bluuebunny/crossref_metadata_2025 huggingface dataset:
Early seedling growth and forage production of diploid and tetraploid crested wheatgrass and Russian wildrye cultivars
Authors: Jefferson Paul G , Coulman Bruce
Published: April 2011

Cultivars selected for improved seedling vigour may also differ in seedling growth and subsequent forage production. The objective of this project was to compare three cultivars of crested wheatgrass (CWG) and four cultivars of Russian wildrye (RWR) for seedling growth in a greenhouse (GH) trial and two field trials when seeded at 15, 30 and 45 mm depths. Cultivars were Goliath, Kirk and Parkway CWG and SCR39903, Swift, Tetracan, and Tom RWR. Seedling emergence, tiller number, and seedling biomass were determined at 28 d after seeding (DAS) in all three trials. In addition, forage dry matter (DM) yield was determined for 2 yr in the field trials. Small-seeded diploid Parkway crested wheatgrass had reduced emergence at 45 mm seeding depth compared with larger-seeded tetraploid Kirk and Goliath. Goliath had reduced tillering compared with the other two CWG cultivars. The emergence of Tetracan tetraploid RWR was greater at deeper seeding depth than diploid cultivars, SCR39902, Swift and Tom in Field Trial 2, but not in Field Trial 1 and the GH trial. Seedling tiller number of Tetracan RWR was less than that of the other three cultivars. Two-year total CWG forage DM yield in the field was best correlated to emergence. In contrast, 2-yr total RWR forage DM was best correlated to seedling tiller number in GH and Field Trial 2 despite the low tiller numbers at 28 d after seeding. Field emergence of Russian wildrye did not appear to be limiting to seedling establishment in contrast to previous reports. Selection in RWR should include seedling tiller number in combination with seedling emergence in order to improve both seedling vigour and forage productivity. Key words: Establishment, tiller, emergence, forage yields, seedling depth
KANE hard red spring wheat
Authors: Fox S. L. , Humphreys D. G. , Brown P. D. , Townley-Smith T. F. , McCallum B. D. , Fetch T. G. , Gaudet D. A. , Menzies J. G. , Gilbert J. A. , Noll J. S.
Published: April 2011

KANE is a hard red spring wheat that meets the end-use quality and kernel visual distinguishability specifications of the Canada Western Red Spring market class. KANE was found to be adapted to the wheat-growing regions of Manitoba and eastern Saskatchewan from the data provided by the Central Bread Wheat Cooperative registration test in 2003–2005. In comparison with the check cultivars Katepwa, McKenzie, CDC Teal, AC Barrie, and Superb, the overall grain yield of KANE was similar to the high yield checks McKenzie and Superb. Compared with the highest yielding check McKenzie, KANE was 1.7 d later maturing, was 6 cm shorter, had stronger straw, and was significantly higher (1.1 kg hL-1) in test weight. KANE is resistant to the prevalent races of leaf rust and stem rust. Resistance to common bunt and loose smut was intermediate, being similar to CDC Teal and McKenzie, respectively. Resistance to fusarium head blight was similar to AC Barrie. KANE has good preharvest sprouting resistance with similar or lower sprouting scores compared to the best check in 4 out of 5 yr of testing. End-use quality tests showed that KANE had a 0.7% higher flour extraction rate than the best checks and was within the range of the checks for the other quality traits. Key words: Triticum aestivum L., cultivar description, red spring wheat, test weight, preharvest sprouting, leaf rust
Spring wheat yield response to variable seeding rates in organic farming systems at different fertility regimes
Authors: Beavers R. L. , Hammermeister A. M. , Frick B. , Astatkie T. , Martin R. C.
Published: April 2011

Seeding rates in organic systems should balance a crop’s competitive ability while maintaining grain yield and quality. A 2-yr study assessed the response of spring wheat (Triticum aestivum L.) to variable seeding rates (1 × conventionally recommended rate, 1.25 ×, 1.5 × and 2 × ) in a plot experiment in Nova Scotia and on organic farms across Canada. The plot experiment was a two-factor factorial assessing seeding rate and fertility. For the Canada-wide experiment, the four seeding rates were completely randomized on each farm. Wheat yield was highest at the 2 × seeding rate in 2003, but average crop emergence across all treatment combinations was only 56%. In 2004, crop emergence was 76% and the 1.25 ×, 1.5 × and 2 × seeding rates had greater yield than the 1 × rate. Seeding rate affected plant density and heads per square metre, but no differences were observed among rates for kernels per head or thousand kernel weight. Grain protein content was similar among seeding rates and was increased by the high fertility treatment. On farms, a 1.25 × seeding rate was sufficient to maximize yield when averaged across all sites. Increasing seeding rate by at least 1.25 × the conventionally recommended rate appears to be an appropriate management practice for organic production. Key words: wheat (spring), seeding rate, crop density, organic agriculture
Use of a detached leaf screening method for segregating Colorado potato beetle (Leptinotarsa decemlineata Say) resistant Solanum hybrid lines
Authors: Nandy Sanjib , Chen Qin , Yang Jilang , Beasley Debbie , Li Hiyan , Goettel Mark S
Published: April 2011

A diploid segregating population for resistance to Colorado potato beetle (CPB) was developed by crossing the resistant Mexican species Solanum pinnatisectum (S. pnt., 2n = 2x = 24) with the susceptible S. cardiophyllum (S. cph., 2n = 2x = 24). A resistant hybrid plant from this cross was selected and backcrossed as a female to S. cph in order to generate a backcross family. A beetle feeding preference test bioassay was developed to examine segregation for CPB resistance in 345 backcross progeny. A screening method that optimized the length of the feeding period allowed the quantification of CPB resistance in the backcross progeny. Percent resistance of the test lines over the susceptible control was determined using the formula

