bluuebunny/crossref_metadata_2025 huggingface dataset:
Eclipse summer turnip rape
Authors: Degenhardt D. F. , Stringam G. R. , Kondra Z. P.
Published: April 2011

Eclipse summer turnip rape (Brassica rapa L.) is a yellow-seeded canola-quality cultivar with a seed yield similar to that of the cultivars AC Parkland and Tobin. The oil content of Eclipse is similar to that of AC Parkland but is significantly higher than Tobin. Eclipse has a significantly lower glucosinolate content than either AC Parkland or Tobin. Eclipse is well adapted to the B. rapa growing areas of western Canada.Key words: Turnip rape (summer), cultivar description
Banjo spring triticale
Authors: Scarth R. , Brûlé-Babel A. , Larter E.
Published: April 2011

Banjo is a spring triticale (× Triticosecale) with high yield, good grain quality and good resistance to leaf rust, stem rust, common bunt and root rot diseases. Banjo is widely adapted to the western Canadian cereal-growing area.Key words: Triticale (spring), × Triticosecale, cultivar description
AC Caribou alfalfa
Authors: Michaud R. , Richard C.
Published: April 2011

AC Caribou alfalfa (Medicago sativa L.) is a cultivar developed by the Agriculture Canada Research Station in Sainte-Foy. It is similar to Iroquois in maturity, rate of growth, and fall dormancy. It is highly resistant to bacterial wilt (caused by Clavibacter michiganensis subsp. insidiosus (McCulloch) Davis, Gillaspie, Vidaver & Harris), resistant to verticillium wilt (caused by Verticillium albo-atrum Reinke & Berth.), and moderately resistant to phytophthora root rot (caused by Phytophthora megasperma Dreschs. f. sp. medicaginis T. Kuan & D. C. Erwin). AC Caribou, an alfalfa with fine leafy stems, is well suited for production in Quebec and the Maritime Provinces where winter survival may be a problem.Key words: Alfalfa, Medicago sativa, cultivar description
Determination of pod and crop maturity for peanuts using percent pod-fill
Authors: Hinds Margaret J. , Singh Bharat , Anderson John C.
Published: April 2011

A simple method for determining pod and crop maturity for peanuts (Arachis hypogaea L.) was developed using percent pod-fill (PF) — the percentage of green-pod volume that is seed. Peanut samples were collected 99–141 days after planting (DAP) for 3 yr from two soil types in the eastern Caribbean. PF of the composite pods and of the individual maturity classes from each treatment was determined. ANOVA, significance of means separation and correlation coefficients were computed. The results from the composite samples were correlated with optimum reaping time (ORT) established from the shellout method. ORT occurred 117–141 DAP. PF rate varied with season and soil type, but PF values for mature pods and for composite pods at ORT were independent of pod size, season and soil type. PF of mature pods was 41.5 ± 1.3% and was significantly different from that of other maturity classes. PF for composite pods at ORT was 38.2 ± 2.2% and was significantly different from PF values before ORT. The results indicated that percent pod-fill could be a reliable indicator of pod and crop maturity for peanuts.Key words: Arachis hypogaea, peanut maturity, pod-fill, maturity index
Effect of temperature, vernalization and water stress on phyllochron and final main-stem leaf number of HY320 and Neepawa spring wheats
Authors: Cutforth H. W. , Jame Y. W. , Jefferson P. G.
Published: April 2011

An understanding of the effect of environment on leaf growth is needed to accurately simulate phenological development of a cereal crop. This study was conducted to determine the effect of temperature, cold (vernalization) and water stress on the phyllochron (degree-days leaf−1) prior to the terminal spikelet stage and on the final leaf number produced by the main stem (FLN) of two spring wheat varieties (Triticum aestivum L.), Neepawa and HY320, grown on the Canadian prairies. Within each of five day/night temperature regimes (30/25 °C, 24/19 °C, 21/12 °C, 16/7 °C and 7/2 °C, with means of 28 °C, 22 °C, 18 °C, 13 °C and 5 °C, respectively), the varieties were grown under two cold (not vernalized and vernalized) and two water (wet and dry) treatments. Within a given temperature regime, both varieties responded similarly to the cold treatments. Vernalization reduced phyllochron and FLN in all but the lowest temperature regime, where phyllochron increased and FLN was unaffected. When effective, severe water stress increased phyllochron and decreased FLN. HY320 was relatively more affected by vernalization and less affected by severe water stress than Neepawa. For both varieties, phyllochron was curvilinearly related to temperature and increased as temperature increased. The relationships were noticeably altered by vernalization and severe water stress. When not vernalized, FLN for HY320 increased as temperature increased; FLN for Neepawa reached a maximum at 20 °C. When vernalized, FLN was independent of temperature under optimum water; the reduction of FLN by severe water stress increased as temperature increased. The results of this study suggest that the effect of environmental change on both phyllochron and FLN must be accounted for when accurate and reliable modelling of the early development of spring wheat is required.Key words: Spring wheat, phyllochron, leaf number, temperature, water stress, vernalization
Fall harvest management for irrigated alfalfa in southern Saskatchewan
Authors: Jefferson P. G. , Gossen B. D.
Published: April 2011

