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Carew, R., Florkowski, W. J. and DePauw, R. 2015. Review: Shifting patterns in plant cultivar protection for field crops in Canada. Can. J. Plant Sci. 95: 813-829. In an era of increased globalization of agricultural trade and rapid biotechnology advances in developing crops with multiple traits, public and private institutions are facing increasing pressure to protect their technologies and develop partnerships to fund research. Under the auspices of international intellectual property rights agreements, Canada adopted stronger intellectual property rights policies to protect new plant cultivars and reward owners for their innovative efforts. This paper illustrates how Plant Breeders' Rights (PBR) applications for agriculture field crop (cereals, oilseeds, pulses) cultivars and registered cultivars by the Canadian Variety Registration Office of the Canadian Food Inspection Agency (VROCFIA) have evolved over the past 20 yr in response to changes in domestic and international plant cultivar protection policies. The paper also examines the patenting pattern for plant-related traits and technologies. The paper found the bulk of PBR applications for field crops were accounted for by oilseeds followed by cereal and pulse crops such as field pea. In contrast to wheat and canola, which are protected by PBR and registered by the Canadian VROCFIA, pulse crops such as lentil have been developed by Canadian universities and funded by producer levies and released to growers without PBR protection. Among plant-related patents, most of them were credited to corn followed by canola and soybean. The Canadian public sector filed plant patents mainly for canola and concentrated on traits such as insect and disease resistance. The bulk of canola or soybean PBRs applications were by multinational life science seed companies, while the majority of wheat and barley were credited to public institutions such as the Canadian federal department of agriculture and universities.
J. T. O'Donovan, Y. Anbessa, C. A. Grant, A. L. Macleod, M. J. Edney, M. S. Izydorczyk, T. K. Turkington, P. E. Juskiw, G. P. Lafond, W. E. May, K. N. Harker, E. N. Johnson, B. L. Beres, T. A. McAllister, E. G. Smith, W. Chapman
KEYWORDS: no tillage, N rate, AC Metcalfe, CDC Meredith, Major, Bentley, Merit 57, protein concentration, nutrient utilization efficiency, chlorophyll content, kernel plumpness, lodging, non-travail du sol, taux de fertilisation N, AC Metcalfe, CDC Meredith, Major, Bentley, Merit 57, teneur en protéines, efficacité d'utilisation des nutriments, concentration de chlorophylle, caractère ventru du grain, verse
O'Donovan, J. T., Anbessa, Y., Grant, C. A., Macleod, A. L., Edney, M. J., Izydorczyk, M. S., Turkington, T. K., Juskiw, P. E., Lafond, G. P., May, W. E., Harker, K. N., Johnson, E. N., Beres, B. L., McAllister, T. A., Smith, E. G. and Chapman, W. 2015. Relative responses of new malting barley cultivars to increasing nitrogen rates in western Canada. Can. J. Plant Sci. 95: 831-839. Only about 25% of barley (Hordeum vulgare L.) is selected for malting annually in western Canada due to quality issues. While nitrogen (N) fertilization can increase yield, it can also impair quality by increasing protein to unacceptable levels. The objective of this study was to determine the responses of relatively new malting barley cultivars (Bentley, Major, CDC Meredith, and Merit 57) to increasing N rates compared to the response of AC Metcalfe, the most commonly grown malting cultivar. Experiments were conducted at seven locations in western Canada in 2010, 2011 and 2012. Nitrogen was banded at seeding at 0, 30, 60, 90, or 120 kg ha-1. All the new varieties produced higher yield (5 to 11%) than AC Metcalfe. Barley kernel yield and protein concentration increased with N rate. However, Merit 57, CDC Meredith and Bentley produced significantly lower protein concentration in response to N than AC Metcalfe and Major. The newer cultivars displayed higher N utilization efficiency than AC Metcalfe, possibly due to partitioning proportionally more N into leaf chlorophyll development. The higher leaf chlorophyll content may have enabled increased photosynthesis and a more efficient utilization of N for grain formation. Bentley produced the least tillers and had the highest kernel plumpness, while Merit 57 had the lowest kernel plumpness. CDC Meredith lodged most followed by Merit 57, while Major and Bentley lodged least, especially at the higher N rates. Merit 57 and CDC Meredith took longer to mature than the other cultivars but yielded well at relatively short growing season locations.
Dorval, I., Vanasse, A., Pageau, D. and Dion, Y. 2015. Seeding rate and cultivar effects on yield, yield components and grain quality of spring spelt in eastern Canada. Can. J. Plant. Sci. 95: 841-849. There is currently an increasing demand from master millers for spelt (Triticum aestivum ssp. spelta), but little is known about crop management of spring spelt under the eastern Canadian climate in organic or low-input systems. Field experiments were carried out at three sites in Quebec from 2011 to 2013 to assess the effect of cultivar (CDC Origin, CDC Zorba, CDC Nexon, CDC Silex) and seeding rate (250, 300, 350, 400 and 450 grains m-2) on grain and straw yields, yield components and some grain quality characteristics of spelt. CDC Origin produced higher hulled grain yields at all sites, while CDC Silex produced similar hulled grain yields and achieved the highest naked grain yields at two of the three test sites. The hull content varied from 24.0 to 37.6% among cultivars. CDC Origin had the highest hull content at each site. The seeding rate generally had no effect on yields, but had an effect on yield components; increasing seeding rates slightly increased the number of spikes per square metre and decreased the number of grains per spike, while the 1000-grain weight remained unaffected. Protein content of all cultivars was high (14.2 to 15.4%), while falling number varied from 219 to 385 s.