R = 100 × [C/(C + L)]
Effects of seed size and seed weight on seedling establishment, vigour and tolerance of Argentine canola (Brassica napus) to flea beetles, Phyllotreta spp.
Authors: Elliott R. H. , Franke C. , Rakow G. F. W.
Published: April 2011

A 3-yr study was conducted on four Brassica napus L. cultivars to determine the effects of seed size and seed weight on the performance and tolerance of canola seedlings to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysom elidae). Seed lots of a doubled haploid cultivar Cyclone, hybrid cultivar AC H102 and two open-pollinated cultivars Profit and AC Elect were sieved to obtain small, medium, large and very large seeds (1.4–1.6, 1.6–1.8, 1.8–2.0 and 2.0–2.2 mm diameter, respectively). Under controlled environmental conditions, leaf area, shoot weight and biomass of seedlings from large and very large seeds were 1.3–2.0 times greater than those of seedlings from small seeds. Under field conditions without insecticides, seedlings from small seeds of each cultivar had the highest flea beetle damage, poorest establishment, and lowest shoot weight, biomass and yield. Compared with small seeds, large seeds improved seedling establishment, shoot weight, biomass and yield by 1.1, 1.6–2.0, 3.0–3.5 and 1.5 times, respectively. Results indicated that seedlings from large seeds are more vigorous and tolerant to flea beetle damage than seedlings from medium or small seeds. Seedling vigour and tolerance was due to a higher initial shoot biomass and higher growth rate when flea beetle damage was severe. When damage exceeded 50%, large heavy seeds had the best stand establishment, best shoot growth and highest yield in each cultivar. Key words: Canola, flea beetles, seed size, seed weight, seedling vigour, tolerance
Root growth of interspecific sunflower seedlings derived from wild perennial sunflower species
Authors: Seiler G. J.
Published: April 2011

Early root and hypocotyl growth and root branching patterns were characterized for five genetically diverse interspecific sunflower hybrids derived from wild perennial Helianthus species and two cultivated hybrids. Seedlings were grown in polyethylene pouches at 25 °C in the dark for 10 d. The hybrid and days after sowing (DAS) were sources of variation for primary and lateral root length, number of lateral roots, root branching density, root fresh weight, and hypocotyl length and fresh weight. There were high positive correlations among root growth characteristics that should be helpful in selecting sunflower hybrids adapted to arid conditions. The wild interspecific sunflower hybrids derived from wild perennial species possessed less-than-expected variability in early root growth. Nevertheless, there appears to be adequate genetic variability for further selection and genetic improvement. Key words: Helianthus species, growth pouch, primary roots, lateral roots, branching density, hypocotyl
The effect of cultivar and applied nitrogen on the performance of Camelina sativa L. in the Maritime Provinces of Canada
Authors: Urbaniak S. D. , Caldwell C. D. , Zheljazkov V. D. , Lada R. , Luan L.
Published: April 2011

Worldwide, oilseed demand is steadily expanding. This study assessed the novel oilseed crop Camelina sativa L. in the Maritime Provinces of Canada. Evaluations of cultivar and applied N were performed at Truro, NS, Harrington, PEI, and Hartland, NB, in 2005 and 2006. The results show that the selection of cultivar is an important determinant for the potential success or failure of C. sativa production. Differences in plant stand, plant height, seed yield, oil content and fatty acid profile were found among the cultivars. The cultivar Calena provided the most consistent performance in terms of plant establishment, yield and oil content across all year-sites. Plant height, seed yield, oil content, total plant N and seed protein all responded to applied N rate. Applied N increased the seed yield of C. sativa, but the increase was not significant when the application rates were over 60 kg N ha-1 in NS or 80 kg N ha-1 in PEI. Plant height, total N content in plant tissue and seed protein content increased with increased N application, while oil content decreased. With the exception of erucic acid, all the main fatty acids in C. sativa oil responded to applied N levels or the interaction of N levels and year. Regression analysis showed that the contents of oleic acid and eicosenoic acid decreased with increased N application. The response of linolenic acid to N application was not consistent at each year-site. Results of this study provide convincing evidence of the agronomic suitability of C. sativa to the Maritime Provinces of Canada. Key words: Camelina sativa, cultivar, nitrogen, yield, seed quality
DRY MATTER AND NITROGEN ACCUMULATION AND REDISTRIBUTION AND THEIR RELATIONSHIP TO GRAIN YIELD AND GRAIN PROTEIN IN OATS
Authors: McMULLAN PATRICK M. , McVETTY PETER B. E. , URQUHART AILEEN A.
Published: April 2011

Dry matter and nitrogen (nitrate and reduced) accumulation and redistribution in four different spring oat (Avena sativa L.) genotypes grown at commercial field density were studied on a plant part and whole plant basis over the growing season for 2 yr. The four cultivars displayed significant differences in plant part and total plant dry matter, harvest index, nitrogen content, nitrogen concentration, nitrogen harvest index, and nitrogen translocated values at most sample dates in both years. Grain yield per plant was correlated with dry matter accumulation (r = 0.80*). Harvest index was highly correlated with grain yield per plant (r = 0.88**). Grain nitrogen content was highly correlated with plant nitrogen content (r = 0.94**). Nitrogen harvest index and harvest index were highly correlated (r = 0.86**), indicating that they may be related processes. Since plant dry matter and plant nitrogen content were not significantly correlated, it should be possible to select simultaneously for these traits to effect grain yield and grain nitrogen content increases on a per plant basis. Further research will have to be done to determine how these changes will relate to grain nitrogen concentrations and grain yield per unit area.Key words: Avena sativa L., oat, dry matter, nitrogen, yield, protein
WILD MUSTARD CONTROL IN SUNFLOWER WITH AC 222,293
Authors: FRIESEN G. H.
Published: April 2011

