Koscielny C. B. and Gulden R. H. 2012. Seedling root length inBrassica napusL. is indicative of seed yield. Can. J. Plant Sci. 92: 1229-1237. Recent studies have shown relationships between root growth and development and seed production potential in some crops; however, little is known about this relationship in Brassica napus. Field and growth room experiments were conducted to determine the relationship between root parameters up to the four-leaf stage and seed yield among a group of four open-pollinated and four hybrid B. napus genotypes with different yield potential. In the field studies, root length was the best indicator of seed yield at the one- to two-leaf and the three- to four-leaf stages of development, and was one of the most consistent parameters among sites and years. Poor ability to recover fine roots from field soils at the cotyledon stage contributed to the relatively poor relationships between root parameters and seed yield compared with shoot parameters at this developmental stage. The growth room study clearly showed that root length is an excellent measure of seedling vigour and an indicator of seed yield as early as 7 d after imbibition. These studies demonstrate the importance of early root development in canola and its potential as a screening trait for seed yield in breeding programs.

Cober, E. R. and Voldeng, H. D. 2012. A retrospective look at short-season soybean cultivar development in Ontario. Can. J. Plant Sci. 92: 1239-1243. Canadian soybean production has increased from about 63 000 ha in 1951 to 1.2 million ha in 2006 with expansion from southern Ontario to shorter season areas. From 1971 to 2000, soybean production in Ontario increased sixfold. Using annual reports from 1971 to 2000 of short-season trials in Ontario, we found that the number of reported cultivars remained between three and five until 1984 when the number of cultivars started to increase at the rate of about 2.5 yr^-1. The amount of time that cultivars remained in the reports has declined from 12 to 4 yr on average over the 30-yr period. Long-lived cultivars, however, were developed throughout the period including: Hardome, Merit, Evans, Maple Arrow, Bicentennial, Maple Glen, KG 41, OAC Eclipse, 9071, OAC Bayfield, PS 36, and S03-W4. Over the 30-yr period of cultivar testing, short-season seed yield increased about 600 kg ha^-1, while mean time to maturity decreased about 10 d. During the same time, mean Ontario commercial seed yields increased about 750 kg ha^-1. Over the 30-yr period, the number of short-season cultivars in annual reports increased 36-fold, while provincial yield increased only 1.4-fold. If the number of cultivars in annual reports is an indication of breeding effort, large research investments may be necessary to increase future yield improvement.

Baker, J. M. 2012. Vegetative propagation of kura clover: a field-scale test. Can. J. Plant Sci. 92: 1245-1251. Kura clover (Trifolium ambiguum M. Bieb.) is a potentially valuable forage legume, but it has been underutilized. A major reason is the difficulty of establishing it from seed. Since kura is rhizomatous, there have been attempts to propagate it vegetatively, but no reports of success at the field scale. Two harvesting methods were tested to transplant material from a mature 17-ha field to a newly tilled 17-ha field: a bermudagrass sprigger that harvests bare rhizome sprigs, and a potato digger that harvests crowns and rhizomes, along with soil. The harvested propagules were distributed over the new field in July 2010 with a manure spreader, then disked and packed. Survival and growth were observed for the remainder of 2010 and through 2011, and recovery of the source field was also monitored. The material harvested with the sprigger did not compete well with weeds and had virtually disappeared by midsummer 2011, but the material harvested with the potato digger thrived, steadily increasing to nearly 80% of the biomass in the new field by the 3rd cutting in summer 2011. Properly done, vegetative propagation is a viable option for kura clover establishment.

Rechel, E., Novotny, T. and Ott, R. 2012. Lower levels of harvest traffic on alfalfa (Medicago sativa L.) have minimal impact on long-term yields. Can. J. Plant Sci. 92: 1253-1258. Studies quantifying the effect of harvest traffic on alfalfa yield often only analyze data from treatments where either 0% or 100% of the surface area of the field is trafficked. These do not represent traffic patterns in commercial alfalfa production operations. To further understand the impact of field traffic on alfalfa yield, different percentages of traffic at harvest were analyzed. Our objectives were to quantify the yield produced from different intensities of harvest traffic throughout a 4-yr production cycle. The experimental units were furrow-irrigated raised bed systems with four harvests per year on a Youngston clay loam. A John Deere 2955, weighing 4004 kg, trafficked 0, 21, 42, or 83% of the area of alfalfa plots 7 d after swathing. The 0, 21, and 42 % trafficked treatments did not reduce yield in any year. The 83% trafficked alfalfa had 7 and 10% lower yields in the second and third years of production but had no effect the first and fourth years. The cumulative 4-yr yield from the 83% trafficked alfalfa was 7% lower than the 0% trafficked alfalfa. Single passes of a tractor impacting a high percentage of the field (83%) decreased yearly yield but was not detectable until the second year. Yield was the same whether the experimental units received 0 or 42% traffic.