Pourazari, F., Vico, G., Ehsanzadeh, P. and Weih, M. 2015. Contrasting growth pattern and nitrogen economy in ancient and modern wheat varieties. Can. J. Plant Sci. 95: 851-860. Nutrient availability, especially nitrogen (N) availability, is a limiting factor for crop production in many regions of the world. Modern crop varieties often produce high yields under high resource availability, whereas ancient varieties are expected to have characteristics more suitable under low resource availability. To test this expectation, we compared the growth and N use efficiency (NUE) of some varieties of ancient hulled wheat, Triticum turgidum spp. dicoccum, and modern free-threshing wheat, T. aestivum and T. turgidum spp. durum. The wheats were grown under different nutrient fertilization (F) levels in two contrasting environments (field in Iran and outdoor growth container in Sweden). Grain yield was significantly higher in modern varieties than in ancient varieties, regardless of fertilization level. In contrast, N uptake efficiency (i.e., mean N in the plant during the main growth period over N in the initial seed grain) and grain N concentration were generally higher in the ancient varieties. Nitrogen use efficiency, defined as the ratio of the grain N content to the sown seed N content, was higher in the ancient varieties only at lower nutrient supply, because in modern varieties higher nutrient supply resulted in a marked increase in NUE through greatly enhanced grain-specific N efficiency (grain yield per mean plant N content during the main growth period). The modern varieties also showed greater fertilization responses in above-ground biomass and leaf area than ancient varieties. The results are relevant in the context of wheat breeding for nutrient use efficiency.
Ganie, Z. A., Stratman, G. and Jhala, A. J. 2015. Response of selected glyphosate-resistant broadleaved weeds to premix of fluthiacet-methyl and mesotrione (Solstice™) applied at two growth stages. Can. J. Plant Sci. 95: 861-869. A premix of fluthiacet-methyl and mesotrione (1:17.5 ratio) has recently been registered for post-emergence (POST) broadleaf weed control in corn. The objective of this study was to determine the response of glyphosate-resistant common waterhemp, giant ragweed, and kochia to a premix of fluthiacet-methyl and mesotrione when applied to 10- and 20-cm-tall plants. Greenhouse dose response studies were conducted and log-logistic models were used to determine how the response varies between the weed species at two growth stages under various rates ranging from 21.8 to 218.5 g a.i. ha-1 (0.25× to 2.5×). The effective rate required to achieve >90% control and shoot biomass reduction varied depending on the weed species and growth stage. The rates required for 90% control (ED90) of 10-cm-tall glyphosate-resistant common waterhemp, giant ragweed, and kochia were 78, 251, and 17 g a.i. ha-1, respectively, compared with 144, 489, and 79,349 g a.i. ha-1, respectively, for 20-cm-tall plants at 21 d after treatment (DAT). Based on visual control estimates at ED90 level, glyphosate-resistant common waterhemp was the most sensitive at both growth stages; kochia was sensitive at 10-cm height, while giant ragweed was the least sensitive at both growth stages. Irrespective of weed species or growth stage, the ED90 values calculated on the basis of shoot biomass reduction were mostly higher compared with visual control estimates. It is concluded that premix of fluthiacet-methyl plus mesotrione can be potentially used as a POST herbicide in corn for controlling glyphosate-resistant common waterhemp and kochia (≤ 10 cm tall) at the labeled rate (87 g a.i. ha-1).
Chi, M., Liu, C., Su, Y., Tong, Y. and Liu, H. 2015. Bioinformatic prediction of upstream microRNAs of PPO and novel microRNAs in potato. Can. J. Plant Sci. 95: 871-877. MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that play roles in many biological processes of plants. This study aimed to identify novel miRNAs and miRNAs targeting polyphenol oxidase (PPO) in potato. Small RNA-seq data (GSE32471 and GSE52599) including sequencing data of flower, leaf, stem, root, stolon and tuber tissue of potato were downloaded from Gene Expression Omnibus. After quality control and data cleaning of the raw data, the clean data were then mapped to Rfam to screen the reads corresponding to miRNA rather than other types of small RNA by Bowtie. Furthermore, the screened high-quality reads were mapped to known miRNAs in miRBase to identify and predict the novel miRNAs by miRDeep2. Finally, target gene prediction was performed for all identified miRNAs using psRNATarget and their roles in stress responses and brown spot of potato tubers through PPO genes were analyzed. A total of 18 novel potato miRNAs were identified and all of them had their specific expression patterns in different tissues. Targets prediction showed that some novel miRNAs (e.g., ST4.03ch03_9018, ST4.03ch05_15199 and ST4.03ch11_31208) could regulate the expression of potato resistance genes. Moreover, eight known miRNAs were found to target 3 PPO encoding genes, while they expressed at a low level in tuber tissue. Novel miRNAs might be associated with stress resistance of potato, and upstream miRNAs of PPO encoding genes might be important in suppression of potato brown spot.