AC 222,293, a 2:3 mixture of [methyl 6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate] and [methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate], effectively controlled wild mustard (Sinapis arvensis L.) in sunflower (Helianthus annuus L. ’Hybrid Sun M 20’) in field experiments at Morden, Manitoba. Applications of 0.10 kg ha−1 at the two- to four-leaf stage of sunflower resulted in over 90% control of wild mustard. Later applications required progressively higher dosages for similar control levels. Sunflower tolerance to AC 222,293 at the rates studied was excellent with no significant effect on seed yields, seed weight, seed density and oil content of the seed.Key words: Wild mustard, Sinapis arvenis, sunflower, Helianthus annuus, AC 222,293.
GROWTH AND YIELD OF PEAR CULTIVARS ON SEVERAL ROOTSTOCKS
Authors: KAPPEL F. , QUAMME H. A.
Published: April 2011

Two rootstock plantings, with Bartlett and Harvest Queen as scion cultivars, were planted in 1976 and 1977 to compare a number of Old Home × Farmingdale (OH × F), Pyrus communis L., clonal rootstocks with Quince A, Cydonia oblonga L. (Buerre Hardy interstock), and Bartlett seedling rootstocks. Many of the Bartlett trees died because of infection by fire blight whereas very few Harvest Queen trees have died. Trunk cross-sectional area was affected by rootstock with OH × F 69 producing the largest trees and Quince A or OH × F 333 the smallest trees. Annual yield was affected by rootstock with OH × F 69 and OH × F 87 having the highest per tree yields. Mean fruit size of Harvest Queen was greater on Quince A, OH × F 69 and OH × F 87 whereas, OH × F 333 produced the smallest fruit. OH × F 51 had the best yield efficiency (accumulated yield/trunk cross-sectional area), followed by OH × F 69 and OH × F 87. Predicted per hectare yields and optimum tree densities were calculated and discussed.Key words: Pyrus communis, Old Home × Farmingdale rootstock, accumulated yield, trunk cross-sectional area
A SURVEY OF THE INCIDENCE OF POTATO SPINDLE TUBER VIROID IN PRINCE EDWARD ISLAND USING TWO TESTING METHODS
Authors: SINGH R. P. , DeHAAN T-L. , JASWAL A. S.
Published: April 2011

Return-polyacrylamide gel electrophoresis (R-PAGE) and nucleic acid hybridization (dot-blot) were used for the detection of potato spindle tuber viroid (PSTV) from potato leaves. Both methods detected potato plants experimentally infected in the first season or those produced from infected tubers (secondarily infected). PSTV concentration was lower in the first-season infected plants than those in the second. Both methods detected PSTV in a single leaf disc from field-grown infected plants combined with 399 – 499 discs from field-grown healthy plants. The sensitivity of detection by R-PAGE was lower for certain cultivars and increased with the age of plants. About 85 000 leaf samples collected from 123 tablestock fields, 170 seed fields, and 63 cultivars from the Fox Island Elite Seed Farm in Prince Edward Island were found to be free from PSTV infection. Reasons for PSTV absence in the potato crop are discussed.Key words: Diagnosis, dot-blot, return polyacrylamide gel electrophoresis, nucleic acid hybridization, Solanum tuberosum, potato
Inheritance of kernel hardness in five spring wheat crosses
Authors: Baker R. J. , Sutherland K. A.
Published: April 2011

Significant variation among grinding times of F3-derived F4 lines of five crosses indicated that there were genetic differences in hardness among five spring wheat (Triticum aestivum L.) cultivars. Bimodal distributions indicated a two-gene difference between a very hard and soft cultivar and a one-gene difference between a hard and soft cultivar. Key words: Triticum aestivum, kernel hardness, grinding time
Influence of temperature on net CO2 exchange in roses
Authors: Jiao J. , Tsujita M. J. , Grodzinski B.
Published: April 2011

The effect of temperature on net CO2 exchange of source and sink tissues of the flowering shoots and of whole plants was examined using single-stemmed Samantha roses. At all stages of shoot development, the optimal temperature range for whole-plant carbon (C) gain at saturating irradiance and ambient CO2 level was between 20° and 25 °C, narrower than the temperature range for optimal leaf net photosynthesis. Dark respiration increased more dramatically than photosynthesis with temperatures between 15 and 35 °C. At 25 °C, C loss due to respiration from the flower bud at colour bud stage accounted for 45% of the C loss of the flowering shoot. At low irradiance levels (e.g. 200 μmol m−2 s−1) whole-plant net photosynthesis was greater at 16° than at 22 °C because of a greater reduction in respiration. Lowering the night temperature from 27 to 17 °C also increased daily C gain due to a reduction in the C lost at night. Whole-plant net photosynthesis of plants grown and measured at enriched (1000 ± 100 μL L−1) CO2 was greater than that of plants grown and measured at ambient (350 ± 50 μL L−1) level at temperatures between 15° and 35 °C. Furthermore, the optimal temperatures for whole-plant net photosynthesis in CO2 enrichment was higher than at ambient CO2 level. Key words: Dark respiration, net photosynthesis, Rosa hybrida, temperature
Influence of radiation and CO2 enrichment on whole plant net CO2 exchange in roses
Authors: Jiao J. , Tsujita M. J. , Grodzinski B.
Published: April 2011