Three trials were conducted under irrigation at Swift Current, Saskatchewan to examine the interaction of fall harvest date and alfalfa cultivar. The treatments were five fall harvest dates, 15 Aug., 1 Sept., 15 Sept., 30 Sept. (two harvests per season) and 15 Aug. + 15 Oct. (three harvests per season), on three or four alfalfa cultivars. Trials were seeded on irrigated alluvial clay loam soil in 1979, 1981 and 1987. Low-temperature injury occurred in 1982, 1985, and 1989 in these three experiments, respectively. In Trial I, the effect of fall harvest date on stand and yield loss was greatest for the least winterhardy cultivar, Anchor, and least for the most winterhardy cultivar, Rambler. Forage yield recovered the year after injury, in spite of an apparent permanent reduction in stand density. In Trial II, low temperature injury was extensive in all treatments and the cultivar × date interaction was not significant. In Trial III, Anchor alfalfa harvested on 15 Oct. exhibited the lowest percent survival and shoot density. Heinrichs and Rambler were less affected by winterkill at all dates than Anchor but did exhibit severe yield reduction when harvested three times per season compared to two times. Anchor exhibited greater stand loss and lower first harvest forage yield in 1989 for both treatments that were cut on Oct. 15. There was no significant fall harvest date effect among the four two-harvest regimes in this trial. The observed date effect was due to the three-harvest regime compared to the rest. A fourth experiment was located at Outlook, Saskatchewan, where alfalfa, cv. Beaver, was harvested on 19 Sept., 24 Sept., 2 Oct. and 10 Oct. in 1989. Low-temperature injury was evident in 1990. First harvest forage yield in 1990 was significantly reduced for the third harvest dates compared to two harvests per season. These results do not provide categorical evidence of a "critical fall harvest period" for these two sites. The low-temperature tolerance of the cultivar determines to a large extent its sensitivity to fall harvest management.Key words: Medicago sativa L., winter survival, autumn management
AC Tristar summer rape
Authors: Rakow G.
Published: April 2011

AC Tristar summer rape (Brassica napus L.) is a triazine-tolerant, canola-quality cultivar. It is early to medium in maturity and high yielding. AC Tristar has high oil content, in comparison with other triazine-tolerant cultivars such as Tribute, but is highly susceptible to blackleg disease. AC Tristar is well adapted to the B. napus growing areas of western Canada.Key words: Rape (summer), triazine tolerance, cultivar description
Introgression of germplasm from 8× to 4× smooth bromegrass
Authors: Armstrong K.C.
Published: April 2011

A study was undertaken to determine the feasibility of introgressing genes from the octoploid to the tetraploid cytotype in Bromus inermis Leyss. The octoploid × tetraploid, hexaploid × tetraploid, and "pentaploid" × tetraploid crosses were successfully made. Progeny varied in chromosome number from 2n = 29 to 2n = 35 with no 2n = 28 plants. These aneuploid plants were highly sterile.Key words: Bromus inermis, octoploid, tetraploid, introgression
Residues of 2,4-D and dicamba in wheat following postemergence field application as a tank mixture
Authors: Cessna Allan J. , Hunter James H.
Published: April 2011

In a 2-yr study, residues of 2,4-D and dicamba were monitored in wheat at several times over a complete growing season following postemergence application as a tank mixture at 420 and 140 g ha−1, respectively. Both herbicides were gas chromatographically analyzed as their respective methyl esters using electrolytic conductivity detection. Initial residues immediately after application decreased rapidly and, at 5–6 wk after application, residues of both herbicides were less than 0.1 mg kg−1. Residues of 2,4-D were not detectable in the straw or seed at maturity in either year. However, residues of dicamba in the order of 0.03–0.04 mg kg−1 were detected both years in the mature straw. Residues of dicamba were not detected in the seed in the first year of the study, but were detected at 0.065 ± 0.014 mg kg−1 the second year. Key words: 2,4-D, dicamba, wheat, residue, postemergence application
Oat β-glucans: An evaluation of eastern Canadian cultivars and unregistered lines
Authors: Miller S. S. , Fulcher R. G. , Vincent D. J. , Weisz J.
Published: April 2011

The (1-3), (1-4)-β-D-glucan (β-glucan) content of a number of domestic Canadian oat cultivars and selected unregistered lines was determined to establish the range of β-glucan content in eastern Canadian oat varieties. Seed samples were taken from oats grown at five locations over 3 years in an attempt to assess the effect of environment on variation in β-glucan content. Analysis of variance indicated that the greater source of variation in β-glucan content was due to genetic rather than environmental factors. The highest β-glucan cultivar (Marion) was about 30% higher than the lowest cultivars (OA516-2 and Donald). Differences in β-glucan content among the intermediate cultivars were generally smaller, and in some cases not significant, although the rank order of the cultivars among environments was consistent. A low, but significant, negative association between β-glucan content and precipitation, and a low, but significant, positive association between β-glucan content and temperature was found, but these were not dominant factors influencing β-glucan levels in oats. There was no consistent association between β-glucan content and protein, oil, thousand kernel weight or grain yield (kg/hectare). Key words: Oat, Avena sativa, β-glucan, variation
Intraspike yield distribution of diverse-tillering spring wheats: Effects of competition
Authors: Hucl P. , Baker R. J.
Published: April 2011

