bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of humic substances on carbohydrate metabolism of maize leaves
Authors: Merlo L. , Ghisi R. , Passera C. , Rascio N.
Published: April 2011

Maize plants were grown in nutrient solution with or without 100 mg organic carbon L−1 of humic substances (HS) (MW > 12 000) extracted from a cambisol. To evaluate the effect of HS on leaf carbohydrate metabolism, after 14 d of growth apical and basal segments from the third leaf were collected and analyzed for sugar content and for the activities of enzymes involved in the synthesis and breakdown of starch and sucrose. Leaf starch content decreased in treated plants, whereas the level of soluble sugars increased. The decrease of starch was accompanied by an enhanced activity of amylase, whereas the activity of ADPglucose pyrophosphorylase was not affected. Activities of invertases and sucrose synthase were stimulated by HS treatment in apical tissue, and inhibited in basal one. Activities of enzymes involved in sucrose biosynthesis (sucrose phosphate synthase, cytoplasmic fructose-1,6- bisphosphatase, UDPglucose pyrophosphorylase) were stimulated or inhibited depending on the enzyme and on the tissue examined. Our results show that HS may affect both the level and percent distribution of sugars of maize leaves; these effects seem to be mediated by changes in the activities of enzymes involved in carbohydrate metabolism. Key words: Humic substances, enzymes, carbohydrate metabolism, maize
Biggar red spring wheat
Authors: DePauw R. M. , Preston K. R. , Townley-Smith T. F. , Hurd E. A. , McCrystal G. E. , Lendrum C. W. B.
Published: April 2011

Biggar red spring wheat (Triticum aestivum L.) combines high grain yield potential with semidwarf stature and wide adaptation. Biggar has improved end-use suitability relative to HY320 such as harder kernels, better flour milling properties, greater water absorption, and stronger gluten properties. It received registration No. 3089 and is eligible for grades of Canada Prairie Spring (red). Key words: Triticum aestivum, wheat (spring), high yield, cultivar description
Harovinton soybean
Authors: Buzzell R. I. , Anderson T. R. , Hamill A. S. , Welacky T. W.
Published: April 2011

Harovinton is a large-seeded soybean (Glycine max) cultivar with a greater protein content than oilseed cultivars and is suitable for tofu production. It is resistant to Phytophthora megasperma f. sp. glycinea (Rps1-c) and tolerant of metribuzin herbicide (Hm). Production will be on a contract basis with Canada Packers, Inc. Key words: Cultivar description, Harovinton soybean
Tiller production and dry matter accumulation in six creeping bentgrass genotypes grown in Manitoba
Authors: Cattani D. J. , Entz M. H. , Bamford K. C.
Published: April 2011

Tiller production and dry matter accumulation were monitored in six creeping bentgrass (Agrostis palustris Hud.) genotypes maintained as a putting green. Core samples for tiller density and aboveground biomass determinations were collected at intervals between October 1987 and October 1989. Two experimental lines, UM84-01 and UM86-01, produced more (P < 0.05) tillers and higher (P < 0.05) aboveground biomass than the commercial cultivars Penneagle, National, Emerald and Seaside. Both tiller density and aboveground biomass rankings among genotypes were consistent over the study period. Although lower tillering genotypes had a significantly higher aboveground biomass per tiller, total aboveground biomass was influenced more by tiller density than by biomass per tiller. The relationship between tiller density and tiller dry weight was expressed mathematically to determine potential wear stress resistance among genotypes. Key words: Creeping bentgrass, tillering, biomass accumulation
Genetic control of a slow-ripening fruit trait in nectarine
Authors: Ramming D. W.
Published: April 2011

Inheritance of a slow-ripening trait was investigated in segregating progenies of nectarine (Prunus Persica (L.), Batsch var. nucipersica Schneid). Segregation ratios suggest that the trait is controlled by a single recessive gene, for which the symbol sr is proposed. Fantasia, Flamekist, and Fairlane nectarines are heterozygous at the sr locus. Key words: Peach, breeding, postharvest, genetics, stone fruit
Temperature and genotypic effects on the expression of pol cytoplasmic male sterility in summer rape
Authors: Burns D. R. , Scarth R. , McVetty P. B. E.
Published: April 2011

The effect of high temperature treatment on the expression of cytoplasmic male sterility (CMS) was studied using inbred lines of four summer rape (Brassica napus L.) cultivars. The nuclear genotypes of inbred lines from each of the cultivars Karat, Lergo, Marnoo and Regent were evaluated for their ability to maintain pollen sterility in the pol cytoplasm. Seven days' exposure to day/night temperatures of 30/24 °C in a controlled environment led to increased pollen production in all of the F1 populations (F1's) in the study. Maximum reversion to male fertility occurred 6–13 d after removal from the high temperature treatment. There was a significant linear relationship between daily mean temperatures in the field and mean male sterility index (MSI). In Lergo, Marnoo and Regent F1's, the effect of high temperatures on male sterility expression in terms of days to maximum pollen production in the field was accurately predicted by the values obtained in the controlled environment study. For the Karat F1's, the maximum response in the field occurred later than in the controlled environment. Variation in the stability of male sterility was evident in the F1's, indicating the presence of different maintainer genes among the inbred lines of each cultivar. The absence of environment-by-line interactions in the F1's of three cultivars indicated a high degree of stability for this trait. Selection for maintenance of high levels of male sterility may therefore be possible. Key words: Brassica napus, male fertility reversion
Seed dispersal and seedling establishment of Linaria vulgaris Mill.
Authors: Nadeau Léonie B. , King Jane R.
Published: April 2011