Wang, Z., Schellenberg, M. P., Biligetu, B., Zhao, M. L. and Han, G. D. 2012. Short Communication: Forage mixture responses to water stress in semi-arid prairie grassland: a pot experiment. Can. J. Plant Sci. 92: 1259-1261. As a negative result of changing climate, drought has become a worldwide concern, particularly in arid and semiarid regions. Under drier conditions, seeding multiple forage species may produce higher biomass than single species. A randomized complete block design experiment was carried out in a growth chamber over a 4-mo period to examine the effect of watering regimes (100, 85 and 70% of field capacity of semiarid grassland) on above- and below-ground biomass of various combinations of five forage species. Alfalfa monoculture and mixtures containing alfalfa produced significantly higher above- and below-ground biomass (P<0.05) than the other species or species combinations when grown at field capacity. They were also among the highest biomass producers under restricted water supply, although differences were not always statistically different. Winterfat showed a good tolerance to water deficit and its below-ground biomass production was not significantly affected by water restriction. The findings suggest that a mixture of native plant species with alfalfa would be important for forage seedling production in the semi-arid prairie grassland under water-limiting conditions.

Jing, Q. and Bélanger, G. 2012. Short Communication:Yield trend analysis of an ageing timothy sward using a modelling approach. Can. J. Plant Sci. 92: 1263-1266. Observed and simulated potential dry matter (DM) yields of the timothy (Phleum pratense L.) primary growth were compared to disentangle the yield trend from the effect of year-to-year climatic variations in an ageing sward (1 to 7 yr). Observed DM yields were close to simulated potential DM yields in the first 4 yr, but they were around 60% of simulated potential DM yields in the last 3 yr. This confirms that variations in air temperature and/or solar radiation could not explain the lower DM yield observed in the last three production years.

Karuppanapandian, T., Rhee, S.-J., Kim, E.-J., Han, B. K., Hoekenga, O. A. and Lee, G. P. 2012. Proteomic analysis of differentially expressed proteins in the roots of Columbia-0 and Landsberg erecta ecotypes of Arabidopsis thaliana in response to aluminum-toxicity. Can. J. Plant Sci. 92: 1267-1282. Aluminum (Al) is phytotoxic when solubilized into Al³ in acidic soils and represents a major constraint for crop production. The present study describes Al-stress responses in roots of Al-tolerant and Al-sensitive Arabidopsis ecotypes, Columbia-0 (Col-0) and Landsberg erecta (Ler), respectively. Comparative proteomic analysis was applied to plants grown in hydroponic solution culture under acidic pH (4.2) conditions. To investigate time-dependent responses, 6-d-old seedlings were treated with 30 µM AlCl₃ for 24, 48, or 72 h; total proteins were prepared from roots and separated by two-dimensional gel electrophoresis (2-DE). From 2-DE analysis, were 600 proteins were inspected, 29 proteins were differentially responsive to Al-treatment. The 2-DE patterns were compared and differentially expressed proteins identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Analysis of protein expression patterns revealed that a set of proteins is functionally associated with tricarboxylic acid (TCA) cycle and glycolysis, reactive oxygen quenching and detoxification mechanism, and signal transduction pathways, etc., could play important roles in mediating plant response to Al in Arabidopsis ecotypes. Comparison of the changes in the protein profiles revealed that Al-stress increased Al-tolerance related proteins in Al-tolerant Col-0, but only generic stress responses occurred in Al-sensitive Ler. Specifically, Al up-regulated proteins such as alcohol dehydrogenase, monodehydroascorbate reductase, GTP-binding nuclear protein Ran-2, and leucine aminopeptidase in Col-0 but not in Ler.