Chiu, G. Z., Shelp, B. J., Bowley, S. R., DeEll, J. R. and Bozzo, G. G. 2015. Controlled atmosphere-related injury in ‘Honeycrisp’ apples is associated with γ-aminobutyrate accumulation. Can. J. Plant Sci. 95: 879-886. ‘Honeycrisp’ apples (Malus×domestica Borkh.), including fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), can be susceptible to controlled atmosphere (CA)-related injury of the flesh tissue during storage. To better understand the biomarkers associated with this physiological disorder, we compared the temporal responses of the universal stress signature, γ-aminobutyrate (GABA), and visual symptoms of CA-related injury in apples subjected to elevated CO2. Fruit were treated with or without 1-MCP prior to CA [2.5 kPa O2, 5 (elevated) or 0.03 (ambient) kPa CO2] storage at either 3 or 20°C for up to 24 wk. At 20°C, 1-MCP-treated apples displayed symptoms of CA-related injury by 3 wk of elevated CO2 storage; a similar 15% disorder incidence was apparent by 6 wk in non 1-MCP-treated fruit. A maximal incidence of 30% for this disorder occurred after 24 wk at 3°C in fruit held at elevated CO2, regardless of 1-MCP treatment. At 20°C, GABA levels were 48% higher within 6 wk of the transfer of 1-MCP-treated fruit to elevated CO2. At 3°C, a 2.6-fold increase in GABA level occurred by week 6 of elevated CO2 storage, and was maintained for an additional 18 wk thereafter; a similar change in GABA level was apparent in non 1-MCP-treated fruit, albeit delayed until week 18 of storage. These findings indicate that shifts in GABA are associated with the onset of visual symptoms of CA-related injury in ‘Honeycrisp’ fruit in response to elevated CO2, regardless of 1-MCP.
McClure, K. A. and Cline, J. A. 2015. Mechanical blossom thinning of apples and influence on yield, fruit quality and spur leaf area. Can. J. Plant Sci. 95: 887-896. Apple (Malus×domestica Borkh.) trees tend to crop heavily, which often makes crop load adjustment necessary. This can now be achieved as early as bloom by mechanical removal/thinning of blossoms. High-density Empire/M.26 and Royal Gala/M.26 apple trees were mechanically (MBT) and hand blossom thinned (HBT) in 2010 and 2011, respectively, and their effects on fruit set, subsequent hand thinning, final crop load, and spur leaf area were measured. In both years, MBT effectively thinned trees and reduced fruit set, but did not reduce the requirement for follow-up hand fruitlet thinning after June drop in 2011. In 2010, harvest yields for MBT treatments decreased, while weight and diameter increased. In 2011, most harvest and fruit quality parameters were unaffected by thinning. Trees that were mechanically thinned had significantly reduced spur leaf area, but were similar to unthinned control trees with respect to many of the yield and quality parameters measured. Mechanical blossom thinning is a new crop load management option for apple growers looking to supplement more traditional chemical and hand thinning techniques.
Zhao, L.-X., Qu, H.-T., Fu, Y., Gao, S. and Ye, F. 2015. Alleviation of injury from chlorimuron-ethyl in maize treated with safener 3-dichloroacetyl oxazolidine. Can. J. Plant Sci. 95: 897-903. The protective effects of herbicide safeners, including 3-dichloroacetyl-2,2-dimethyl-1,3-oxazolidine (R-28725), 3-dichloroacetyl-2,2-dimethyl-4-ethyl-1,3-oxazolidine (Racemate), and its two enantiomers (R)-3-dichloroacetyl-2,2-dimethyl-4-ethyl-1,3-oxazolidine (R-enantiomer) and (S)-3-dichloroacetyl-2,2-dimethyl-4-ethyl-1,3-oxazolidine (S-enantiomer), on reducing the phytotoxicity of chlorimuron-ethyl to maize were investigated. Soaking the seeds in safeners increased the endogenous glutathione (GSH) content and glutathione-S-transferase (GST) activity of maize. When induced by R-enantiomer, the GST activity in vivo and in vitro increased 180 and 192% compared with control, respectively. R-28725 and R-enantiomer also increased the acetolactate synthase (ALS) activity inhibited by chlorimuron-ethyl from 45 to 100 and 97% compared with the control, respectively. The kinetic parameter Vmax of GST in the maize treated with R-28725 and R-enantiomer increased by 103 and 92%, respectively, compared with the control. Our results suggest that R-28725 and R-enantiomer could significantly improve the GSH content, GST activity, and ALS activity of maize. Overall, maize could be protected from the injury caused by chlorimuron-ethyl.