The importance of seeds to the establishment and spread of Linaria vulgaris infestations in Alberta was assessed in 1988 and 1989. Stands were established on 17 May 1988. One 10-cm-long root piece with a 10-cm-tall shoot was planted in the centre of each of nine plots on fallow land and of nine plots in a barley crop. Over 90% of seeds in 1988, and over 80% in 1989 fell within a 0.5-m radius of the parent plants with very few seeds falling outside a 1.5-m radius. Seed deposition vs. distance followed a negative polynomial function. It was estimated that over 210 000 seeds m−2 fell less than 0.5 m away from the parent plant over the 1988 growing season. The presence of Gymnaetron sp. and Brachypterolus sp. in 1989 reduced seed deposition to a total of 1410 seeds m−2 within 0.5 m of the parent plant. The few seedlings that were established occurred in clumps, with densities varying from 1.3 to 7.0 seedlings cm−2 in May and from 0.8 to 7.8 seedlings cm−2 in June 1989. In 1988, total seedling emergence per plot varied between 0.13 and 0.23%. Seed viability and dormancy were major factors influencing seedling establishment. Seed viability was as low as 40% (tetrazolium test), and germination was maximized in the laboratory following a wet stratification at 5 °C for a period of at least 8 wk. Key words: Toadflax, Linaria vulgaris, seed dispersal, seedling establishment, seedling distribution
Tillage and rotation influences on weed community composition in wheat (Triticum aestivum L.) in southwestern Saskatchewan
Authors: Hume L. , Tessier S. , Dyck F. B.
Published: April 2011

The effects on weed community composition of zero-, minimum-, and conventional tillage practices were examined on three soil types under both continuous wheat (Triticum aestivum L.) and wheat-fallow rotations between 1982 and 1989. Green foxtail [Setaria viridis (L.) Beauv.] became a problem on continuously cropped plots, especially on the sandy loam soil where densities reached a maximum of 2354 plants m−2 with conventional tillage. Without tillage, high densities of foxtail barley (Hordeum jubatum L.) developed since this species was not adequately controlled by herbicides. Even in a year when precipitation was only 63% of normal, perennial shoots of this species achieved a maximum density of 1222 plants m−2. A hoe seeder tended to improve foxtail barley control relative to the disc seeder used, likely due to greater soil disturbance. Wheat losses were significantly correlated to weed density, and it was concluded that, in terms of weed control in wheat, some degree of tillage may be required in southwestern Saskatchewan. Key words: Tillage, Setaria viridis, green foxtail, Hordeum jubatum, foxtail barley, wheat
Floristic composition and relative abundance of weeds in annual crops of Manitoba
Authors: Thomas A. G.
Published: April 2011

Annual surveys for weeds of fields seeded to spring wheat, barley, oats, flax, and canola in Manitoba were conducted during 1978, 1979, and 1981. Fields were surveyed during July and early August each year using a stratified random sampling procedure. Data for the crops and years were combined for analysis. The frequency, the area infested, and the density of the infestation were determined for each species. These three measures of the abundance of the weed were combined into a single synthetic value called relative abundance. Nine of the 152 species recorded by the surveyors accounted for 77% of the total relative abundance. Ranked in order by relative abundance, these species were green foxtail (Setaria viridis (L.) Beauv.), wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), annual smartweed (Polygonum spp.), Canada thistle (Cirsium arvense (L.) Scop.), lamb's-quarters (Chenopodium album L.), wild mustard (Sinapis arvensis L.), perennial sow-thistle (Sonchus arvensis L.), and redroot pigweed (Amaranthus retroflexus L.). Green foxtail was the predominant weed with an abundance value three times larger than wild oats or wild buckwheat. The pattern of dominance found in Manitoba fields was similar to results from comparable surveys in Saskatchewan and North Dakota. Key words: Relative abundance, weed survey, weed density, green foxtail, wild oats, wild buckwheat
Nattoking K86 soybean
Authors: Bradner N. R. , Simpson R. D. , Hadlock A. A.
Published: April 2011

NattoKing K86 is a Maturity Group 00 soybean (Glycine max (L.) Merr.) cultivar having higher yield performance, smaller seed size, and later maturity than Canatto. Key words: Glycine max, NattoKing K86 cultivar, cultivar description, soybean
Integrated pest management of disease and arthropod pests of greenhouse vegetable crops in Ontario: Current status and future possibilities
Authors: Shipp J. L. , Boland G. J. , Shaw L. A.
Published: April 2011

Disease and arthropod pests are a continual problem for greenhouse vegetable production. These problems range from minor infestations to major disease or arthropod pest outbreaks that can destroy an entire crop. In Ontario, in the past, the major management strategy was pesticide control. However, many plant pathogen, insect and mite pests are resistant to registered pesticides and few new pesticides are being developed. Alternative control strategies exist or are being developed for most major pests. This review describes the current status of pesticide, cultural and biological control of disease and arthropod pests of greenhouse vegetables in Ontario and discusses the future possibilities for the integration of pest management practices utilizing plant resistance, nutrition, environment and biological control agents into an expert system approach. Key words: Vegetable (greenhouse) crops, integrated pest management
Protein production and nitrogen utilization by barley cultivars in response to nitrogen fertilizer under varying moisture conditions
Authors: Grant C. A. , Gauer L. E. , Bailey L. D. , Gehl D. T.
Published: April 2011