Three spring wheat (Triticum aestivum L.) genotypes (Neepawa, Siete Cerros and M1417) were subjected to four levels of tiller removal (MS remaining, MS + T1 remaining, MS + T1 + T2 remaining, control) at three plant densities (two, four and eight plants per 15-cm-diameter pot) in a controlled environment to assess the effects of interplant and intraplant competition on the intraspike yield distribution of genotypes with diverse tillering habits. Intraspike yield distribution traits varied significantly (P = 0.01) among genotypes and levels of plant competition. Genotypes did not respond uniformly to interplant or intraplant competition. When interplant competition was increased, the oligoculm genotype, M1417, exhibited a greater reduction in maximum kernels per spikelet (13%) and spikelet yield (36%) than either Siete Cerros (9, 17%) or Neepawa (6, 15%). Similarly, with increasing intraplant competition, M1417 responded by reducing maximum kernels per spikelet (6%) and spikelet yield (9%) whereas Siete Cerros and Neepawa exhibited increases for both traits (3 – 15%). The low-tillering genotypes tended to exhibit a greater sensitivity to competition for maximum spikelet yield or kernel number while Neepawa was more responsive for the rachis node at which yield or kernel number was maximized. Strong developmental dominance of the oligoculm habit appears to reduce plasticity and the ability to respond to competition-induced stress. Key words: Spring wheat, intraspike yield, tiller removal, plant competition
The common lowbush blueberry, Vaccinium angustifolium Aiton, may be an allopolyploid
Authors: Hokanson K. , Hancock J.
Published: April 2011

Data collected by Hall and Aadlers (1963) on the white-fruited trait were used to determine whether Vaccinium angustifolium is an allopolyploid displaying disomic inheritance or an autopolyploid with tetrasomic inheritance. Chi square tests for goodness-of-fit were non-significant for both models in all crosses, but the probabilities were higher in two of them for tetrasomic inheritance. Key words: Tetrasomic inheritance, disomic inheritance, allopolyploidy
Heritability of seed yield, oil concentration and oil quality among wild biotypes of Ontario evening primrose
Authors: Brandle J. E. , Court W. A. , Roy R. C.
Published: April 2011

Evening primrose (Oenothera biennis L.) is a wild species native to Eastern-North America that has recently come under cultivation as an oilseed. The oil is primarily used as a treatment for skin disorders. As a starting point for genetic improvement and domestication of this species, it was thought essential to first characterize genetic variability in Ontario evening primrose, so that members of this population may be drawn upon as a resource during cultivar development. Thirty-six wild evening primrose biotypes were evaluated in replicated trials conducted at the Delhi Research Station during 1988–1990. Seed yield, oil content and the concentration of individual fatty acids were measured. Heritability estimates demonstrated the presence of heritable genetic variation for all characters measured except the C16:1 (n–9) fatty acid. Selection for yield, oil content or fatty acid composition amongst the wild bio-types should therefore be effective. Key words: Oenothera biennis, gamma-linolenic acid, GLA, oil, fatty acid composition
Iona barley
Authors: Choo T. M. , Sterling J. D. E. , Martin R. A. , Bubar J. S. , Walton R. , Blatt R. , Rodd V.
Published: April 2011

Iona is a two-row, spring feed barley (Hordeum vulgare L.) developed at the Agriculture Canada Research Station, Charlottetown, Prince Edward Island. It has high yield and good resistance to powdery mildew. Iona is well adapted to Eastern Canada and is responsive to intensive management. Breeder seed is maintained at the Agriculture Canada Experimental Farm, Indian Head, Saskatchewan. Key words: Hordeum vulgare L., two-row barley, feed barley, high yield
Responses of soybean and five weeds to CO2 enrichment under two temperature regimes
Authors: Tremmel David C. , Patterson David T.
Published: April 2011

Rising atmospheric CO2 levels could affect plant growth both directly, through effects on physiology, and indirectly, through the effects of possible CO2-induced temperature increases. In this study we examined the interacting effects of CO2 enrichment and temperature on the growth and allocation of soybean and five weeds. Individual plants of soybean [Glycine max (L.) Merr. ’Braxton’], johnsongrass [Sorghum halepense (L.) Pers.], quackgrass [Elytrigia repens (L.) Nevski], redroot pigweed (Amaranthus retroflexus L.), sicklepod (Cassia obtusifolia L.), and velvetleaf (Abutilon theophrasti Medic.) were grown in growth chambers in all combinations of two temperatures (avg. day/night of 26/19 °C and 30/23 °C) and two CO2 concentrations (350 and 700 ppm) for 35 d. Leaf area and plant biomass were greater at higher temperatures, regardless of CO2 level, in all species except quackgrass. Quackgrass (C3) produced its greatest leaf area and biomass at elevated CO2, whereas johnsongrass (C4) showed little response. Redroot pigweed (C4) and the C3 dicotyledenous species (soybean, sicklepod, velvetleaf) produced their greatest biomass at high CO2, though effects on leaf area were less consistent or absent. In general, when significant CO2 by temperature interactions were found, CO2 responses were smallest at higher temperatures. These differential responses to elevated CO2 concentrations may cause changes in the relative importance of competitive pressure from these weeds. Key words: CO2 by temperature interaction, soybean, johnsongrass, quackgrass, redroot pigweed, sicklepod, velvetleaf
Emulsifier surfactant-oil combinations with tralkoxydim
Authors: McMullan Patrick M.
Published: April 2011