Schröder, S., Kortekamp, A., Heene, E., Daumann, J., Valea, I. and Nick, P. 2015. Crop wild relatives as genetic resources - the case of the European wild grape. Can. J. Plant Sci. 95: 905-912. Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi, the European Wild Grape and ancestor of cultivated grapevine varieties (V. vinifera L. ssp. vinifera) is the sole wild grapevine species existing in Europe. This important crop wild relative (CWR) species is almost extinct, and persists only in residual habitats. Since these habitats are close to vineyards, this CWR species is endangered by hybridisation with its descendant crop and naturalised rootstocks that originate from viticulture. For this reason, we addressed two questions: To what extent have the remaining South German European Wild Grape accessions escaped hybridisation and preserved genetic identity? Second, what is the potential of this CWR species as a genetic resource for breeding in relation to several grapevine diseases? Using a set of highly resolving genetic markers, we were able to exclude introgression of autochthonous sylvestris accessions by cultivated grapevine. However, we detected introgression mostly from wild American species used as rootstocks in viticulture. The autochthonous accessions can be grouped into clusters. Comparative inoculation studies with the grapevine pathogens powdery mildew (Erysiphe necator), downy mildew (Plasmopara viticola), and black rot (Guignardia bidwellii) revealed relatively high levels of resistance in some of the ssp. sylvestris accessions and represents a valuable genetic resource for resistance breeding.
KEYWORDS: disease transmission, canopy moisture, equipment, material transmission, Transmission de la maladie, humidité du feuillage, équipement, transmission par le matériel
LeClair, E., Conner, R., Robinson, D. and Gillard, C. L. 2015. Transmission of anthracnose (Colletotrichum lindemuthianum) in dry bean (Phaseolus vulgaris L.) with artificial and natural inoculum in a wet and dry canopy. Can. J. Plant Sci. 95: 913-921. Anthracnose [Colletotrichum lindemuthianum (Sacc. and Magn.) Lams. - Scrib.] is a serious pathogen of dry bean (Phaseolus vulgaris L.). Disease transmission on artificial materials and clothing has been observed in other crops, where equipment and workers transmit pathogens from infected to clean plants. Initial studies in 2008 and 2009 at Exeter, ON, determined that anthracnose transmission in dry bean as measured by resultant disease severity occurred with denim, leather, metal, and rubber using a 107 spores mL-1 prepared artificial spore inoculum in both wet and dry crop canopies. In 2012 and 2013 at Morden, MB, and Ridgetown, ON, the studies were expanded by adding a 105 spores mL-1 prepared artificial and a natural inoculum source. Inoculum source and canopy moisture had the greatest effect on disease severity, while no differences were observed between materials within an inoculum sources. Transmission in wet canopy conditions resulted in a higher infection rate. Canopy moisture impacted the natural inoculum the most. The 107 spores mL-1 inoculum transmitted the most disease followed by natural incidence and 105 spores mL-1 inoculum in wet conditions. In dry conditions 107 spores mL-1 inoculum transmitted the most disease followed by 105 spores mL-1 inoculum and natural incidence. Producers need to recognize that there is real risk for the anthracnose transmission by common materials in dry bean, and take appropriate precautions to prevent it.
KEYWORDS: deoxynivalenol, Fusarium head blight screening, Fusarium-damaged kernels, Fusarium graminearum, Hordeum vulgare L., Désoxynivalénol (DON), dépistage de la brûlure de l'épi causée par Fusarium, grains abîmés par Fusarium, Fusarium graminearum, Hordeum vulgare L.
He, X., Osman, M., Helm, J., Capettini, F. and Singh, P. K. 2015. Evaluation of Canadian barley breeding lines for Fusarium head blight resistance. Can. J. Plant Sci. 95: 923-929. Fusarium head blight (FHB) is a major challenge to the successful production of barley in Canada, as well as for end-users such as the malting and brewing industries. Due to the quantitative inheritance of FHB resistance, continuous effort is required to identify breeding lines with improved FHB resistance and incorporate them into crossing schemes to enhance FHB resistance. In the present study, 402 advanced breeding lines from Alberta, Canada, were evaluated in the FHB screening nursery at CIMMYT, Mexico. In 2011 and 2012, FHB incidence was measured on a scale of 1 to 4 to eliminate the most susceptible lines. In 2013 and 2014, 181 lines with the lowest disease scores in the previous 2 yr were tested in replicated experiments for field FHB index, Fusarium-damaged kernels, and deoxynivalenol content. Agronomic and morphological traits, specifically days to heading, plant height, and row and hull types were also evaluated in relations to FHB parameters. Correlation coefficients among the three FHB parameters in both 2013 and 2014 were all significant at P<0.0001, ranging from 0.36 to 0.63. Additional correlation analysis showed that late-maturing, tall, and two-row lines tended to have lower disease, whereas hull type did not show a significant correlation with FHB. Several lines with high and stable FHB resistance similar to that of the resistant checks were identified. These could be used in breeding programs as resistance sources or be registered as new cultivars if their overall attributes meet commercial standards.