At three stages of flowering shoot development, varying the irradiance and CO2 levels had a similar effect on the whole-plant net CO2 exchange rate (NCER) of Samantha rose plants. At 22 °C, the NCER was saturated at 1000 μmol m−2 s−1 photosynthetically active radiation (PAR). The duration of the light period was also important in determining daily carbon (C) gain. When roses were exposed to a constant daily radiant energy dose of 17.6 μmol m−2 provided either as a 12-h irradiation interval at 410 μmol m−2 s−1 PAR or 24 h of irradiation at 204 μmol m−2 s−1 PAR, the plants exposed to 24 h of continuous irradiation at the lower photon flux density retained 80% more C. Under saturating irradiance, the net photosynthetic rate at an enriched (1000 μL L−1) CO2 level was almost double that at ambient (350 μL L−1) CO2. However, plants grown at ambient and enriched CO2 levels had similar whole-plant NCERs when compared at the same assay CO2 level. Under CO2 enrichment the flower stem was longer and thicker but the flower bud size at harvest was not significantly different to that of roses grown at the ambient CO2 level. Key words: CO2 enrichment, daily carbon gain, net CO2 exchange rate, radiation, Rosa hybrida
Within-photoperiod differences in ozone sensitivity of soybean and tomato
Authors: Goodyear S. N. , Ormrod D. P.
Published: April 2011

Tropospheric ozone (O3) is produced photochemically resulting in daily patterns of concentrations that normally peak in mid-photoperiod, but timing of the peak concentration may vary according to atmospheric conditions. This study was conducted to determine if there are within-photoperiod differences in plant sensitivity to O3. Soybean (Glycine max Merr.) and tomato (Lycopersicon esculentum Mill.) plants were grown in controlled environment chambers for 14 d and exposed to O3 concentrations of 0.08, 0.12, 0.16, 0.20 and 0.24 μL L−1 for 1 h. Exposures occurred beginning at 10:30, 13:30 or 16:30 h, during a daily photoperiod of 06:00–22:00 h. Differences in sensitivity (as indicated by significant (P ≤ 0.05) growth differences) depending on time of O3 exposure were observed for both species. The order of plant sensitivity for exposure times was 10:30 > 13:30 > 16:30 h. Sensitivity to O3 was concluded to depend on the time of exposure within the photoperiod. Key words: Glycine max Merr., Lycopersicon esculentum Mill., ozone injury, within-photoperiod, controlled exposures, plant growth
The effect of in-row seed piece spacing and harvest date of the tuber yield and processing quality of Conestoga potatoes in southern Manitoba
Authors: Rex Brian L.
Published: April 2011

Conestoga was registered in Canada in 1982. It has been readily accepted by chip producers and processors in Manitoba, although little information on the effect of commercial production practices on the yield and processing quality under Manitoba conditions is available. In this study, the effect of within-row seed piece spacing at three harvest dates on Conestoga potatoes for the early-season chip processing market was evaluated under rainfed conditions in southern Manitoba in 1982, 1983 and 1986. Treatments consisted of spacings of 22, 30, 38 and 46 cm between seed pieces within the row, with 1 m between row centers, harvested at 10-d intervals starting at 75 ± 5 d after planting (DAP) each year. As spacing between seed pieces increased, total, small and maingrade tuber yield and number, and specific gravity decreased. Large tuber yield and number increased. The number of mainstems per plant, the incidence of hollow heart and chip color were unaffected. Delaying harvest resulted in an increased yield of total and maingrade tubers, and higher specific gravity. The highest marketable yield (maingrade plus large tubers) resulted from the 22-cm in-row spacing. The total number of tubers harvested and the number of maingrade tubers increased between 75 and 85 DAP, but did not increase substantially after 85 DAP. Chip color and the incidence of hollow heart were not significantly affected by harvest date. Key words: Potato, population, spacing, harvest date, hollow heart, chip color
Plant spacing effects on growth and development of the greenhouse tomato
Authors: Papadopoulos Athanasios P. , Ormrod Douglas P.
Published: April 2011

The effect of six equidistant spacings (23, 30, 38, 45, 53 and 60 cm, corresponding to 113 000, 74 000, 53 000, 40 000, 31 000 and 25 000 plants ha−1, respectively) on growth and development of greenhouse tomato (Lycopersicon esculentum Mill. 'Jumbo' and 'Ohio CR-6') was studied over two fall and one spring seasons. A consistent increase in plant height and intermode length with closer plant spacing and an apparent trend for taller plants and longer intemodes in the inside of four-row canopies compared to outside were found in both spring and fall seasons. Plant development, as evidenced by the rate of flower cluster development, was affected adversely only when plant spacing was less than 45 cm. Leaf area decreased steadily at all reductions in plant spacing (faster in inside than outside plants) in the fall, but in the spring it attained a maximum value at the intermediate spacing of 45 cm. The fruit set rate of both cultivars was not affected by plant spacing in the fall except under extreme shading conditions (23-cm spacing) while it declined steeply in the spring with decreasing plant spacing. Results suggest a shorter supply of carbohydrates in the spring, compared to the fall, which is attributed to a more intense competition for light in the spring than the fall and this is likely to result in higher productivity in the fall than in the spring when plants are closely spaced. Key words: Lycopersicon esculentum, plant height, fruit set, LAI
Evaluation of oat germplasm for resistance to diclofop-methyl
Authors: Kibite Solomon , Harker K. Neil
Published: April 2011