Wan, S., Goto, K., Mottiar, Y., Staebler, J. M., Johnson, A. M., Voronova, A., Blais, D. R., Zaidi, M. A. and Altosaar, I. 2012. Bacterial nitrous oxide reductase expressed in transgenic plants: Evidence for sufficient anaerobicity to permit activity. Can. J. Plant Sci. 92: 1283-1294. Soil nitrogen enrichment practices enhance crop yields but greatly exacerbate the production and release of nitrous oxide (N₂O), a potent greenhouse gas. The conversion of N₂O to dinitrogen (N₂) in soil denitrifiers is normally driven by the anaerobic enzyme nitrous oxide reductase (N₂OR). Since this step is often limited in fertilised soils, we have transferred this unique microbial biocatalyst from the soil bacterium Pseudomonas stutzeri to transgenic Nicotiana tabacum plants. Our results confirm that engineered plants expressing the N₂OR structural gene nosZ are capable of producing functional reductase enzyme without the involvement of the native accessory gene products. Since bacterial N₂OR normally exists in the anaerobic environment of the soil bacterium's periplasmic space, this novel in planta activity suggests that plant cells can provide a similar hypoxic refuge for anaerobic enzyme activity. Genetically engineered crops containing N₂OR could have considerable potential in the phytoremediation of atmospheric N₂O.

Huang, H.-Q., Liu, J.-D., Duan, J.-Q., Liang, X.-N. and Liu, F.-H. 2012. Cloning and characterization of the mitochondrial genesCox II and atpA from ramie (Boehmeria nivea (L.)Gaud.) and their possible role in cytoplasmic male sterility. Can. J. Plant Sci. 92: 1295-1304. In plants, cytoplasmic male sterility (CMS) is known to be associated with structural changes and the presence of new chimeric genes in mtDNA. In this study, fragments of the Cox II and atpA genes, cloned from mtDNA of three lines (CMS line, its maintainer and restorer lines) of ramie [Boehmeria nivea (L.) Gaud.], showed homology of 95% for Cox II and 97% for atpA compared with the reference dicotyledons in GenBank. The whole sequences of these two genes were obtained using the DNA walking strategy. Cox II showed no difference among the three lines in sequences of DNA and deduced amino acids. However, atpA from the CMS line obviously differed from that of fertile lines in DNA sequence, amino acid sequence and secondary structure of the predicted protein. Unusually low expression was revealed via RT-PCR for atpA in the CMS line at the budding and late-bloom stages. In conclusion, the variation in DNA sequence and the encoded product, and/or the abnormal expression of atpA in the CMS line, may cause male sterility in ramie.

Eaton, L. J. and Nams, V. O. 2012. Honey bee stocking numbers and wild blueberry production in Nova Scotia. Can. J. Plant Sci. 92: 1305-1310. Wild blueberries (Vaccinium angustifolium Ait.) require cross pollination by insects. Introduction of managed species such as honey bees (Apis mellifera L.) and alfalfa leafcutting bees (Megachile rotundata Fabr.) is costly. We assessed the effects of stocking rates of honey bee hives and the interacting effects of the numbers of honey bees and other bees on yield of blueberries in commercial fields. Blueberry fields were sampled from 101 fields in years 1991 to 2010 in Nova Scotia. We recorded field size, numbers of beehives, yield, densities of bees, numbers of buds, blossoms and set fruit. Yields increased linearly with numbers of beehives, up to~4 hives/hectare, but at higher stocking rates there was too much variation to adequately determine the effects. Yields also increased linearly with numbers of honey bees, but there was an interaction with other bees that decreased the effects of honey bees, such that at maximum densities of other bees, there was no effect of honey bees on yield. These results suggest that other bees and honey bees compete for pollination. If producers have limited numbers of beehives, we suggest that more should be placed in areas where densities of other bees are lower, up to approximately 4 hives/hectare.

Rupasinghe, H. P. V., Yu, L. J., Bhullar, K. S. and Bors, B. 2012. Short Communication: Haskap (Lonicera caerulea): A new berry crop with high antioxidant capacity. Can. J. Plant Sci. 92: 1311-1317. This study evaluated the antioxidant capacity and total phenolic content as well as total flavonoid content of three haskap (Lonicera caerulea) cultivars, Borealis, Indigo Gem and Tundra, grown in Saskatchewan in comparison with six other commercial fruits using ferric reducing antioxidant power (FRAP) assay, oxygen radical absorbance capacity (ORAC) assay, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, the aluminum chloride colorimetric method and the Folin-Ciocalteu method, respectively. The results indicate that haskap berries, especially cv. Borealis possessed the highest antioxidant capacities and total phenolic contents, specifically total flavonoid among tested fruits, and could be used as a promising fruit source of natural antioxidants. The nutritional values of the fruits were also assessed using proximate analysis. Strawberry possessed the highest amount of most minerals and nutrients, whereas the nutritional values for the three haskap cultivars were average.