Tamburic-Ilincic, L., Wragg, A. and Schaafsma, A. 2015. Mycotoxin accumulation and Fusarium graminearum chemotype diversity in winter wheat grown in southwestern Ontario. Can. J. Plant Sci. 95: 931-938. Fusarium head blight caused by Fusarium graminearum is a serious disease of wheat (Triticum aestivum L.). Deoxynivalenol (DON) is the mycotoxin most commonly detected in contaminated wheat grain in Ontario. A chemotype shift from 15-acetyldeoxynivalenol (15-ADON) to 3-acetyldeoxynivalenol (3-ADON) has been reported in some parts of North America. The objectives of this study were to investigate the mycotoxins accumulation and Fusarium graminearum chemotype diversity in different winter wheat cultivars grown in southwestern (SW) Ontario. Twenty winter wheat grain samples from SW Ontario were tested for DON concentrations in 2008, 24 in each of 2009 and 2010, 42 in 2011 and 36 in 2013 growing seasons. DON levels in grain ranged from none detected to 33 parts per million (ppm). The highest averaged levels of DON were detected in the 2013 season (19.8 ppm at Centralia, 11.8 ppm at Inwood and 4.1 ppm at Ridgetown). In addition to total DON, H-T2, T-2 and nivalenol mycotoxins were detected in low concentrations in a small number of samples collected in 2009 and/or 2013. The 15-ADON analogs were detected at approximately 1.5% of the total DON in harvested wheat grain in 2013. Ninety-seven percent of F. graminearum isolates, tested in 2010 using the polymerase chain reaction (PCR) method, were 15-ADON chemotype, while just 3% of isolates were the 3-ADON chemotype. Overall, there was no evidence in this study to support a shift from 15-ADON to 3-ADON chemotypes of F. graminearum in SW Ontario in 2010. It is recommended to continue monitoring mycotoxin accumulation and F. graminearum chemotype diversity so any changes can be detected early and addressed.
Binay K. Singh, Divakar Nandan, Supriya Ambawat, Bhagirath Ram, Arun Kumar, Tawar Singh, H. S. Meena, Vinod Kumar, V. V. Singh, P. K. Rai, Dhiraj Singh
Singh, B. K., Nandan, D., Supriya, A., Ram, B., Kumar, A., Singh, T., Meena, H. S., Kumar, V., Singh, V. V., Rai, P. K. and Singh, D. 2015. Validation of molecular markers for marker-assisted pyramiding of white rust resistance loci in Indian Mustard (Brassica juncea L.). Can. J. Plant Sci. 95: 939-945. Successful application of molecular markers in marker-assisted pyramiding relies on effective determination of the target phenotype. In this respect, evaluation of the efficiency of markers for marker-assisted selection through cross-validation in different genetic backgrounds and in different populations is a crucial step. In the present study, the previously identified Arabidopsis-derived intron polymorphic (IP) markers At5g41560 and At2g36360, which were highly linked with AcB1-A4.1 and AcB1-A5.1, respectively, were validated in a set of 25 genotypes of Indian Mustard and in three different F2 populations. The relationships between the variation of PCR products of the two markers with the percent disease index (PDI) of the tested genotypes, and the co-segregation analysis of the markers with disease phenotype in F2 populations clearly indicated that At5g41560 and At2g36360 are genotype-nonspecific markers and are closely linked to white rust resistance loci AcB1-A4.1 and AcB1-A5.1, respectively. It also became evident from the present study that AcB1-A4.1 and an another white rust resistance locus Ac(2)t are likely the same gene locus.
Manici, L. M., Kelderer, M., Caputo, F., Nicoletti, F., De Luca Picione, F. and Topp A. R. 2015. Impact of cover crop in pre-plant of apple orchards: relationship between crop health, root inhabiting fungi and rhizospheric bacteria. Can. J. Plant Sci. 95: 947-958. Replant disease of fruit tree orchards has a multifactorial etiology, mainly due to the decline in soil biodiversity along with an increase in root rot pathogens, which can be principally countered with appropriate cropping practices. Therefore, a study on the impact of cover crops on plant health of young fruit trees in long-term orchards was performed. Bioassays were performed over two consecutive growing cycles using soil from a multigeneration apple orchard affected by replant disease. First, a cycle was performed with three cover crops (alfalfa, barley, marigold) and apple rootstock plantlets; at the end, the above-ground part of the plant was removed and root residues left in the soil. In the second cycle, an apple orchard planting was simulated upon the first experimental design. Changes of diversity and composition of root inhabiting fungi and rhizospheric bacteria were evaluated as well as apple plant growth response to the pre-plant treatments. Results suggest that one cycle with alternate plants was sufficient to induce changes at the rhizosphere level, despite soil microbial resilience caused by the same long-term soil management. Rhizospheric bacteria were generally affected by plant genotype. Findings suggest that all three different cover crops can harbor almost all fungal species that colonize apple in replanted orchards (Fusarium spp., Pythum spp., binucleate Rhizoctonia sp., Cylindrocarpon-like-fungi and a several nonpathogenic saprophytic fungi named “other”), but their infection frequency varied according to the host plant. A single pre-plant break treatment did not overall differ significantly in plant growth of subsequent apple tree; however, break with marigold, which increased abundance of nonpathogenic root inhabiting fungi more than other cover crops, gave significantly higher plant growth than obtained after barley. This study provides evidence about cover-crop potential to increase soil diversity in long-term permanent cropping systems and to manipulate root colonizing fungi involved in crop health.