In field experiments at Lacombe, Alberta, four diclofop-methyl tolerant oat (Avena sativa L.) genotypes introduced from Australia generally exhibited greater tolerance to postemergence applications of diclofop-methyl at 0.8 kg a.i. ha−1 than five Canadian oat genotypes. Grain yield, height, test weight and kernel weight reductions caused by the herbicide were generally less for the Australian than the Canadian genotypes. However, the level of tolerance observed in the Australian genotypes was not sufficient to justify their use as parental lines to develop diclofop-methyl resistant cultivars. Key words: Avena sativa L., Avena fatua L., oat (wild), herbicide tolerance
OAC Musca soybean
Authors: Beversdorf W. D. , Hume D. J. , Gostovic P. , Muscat J. C. , Pararajasingham S.
Published: April 2011

OAC Musca is a soybean (Glycine max (L.) Merr.) cultivar which is 3 d earlier than Hodgson and 2% higher in yield in Ontario trials. It has exhibited low field losses to Phytophthora megasperma f. sp. glycinea in Ontario testing, is a tall cultivar and is intended for use on clay soils. Key words: Soybean, cultivar description
Plenty Durum wheat
Authors: Knott D. R.
Published: April 2011

Plenty durum wheat (Triticum turgidum L.) is a high-yielding, moderately late durum wheat that is eligible for the top grades of amber durum wheat. It has moderately tall, strong straw and is well-adapted to the drier areas of durum production. It is similar to other durum cultivars in disease resistance. Key words: Triticum turgidum, durum wheat, cultivar description
Analysis of rating scale data
Authors: Lefkovitch L. P.
Published: April 2011

Rating scale data need not be manipulated to satisfy the assumptions of the analysis of variance, but formed into an incidence table classified by the ratings and other factors, and compacted over factors to focus on those which are important. References are given to methods for formal statistical analysis of these tables. Key words: Subjective rating, ordinal logistic
Postanthesis temperature effects on duration and rate of grain filling in some winter and spring wheats
Authors: Hunt L. A. , Poorten G. van der , Pararajasingham S.
Published: April 2011

To help define traits that are likely to improve wheat (Triticum aestivum L.) grain yield in a warm, humid continental climate, genotypic variations in various grain growth characteristics in wheat were examined. Winter habit cultivars were grown indoors under a 16-h photoperiod and at day/night temperatures of 20/15 °C, and spring habit cultivars at temperatures ranging from 15/15 °C to 30/25 °C. Grain-filling duration of the winter wheats varied from 36.4 d for Peking-10 to 31.8 d for Priboy. Final kernel weights, which varied from 61.7 mg for Lovrin-10 to 38.3 for Jokionen-3057, were highly correlated with rates of dry matter accumulation. Grain-filling duration of the spring wheats ranged from 56.4 to 47.0 d at 15/15 °C, and from 23.8 to 18.1 d at 30/25 °C. Grain number per spike decreased from 15/15 °C to 30/25 °C. The inverse of grain-filling duration was linearly related to mean temperature, with the intercept on the x-axis (the base temperature of grain filling) being the same for all cultivars. Variation for grain-filling duration among the genotypes tested was present, although small in relation to temperature effects. Breeding for extended grain-filling duration as a strategy for increasing wheat grain yield in a warm climate will thus be difficult. However, an application of the degree-day concept would be desirable. Key words: Triticum aestivum (L.), grain-filling duration, rate of grain filling, temperature
Seed vigor of Katepwa Wheat: Interaction of kernel water content and threshing cylinder speed
Authors: Entz Martin H. , Moes Jack , Stobbe Elmer H.
Published: April 2011

An important goal in seed production is the maintenance of seed vigor. Breakage of wheat seed (Triticum aestivum L.) during threshing can be reduced by threshing at relatively high kernel water content (KWC) and low cylinder speed. The purpose of this study was to investigate the interacting effects of KWC and threshing cylinder speed on seed vigor and field emergence of Katepwa wheat. Wheat plants were harvested at approximately 250 g kg−1 (dry basis) KWC and allowed to dry for varying lengths of time, then were threshed at cylinder speeds of 450, 850, and 1250 rpm using a Vogel thresher. At threshing, KWC averaged 89, 121, 156 and 231 g kg−1. Significant KWC × cylinder speed interactions occurred for seed yield per plot and various seed vigor indicators. Threshing at 850 rpm gave the highest yield of uncracked seeds regardless of KWC. Threshing at 450 rpm was incomplete, especially at high KWC, while threshing at 1250 rpm caused high levels of external seed damage, especially at low KWC. Vigor of uncracked seed was measured by cold germination tests. Increasing cylinder speed reduced cold germination, especially at high KWC. The incidence of abnormal seedlings and leachate conductivity increased with cylinder speed but increased only slightly as KWC decreased. Field emergence decreased with increasing cylinder speed, but was not affected by KWC at threshing. The number of abnormal seedlings in cold germination tests and leachate conductivity were the best indicators of field emergence. Threshing cylinder speed had a greater influence than KWC on seed damage, vigor, and field emergence. The results of this study are of greatest direct interest to plant breeders who use Vogel threshers regularly. Key words: Seed quality, seed vigor, seed damage, threshing, wheat, plant breeding, Triticum aestivum L.
Stability and inheritance of storage-induced hardening in 20 common bean cultivars
Authors: Michaels T. E. , Stanley D. W.
Published: April 2011