Miller, R. T., Soltani, N., Robinson, D. E., Kraus, T. E. and Sikkema, P. H. 2012. Soybean (Glycine max) cultivar tolerance to saflufenacil. Can. J. Plant Sci. 92: 1319-1328. Six field studies were conducted over a 2-yr period (2009 and 2010) at three Ontario locations to determine the sensitivity of 12 glyphosate-resistant soybean cultivars to saflufenacil applied preemergence (PRE). The level of crop injury was dependent on environmental conditions shortly after application. When soybean emergence was delayed due to cool, wet conditions following planting, 52 and 59 g a.i. ha^-1 of saflufenacil resulted in 10% injury 1 wk after emergence (WAE) in cultivars OAC Hanover and RCAT Matrix, respectively. In the other environments, greater than 200 g a.i. ha^-1 of saflufenacil was required to induce the same level of injury at 1 WAE. Injury decreased with time; however, the more sensitive soybean cultivars were unable to recover from early-season injury sustained under adverse environmental conditions. A hydroponic bioassay was developed to screen differences in soybean tolerance to saflufenacil. OAC Hanover was more sensitive than all the other cultivars in both field and hydroponic testing (P<0.05). OAC Hanover yield was reduced regardless of environmental conditions. Under cool, wet conditions, 22 g a.i. ha^-1 of saflufenacil resulted in a 10% yield reduction, while 46 g a.i. ha^-1 was needed under warm dry conditions. All other cultivars required between 82 and 146 g a.i. ha^-1 to obtain the same level of yield reduction. This research demonstrates that there is a difference in soybean cultivar sensitivity to saflufenacil applied PRE.

Beckie, H. J., Francis, A. and Hall, L. M. 2012. The Biology of Canadian Weeds. 27.Avena fatuaL. (Updated). Can. J. Plant Sci. 92: 1329-1357. An updated review of biological information is provided for Avena fatua. A widespread species originating in Eurasia, A. fatua is one of the 10 worst annual weeds of temperate agricultural regions of the world. Key weediness traits of this highly selfing species include fecundity, seed shatter, and a large and persistent seed bank with variable degrees of primary seed dormancy. The species occurs in all Canadian provinces and most states in the USA. In Canada, it is most troublesome as a weed in the prairies, where it has spread throughout crop areas in all climatic zones. Depending upon plant density and relative time of emergence, A. fatua competition may reduce annual crop yields by as much as 70%. First cohort emergence of A. fatua coincides with planting and emergence of spring-seeded crops, although additional cohorts can emerge throughout the growing season. Avena fatua is more abundant in zero-than intensive-tillage systems; the former regime promotes earlier and greater emergence because of a shallower and less persistent seed bank. Despite the introduction of highly efficacious herbicides in the 1970s and 1980s, abundance of the species has not declined across the Canadian prairies or elsewhere. The continual evolution of herbicide-resistant A. fatua populations, seed spread via farm machinery, and limited herbicide modes of action for its control threaten sustained annual field crop production in many temperate agricultural areas. Further adoption and integration of multiple non-herbicidal weed management practices, such as enhanced crop seeding rate, competitive crops and cultivars, and precision fertilizer placement, should help mitigate A. fatua interference. The species has some beneficial uses as an alternative feed and food constituent or industrial feedstock, as well as potential in cultivated oat (Avena sativa L.) improvement.

Francis, A., Darbyshire, S. J., Légère, A. and Simard, M.-J. 2012. The Biology of Canadian Weeds. 151.Erodium cicutarium(L.) L'Hér. ex Aiton. Can. J. Plant Sci. 92: 1359-1380. Stork's bill, Erodium cicutarium, is an annual weed of the geranium family (Geraniaceae), native to Mediterranean Europe, North Africa and western Asia. It has spread widely to temperate regions of both hemispheres, in particular to semi-arid ranges and prairies where it is frequently a dominant weed. In western Canada, it has increased in importance as a weed of cereal, canola, legume, sugarbeet and potato crops, particularly with the adoption of conservation tillage, and is both a field weed and seed contaminant of forage crops. The species had been sporadically collected in Québec since 1874 from cultivated fields (oats, potatoes, corn), but it recently appeared in experimental plots grown in corn, soybean, and red clover in eastern Québec, suggesting its potential as a serious weed. Outside of Canada, it is found in a range of crops, and has been host to viral, fungal and insect pathogens that can cause damage to crops and pastures. The plant's early germination, rapid growth and prolific seed production give it a competitive advantage in crops. In spring crops, the weed may be past the stage for optimal control by the time that the crop has reached the stage when herbicides are normally applied. Control may consequently require an extensive and often costly integrated weed management system. In semi-arid grazing areas it probably displaced some native vegetation, but has also become an important forage plant and a source of food for native wildlife. Its antioxidant and other chemical properties have drawn attention to potential medicinal and other beneficial uses.