In a 3-yr field experiment, six barley cultivars — one conventional height malting type, two semidwarf, two conventional height, and one short feed type — were grown at three sites, with six nitrogen application rates ranging from 0 to 200 kg ha−1, to determine the effects of cultivar and N level on N utilization under varying moisture conditions. Nine site-years of data were divided into three levels, low, moderate, and high, based on estimated moisture supply. As moisture level increased, protein concentration of the barley cultivars decreased, while protein yield and total N uptake increased. Cultivars with higher grain yield tended to be lower in protein concentration, but higher in protein yield, total N uptake and N use efficiency than those with lower grain yields. Differences among the cultivars in protein concentration were greater at low than high moisture levels, while differences due to N application were greater at high than low moisture levels. Within the range of N applied, nitrogen use efficiency decreased at high N levels under low and moderate moisture conditions, but was relatively constant at high moisture levels. Protein concentration response to N applications differed slightly among cultivars at all moisture levels, but cultivar by N level interactions in protein yield response only occurred under high moisture conditions. Cultivars respond similarly to N applications in terms of straw N concentration, total N uptake and N use efficiency. Key words: N, nitrogen, barley (Hordeum vulgare), moisture, protein, N use efficiency
Isozymes as markers for identification of tissue culture and greenhouse-grown strawberry cultivars
Authors: Nehra N. S. , Kartha K. K. , Stushnoff C.
Published: April 2011

Polyacrylamide gel electrophoresis (PAGE) was used for analysis of isozyme banding patterns of leucine aminopeptidase (LAP), phosphoglucomutase (PGM), phosphoglucoisomerase (PGI), esterase (EST) and 6-phosphogluconate dehydrogenase (6-PGD) in strawberry leaves. The extracts prepared from young leaf tissues using polytron homogenization and an extraction buffer containing 15 mg ml−1 dithiothreitol (DTT) and 10% insoluble polyvinylpyrrolidone (PVP-6755) gave best resolution for these enzymes. The influence of plant age and various growing environments on the stability of isozyme phenotypes was examined. The isozyme banding patterns of 6-PGD were found to vary with the change in growing environment as well as age of the plants. EST produced different banding patterns in greenhouse and tissue culture leaves. However, the isozyme phenotypes of LAP, PGM and PGI remained stable under all the conditions tested. Using a combination of these three stable enzymes, it was possible to distinguish eight strawberry cultivars under both tissue culture and greenhouse conditions. Key words: Fragaria × ananassa Duch., meristem culture, polyacrylamide gel electrophoresis
Branching, flowering and pod-set patterns in snap-bean (Phaseolus vulgaris L.) as affected by temperature
Authors: Kigel Jaime , Konsens Irit , Ofir Micha
Published: April 2011

The effect of temperature on branching, flowering and pod-set patterns of determinate snap-bean (Phaseolus vulgaris L.) cultivars has not been well documented. In this work, well-defined rigid gradients of branching and flowering were found in determinate snap-bean. However, in spite of the great developmental stability of these gradients, pod production and distribution along the main axis of the bean plant was highly plastic in its response to environmental conditions. Under controlled conditions, high temperature (32/27 °C) drastically reduced pod production even though branching and flowering were greatly increased. Under lower temperatures most (>50%) mature pods were produced by branches of the first and second trifoliolate leaves. Low night temperature (12 °C) increased branching and relative pod production by more basal nodes, mainly by primary leaves branches. Large shifts in the relative contribution to mature pod production by main inflorescence and branches at different nodal positions along the main shoot were observed also in the field. It appears that in determinate cultivars of snap-bean the rigid gradients in branching and flowering do not limit pod production because of compensatory rapid developmental adaptation to transient environmental stresses. Key words: Snap-bean, Phaseolus vulgaris L., branching, pod-set, temperature
Fruit quality of McIntosh apples irrigated with well or municipal waste water
Authors: Meheriuk M. , Neilsen G. H.
Published: April 2011

McIntosh apples (Malus domestica Borkh.) irrigated with municipal waste water were softer at harvest and had lower fruit Cu than comparable fruit irrigated with well water. Fruit size, percent red skin color, soluble solids content and fruit N, Ca, K/Ca, K + Mg/Ca, K + Mg + Na/Ca, B, Fe, Mn and Zn were not affected by source of water. Fruit P, Mg, K and Na were higher in apples irrigated with waste water in the second but not the first year of the 2-yr study. Titratable acidity was higher with well water the first year and with waste water the second year. Incidence of core flush was higher in the fruit irrigated with waste water. Key words: Apple, skin color, flesh firmness, titratable acidity, soluble solids content, fruit Ca, Mg, K, Cu, Na, N and P, core flush
Yield and protein response of hard red winter wheat to rate of nitrogen fertilization and previous legume crop
Authors: Zebarth B. J. , Sheard R. W.
Published: April 2011