Storage of common bean (Phaseolus vulgaris L.) in elevated temperature and/or humidity conditions leads to a textural defect where the beans harden and fail to soften upon soaking and cooking. The objectives of this study were to determine the stability of 20 common bean cultivars grown in three environments for initial hardness, final hardness following storage and hardening ratio, and to estimate the heritability of these hardening parameters. Cultivar × environment interaction was highly significant for the hardening parameters. When stability was examined by plotting hardness against coefficient of variation across environments, three cultivars, GN-77135B, ICA Pijao and T39 Black Turtle, were marginally below the mean for both final hardness and coefficient of variation. While the coefficients of variation for the red kidney bean cultivars Redkloud and Montcalm were high, the maximum compression forces were only slightly (< 20%) greater than the maximum acceptable hardness level as determined by a sensory panel. Fiesta Pinto had the lowest coefficient of variation and near mean values for both final hardness and hardening ratio making it arguably the cultivar with best combination of texture and stability. Heritability estimates were low (0–0.24) with high standard error and estimates of the proportion of phenotypic variance due to G × E were moderate to high (0.29–0.69). Initial cultivar improvement efforts should focus on developing cultivars with greater stability across environments for the hardening parameters. Key words: Phaseolus vulgaris L., storage-induced hardening, stability, broad sense heritability, bean (common)
Interactions between stem termination type and linolenic acid content in soybean
Authors: Rennie B. D. , Tanner J. W.
Published: April 2011

Three determinate (dt1/dt1) soybean (Glycine max (L.) Merr.) lines: Hoyt, HC 80-1742 and HC 80-1756, with a "standard" linolenic acid content (Fan/Fan) were crossed to the indeterminate (dt1/dt1), "low" linolenic acid (fan/fan) line G-LLA-F3. The F2 plants descended from these crosses were grown in the field at Harrow in 1988 and the F2:3 plants were grown at Harrow and Ridgetown, Ontario in 1989. In the F2 progeny, the mean linolenic acid content of the determinate plants was not different from the mean of the indeterminate plants for the "standard" class (8.5 and 8.6%) or for the "low" class (4.1 and 4.2%). In the F2:3 progeny, for the "standard" class, the determinate plants (9.4%) had a significantly (P < 0.05) higher mean linolenic acid content than the indeterminate plants (9.1%). For the "low" class, the mean linolenic acid content of the determinate plants (4.9%) was significantly (P < 0.05) lower than the mean of the indeterminate plants (5.2%) at Ridgetown, but was not different (4.7 and 4.7%) at Harrow. The differences in linolenic acid content between stem types were less than the differences between lines or between locations. Overall, there was no pattern associated with stem termination type and linolenic acid content for soybean plants grown in short season areas. Key words: Soybean, Glycine max (L.) Merr., determinate, indeterminate, linolenic acid
Use of inbred seedling cold tolerance to predict hybrid cold tolerance in maize (Zea mays L.)
Authors: Aidun V. L. , Migus W. N. , Hamilton R. I.
Published: April 2011

The ability of a corn genotype to emerge in the cold, and the development of hardier corn lines is important for reliable corn production in Southern Manitoba. The study sought to determine if inbred cold tolerance could be used to predict accurately hybrid cold tolerance. Eighteen single-cross maize (Zea mays L.) hybrids were formed by crossing the known cold-tolerant inbred CO255 to each of 18 inbred lines. Following germination, five seedlings of each inbred and hybrid were arranged in a five-replicate RCBD and grown in a growth cabinet maintained at 10 °C. Weekly observations of colour and leaf viability, shoot growth, stage of development, and number of dead plants were averaged over the five replicates providing weekly mean values. By averaging weekly values over the 5-wk study, overall mean values were obtained upon which the genotypes were ranked for relative cold tolerance. Correlation coefficients between weekly measures and the final rankings suggested future estimates of cold tolerance could be accurately obtained from an initial observation at emergence, and one at seedling harvest, with only shoot length, leaf viability, leaf colour, and dead plants being noted. No maternal effects were found among six reciprocal crosses involving the common parent CO255. In the final evaluation of cold tolerance CO255 did impart cold tolerance to the respective hybrids, although no common pattern of inheritance was found for the hybrids studied. We concluded that inbred cold tolerance cannot be used to predict accurately hybrid cold tolerance. Key words: Zea mays L., corn, maize, inheritance, cold tolerance, chilling, seedling
Stomatal conductance and CO2 assimilation as screening tools for drought resistance in sorghum
Authors: Al-Hamdani Safaa H. , Murphy Jennifer M. , Todd Glenn W.
Published: April 2011

Stomatal conductance and CO2 assimilation were evaluated at three different levels of soil water availability as tools for estimating relative drought resistance in sorghum (Sorghum bicolor (L.) Moench) at vegetative stage (preanthesis). Four genotypes differing in drought resistance in the field (A Texas line TX 622; Oklahoma lines, BOK 11 and BOK 111; and IN-15, a line from the Sudan of Africa) were investigated. Plants were grown in a growth chamber at 27 °C, (day/night) day length of 14 h and photosynthetic photon flux density of 350 μmol m−2 S−1. Three weeks after germination, plants were divided into control, 50% and 25% soil water saturation groups. At the end of the second week of treatment, simultaneous measurements were made of stomatal conductance, CO2 assimilation, leaf water potential and transpiration, on the youngest most mature leaf. After gas exchange measurements were taken, leaf water potential was measured. In a separate experiment, survival rate under water stress conditions was also determined on plants grown under the same conditions as above. Four weeks after germination, the plants were subjected to two cycles of drought and the survival rate and growth of each genotype determined. Survival rate and growth throughout dought cycles I and II was, in the decreasing order of, IN-15, BOK 111, TX 622 and BOK 11. Water potential, stomatal conductance and CO2 assimilation of each genotype declined with decreased soil water availability; the smallest decrease was observed in IN-15 and the largest decreases in BOK 111, followed by TX 622 and BOK 11. Water use efficiency of each genotype was increased, in the same order as above, with decreased soil water availability. This correlates with the ranking obtained in the artificial drought test. In conclusion, stomatal conductance and CO2 assimilation appear to be useful tools for screening sorghum genotypes at vegetative stage (preanthesis) of growth for drought resistance. Key words: Water potential, water use efficiency (WUE), Sorghum bicolor (L.) Moench
A survey of the occurrence of seedling weeds in spring annual crops in Manitoba
Authors: Thomas A. G. , Donaghy D. I.
Published: April 2011

