturity Group 00 soybean (Glycine max (L.) Merr.) cultivar which is 2 d later and higher yielding than the cultivar OAC Scorpio. Its main advantages are its yield performance, lodging resistance and phytophthora rot tolerance. Key words: Glycine max, PS 42 cultivar, cultivar description
Resistance of alfalfa cultivars to brown root rot
Authors: Berkenkamp B. , McCartney D. , Bittman S.
Published: April 2011

Alfalfa cultivars were evaluated for resistance to the low-temperature disease, brown root rot, caused by Phoma sclerotioides, and for forage yield in field trials with naturally occurring disease. The cultivar Peace was the most resistant, followed by Algonquin, Beaver, Apica, Anchor and Pacer. Yields were closely related to root rot resistance. Key words: Brown root rot, alfalfa, Phoma sclerotioides, Plenodomus meliloti, resistance, losses
Incidence of rain splitting in sweet cherries treated with calcium or coating materials
Authors: Meheriuk M. , Neilsen G. H. , McKenzie D.-L.
Published: April 2011

Calcium chloride (CaCl2) and Ca(OH)2 sprays reduced rain splitting in Van cherries (Prunus avium L.). Multiple applications were better than single sprays. Soluble solids content was increased in many instances by the treatments. Fruit shrivel was appreciable in cherries sprayed with Ca(OH)2 particularly in hot seasons. Single or multiple applications of Nutri-Save (a polymeric coating), Pro-Stick (a sticking agent) and Envy (an antitranspirant) did not affect rain splitting in Stella cherries. Key words: Prunus avium L., calcium sprays, fruit shrivel, cherry
Controlled atmosphere and lighting effects on storage of winter cabbage
Authors: Prange R. K. , Lidster P. D.
Published: April 2011

Two late-storage cultivars of cabbage, Lennox and Bartolo, were stored in three atmospheres (% oxygen + % carbon dioxide) of air (21 + 0), 3 + 5 and 2.5 + 3 in darkness and in low light, replicated over two seasons. Samples were removed after 3 and 6 mo of storage. Cabbage heads were analyzed for storage and trim loss, disease and physiological disorders. Outer leaves of marketable heads were sampled for chlorophyll content, cell solute leakage, relative water content and colorimetric L (Lightness), hue (color) and saturation (intensity). Neither storage atmosphere nor light affected final and marketable head weights. Controlled atmosphere storage reduced disease, although disease problems were mainly superficial; penetration through the head was not enough to cause trim losses or yield reductions. Controlled atmosphere helped to retain green color in Lennox, which was less green than Bartolo. There was a beneficial effect of light on reduction of physiological disorders, indicating that future research using a higher radiation level in storage may reduce trim losses, enhance leaf color, and improve marketability of stored cabbage. Key words: Controlled atmosphere, light, cabbage, color, disease, cell leakage
Use of residual maximum likelihood to evaluate accuracy of two NIRS calibration procedures, relative to Kjeldahl, for determining nitrogen concentration of soybeans
Authors: Schaalje G. B. , Mündel H. -H.
Published: April 2011

The accuracy of estimates of plant properties based on near-infrared reflectance spectroscopy (NIRS) varies with many factors including the biological material in question and the method used to calibrate the NIRS instrument. This study investigated the accuracy, relative to Kjeldahl analysis, of NIRS analysis based on two calibration methods in estimating nitrogen concentration of four stages and/or parts of soybean (Glycine max (L.) Merr.) plants. Samples of whole top growth at anthesis, whole top growth at maturity, whole top growth at maturity excluding seeds, and seeds were obtained from two field trials and one phytotron experiment. Two Kjeldahl determinations of nitrogen concentration were obtained for each sample, as well as reflectance values at each of 19 infrared wavelengths, using a Technicon InfraAlyser 400R. Different subsets of the sample data were used for calibration and assessment of accuracy. The instrument was calibrated using stepwise multiple linear regression (SMLR) and principal component regression (PCR). The residual maximum likelihood procedure was useful in showing that NIRS estimates based on either SMLR or PCR were at least as accurate as Kjeldahl estimates for all stages and/or parts except whole top growth at maturity excluding seeds. Key words: Calibration, principal component regression, stepwise regression
Influence of seed size in canola, Brassica napus L. and mustard, Sinapis alba L., on seedling resistance against flea beetles, Phyllotreta cruciferae (Goeze)
Authors: Bodnaryk R. P. , Lamb R. J.
Published: April 2011

Seedlings of Brassica napus L. 'Westar' or Sinapis alba L. 'Ochre' grown from seeds of various size were offered to flea beetles, Phyllotreta cruciferae (Goeze) in feeding tests for damage assessment. The proportion of cotyledon area damaged in both species was highest for seedlings grown from small seeds in choice and no-choice feeding tests. The proportion of seedlings killed by flea beetle feeding was also highest in seedlings from small seeds, an effect that was especially pronounced at high beetle densities (10/seedling) where 100% of seedlings from small seeds of B. napus were killed compared to 28.3% of seedlings from big seeds. For S. alba, at 20 beetles/seedling, 45.4% of seedlings from small seeds were killed compared to only 9.1% of seedlings from big seeds. Seedlings grown from big seeds of S. alba tolerated low levels of damage caused by flea beetle feeding or by scissors. No evidence for tolerance was obtained for seedlings from small seeds of S. alba or for seedlings from big or small seeds of B. napus. "Big seeds" appears to be a desirable trait that enhances crucifer seedling resistance to flea beetle attack and results in increased seedling survival. Key words: Brassica napus 'Westar', Sinapis alba 'Ochre', Phyllotreta cruciferae, flea beetle, seed size, resistance
A nondestructive method to monitor leaf greenness in corn
Authors: Dwyer L. M. , Tollenaar M. , Houwing L.
Published: April 2011

A portable chlorophyll meter was calibrated with extractable chlorophyll measurements from six corn (Zea mays L.) hybrids, and the utility of the meter in identifying differences in leaf greenness was assessed in growth-cabinet and field studies. A single linear regression described the relationship between meter readings and extractable chlorophyll concentration for leaves of all hybrids at a range of growth stages (r2 = 0.83). Meter measurements resolved differences in chlorophyll concentration of two additional test hybrids resulting from different temperature regimes in the growth-cabinet, and from different leaf positions and stages of development in the field (P < 0.01). Considerable replication of meter readings was found necessary to resolve treatment differences in chlorophyll concentration. Caution is advised in using the calibration at very low chlorophyll concentrations such as those occurring as the plant nears senescence. Key words: SPAD 501, chlorophyll, leaf senescence, linear regression
Waldern oat
Authors: Kibite Solomon
Published: April 2011

Waldern is a high-yielding spring oat (Avena sativa L.) cultivar developed at the Agriculture Canada Research Station in Lacombe, Alberta. It was selected from a Gemini/Cascade cross. Waldern yields more grain than Calibre and Cascade, has heavier kernels and a larger percentage of plump kernels. It is recommended for the Dark Brown, Black and Grey-Wooded soils of Alberta and Western Saskatchewan. Key words: Avena sativa, oat, cultivar description