Zhang, W.-B., Jiang, H.-W., Qiu, P.-C., Liu, C.-Y., Chen, F.-L., Xin, D.-W., Li, C.-D., Hu, G.-H. and Chen, Q.-S. 2012. Genetic overlap of QTL associated with low-temperature tolerance at germination and seedling stage using BILs in soybean. Can. J. Plant Sci. 92: 1381-1388. Low temperature is one of the critical environmental factors that limit agricultural production worldwide. In northeast China soybean frequently suffers low temperature stress, especially at germination stage and seedling stage. The most effective way to solve this problem is to breed cultivars with low-temperature tolerance. A set of advanced backcross introgression lines was constructed with Hongfeng 11 as recurrent parent, which was a local variety in Heilongjiang province, and Harosoy as donor parent, which was introduced from Canada. Their BC₂F₄ lines were screened in low-temperature condition at the two stages, and 41 transgressive lines were selected out at germination stage and 45 lines at seedling stage. Sixty-four and fifty-one pairs of simple sequence repeat primers with fine polymorphism were used for genotyping the selected population and random population at the two stages, respectively. Related quantitative trait loci (QTL) were obtained by chi-test and ANOVA analysis with genotypic and phenotypic data. Finally, 25 QTL at germination stage and 13 QTL at seedling stage were mapped. Among them, 10 QTL overlapped between two stages, which showed a partial genetic crossover on low-temperature tolerance stages in soybean. This would play an important role in marker-assisted selection for breeding elite variety with low-temperature tolerance at both stages.

Karamanos, R. E., Selles, F., James, D. C. and Stevenson, F. C. 2012. Nitrogen management of fallow crops in Canadian prairie soils. Can. J. Plant Sci. 92: 1389-1401. The ability of fallow to supply nitrogen (N) to crops has been questioned, particularly for crops with greater N requirements. A study was conducted to determine canola (Brassica napus L.) and wheat (Triticum aestivum L.) responses to a range of N fertilizer rates (0-75 kg N ha^-1 for canola and 0-50 kg N ha^-1 for wheat) at 17 fallow sites across Saskatchewan and Alberta, Canada, from 2003 to 2005. Yield and N uptake responses to progressively greater N fertilizer rates were curvilinear for both crops. Maximum yield occurred with 76 kg N ha^-1 for canola yield (2190 kg ha^-1) and 47 kg N ha^-1 for wheat (2910 kg ha^-1). Maximum N uptake occurred at about 90 kg N ha^-1 for both crops. Wheat grain yield and N uptake responses were mostly associated with normalized difference vegetation index (NDVI) at anthesis or flag leaf, whereas canola yields and N uptake were most associated with NDVI at five-leaf or bolting, or Cardy Nitrate meter at bolting. The preceding relationships were most apparent at the highest N fertilizer rates. Canola and wheat water use were not affected by N fertilizer rate, but water use efficiency increased linearly for both crops as N fertilizer rate was increased.

Balasubramanian, P. M., Mündel, H.-H., Conner, R. L. and Hou, A. 2012. AAC Tundra great northern dry bean. Can. J. Plant Sci. 92: 1403-1405. AAC Tundra is a high-yielding, early-maturing great northern bean (Phaseolus vulgaris L.) with an upright, indeterminate bush growth habit with long vines (Type IIb). AAC Tundra was developed at the Agriculture and Agri-Food Canada (AAFC) Research Centre, Lethbridge, AB. AAC Tundra has a large seed size and improved field resistance to white mould compared with the check cultivar AC Polaris. AAC Tundra is suitable for irrigated wide row production in Alberta and Saskatchewan.

McVetty, P. B. E., Duncan, R. W., Fernando, W. G. D., Li, G. and Zelmer, C. D. 2012. Red River 1861 Roundup Ready™ high erucic acid, low glucosinolate summer rape. Can. J. Plant Sci. 92: 1407-1409. Red River 1861 summer rape (Brassica napus L.) is the world's fourth Roundup Ready™ high erucic acid, low glucosinolate cultivar. On average, Red River 1861 yielded 19% more seed, 7 g kg^-1 more seed oil and 7 g kg ^-1 more meal protein than MillenniUM 03 high erucic acid, low glucosinolate summer rape. Red River 1861 has an erucic acid content of 52.6% in isolated field trials of HEAR lines and is adapted to the southern B. napus growing regions of western Canada.