Thiessen Martens, J. R., Entz, M. H. and Wonneck, M. D. 2015. Review: Redesigning Canadian prairie cropping systems for profitability, sustainability, and resilience. Can. J. Plant Sci. 95: 1049-1072. Redesign of agricultural systems according to ecological principles has been proposed for the development of sustainable systems. We review a wide variety of ecologically based crop production practices, including crop varieties and genetic diversity, crop selection and rotation, cover crops, annual polyculture, perennial forages, perennial grains, agroforestry systems, reducing tillage, use of animal manures and green manures, soil biological fertility, organic production systems, integrated crop-livestock systems, and purposeful design of farm landscapes (farmscaping), and discuss their potential role in enhancing the profitability, environmental sustainability, and resilience of Canadian prairie cropping systems. Farming systems that most closely mimic natural systems through appropriate integration of diverse components, within a context of supportive social and economic structures, appear to offer the greatest potential benefits, while creating a framework in which to place all other farming practices. Our understanding of ecological relationships within agricultural systems is currently lacking, and a major shift in research, education, and policy will be required to purposefully and proactively redesign Canadian prairie agricultural systems for long-term sustainability.

Badu-Apraku, B., Yallou, C., Oyekunle, M., Akinwale, R., Aweke, G. and Kamara, A. 2015. Consistency of performance of early-maturing maize cultivars in Striga-infested and Striga-free environments. Can. J. Plant Sci. 95: 1073-1084. Despite the immense potential of maize (Zea mays L.) in savannas of West and Central Africa (WCA), production and productivity is constrained by Striga hermonthica parasitism. Sixteen early-maturing cultivars were evaluated at two locations in Nigeria and three locations in the Republic of Benin from 2007 to 2009 to assess the grain yield, stability and the consistency of the rankings of the cultivars under Striga-infested and Striga-free environments. The combined analysis of variance showed significant (P<0.01) cultivar and cultivar×environment interactions for grain yield and other traits under Striga-infested and Striga-free environments. The test of concordance was significant (P<0.001) for grain yield (W=0.68), number of emerged Striga plants (W=0.74) and Striga damage (W=0.56) under Striga infestation, indicating stability of resistance in the cultivars developed from diverse sources under artificial S. hermonthica infestation across environments. There was high consistency of the rankings of the cultivars for grain yield and other Striga-resistance traits under Striga-infested and Striga-free environments in Benin and Nigeria. The additive main effects and multiplicative interaction (AMMI) biplot analysis for grain yield revealed POOL15SR/ACR94TZECOMP5-W/ACR94TZECOMP5-W and 2004 TZE-Y Pop DT STR C4 as the most stable cultivars with above-average mean grain yield in Striga-infested environments and they can be combined with other crop management options to control the parasite in the Striga endemic environments. Cultivars TZE Comp 5-W C7F2 and TZE Comp5-Y C6 S6 (Set B) had less Striga damage and number of emerged Striga plants across test environments. These cultivars could therefore serve as unique sources of favorable alleles for improving Striga resistance in maize in different production environments and farming systems.

Harker, K. N., O'Donovan, J. T., Turkington, T. K., Blackshaw, R. E., Lupwayi, N. Z., Smith, E. G., Dosdall, L. M., Hall, L. M., Kutcher, H. R., Willenborg, C. J., Peng, G., Irvine, R. B. and Mohr, R. 2015. Canola cultivar mixtures and rotations do not mitigate the negative impacts of continuous canola. Can. J. Plant Sci. 95: 1085-1099. High-frequency canola (Brassica napus L.) rotations increase canola production risks. From 2008 to 2013, direct-seeded experiments involving several variations of continuous canola were compared with wheat (Triticum æestivum L.) and field pea (Pisum sativum L.) rotated with canola at five western Canada locations. Continuous canola rotations involved sequences of different herbicide-resistant canola and two-cultivar mixtures of herbicide-resistant canola from different sources in the same year. Fertilizers, herbicides, and insecticides were applied as required for optimal production of all crops. Rotating herbicide-resistant canola types over years or mixing two cultivars of the same herbicide-resistant type provided no pest management, yield or seed quality advantages compared with planting the same herbicide-resistant cultivar type each year. In 2013, weed biomass was lower in canola preceded by other crops than most continuous canola treatments. Compared with continuous canola, when 1 or 2 yr of wheat or field pea and wheat were inserted into 3-yr rotation cycles, 2010 root maggot damage was reduced 6% and 2013 blackleg [Leptosphæeria maculans (Desmaz.) Ces. & De Not.] incidence and severity were reduced 53 and 54%, respectively. Furthermore, yields were 22% higher when canola was grown only once in 3 yr compared with continuous canola and the wheat-canola-canola rotation. The most important mitigation strategy to ensure long-term sustainable canola production is to rotate canola with other crops.