Research was conducted at the Brandon Research Station to determine the optimum oil-emulsifier surfactant ratio for each of two oil-emulsifier surfactant pairs for use with tralkoxydim. A series of adjuvants containing 8.5, 17, 34, and 68% emulsifier surfactant (by weight) plus oil were formulated for a petroleum oil (PO)- or methylated seed oil (MSO)-based adjuvant. Tame oats (Avena sativa L.) fresh weight was used to determine percent control as the indicator for phytotoxicity. PO (Sunoco 11 N oil) adjuvants had greater emulsion stability ratings than MSO adjuvants. Emulsion stability was not related to oats control, as MSO adjuvants enhanced tralkoxydim phytotoxicity more than PO adjuvants. Oats control increased as adjuvant volume increased from 0.25 to 2.0% (vol/vol) of the spray solution for either PO- or MSO-based adjuvants. For PO-based adjuvants, the adjuvant containing 34% emulsifier surfactant (by weight) and used at 0.5% (vol/vol) was as effective as the adjuvant containing 17% emulsifier surfactant and used at 1.0%. However, for MSO-based adjuvants, 17% emulsifier surfactant content was as effective as higher emulsifier surfactant content. Oats control did not correlate with the amount of oil in the spray solution. These data indicate that the optimum oil-emulsifier surfactant ratio will vary for each particular oil-emulsifier surfactant pair. Key words: Tralkoxydim, adjuvant, adjuvant volume, methylated seed oil, petroleum oil, surfactant content
Effects of immersing dry seeds in alkaline solutions on seed dormancy and water uptake in wild oat (Avena fatua)
Authors: Hou J. Q. , Simpson G. M.
Published: April 2011

Effects of immersing dry seeds in KOH and NaOH solutions on seed dormancy and water uptake were studied in three dormant lines of wild oat (Avena fatua L.). KOH was more effective than NaOH in breaking dormancy. Maximum dormancy-breaking effect of 5.3 N KOH could be achieved with a 10- or 15-min treatment. Increase in treatment time did not necessarily increase germination; rather, it caused damage to the seeds. For 10-min treatment, 5.3 and 7.6 N KOH solutions were more effective than 3 and 9.8 N. Genetic lines responded differently to the KOH treatment. Initial rate and amount of water uptake by KOH-treated seed were significantly higher than by the untreated. It is believed that breaking dormancy by the alkaline treatment is related to removing the barrier to water uptake formed by the seed coat. Key words: Alkalis, Avena fatua, dormancy, seed coat, seedling growth
Relationship between guard cell length and cold hardiness in wheat
Authors: Limin A. E. , Fowler D. B.
Published: April 2011

Identification of plant characters associated with cold tolerance is useful for the development of plant-breeding selection procedures and understanding the underlying mechanisms of cold hardiness. This research investigates the association of guard cell length with cold tolerance and examines the relationship between cell size, as estimated from guard cell length, and other characters previously found to be highly correlated with cold tolerance in wheat (Triticum aestivum L. em. Thell.). Guard cell length was compared with field survival, LT50, tissue water content, and plant erectness of cultivars representing a wide range of cold tolerance levels. The three most cold-tolerant cultivars had the smallest cells, while the cultivar with the largest cell size was a spring type. There were significant (P ≤ 0.05) correlations between guard cell length and all cold-tolerance-related characters considered. Differences in guard cell length were most closely related to field survival as measured by Field Survival Index (FSI). Stepwise regression analysis indicated that cell size explained 45% of the variability in FSI. Cell size combined with plant erectness and tissue water content explained 88% of the variability in FSI. LT50 and cell size together explained 96% of the variability in FSI. The effects of cell size on cold hardiness may relate to its influence on cell water content and cellular mechanical stress during intercellular ice-crystal formation and freezing-induced dehydration. Guard cell size should be a useful selection tool in cultivar development programs that have increased cold hardiness as the breeding objective. Key words:Triticum aestivum, winter wheat, cold hardiness, guard-cell length, cell size
Root and crown characteristics of alfalfas varying in fall dormancy
Authors: Juan N. A. , Sheaffer C. C. , Barnes D. K.
Published: April 2011

We compared root and crown characteristics of five alfalfa (Medicago sativa L.) entries which differed in fall dormancy. Alfalfas were subjected to bud or mid-bloom harvests. The most consistent entry effect occurred for root and crown dry weight and root total nonstructural carbohydrate (TNC) concentrations. Root TNC concentration was highest and root and crown weight were greatest for the nondormant and least in the most dormant entries. Entries did not consistently differ in crown bud numbers, shoot number, or shoot origin. In October, the number of elongated crown buds were greater for a non-fall dormant alfalfa Nitro than for the most fall dormant alfalfa. Key words: Alfalfa, root and crown morphology, fall dormancy, root carbohydrates
Evaluation of chitting to enhance earliness of potatoes grown in southern Ontario
Authors: McKeown Alan W.
Published: April 2011

Potato cultivars Atlantic, Conestoga, Jemseg, Superior and Yukon Gold, grown for early markets and mid-season use in Ontario were evaluated for response to chitting in 1987 to 1989. Seed tubers were chitted at 8 °C commencing in January, for an average of 408, 284 or 172 degree-days (base 4 °C). Controls were stored at 4 °C. Plants emerged quicker from chitted seed and produced higher early yields than the controls. Approximately 260 degree-days of chitting was optimal for early yield of Jemseg and Superior. For maximum emergence, 318 degree-days was required for Jemseg. Commencing chitting before March did not increase yields for the other cultivars. Low degree-day requirements are likely the result of cold storage of seed prior to chitting, resulting in more rapid accumulation of degree-days and/or lower base temperatures for growth. Key words:Solarium tuberosum, cultivars, emergence, yield, physiological age
The effects of soil compaction on nodulation and growth of common bean (Phaseolus vulgaris L.)
Authors: Buttery B. R. , Tan C. S. , Park S. J.
Published: April 2011