Soltani, N., Nurse, R. E., Shropshire, C. and Sikkema, P. H. 2015. Tolerance of adzuki bean to pre-emergence herbicides. Can. J. Plant Sci. 95: 959-963. Limited pre-emergence herbicide options are available for weed management in adzuki bean in Ontario. Eight field trials were conducted in Ontario over a 3-yr period (2012, 2013, 2014) to evaluate the tolerance of adzuki bean to pyroxasulfone (150 and 300 g a.i. ha-1), flumioxazin (71 and 142 g a.i. ha-1), sulfentrazone (420 and 840 g a.i. ha-1), fomesafen (240 and 480 g a.i. ha-1), imazethapyr (75 and 150 g a.i. ha-1), and cloransulam-methyl (35 and 70 g a.i. ha-1) applied pre-emergence. Pyroxasulfone, flumioxazin and sulfentrazone applied pre-emergence at the proposed 1× and 2× rates caused 25-96% injury and reduced plant stand up to 78%, shoot dry weight up to 95%, plant height up to 67% and seed yield up to 76% in adzuki bean. Cloransulam-methyl resulted in 1 to 9% injury with no adverse effect on plant stand, shoot dry weight, plant height, seed moisture content and seed yield of adzuki bean. Fomesafen and imazethapyr resulted in 1-3% injury with no adverse effect on plant stand, shoot dry weight, plant height, seed moisture content and seed yield of adzuki bean. Based on these results, pyroxasulfone, flumioxazin and sulfentrazone do not have an adequate margin of crop safety for weed management in adzuki bean. Cloransulam-methyl has potential for use in adzuki bean, especially at the lower rate. Imazethapyr and fomesafen at the rates evaluated can be used safely in adzuki bean production under Ontario environmental conditions.
Jha, P., Kumar, V. and Lim, C. A. 2015. Variable response of kochia [Kochia scoparia (L.) Schrad.] to auxinic herbicides dicamba and fluroxypyr in Montana. Can. J. Plant Sci. 95: 965-972. Herbicide-resistant kochia is an increasing concern for growers in the Northern Great Plains of United States and Canada. The objective of the research was to characterize the response of the three putative auxinic herbicide-resistant kochia inbreds (derived from accessions collected from wheat/chemical fallow fields in northern Montana) to dicamba and fluroxypyr relative to a susceptible (SUS) inbred. A dicamba dose-response study indicated that the three putative resistant inbreds (Chot-01, Chot-02, and Chot-03) had R/S ratios of 1.3 to 6.1 based on the visible control response (I50 values), and R/S ratios of 1.5 to 6.8 based on the shoot dry weight response (GR50 values). Dose-response experiments with fluroxypyr determined I50 R/S ratios of 1.4 to 5.7 and GR50 R/S ratios of 1.6 to 4.0 for the three putative resistant inbreds. The selected inbreds showed variable symptomology (phenotype) in response to dicamba and fluroxypyr. Among the three inbreds, Chot-01 exhibited the least epinasty, stem curling/swelling, and chlorosis/necrosis symptoms, and was resistant to dicamba and fluroxypyr. Growers should diversify their weed management tools to manage further spread of auxinic or multiple herbicide-resistant kochia in the region.
Jhala, A. J., Malik, M. S. and Willis, J. B. 2015. Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean. Can. J. Plant Sci. 95: 973-981. Acetochlor, an acetamide herbicide, has been used for many years for weed control in several crops, including soybean. Micro-encapsulated acetochlor has been recently registered for preplant (PP), pre-emergence (PRE), and post-emergence (POST) application in soybean in the United States. Information is not available regarding the sequential application of acetochlor for weed control and soybean tolerance. The objectives of this research were to determine the effect of application timing of micro-encapsulated acetochlor applied in tank-mixture with glyphosate in single or sequential applications for weed control in glyphosate-resistant soybean, and to determine its impact on soybean injury and yields. Field experiments were conducted at Clay Center, Nebraska, in 2012 and 2013, and at Waverly, Nebraska, in 2013. Acetochlor tank-mixed with glyphosate applied alone PP, PRE, or tank-mixed with flumioxazin, fomesafen, or sulfentrazone plus chlorimuron provided 99% control of common waterhemp, green foxtail, and velvetleaf at 15 d after planting (DAP); however, control declined to ≤40% at 100 DAP. Acetochlor tank-mixed with glyphosate applied PRE followed by early POST (V2 to V3 stage of soybean) or late POST (V4 to V5 stage) resulted in ≥90% control of common waterhemp and green foxtail, reduced weed density to ≤2 plants m-2 and biomass to ≤12 g m-2, and resulted in soybean yields >3775 kg ha-1. The sequential applications of glyphosate plus acetochlor applied PP followed by early POST or late POST resulted in equivalent weed control to the best herbicide combinations included in this study and soybean yield equivalent to the weed free control. Injury to soybean was <10% in each of the treatments evaluated. Micro-encapsulated acetochlor can be a good option for soybean growers for controlling grasses and small-seeded broadleaf weeds if applied in a PRE followed by POST herbicide program in tank-mixture with herbicides of other modes of action.