The purpose of the study was to determine the influence of a previous legume or non-legume crop on the yield and crude protein response of hard red winter wheat to the rate of N fertilization. The average N requirement for the maximum economic production of wheat was reduced from 69 kg N ha−1 following corn to 0 kg ha−1 following alfalfa. Crude protein concentration was as much as 2% higher following alfalfa than corn; however, an average of 144 kg N ha−1 following corn and 59 kg N ha−1 following alfalfa was necessary to achieve the optimum level of 13.5% crude protein in the wheat.Key words: Corn, alfalfa, ICM
Effects of nitrogen supply and spatial arrangement on the grain yield of a maize/soybean intercrop in a humid subtropical climate
Authors: Clément Alain , Chalifour François-P. , Gendron Ghislain , Bharati Maheshwar P.
Published: April 2011

Cereal/legume intercropping is a common practice in low-input agricultural systems. Under appropriate conditions, it usually results in higher overall productivity as compared with pure stands. Appraisal of agronomic practices is of particular importance, since component crops sometimes differ considerably in their structure and fertilization needs. An experiment was conducted under the subtropical conditions of Southern Nepal, in the Terai belt, in 1988 and 1989. Maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) received 0, 35 or 70 kg N ha−1 when grown either in pure stands or when intercropped in two spatial arrangements differing in spatial intimacy. Nitrogen fertilization resulted in similar grain yield increases for maize either in pure stands or in intercropping with soybean, indicating that the availability of nitrogen for the cereal was comparable in both cropping systems. Soybean yields were 22% lower in the presence of maize, as compared with a pure stand. The overall productivity of intercropping, as assessed by ATER (area-time equivalent ratio), was significantly higher than that of pure stands in 1988 and 1989. Land-use efficiency was higher when maize was intercropped with nodulating soybean, as compared to non-nodulating soybean, but only at 0 and 35 kg N ha−1.Key words: ATER, land-use efficiency, non-nodulating soybean isoline, nitrogen fertilization, spatial arrangement, interactions
Nitrogen and light partitioning in a maize/soybean intercropping system under a humid subtropical climate
Authors: Clément Alain , Chalifour François-P. , Gendron Ghislain , Bharati Maheshwar P.
Published: April 2011

Land-use efficiency in a cereal/legume intercropping system is related to the complementarity of resource use in time or space. Nitrogen and light partitioning in a maize (Zea mays L.)/soybean (Glycine max (L.) Merr.) intercropping system under subtropical climatic conditions in Nepal was studied during the summers of 1988 and 1989. Factors studied included the cropping system (sole cropping vs. intercropping), three levels of nitrogen fertilization (0, 35 and 70 kg N ha−1) and two spatial arrangements of the intercrops. During the second season, a non-nodulating soybean isoline of the same cultivar was used as a control. The cropping system had a limited impact on soybean nodulation, since intercropped soybean nodules dry weights were only 11% and 6% inferior, as compared with sole cropped soybean, in 1988 and 1989, respectively. However, the seed N yield of sole cropped nodulating soybean was significantly higher than the total seed N yield of intercropped maize/nodulating soybean. The reverse effect was measured in the case of the maize/non-nodulating soybean intercropping system. Intercropping maize with soybean did not result in the interception of a higher proportion of the incident photosynthetic photon flux density (PPFD) than sole soybean, except early during the season. Intercropped nodulating soybean developed a dense underlying canopy, and was able to intercept 95% of incident PPFD after maize harvest.Key words: LER, resource capture efficiency, Bradyrhizobium japonicum, PPFD interception
Effect of three systemic fungicides on deoxynivalenol (vomitoxin) production by Fusarium graminearum in wheat
Authors: Boyacioglu D. , Hettiarachchy N. S. , Stack R. W.
Published: April 2011

The effect of triadimefon, propiconazole and thiabendazole fungicides on the growth of Fusarium graminearum and the production of deoxynivalenol in wheat was investigated in a field trial. The heads of wheat plants were infected with F. graminearum spores (1 × 105 conidia mL−1, approximately 62.5 mL m−2) 2 d following anthesis. Triadimefon (Bayleton 1.8 E.C), propiconazole (Tilt 3.6 E.C) and thiabendazole (Mertect 340-F) were sprayed at the dosages of 60, 120, and 360 g a.i. ha−1, respectively. Treatments of wheat plants with the fungicides were conducted at three time schedules: (1) one application at 2 d before inoculation, (2) one application at 2 d after inoculation, and (3) two applications at 2 d before and 2 d after the inoculation of wheat plants with F. graminearum. Treatments with triadimefon and propiconazole fungicides resulted in 39–61% and 34–79% decreases in F. graminearum infection and deoxynivalenol levels, respectively. Although treatment with thiabendazole resulted in the maximum reduction (83%) in deoxynivalenol level, it had no significant effect on F. graminearum infection.Key words: Fusarium graminearum, deoxynivalenol, vomitoxin, fungicides, triadimefon, thiabendazole, propiconazole
Post-flowering forage potential of spring and winter cereal mixtures
Authors: Baron V. S. , Dick A. C. , Najda H. G. , Salmon D. F.
Published: April 2011