As part of an investigation of factors limiting nodulation in the field, cultivars of common bean were grown in a sandy loam soil that had been either deep tilled (DT) to reduce compaction or repeatedly rolled by a golf cart or by a tractor followed by a golf cart. In 1991 and 1992, the tractor-rolling treatment was replaced by a conventional tillage system. Nineteen cultivars were grown in 1990; 10, in 1991; and 4, in 1992. In general, soil compaction decreased plant growth and yield but had no adverse effect on numbers or weights of nodules per plant. In 1990, nodule numbers and weights were increased by compaction in the first sample, 35 d after planting. In a combined analysis of the four cultivars common to all 3 yr, nodule weight as a fraction of total plant weight was increased by compaction. Thus, compaction had a more severe effect on overall plant growth than on nodulation per se. Numbers and weights of nodules differed among the cultivars, but they all responded similarly to compaction. Cultivars yielded differently, depending on the degree of compaction (i.e., cultivar × compaction interaction), but, even so, the cultivar that had the highest yield in the DT plots also had the highest yield in the compacted plots. For most characteristics, the severity of the effects of compaction varied with the year, presumably in response to different weather conditions. Key words: Bean yield, common bean, nodulation, Phaseolus vulgaris, soil compaction
Indicators for optimum stage for swathing oilseed flax
Authors: Gubbels G. H. , Bonner D. M. , Kenaschuk E. O.
Published: April 2011

Four maturity indicators were evaluated for determining the optimum time to swath flax. The indicators — percentage brown capsules determined by counting, percentage brown capsules determined by visual estimate, percentage green capsules determined by counting and capsule moisture — were found to be of similar value. Key words: Flax, Linum usitatissimum, swathing time, maturity
Response of spring barley and weed communities to lime, phosphorus and tillage
Authors: Légère Anne , Simard Régis R. , Lapierre Claude
Published: April 2011

Soils under permanent pasture in eastern Canada are often characterized by acidic conditions and low P availability. A 3-yr experiment was initiated in the spring of 1988 to evaluate the feasibility of using conservation tillage practices and fertilization to improve the fertility of old, poorly managed pastures taken into cereals. The effects of tillage, liming and P additions on weed communities and spring barley (Hordeum vulgare L.) yields were measured on a Joseph sandy loam (Humic Gleysol). The tillage systems were 1) moldboard plowing in the fall, with disc harrowing in the spring; 2) chisel plowing in the fall, with disc harrowing in the spring; and 3) minimum spring surface tillage. Liming and P applications favoured growth and yields of barley. Weeds competing with barley were unable to derive benefits from either liming or increased P availability, despite their potential capacity to respond positively to this nutrient. Increasing soil fertility was generally detrimental to weeds, but this effect decreased with a reduction in tillage intensity. Yield response to improved fertility also decreased as tillage intensity was reduced. Despite a fertility status comparable to that found in the moldboard-plow treatment, conditions in reduced-tillage systems were less conducive to the competitiveness of the crop and, thus, favoured the development of weed infestations, particularly under minimum tillage. Optimum crop management that can maximize the competitiveness of the crop needs to be applied if benefits of fertilization in reduced-tillage systems are to be fully realized. Key words: Conservation tillage, reduced tillage, minimum tillage, lime, phosphorus, weeds
Zero-tillage establishment of alfalfa and meadow bromegrass as influenced by previous annual grain crop
Authors: Allen C. L. , Entz M. H.
Published: April 2011

Conventional forage establishment techniques (i.e. preseeding tillage) can result in soil erosion and inefficient water use during the establishment period, and may result in poor plant establishment. Using a zero-tillage (ZT) system may overcome these limitations. The first experiment, conducted under favourable post-seeding moisture conditions, compared establishment, plant development, growth, and dry matter production of alfalfa (Medicago sativa L.) and meadow bromegrass (Bromus biebersteneii Roem and Shult.) under ZT and conventional tillage (CT) following three different annual crops. Significant previous crop × tillage system interactions in both years, indicated that forage crop establishment and dry matter production were lower under ZT than CT when the preceding crop was wheat (Triticum aestivum L.), however, no significant differences were observed when the preceding crop was either field pea (Pisum sativum L.) or canola (Brassica napus L.). Significant previous crop × forage species interactions for crop establishment indicated that while alfalfa was unaffected by previous crop type, emergence of meadow bromegrass was reduced when wheat was the previous crop. Significant previous crop × tillage system interactions for plant development indicated that development of both forage species was temporarily delayed under ZT when wheat was the previous crop. No treatment effects were observed for year after establishment dry matter production. A second experiment, conducted under conditions of post-seeding drought, assessed the impact of spring wheat straw management on establishment of alfalfa and meadow bromegrass under CT and ZT. Superior establishment of both alfalfa and meadow bromegrass under ZT was attributed to higher levels of soil water under ZT. Straw management (removal vs. returned to land) had no effect on either forage species. Results of these studies indicate that ZT is a feasible alternative for establishing forage crops, even where levels of previous crop residue are very high. Key words: Direct-seeding, straw management, wheat, canola, field pea, Haun stage, forage
Investigation of a chlorsulfuron-resistant chickweed [Stellaria media (L.) Vill.] population
Authors: O'Donovan J. T. , Jeffers G. M. , Sharma M. P. , Maurice D.
Published: April 2011