Soltani, N., McNaughton, K. and Sikkema, P. H. 2015. Field horsetail (Equisetum arvense L.) control in corn. Can. J. Plant Sci. 95: 983-986. Six field trials were conducted during 2013 and 2014 on various Ontario farms with heavy field horsetail infestations to determine the effectiveness of various postemergence (POST) herbicides for the control of field horsetail in corn. There was minimal and transient corn injury (3% or less) with nicosulfuron/rimsulfuron, flumetsulam or nicosulfuron/rimsulfuron flumetsulam. In contrast, MCPA amine, nicosulfuron/rimsulfuron MCPA amine, flumetsulam MCPA amine, and nicosulfuron/rimsulfuron flumetsulam MCPA amine caused as much as 6% injury in corn. Nicosulfuron/rimsulfuron, flumetsulam, MCPA amine, nicosulfuron/rimsulfuron flumetsulam and nicosulfuron/rimsulfuron MCPA amine applied POST controlled field horsetail 22-68% and reduced density 27-64% and biomass 38-77%. Flumetsulam MCPA amine and nicosulfuron/rimsulfuron flumetsulam MCPA amine controlled field horsetail 69-83% and reduced density and biomass as much as 87%. Based on these results, flumetsulam MCPA amine and nicosulfuron/rimsulfuron flumetsulam MCPA amine provide the best and most consistent control of field horsetail in corn among POST herbicides evaluated.
Liu, L., Nan, L., Zhao, X., Wang, Z., Nan, H. and Li, H. 2015. Effects of two training systems on sugar metabolism and related enzymes in cv. Beibinghong (Vitis amurensis Rupr.). Can. J. Plant Sci. 95: 987-998. Eight individual sugars and four sugar-metabolism-related enzymes were investigated in the development of Vitis amurensis Rupr. ‘Beibinghong’ grape berries. Two different training systems, vertical shoot positioning (VSP) and Y-shaped training system (Y-shape) were applied. Sucrose contents in the two training systems were significantly related to the sucrose phosphate synthase (SPS) and sucrosynthetic activity of sucrose synthase (SS-s) in berries before veraison. The results show that throughout the veraison period, individual sugars, such as glucose, fructose, galactose and lactose, increased. Glucose and fructose were affected by both training systems, mainly at 15 and 16 wk (weeks after fruit setting). Training systems had no significant effects on the rhamnose, arabinose, galactose and maltose contents, and barely had an effect on the lactose content. The VSP training system mainly affected the sucrose content during the harvest period, while the Y-shape affected sucrose content mainly after 9 wk. During 2011 to 2013, VSP and Y-shape strongly affected the sucrose contents before veraison, and also affected the cleavage activity of sucrose synthase (SS-c) mainly between 5 and 8 wk; however, different training systems barely affected the soluble acid invertase (SAI) activities in whole berry growth. From the perspective of the whole berry development, the results showed that different systems had no significant effects on individual sugars and enzymes.
Jitsuyama, Y. 2015. Morphological root responses of soybean to rhizosphere hypoxia reflect waterlogging tolerance. Can. J. Plant Sci. 95: 999-1005. Excess soil moisture induces hypoxia, causing waterlogging injury in soybeans [Glycine max (L.) Merr.]. Twelve Japanese soybean cultivars with varying hypoxia tolerance were used. Of these, 11 (all but Hayahikari) were evaluated for waterlogging tolerance using a scaled index with data from previous studies. To investigate hypoxic responses, cultivars were grown under hydroponic conditions for 2 wk a year for 2 yr, with aerobic or hypoxic oxygen concentrations artificially maintained in the rhizosphere. Hypoxic responses (measured as plant dry weight and root morphology) were assessed at the early vegetative stage. The effects of hypoxic treatment on root dry weight were significant, and the effect of year on soybean dry weight was not significant. The change in root dry weight, and particularly, in coarse root length, was significantly correlated with waterlogging tolerance index at the 0.001 probability level. This study showed that root responses to rhizosphere hypoxia might reflect waterlogging tolerance in soybeans.
KEYWORDS: Triticum turgidum L. var durum, Durum wheat, yield, yellow pigment, orange wheat blossom midge resistance, Cultivar description, Triticum turgidum L. var durum, Blé dur, rendement, pigmentation jaune, résistance à la cécidomyie du blé, description de cultivar
Pozniak, C. J. and Clarke, J. M. 2015. CDC Carbide durum wheat. Can. J. Plant Sci. 95: 1007-1012. CDC Carbide durum wheat is adapted to the durum production area of the Canadian prairies. This conventional-height durum wheat cultivar combines high grain yield potential with high grain pigment and protein concentrations, and low grain cadmium. CDC Carbide carries the Sm1 gene conferring resistance to the Orange Wheat Blossom Midge [Sitodiplosis modellana (Gehin)]. CDC Carbide is resistant to prevalent races of leaf, stem and stripe rust, and common bunt, and expresses end-use quality suitable for the Canada Western Amber Durum class.
Pozniak, C. J., Nilsen, K., Clarke, J. M. and Beres, B. L. 2015. CDC Fortitude durum wheat. Can. J. Plant Sci. 95: 1013-1019. CDC Fortitude durum wheat is adapted to the durum production area of the Canadian prairies. This conventional-height durum wheat cultivar combines high grain yield potential with high grain pigment and protein concentrations and low grain cadmium. CDC Fortitude has strong straw with a solid stem (high degree of pith expression) conferring wheat stem sawfly resistance. CDC Fortitude expresses leaf, stem, and stripe rust, common bunt, loose smut and Fusarium head blight resistance similar to the current check cultivars.