Forage quality of small grain cereals harvested after flowering affects animal performance adversely. The feasibility of using mixtures (MX) of spring-planted winter cereals with spring cereals to improve forage quality at the late milk stage of the spring cereal was investigated at Lacombe and Brooks, Alberta during 1987 and 1988. Spring monocrops (SMC) of oats (Avena sativa L.) and barley (Hordeum vulgare L.) and winter monocrops (WMC) of wheat (Triticum aestivum L.) and winter triticale (× Triticosecale Wittmack) were compared with binary MX of spring and winter combinations using a randomized complete block design. Dry matter (DM) yield and concentrations of in vitro digestible organic matter (IVDOM), crude protein, neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin were determined. Dry matter yields of MX as a percent of their SMC counterparts ranged from 84 to 99% at Lacombe and from 82 to 113% at Brooks; no crop combination was consistently superior. For forage quality the cropping systems ranked WMC > MX > SMC. The effects of winter wheat and triticale on forage quality in the MX were similar. However, MX containing barley generally had higher IVDOM and lower NDF, ADF and lignin concentrations than those containing oats. At Lacombe and Brooks, IVDOM and crude protein concentrations of the MX were increased by 6.5 and 7.2% and by 21.2 and 23.6%, respectively, while NDF, ADF and lignin concentrations were decreased by 6.7 and 6.5%, 9.9 and 7.5%, 10.9 and 20.4%, respectively, compared with the SMC group. While the extent of compensation is not known the improved forage quality of the MX should partially offset the slight reduction in DM yield compared to the SMC.Key words: Forage potential, forage quality, mixtures, spring cereals, winter cereals
Influence of summer cutting and fertilizer application on Altai wild rye in winter
Authors: Willms W. D.
Published: April 2011

The effects of summer cutting and fertilizer application treatments on Altai wild rye (Elymus angustus Trin.) yield and nutritive value in winter were examined in a 3-yr study in the Chernozemic Black soils of the foothills region in southwestern Alberta. Regrowth after harvest had significantly decreased acid detergent fiber (ADF) and increased crude protein (CP), phosphorus (P), and calcium (Ca) by January but decreased forage yield and plant height in regrowth after cutting. Fertilizer application significantly (P < 0.05) increased dry matter yields and the concentration of CP, P, and Ca, while decreasing the concentration of ADF. Forage decreased in nutritive value, as determined by the concentration of each constituent, until November; after that, changes were no longer significant (P < 0.05). However, the effects of either fertilizer or cutting treatments on the nutritive value were generally maintained to the end of the sampling period in March. Fertilizer application made access to standing forage easier for cattle in winter, as defined by plant height, but summer cutting reduced it. Cutting and fertilizer application can be used to improve the nutritive value of forage in winter to meet the requirements of dry pregnant beef cows, but this requires substantial fertilizer application. Rather than applying high rates of fertilizer, it may be advantageous to supplement nutrients to livestock on winter pasture.Key words: Winter grazing, forage quality, weathering losses
Forage production by four annual cropping sequences emphasizing barley under irrigation in southern interior British Columbia
Authors: Thompson D. J. , Stout D. G. , Moore T.
Published: April 2011

Forage yield and quality of four annual cropping sequences were compared under irrigation in the southern interior of British Columbia. Spring barley (Hordeum vulgare L.) was intercropped with annual ryegrass (Lolium multiflorum Lam.) (BR), double cropped alone (B–B), double cropped in mixtures with common vetch (Vicia saliva L.) (BV-BV), or double cropped with annual ryegrass included with the second crop (B–BR). Averaged over 2 yr, BR produced 19% more dry matter, 38% more in vitro digestible dry matter and 43% more crude protein than B–B. Intercropped common vetch (BV–BV) improved forage quality and increased protein yield of both barley crops without reducing seasonal dry matter yield. Intercropping annual ryegrass reduced the neutral detergent fiber of both barley crops, but did not affect other quality characteristics or yield.Key words: Forage mixtures, barley, annual ryegrass, common vetch, forage yield and quality
Potential for increasing nitrogen fixation in grain legumes
Authors: Buttery B. R. , Park S. J. , Hume D. J.
Published: April 2011

This review considers the main factors determining the level of nitrogen fixation in the major grain-legume crops (chickpea, common bean, cowpea, faba bean, lentil, pea, peanut, pigeon pea and soybean) and discusses the possibilities and means for improving symbiotic nitrogen fixation. Methods of determining whether nitrogen is limiting growth and yield are discussed, and responses of the various crops to both the addition of nitrogen fertilizer and inoculation with effective strains of rhizobia are described. The present situation and future prospects for increasing nitrogen fixation through plant breeding, development of superior strains, superior host–strain combinations, improved inoculation techniques, bioengineering and other non-traditional methods are discussed. The general conclusions are that increases in nitrogen-fixation potential should be possible in all grain legumes through both plant breeding and strain improvement. Major increases in the quantity of nitrogen fixed could be achieved simply by improving general cultural practices; however, in developing countries, where the gap between actual and potential crop yield is so large, such improvements are likely to occur very slowly.Key words: legumes (grain), nitrogen fixation, nodulation, Rhizobium, Bradyrhizobium, breeding, strain selection
Stomatal conductance, photosynthesis and acetylene reduction rate in soybean genotypes
Authors: Djekoun A. , Planchon C.
Published: April 2011