A floristic survey for weeds in spring annual crops throughout Manitoba from 1975 to 1978 indicated the occurrence of a total of 83 species in 654 fields. Field counts were done during June when the crop and weeds were in the seedling stage. In terms of total abundance, the 28 annual dicotyledonous weeds were found to be the most important group among the 50 species occurring in more than 1% of the fields. Wild buckwheat (Polygonum convolvulus L.), wild mustard (Sinapis arvensis L.), redroot pigweed (Amaranthus retroflexus L.), and lamb's-quarters (Chenopodium album L.) were the most widespread and abundant species in this group with mean densities from 9.6 to 16.2 plants m−2. The combined abundance of green foxtail (Setaria viridis L.), wild oats (Avena fatua L.), and barnyard grass (Echinochloa crusgalli (L.) Beauv.), the three major annual monocotyledonous weeds, was nearly equal to that of the annual dicotyledonous weed group. Green foxtail was the most abundant weed, occurring in 89% of the fields at mean densities of 270.5 plants m−2. Canada thistle (Cirsium arvense (L.) Scop.) and perennial sow-thistle (Sonchus arvensis L.) were the most abundant species in the biennial and perennial weed group and had mean densities of 4.4–4.8 plants m−2 in infested fields. Key words: Weed survey, green foxtail, wild oats, wild buckwheat, wild mustard, Canada thistle
Postanthesis biomass accumulation and respiration in shaded and unshaded wheat (Triticum aestivum L.)
Authors: Pararajasingham S. , Hunt L. A.
Published: April 2011

Respiration significantly influences the carbon balance of a crop. In wheat (Triticum aestivum L.), biomass equivalent to between 40 and 75% final grain mass can be lost through shoot respiration during grain fill. This study examines the relationship between changes in biomass and respiration of the aboveground plant parts of shaded and unshaded wheat during grain fill. Two spring wheat cultivars, Max and Katepwa, were grown indoors with and without shade, and various biomass components and aboveground CO2 efflux rates were determined from anthesis to maturity. Maximum leaf biomass in Max was attained prior to anthesis while in unshaded Katepwa plants leaf biomass increased up to 35 d after anthesis. The stem changed from functioning as a source and became a sink 28 and 35 d after anthesis in the control plants of Max and Katepwa, respectively. The effect of shading on spike growth became apparent two weeks after anthesis. The CO2 efflux rate for unshaded Max and Katepwa plants declined significantly from 279 to 122 and from 210 to 141 mg CO2 plant−1 d−1, respectively, from anthesis through to maturity. Imposition of shade resulted in significantly lower CO2 efflux rates compared to the unshaded plants. Shade, however, exerted no influence on the estimated maintenance respiration coefficient (m) of a two component respiration model, although this coefficient declined 88% in Max throughout grain fill and declined up to 14 d after anthesis and remained stable thereafter in Katepwa. It was concluded, therefore, that shading affects total respiration through its impact on growth, but exerts no direct effect on the basic pattern of change in maintenance respiration during grainfill. Key words: Biomass accumulation, respiration rate, maintenance respiration coefficient, Triticum aestivum L.
Cutler red spring wheat
Authors: Briggs K. G. , Kutschera K. , Kibite S.
Published: April 2011

Cutler spring wheat (Triticum aestivum L.) is a very early maturing, semidwarf, spring wheat with special adaptation to the Parkland region of the Western Prairies, and is suitable for production where early maturity is a prime consideration and where leaf rust rarely occurs. It received registration No. 3356 and is eligible for grades of Canada Prairie Spring (red).Key words: Triticum aestivum L., spring wheat, early maturity, cultivar description
Effect of altering the physiological age of potato seed-tubers in the fall on subsequent production in a short-season environment
Authors: Knowles N. Richard , Botar Gabor I.
Published: April 2011

The efficacy of utilizing "controlled seed-tuber aging" as a technique to enhance yield and improve tuber quality in areas with relatively short growing seasons was investigated in a 3-yr study. Prior to planting in the field, five physiological ages of Russet Burbank, Carlton, Norchip and Superior seed-tubers were produced by varying the heat-unit accumulation over a 200-d storage interval. Total yield increases of up to 90% and substantial improvements in tuber grade were achieved by planting aged (600–900 degree-day (dd)) seed-tubers. Plant growth from aged Russet Burbank seed-tubers was modelled to identify the mechanisms by which yield and quality were altered. Growth analysis demonstrated that the age-induced yield increases were due to faster emergence, faster leaf-area establishment, and tuberization earlier in the growing season compared with that from younger seed-tubers. The annual life cycle was thus accelerated, allowing plants from older seed-tubers to utilize the short (120-d) growing season more efficiently than those from younger seed-tubers. This was reflected in a higher harvest index: plants from 739 dd seed-tubers partitioned 63% of their total fresh weight into tubers compared with 48% for those from 66 dd seed-tubers (based on the quadratic model describing the relationship between seed-tuber age and and harvest index at 121 d after planting). The technique appears to be very promising for enhancing yield and/or promoting ’earliness’ of potatoes in regions with short growing seasons.Key words: Solanum tuberosum, seed-tuber age, plant growth, yield
Effect of restricted watering on sap flow and growth in corn (Zea mays L.)
Authors: Gavloski J. E. , Ellis C. R. , Whitfield G. H.
Published: April 2011