Graf, R. J., Beres, B. L., Randhawa, H. S., Gaudet, D. A., Laroche, A. and Eudes, F. 2015. AAC Elevate hard red winter wheat. Can. J. Plant Sci. 95: 1021-1027. AAC Elevate is a hard red winter wheat (Triticum aestivum L.) cultivar that is well adapted across western Canada and eligible for all grades of the Canada Western Red Winter (CWRW) wheat class. It was developed using wheat×maize-pollen doubled haploid methodology. AAC Elevate was evaluated in the Western Winter Wheat Cooperative Registration trials relative to CDC Osprey, AC Bellatrix, Radiant and CDC Buteo for 3 yr (2011-2013), with Flourish and Moats added as checks in the latter 2 yr. Based on these 35 replicated trials, AAC Elevate produced higher grain yield than all of the checks (103.3-114.4%) and exhibited good winter survival, medium height with excellent straw strength, large kernels, acceptable end-use quality, and broad disease resistance. AAC Elevate expressed moderate resistance to stem rust and common bunt, intermediate resistance to leaf rust, stripe rust and Fusarium head blight, and resistance to colonization by the wheat curl mite vector for wheat streak mosaic virus.
Tamburic-Ilincic, L. and Smid, A. 2015. Marker soft red winter wheat. Can. J. Plant Sci. 95: 1029-1031. Marker is a soft red winter wheat (Triticum aestivum L.) cultivar registered for Ontario, Canada. It has high grain yield, with good pastry quality and is moderately resistant to Fusarium head blight. Marker is well adapted to the winter wheat growing areas of Ontario.
Tamburic-Ilincic, L. and Smid, A. 2015. UGRC Ring, soft red winter wheat. Can. J. Plant Sci. 95: 1033-1035. UGRC Ring is a soft red winter wheat (Triticum aestivum L.) cultivar registered for Ontario, Canada. It has high grain yield, with good pastry quality (high flour yield, high falling number) and is moderately resistant to powdery mildew. UGRC Ring has good winter hardiness and is well adapted for the winter wheat growing areas of Ontario.
KEYWORDS: spring wheat, Canada Western Red Spring, rust resistance, grain yield, Blé de printemps, blé roux de printemps de l'Ouest canadien, résistance à la rouille, rendement grainier
Spaner, D., Navabi, A., Strenzke, K., Iqbal, M. and Beres, B. 2015. Coleman hard red spring wheat. Can. J. Plant Sci. 95: 1037-1041. ‘Coleman’ hard red spring wheat is an awned, hollow-stemmed cultivar of high yield potential adapted to the wheat growing regions of western Canada. Averaged over 30 site-years, during 3 yr of testing in the Parkland Wheat Cooperative Registration Test (2010-2012), Coleman was higher yielding than Katepwa (8.5%) (P≤0.05), AC Splendor (5.8%) (P≤0.05), CDC Teal (2.1%) and CDC Osler (2%), exhibited maturity, height and lodging resistance similar to, or in the range of the checks, had higher test weights than the checks and showed good resistance to leaf, stem and stripe rust. Coleman exhibited Fusarium head blight resistance greater than and DON contamination levels lower than the check cultivars. Coleman exhibited susceptible reactions to common bunt and loose smut. End-use quality attributes of Coleman meet the specifications of the Canada Western Red Spring (CWRS) wheat market class.
Cheng, B., Rakow, G., Olson, T., Williams, D. J. and Gugel, R. K. 2015. AAC Adagio yellow mustard. Can. J. Plant Sci. 95: 1043-1045. Mucilage content in yellow mustard (Sinapis alba L.) is an important seed quality parameter for the mustard trade since mucilage contributes to the consistency of prepared mustard products. Some wild type brown-seeded accessions of S. alba have much higher mucilage contents than have been observed in yellow-seeded cultivars and breeding lines. Increasing the mucilage content of cultivated, yellow-seeded S. alba by transferring the high mucilage trait from brown-seeded S. alba was initiated in 2004 at the Saskatoon Research Centre, Agriculture and Agri-Food Canada. The yellow mustard variety AAC Adagio with high mucilage content [96.8 centistokes (cst) g-1 seed] was successfully developed from crosses between the elite yellow-seeded breeding line SA00-PYM (mucilage: 35.2 cst g-1 seed) and five brown-seeded S. alba accessions (mucilage: 87.5-108.7 cst g-1 seed). AAC Adagio is well-adapted to all mustard growing areas of western Canada.
Papadopoulos, Y. A., Christie, B. R., McRae, K. B., Gehl, D. and Fillmore, S. A. E. 2015. Pratt timothy. Can. J. Plant Sci. 95: 1047-1048. Pratt timothy (Phleum pratense L.) is an 11-clone synthetic cultivar developed through progeny testing for general combining ability at Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, Charlottetown, Prince Edward Island. Pratt timothy was selected for winter hardiness, plant vigour, plant height, and intermediate maturity (similar to the check cultivar Climax but later than Champ). In Atlantic Canada, Pratt timothy produced more forage than Champ during 3 production years. This cultivar was superior in persistence and re-growth potential with greater production of second-cut herbage.
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