Yield limitation in soybean (Glycine max L. Merr.) can result from decreases in photosynthesis and N2 fixation during periods of water deficiency. In this study, the relationships among stomatal conductance, photosynthesis and N2 fixation were analyzed in connection with drought tolerance of genotypes. Plants were grown in pots and exposed to field conditions. Carbon dioxide exchange rate was measured by gas analysis and nodule activity by the acetylene reduction method. Leaf water status was determined with a pressure bomb, and nodule water potential and leaf osmotic potential were measured psychrometrically. The differing tolerances of the cultivars Kingsoy and Hodgson to leaf water deficit resulted in a more or less developed ability of the lower side of the leaf to maintain good stomatal conductance during water stress. Stomatal conductance affects photosynthetic rate directly and acetylene reduction activity indirectly. Early stomatal closure, by limiting H2O exchange, contributes to conservation of nitrogenase activity. On the contrary, maintenance of high conductance during a water stress decreases soil water availability and nodule water content, which in turn has a decisive and limiting effect on acetylene reduction activity. Thus, if tolerance at low leaf water potentials associated with osmotic adjustment is an important drought mechanism for maintaining photosynthetic processes under water-limited conditions, the result would be obtained at the expense of symbiotic N2 fixation.Key words: Glycine max L. Merr., nitrogenase activity, photosynthesis, drought stress, soybean
Settler strawberry
Authors: Dale A. , Vandenberg A. A. , Wang S. L. , Ricketson C. L.
Published: April 2011

Settler strawberry (Fragaria × ananassa Duch.) has large, firm, high-quality fruits with high yield. It is recommended for pick-your-own outlets, local markets and roadside stands in Ontario. It has also performed well in Michigan and New York.Key words: Fragaria × ananassa, cultivar description
Yield and yield component response of barley in subarctic and temperate environments
Authors: Dofing S. M. , Knight C. W. , Berke T. G. , Baenziger P. S.
Published: April 2011

Plant breeders are continually searching for new sources of genetically diverse germplasm from which superior genotypes might be developed. The objective of this study was to assess the performance of subarctic- and temperate-adapted barley cultivars when grown in reciprocal areas of adaptation to determine their potential for use in breeding programs. Four subarctic-adapted and four temperature-adapted barley (Hordeum vulgare L.) cultivars were grown at two environments each in Alaska (subarctic) and Nebraska (temperate) for 2 yr. Subarctic-adapted cultivars were earlier heading and earlier maturing in both environments, although differences were larger in subarctic environments. Grain yield of the two classes of cultivars was similar in subarctic environments, but temperate-adapted cultivars were far superior when grown intemperate environments. Kernel weight of all cultivars was higher in subarctic environments than in temperate environments. Maturity differences alone did not account for the poor performance of subarctic-adapted cultivars in temperate environments. Yield was positively correlated with all three yield components in temperate environments, but only with spikes per square meter in subarctic environments. Results from this study suggest that greater potential exists for the utilization of temperate-adapted germplasm to favourably increase the genetic diversity of subarctic-adapted germplasm than vice versa.Key words: Barley, Hordeum vulgare L., adaptation, yield components
Morphological characteristics of wheat associated with high productivity
Authors: Major D. J. , Janzen H. H. , Sadasivaiah R. S. , Carefoot J. M.
Published: April 2011

Eight wheat (Triticum aestivum L.) cultivars including soft white spring, hard red spring, Canada Prairie Spring (CPS) and durum types were grown on rain-fed and irrigated land from 1987 to 1990 at Lethbridge, AB, to assess the relationship between yield components and radiation-use efficiency. Canopy reflectance measurements were used to estimate seasonal absorption of photosynthetically active radiation (APAR). At maturity, yield components including tillers per plant, heads per plant, kernels per head and kernel weight were determined. Whole-plant phytomass and grain yield were also determined. Harvest index was determined from the ratio of grain yield to whole-plant (excluding roots) phytomass and radiation-use efficiency (RUE) was calculated from the ratio of whole-plant phytomass to APAR. Significant grain yield differences confirmed that soft white and CPS wheats yielded more and responded more to irrigation than hard red or durum wheats. The yield components that were consistently different among cultivars were kernels per head and kernel weight which would be expected to increase if a consistent supply of assimilate was available during grain filling. Soft white and CPS wheats had higher harvest indices than the hard red or durum wheats, particularly under irrigation. Whole-plant phytomass was closely related to APAR and there were few differences among cultivars for RUE. There was no difference in RUE between rain-fed and irrigated treatments, indicating that there was probably no crop water stress on the rain-fed plots. RUE estimates for 1988 were lower than for the succeeding years, indicating an environmental or edaphic stress in that year.Key words: Remote sensing, radiation-use efficiency, yield components
Effect of environment and harvest date on maturation and ripening of kiwifruit in British Columbia
Authors: Kempler C. , Kabaluk J. T. , Toivonen P. M. A.
Published: April 2011

Kiwifruit (Actinidia deliciosa var. deliciosa ’Hayward’ (A. Chev.) C. F. Liang et A. R. Ferguson) were harvested periodically from 10 Oct. to 21 Dec, 1990 to monitor "on-the-vine" ripening in three environments (field; greenhouse, covered for the full season; greenhouse, covered until pollination and then uncovered). Fruits were also placed in 1 °C, 97% RH storage on 19 Oct., 22 Oct., 25 Oct., and 3 Nov. and sampled periodically to monitor their "in storage" ripening. Field-grown fruit remained firmer than greenhouse-grown fruit (both treatments) on the vine, and in storage for about 7 weeks following harvest. There was little difference in the harvest maturity date of fruits from the three growing environments. In storage, fruits showed no differences in soluble solids content (SSC), and tissue deterioration (as measured with firmness and chlorophyll fluorescence) due to growing environments. The peak SSC values attained by fruits harvested prior to reaching a SSC of 6.2% were significantly lower than for fruits harvested after the SSC had reached or surpassed 6.2%. Later-harvested fruits remained firmer in storage than those harvested earlier. Changes in the fruits’ SSC and firmness were similar whether on the vine or in storage; however, fluorescence decline was more rapid in storage.Key words: Actinidia deliciosa, soluble solids content, fruit firmness, post harvest, chloroplast, temperature
Evaluation of row covers for overwintering of strawberries under prairie conditions
Authors: Turner J. M. , Tanino K. K. , Stushnoff C.
Published: April 2011