A chickweed population (R) from a farm near Stony Plain, Alberta, was more resistant to chlorsulfuron than a population (S) collected near Vegreville, Alberta. In greenhouse experiments, the S population was controlled completely by chlorsulfuron applied at 5 g ha−1, whereas 22 g ha−1 was required to reduce dry weight of the R population by 50%. Experiments conducted in a germinator indicated that percentage germination of the R population was higher than that of the S population up to ~ 60 h. Growth analyses in the greenhouse indicated that leaf number, leaf area, shoot dry weight, days to flowering, flower number, seed weight and relative yields differed little between the two populations. In field experiments, control of the R population was poor with the sulfonylurea herbicides, chlorsulfuron, metsulfuron methyl, triasulfuron, amidosulfuron and thifensulfuron. Good to excellent control was obtained with cyanazine/MCPA, linuron, metribuzin, mecoprop, bentazon, metribuzin + MCPA, linuron + MCPA, and mecoprop + bentazon. Key words: Sulfonylurea herbicides, chlorsulfuron, herbicide resistance, relative competitiveness
Development of zero erucic acid Ethiopian mustard through an interspecific cross with zero erucic acid Oriental mustard
Authors: Getinet A. , Rakow G. , Raney J. P. , Downey R. K.
Published: April 2011

Ethiopian mustard (Brassica carinata A. Braun) is a high-yielding oilseed crop of the Ethiopian highlands, but the seed is high in erucic acid. The objective of this study was to develop zero erucic acid forms in this mustard species. This was achieved through an interspecific transfer of genes for zero erucic acid from Brassica juncea. Key words:Brassica carinata, zero erucic acid
Development and selection for apomixis in cassava, Manihot esculenta Crantz
Authors: Nassar Nagib M. A.
Published: April 2011

Apomixis provides fixation of heterosis and avoids contamination of seedlings by diseases. Observations on offspring uniformity for selected morphological characteristics and use of a marker gene in controlled crosses produced facultative apomictic lines in cassava. Cytogenetic analysis showed apomixis occurrence to be associated with aneuploidy and interspecific hybridization. Key words: Wild species, aneuploidy, interspecific hybridization
The U.S. National Plant Germplasm System
Authors: Shands Henry L.
Published: April 2011

The United States Department of Agriculture's (USDA) Agricultural Research Service (ARS) manages the National Plant Germplasm System (NPGS). The USDA's National Genetic Resources Program was created in 1990, using the NPGS as the model by which other life forms would also be preserved and utilized. While the NPGS is a broadly defined system, ARS has a specific role of acquiring, characterizing, preserving, documenting, and distributing germplasm to scientist users for research and breeding. The NPGS provides genetic resources to users at no cost but with a request to return data to incorporate in the Germplasm Resources Information Network (GRIN) database. The database is available as hard copy, diskette through PC-GRIN, and, for some crops, a CD-ROM disk. Service to users is the primary objective. The NPGS and 40 crop advisory committees exchange technical information on the most important conservation issues. Recent research advances at the National Seed Storage Laboratory provide guidance for storage management of orthodox and desiccation-sensitive seed and vegetative germplasm. Cryopreservation may receive more attention and play a more important role for the vegetative germplasm because improved seed management under conventional refrigerated storage is now possible. Key words: Germplasm, databases, cryopreservation
Phenological development–yield relationships in spring barley in a subarctic environment
Authors: Dofing S. M.
Published: April 2011

Barley (Hordeum vulgare L.) producers in northern, marginal agricultural areas require cultivars that are both early maturing and high yielding. However, negative relationships between these two characteristics limit their simultaneous improvement. A better understanding of the relative contribution of the developmental stages to grain yield would assist breeders' selection. This study was undertaken to assess the relationships between patterns of phenological development and grain yield in barley grown in a subarctic environment. Sixteen genetically diverse spring barley cultivars were grown for 3 yr at Palmer, Alaska, and evaluated for grain fill rate, grain fill period, growing degree days (GDD) to heading, GDD from heading to physiological maturity, and GDD from physiological maturity to ripe maturity. Cultivars developed in temperate regions tended to have slower grain fill rates than those developed in subarctic regions. Rapid grain fill rate was associated with high kernel weight, but not with grain fill duration or grain yield. Increasing GDD to heading would result in higher grain yield, while increasing grain fill duration would have little effect. These results indicate that northern-adapted cultivars should have pre-heading periods lasting as long as possible, followed by short grain-fill periods. Simultaneous selection for early maturity and relatively long time to heading is recommended for the development of early-maturing, high-yielding cultivars adapted to northern conditions. Key words: Barley, Hordeum vulgare L., phenology, development, yield
Free fatty acid contents in developing seed of three summer rape cultivars in Ontario
Authors: May W. E. , Hume D. J.
Published: April 2011