The heat balance technique for measuring sap flow was used to determine how plant stress from watering various proportions of the root system in corn (Zea mays L.) affects sap flow and root and shoot growth. Sectional root-boxes were used to divide the root system into four equal compartments so that known proportions of the root system could be subjected to water stress. Results indicated that the root-box technique is useful in studying the effects of adverse growing conditions in corn. Treatments consisted of no watering and watering one, two, three, or four sections of the box. Sap flow was measured using gauges that worked on a heat balance principle, and aspects of root and shoot growth were also measured. Withholding water from two or more sections of the box for 26 d resulted in decreased sap flow and fresh and dry weight of stalks compared with plants where all four sections were watered (control). Plant height was lower in boxes where one or more sections were deprived of water compared with the control. Dry weight of roots was less when water was withheld from three or all sections of the roots, and fresh weight of roots was less when water was withheld from all four sections. Corn plants with even half the roots growing under stressed conditions resulted in decreased sap flow and shoot growth.Key words: Root-box, moisture stress
Labelle barley
Authors: Mather D. E. , Klinck H. R.
Published: April 2011

Labelle is a six-rowed spring feed barley (Hordeum vulgare L.) developed at McGill University from the cross between Loyola and Laurier. Its main advantage is its high yield performance in Quebec.Key words: Barley (spring), cultivar description
Analysis of maize leaf photosynthesis under drought stress
Authors: Dwyer L. M. , Stewart D. W. , Tollenaar M.
Published: April 2011

Determination of reduction in leaf photosynthesis due to drought conditions is complicated by plant-to-plant variability in the progressive onset of drought stress. In this study a method of analysis was developed to quantitatively compare the reduction in leaf photosynthesis due to drought stress for an old and a new maize (Zea mays L.) hybrid introduced 30 yr apart in Ontario.Key words: Maize, leaf photosynthesis, drought stress, non-linear fitting, hybrid difference
Alfalfa yields in establishment and subsequent years after herbicide and phosphorus application during establishment
Authors: Moyer J. R.
Published: April 2011

Phosphorus and weed control treatments were applied to assess their effect on establishment and long-term yields of alfalfa (Medicago sativa L.) and weeds. Experiments were established on soil with less than 5 kg available P2O5 ha−1 at two dryland locations near Lethbridge, Alberta. Wild oats (Avena fatua (L.) Beauv.) and volunteer barley (Hordeum vulgare L.) at location 1 and Russian thistle (Salsola pestifer A. Nels) at location 2 yielded more than 100 g m−2 in the establishment year where herbicides were not applied; however, control of these weeds during establishment year had no effect on long-term alfalfa yields or weed infestation following establishment. Phosphorus applications ranging from 80 to 320 kg P2O5 ha−1 prior to alfalfa establishment caused large increases in alfalfa yield for several years. Weed infestations were minimal following alfalfa establishment. Ten years after alfalfa was established at location 2 there was a significant linear increase in weed yield (mainly dandelions) with rate of P2O5 applied prior to seeding alfalfa. Thus, P2O5 applications had little effect on weed infestation in established alfalfa.Key words: Medicago sativa, Russian thistle, wild oat, dandelion, 2,4-DB, bromoxynil, diclofop
Content and deposition rates of cellulose, hemicellulose, and lignin during regrowth of forage grasses and legumes
Authors: Bidlack J. E. , Buxton D. R.
Published: April 2011

Cell-wall (CW) components greatly influence digestibility of forages as they mature. There is only limited information on the timing of rates of deposition of CW components. This investigation examined differences in CW and CW component deposition in greenhouse-grown alfalfa (Medicago sativa L.), birds-foot trefoil (Lotus corniculatus L.), red clover (Trifolium pratense L.), orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), and switchgrass (Panicum virgatum L.). Plant material was sampled from the basal 10 cm of forage after harvesting at 3–5 cm above the soil level. Samples analyzed included sheaths from orchardgrass, sheaths and stems from bromegrass and switch-grass, and stems from all legumes. After establishment and herbage removal, samples were collected biweekly between 2 and 10 wk of regrowth. Results indicated that, except for orchardgrass, maximum rates of CW and CW component deposition usually occurred earlier in legumes compared with those of grasses. Maximum CW deposition for all species occurred within 1–3 d of maximum dry weight deposition. Among CW components in grasses and legumes, maximum deposition of hemicellulose occurred first, followed by that of cellulose (1–6 d later), and then lignin (up to 14 d after maximum hemicellulose deposition). Maximum cellulose deposition in all species occurred at the same time as maximum CW deposition.Key words: Cell wall, deposition, cellulose, hemicellulose, lignin, forage
Seedling growth and yield of field corn grown on summer fallow
Authors: Gubbels G. H.
Published: April 2011

Field corn (Zea mays L.) experiments were conducted in the field in a 7-yr study to determine the cause of poor growth on summer-fallowed land and find a means of reducing the problem. Low phosphorus (P) levels in seedling tissue were associated with the poor growth. The symptoms were most severe where P levels in the soil were low, spring temperatures high and soil moisture low. The addition of P fertilizer with the seed greatly improved seedling growth of the corn and sometimes increased grain yield.Key words: Field corn, Zea mays L., summer fallow, phosphorus