Plant survival, bloom response and fruit yield following fall application of a plastic row cover, plastic row cover covered with barley straw, conventional straw, and no cover were compared for two strawberry cultivars, Fragaria × ananassa Duch. Bounty and Hecker. Response was highly dependent on weather conditions. Plastic row cover + barley straw provided the best protection in winters with below-normal temperatures and low snowfall, resulting in the highest yields. Plastic row cover advanced blooming dates of both cultivars by at least 6 d over conventional straw mulch. With proper protection, both the day-neutral and June-bearing cultivars tested in this study appear to be viable for commercial production in Saskatchewan.Key words: Strawberries, Fragaria × ananassa Duch., polyethylene row cover, overwintering
Inheritance of precocious seed germination in siliques of cabbage
Authors: Chiang M. S. , Jacob A.
Published: April 2011

The inheritance of precocious seed germination (PSG) in siliques was studied in cabbage (Brassica oleracea L. ssp. capitata L.) plants obtained from crosses between breeding line 87-19-5 (with PSG) and cultivar Little Rock (without PSG). PSG was inherited by a single dominant gene without maternal effect.Key words: Precocious germination, seed germination, cabbage, Brassica
An improved procedure for the purification of apple chlorotic leaf spot virus
Authors: James Delano , Monette Paul L.
Published: April 2011

A reproducible procedure is described for the purification of apple chlorotic leaf spot virus (CLSV) from Chenopodium quinoa. Two cycles of sucrose density-gradient centrifugation in a magnesium-containing buffer were used. A relatively high yield of virus particles was obtained with little degradation observed. The average yield was 2.3 mg 100 g−1 fresh leaf tissue. The modal lengths of purified virus particles and particles from leaf sap were 692 nm and 704 nm, respectively.Key words: Chenopodium quinoa, sucrose density gradient, magnesium-containing buffer, intact virus
Effect of anthracnose stalk rot on grain yield and related traits of maize adapted to the northeastern United States
Authors: Callaway M. B. , Smith M. E. , Coffman W. R.
Published: April 2011

Anthracnose stalk rot (ASR), caused by Colletotrichum graminicola (Ces.) Wils., has been recognized as a threat to North American maize (Zea mays L.) production since the early 1970s. The purpose of this study was to determine the effect of ASR on grain yield and yield-related traits of eight maize inbreds adapted to the northeastern United States. The inbreds and their crosses were grown at locations in New York, Delaware and Pennsylvania. Treatments were organized in a split-plot design, with genotypes as main plots and inoculation with C. graminicola or no inoculation as subplots. Results are reported for grain yield, number of ears (EARS), and 500-kernel weight (KWT). The effect of inoculation was not significant for grain yield or the two yield-related traits, although the location × inoculation interaction was significant for grain yield. These results show that physiological reduction in grain dry weight attributed to ASR is highly dependent on environment. Significant differences among parents were found for EARS and KWT. General combining ability was significant for KWT, while specific combining ability was significant for KWT and grain yield. Average heterosis was significant for all four variables.Key words: Zea mays, Colletotrichum graminicola, diallel
Comparison of seasonal thermal indices for measurement of corn maturity in a prairie environment
Authors: Plett S.
Published: April 2011

This study was initiated to determine (i) which thermal index — corn heat units (CHU), modified CHUs (mCHU) or growing degree–days (GDD) — was most consistent across years and locations and (ii) which maturity index — 50% silk, time to 30% grain moisture or time to 100% milk line — was the most consistent measure. Fifteen corn hybrids were evaluated at Morden and Brandon, Manitoba, over 3 yr (1988–1990). Correlation coefficients between total accumulation of thermal units from planting to first frost and thermal units required to reach a specific stage of maturity ranged from 0.283 to 0.969. The lowest correlations were between CHU and time to 50% silk. Coefficients of variation (CVs) were always lower for CHU than for either mCHU or GDD. CV was highest for time to 100% milk line but similar between time to 50% silk and time to 30% grain moisture. Correlations between ranking of hybrids across site–years was highest for mCHU. Overall ranking of thermal indices for consistency was CHU > GDD > mCHU. Time to 50% silk was the most consistent of the measures of maturity. Time to 30% grain moisture was a more consistent measure of maturity than time to 100% milk line.Key words: Maize, heat units, growing degree–days, milk line, grain moisture
Scentless chamomile (Matricaria perforata Mérat) interference in winter wheat
Authors: Douglas D. W. , Thomas A. G. , Peschken D. P. , Bowes G. G. , Derksen D. A.
Published: April 2011

The effect of summer and winter annual scentless chamomile (Matricaria perforata Mérat) on the grain yield of winter wheat was investigated for 3 yr in experimental plots. Summer annuals only affected yield in a year with much greater than normal precipitation. Under near-normal weather conditions, winter annuals reduced yield. Yield reductions due to interference from either summer annual or winter annual scentless chamomile were not detected in a year marked by hot and dry conditions.Key words: Scentless chamomile, Matricaria perforata, winter wheat, weed interference, yield loss
Seeding rate response of Wapiti triticale in short-season growing areas
Authors: Jedel P. E. , Salmon D. F.
Published: April 2011