Field studies were conducted in 1989 and 1990 to determine the FFA levels during seed development of three Ontario-grown canola-quality summer rape (Brassica napus L.) cultivars, Global, Kristina and OAC Triton, to determine the relationship between FFA and brown seeds and to assess the effect of silique position within the raceme on FFA. Seed mass increased linearly until 44 DAF in 1989 and curvilinearly until 43 DAF in 1990. Seed oil increased until approximately 32 and 31 DAF in 1989 and 1990, respectively. The concentration of FFA in seeds declined in both years until oil concentration stopped increasing, suggesting that FFA were being incorporated into triacylglycerol. During oil synthesis total FFA per seed increased and, as oil synthesis slowed and stopped, FFA decreased. The individual cultivars decreased FFA to different levels as oil synthesis slowed, with Kristina having the lowest FFA. As the crop finished ripening the FFA levels increased in Global and OAC Triton in 1989 and in all cultivars in 1990. There was a strong positive correlation between FFA and percent brown seed in 1990 (r = 0.64) and in 1991 (r = 0.88). FFA and percent brown seed were 33 and 66%, respectively, higher in seed samples from siliques located on branches than in seed samples from siliques located on the main raceme. FFA and percent brown seed were higher in seed samples from siliques on tips than in seed samples from siliques located on the basal portion of the raceme by 137 and 142%, respectively. The results indicated that cultivars differed in their ability to decrease FFA during oil synthesis and a consistent rise in mg FFA kg−1 oil occurred at the end of the seed filling period. Key words: Free fatty acids, Brassica napus, seed development, brown seed, raceme position
Emergence and development of Russian wild ryegrass seedlings as influenced by seed source, seed mass, and seeding depth in an artificial medium
Authors: Limbach W. E. , Call C. A.
Published: April 2011

Seedling emergence, seedling biomass, and root lengths of Russian wild ryegrass seedlings were analyzed with respect to seed source, seed mass, seeding depth, and harvest. Multiple regression models containing these factors were statistically significant predictors of the log-transformed seedling biomass and root length data (DF = 9, Fbiomass = 1763.67, Froot = 949.33, and P < 0.0001 for both variables). The effects of seed mass, seeding depth, and harvest were significantly related to the dependent measures while the effect of seed source was not significant. Seedling emergence from suboptimal seeding depths was significantly greater for heavy seeds than for light seeds (χ = 14.076, DF = 7, P < 0.0001). Key words: Fritted clay, Psathyrostachys juncea (Fisch.) Nevski, rooting depth, Russian wild ryegrass, seed size, Syn-A, Vinall
Tillage effect on root rot severity, growth and yield of beans
Authors: Tan C. S. , Tu J. C.
Published: April 2011

The effect of soil tillage on plant growth, yield and root rot severity of beans was investigated in field plots with and without root rot infestation in 1992 and 1993. There was a significant reduction in root rot severity, and an increase in plant dry weight and yield in the root-rot-infested soils with deep tillage in both years. Deep tillage also significantly increased plant dry weight and yield in the non-root-rot soils in a dry year. The resistant cultivar (A300) had significantly less root rot damage than the susceptible cultivar (Harowood) in both root rot and non-root rot infested soils. Significant differences in plant dry weight and yield in relation to cultivars were not detected. Therefore, deep tillage can reduce soil compaction and increase yield of beans and reduce root rot severity. Key words:Phaseolus vulgaris L., deep tillage, fusarium root rot, rhizoctonia root rot, yield
Linola™ '947' low linolenic acid flax
Authors: Dribnenki J. C. P. , Green A. G.
Published: April 2011

Linola™ '947' flax (Linum usitatissimum L.) was the first low linolenic flax cultivar registered in 1993 in Canada. It had very good lodging resistance, was late maturing and produced seed with a very high oil content. In western Canada, '947' had yield similar to McGregor, its recurrent backcross parent. '947' has a yellow seedcoat. Key words: Flax, low linolenic acid, cultivar description
Susceptibility of barley cultivars to vesicular-arbuscular mycorrhizal fungi
Authors: Boyetchko S. M. , Tewari J. P.
Published: April 2011

The relative susceptibility of selected barley cultivars produced in western Canada to vesicular-arbuscular mycorrhizal (VAM) fungi under field and greenhouse conditions was evaluated in this study. Cultivars tested under field conditions at the University of Alberta and Lacombe research stations showed no significant differences in VAM colonization of barley roots; colonization was light. Greenhouse trials at the University of Alberta with eight cultivars inoculated with individual mycorrhizal species illustrated significant differences among the barley cultivars in their reactions to Glomus dimorphicum, G. intraradices, and G. mosseae. Distinct differences were observed in the ability of each Glomus species to colonize the barley cultivars. The VAM fungi increased growth and yield in some cultivars, depending on the Glomus species. This study indicates that a degree of host-specificity exists in VAM fungi and that the host-mycorrhizal fungus genotypes may influence the effectiveness of the symbiosis. Key words: Barley, cultivars, susceptibility, VA mycorrhizal fungi
Flower and pod abortion in chickpea as affected by sowing date and cultivar
Authors: Zaiter H. Z. , Barakat S. G.
Published: April 2011