Little information is available on the response of high test-weight triticales to seeding rate in short-season growing areas. The objective of this research was to determine the effects of seeding rates of 212–307 seeds m−2 (95–138 kg ha−1) on me agronomic response of Wapiti, the first spring triticale (× Triticosecale Rimpani Wit.) registered in western Canada having a high test weight. Field tests were conducted from 1988 to 1990 at six sites in central Alberta (Botha, Drumheller, Lacombe, Olds, Provost and Trochu). Grain yield was positively related to seeding rate, with a 0.371 ha−1 increase between the lowest and highest rates tested. Test weights and protein content of the grain were affected by seeding fate but no consistent trends were established. Effects of seeding rate on days to anthesis were small (< 0.5 d) and would not be of great concern. Days to maturity responded with a significant quadratic effect, with lateness being associated With the lowest seeding rate. Seeding rate had a negative but linear association with spikelets spike−1, florets spike−1 and kernels spike−1. Only at Lacombe was a reduction in florets spikelet−1 detected with high seeding rates, while at Provost the opposite was found. Kernel weight, plant height, kernels spikelet−1 and floret fertility were not affected by seeding rate. Kernel quality was not negatively affected by the higher seeding rates. Therefore, the recommended seeding rates of Wapiti could be raised from 180–250 seeds m−2 (80–110 kg ha−1) to 270–300 seeds m−2 (120–140 kg ha−1). Key words: × Triticosecale, seeding rates, yield, test weight
Spring wheat yield trends in long-term fertility trials
Authors: Selles F. , Zentner R. P.
Published: April 2011

Results from a 16-yr fertility study conducted on fallow and stubble throughout southwestern Saskatchewan were used to assess the effects of technology adoption on spring wheat (Triticum aestivum L.) yields and the influence of available N on the yield effect of these new technologies. The magnitude of the residual trend (after the effect of growing-season precipitation was removed) was considered to reflect the yield increases attributable solely to the newly adopted technologies. Of the independent variables monitored, May and July precipitation and total available water on fallow plots were affected by time. Yields of wheat grown on stubble and fallow increased by an average 48 and 64 kg ha−1 yr−1, respectively. Of this annual yield increase, 52% on stubble and 78% on fallow were attributed to the adoption of new production technologies, with the remainder being explained by the trends observed in May and July precipitation. Nitrogen availability was an important factor in determining the magnitude of the trend due to technology adoption. The technology trend increased linearly from about 10 kg ha−1 yr−1, at the lowest available N levels, to about 65 kg ha−1 yr−1 when 98 kg N ha−1 was available; there were no further yield increases above this level of N. These results demonstrate that the full benefits of adopting new production technologies and more productive cultivars may not be achieved unless other growth-limiting factors, such as N availability, are removed. Further, this study demonstrates that researchers conducting long-term studies must be aware of possible time trends that may alter or obscure effects of treatments, thus making detrending procedures a basic requirement of data analyses in these types of studies. Key words: Spring wheat, yields, N fertilizer, available nitrogen, available water, trends
Agronomic feasibility of producing seed of tall fescue in the Peace River region
Authors: Fairey N. A. , Lefkovitch L. P.
Published: April 2011

The geographic distribution of a species may be extended by the availability of improved crop genotypes. Many tall fescue (Festuca arundinacea Schreber) genotypes have been developed for amenity, forage and soil-conservation purposes to supply the expanding market in the United States. A study was conducted to determine the agronomic feasibility of producing seed of tall fescue in the Peace River region of Canada (50–60°N) in order to facilitate diversification of the region’s forage seed industry. Eleven cultivars were evaluated at three locations over two production years. Over the 6 site-yr, Kentucky 31, a cultivar that has been in use for about a century, produced 429 kg ha−1 seed, significantly less than the average of the other 10 cultivars 684 kg ha−1. Seed yields of these 10 cultivars, averaged over the 6 site-yr, varied from 534 to 794 kg ha−1 but did not differ significantly. There was a significant site effect on seed yield, but the cultivars produced consistently at each site in each year. Yield improvements over that of Kentucky 31 were associated with superior winter survival. Current cultivars of tall fescue can survive and produce economically feasible seed yields at latitudes as high as 58°N in the Peace River region, 8° farther north than the previously suggested demarcation limit of adaptation for the species in Canada. Key words: Tall fescue, Festuca arundinacea Schreber, seed production, geographic distribution, northern limit, winter survival
A practical method of assessing the freezing tolerance of large populations of field-grown winter cereals
Authors: O’Connor B. J. , Gusta L. V. , Reaney M. J. T.
Published: April 2011

A practical method for determining the freezing tolerance of winter cereals using "rootrainers"™ is outlined and compared to the method described by Gusta et al. (1978). Advantages to this method are: a reduction in labour, the plants are stored intact, the crown and root system are disturbed minimally, no transplanting following freezing is required, root regrowth can readily be evaluated and large numbers of plants can be catalogued and stored at sub-zero temperatures for future evaluation. Whole plants frozen using the rootrainer method had a freezing tolerance similar to trimmed plants frozen in moist sand as described in the original method by Gusta et al. (1978). Key words: Winter wheat, winter cereals, freezing tolerance