Chickpea (Cicer arietinum L.) flowers abundantly but a large proportion of its flowers and pods abscise. The objective of this study was to quantify the variation in the flower number and the fate of flowers as affected by sowing date and cultivar, with the aim of understanding the significance of the variability to final yield. The production and fate of chickpea flowers were studied on two cultivars (Janta-2 and Lebanese Local) sown on 9 December 1992 and 17 February 1993 at the American University of Beirut Farm, Beka'a Valley, Lebanon. The pattern of flower production, pod rentention, number of flowers produced, and percentage of flowers and pods abscised varied with sowing date and cultivar. Winter sowing produced significantly more yield than spring sowing. Cultivar Janta-2 yielded more than Lebanese Local in the winter, but the difference disappeared under spring-sown conditions. In general, primary branches contributed 54% to final pod yield with the secondary branches contributing 27% and the main stem contributing 19%. Adjustments to yield from stress after flowering and during pod-filling came primarily from flowers on primary and secondary branches rather than from those on the main stem, from higher order primary and secondary branches rather than from those on basal branches, and from upper-most nodes of the main stem and primary and secondary branches. The primary and secondary branches on the basal nodes 1–3 on the main stem produced most of the pods that were retained.Mention of trade name, proprietary product, or vendor does not constitute an endorsement or warranty by the American University of Beirut, nor does it imply its approval to the exclusion of other products or vendors that may be suitable. Key words: Flower biology, pod retention pattern, Cicer arietinum L.
Effects of Ca2+- and Mg2+-enriched germination media on germination and sugar leakage of Ca-deficient soybean seed
Authors: Keiser J. R. , Mullen R. E. , Hinz P. N.
Published: April 2011

Inadequate seed Ca concentrations are associated with reduced seed quality of soybean [Glycine max (L.) Merr.]. Standard germination and sugar leakage tests were conducted to determine the effect of seed Ca content and exogenous Ca2+ or Mg2+ on seed quality and seed leakage. Soybean seeds containing different Ca levels were germinated in rolled towels that had been soaked in distilled water, 0.01 M Ca(NO3)2, or 0.01 M Mg(NO3)2. Sugar leakage was measured by soaking seed containing 1.10, 1.72 or 2.36 mg g−1 Ca in distilled water, 0.01 M Ca (NO3)2, 0.01 M Mg(NO3)2 or polyethylene glycol (PEG). An aliquot of the bathing solution was analyzed for sugar content after 6, 12 and 24 h of soaking, by using high-performance liquid chromatography. As seed Ca content decreased from 2.36 to 1.10 mg g−1, germination in distilled water decreased from 87 to 56%. Addition of either Ca(NO3)2 or Mg(NO3)2 to the medium resulted in increased germination of low-Ca seed, but Ca(NO3)2 was more effective in improving germination of low-Ca seed than Mg(NO3)2. Total sugar leakage was significantly greater in low-Ca seed than in high-Ca seed. Bathing solutions of Ca(NO3)2 or Mg(NO3)2 significantly decreased sugar leakage, compared with distilled water or PEG. These results suggest that the role of Ca in seed germination may involve membrane stabilization. They also indicate that the addition of Ca(NO3)2 or Mg(NO3)2 to the germination medium may improve germination of Ca-deficient seed. Key words: Soybean, germination, calcium, magnesium, sugar leakage, membrane integrity
Breeding hard red spring wheat in western Canada: Historical trends in yield and related variables
Authors: McCaig T. N. , DePauw R. M.
Published: April 2011

The Western Bread Wheat Cooperative test and Central Bread Wheat Cooperative test are the bases of evaluation for cultivar registration in the Canada Western Red Spring (CWRS) wheat class. Historical data from these tests were analyzed with the objectives of comparing grain-yield-related variables of recently registered cultivars with those of earlier cultivars and determining the yield advances made within the CWRS wheat class. Canadian cultivars increased maximum yield potential approximately 6–9 kg ha−1 yr−1 during a 90–yr period. Yield potential of sawfly-resistant cultivars has been increasing at a rate of 11 kg ha−1 yr−1, although they consistently yielded less than the highest yielding hollow-stem cultivars. In general, the genetic yield increases resulted from an increase in the number of kernels produced rather than an increase in kernel size. This suggests that bread wheat grown on the prairies has been sink limited during grain filling. Breeding efforts focused on increasing Canadian production through the development of numerous CWRS cultivars with specific traits (e.g., early maturity, disease resistance) to allow hard red spring wheat to be grown over a broad geographical range. Plant height, time to maturity, and hectolitre weight did not change significantly during the 1947–1992 period. Key words:Triticum, kernel number, kernel weight, height, hectolitre weight
Chlorophyll degradation in summer oilseed rape and summer turnip rape during seed ripening
Authors: Ward K. , Scarth R. , Vessey J. K. , Daun J. K.
Published: April 2011

Chlorophyll breakdown in ripening seed of three summer rape cultivars (Brossica napus L.) and one summer turnip rape cultivar (Brassica rapa L.) was investigated to clarify the influence of genotype, environment, seed moisture and endogenous ethylene production. Final seed chlorophyll levels were determined for summer oilseed rape and turnip rape cultivars grown at several locations during 4 yr. Both genotype and environment affected seed chlorophyll levels at harvest, but genotype by environment interactions were minimal for the cultivars included in this study. Differences in maturity did not adequately explain the genotypic variation among the rape cultivars tested. Rates of seed chlorophyll breakdown, moisture loss and ethylene evolution were measured in ripening seeds of three rape cultivars. Stellar, Delta and Westar had significantly different rates of seed chlorophyll breakdown. Lower temperatures resulted in slower chlorophyll degradation. Chlorophyll and moisture (expressed as percentage seed mass) were positively correlated in ripening seed, but moisture loss occurred at the same rate during seed ripening in all cultivars and environments. Chlorophyll and endogenous ethylene production were positively correlated, but the peak of ethylene production occurred after moisture loss and chlorophyll breakdown had begun, implying that an increase in endogenous ethylene was not the trigger for the initiation of these events. Key words: Chlorophyll degradation, green seed, ripening, moisture loss, ethylene, oilseed rape, turnip rape