Sanderson, M. A., Liebig, M. A., Hendrickson, J. R., Kronberg, S. L., Toledo, D., Derner, J. D. and Reeves, J. L. 2015. Long-term agroecosystem research on northern Great Plains mixed-grass prairie near Mandan, North Dakota. Can. J. Plant Sci. 95: 1101-1116. In 1915, a stocking rate experiment was started on 101 ha of native mixed-grass prairie at the Northern Great Plains Research Laboratory (NGPRL) near Mandan, ND (100.9132N, 46.7710W). Here, we document the origin, evolution, and scientific outcomes from this long-term experiment. Four pastures of 12.1, 20.2, 28.3, and 40.5 ha were laid out and stocked continuously from May until October with 2-yr-old or yearling beef steers at four rates [initially 0.98, 1.39, 1.83, and 2.4 animal unit months ha^-1]. The experiment generated some of the first information on the resilience of mixed-grass prairie to grazing and drought and relationships of livestock productivity to soil moisture for predictive purposes. After 1945, the experiment was reduced to the light and heavy stocking rate pastures only, which have been managed and grazed in approximately the same manner to the present day. The pastures were used to assess responses of vegetation to fertilizer in the 1950s and 1960s, develop grazing readiness tools in the 1990s, and assess remote sensing technologies in the 2000s. The long-term pastures currently serve as a unique resource to address contemporary questions dealing with drought, soil quality, carbon dynamics, greenhouse gas emissions, invasive species, and climate change.

Schellenberg, M. P. and Biligetu, B. 2015. The effects of temperature and scarification on seed germination of three Dalea species. Can. J. Plant Sci. 95: 1117-1120. Ecological varieties of North American native plants are used for reclamation or rangeland seeding in Canada. The objectives of the study were to determine the optimum temperature for seed germination and to evaluate the effect of seed scarification on germination of ecological varieties of purple prairie clover [Dalea purpureum (Vent) Rydb.], white prairie clover [Dalea candida (Michx.) Willd.], and a wild collection of hairy prairie clover [Dalea villosa (Nutt.) Spreng var. villosa]. Germination was studied in growth chambers with constant temperatures of 5, 10, 20, and 30°C for 28 d using a randomized complete block design (RCBD). An additional germination experiment was conducted at 20°C after seed scarification. Based on days to initiate first germination and final germination, the optimum temperature for germination was 20°C for the three species. Final germination was the highest for purple prairie clover (51%), intermediate for white prairie clover (27%), and lowest for hairy prairie clover (5%). Seed scarification increased final germination by around 20% for all three species.

Xu, X., Wang, R., Chao, J., Lin, Y., Jin, Q., He, X., Luo, S. and Wu, T. 2015. The expression patterns of Cucumis sativus WRKY (CsWRKY) family under the condition of inoculation with Phytophthora melonis in disease resistant and susceptible cucumber cultivars. Can. J. Plant Sci. 95: 1121-1131. Based on RNA-seq, we analyzed expression patterns of 55 CsWRKYs in the disease-resistant cultivar (JSH) and the disease-susceptible cucumber cultivar (B80) at 0 and 40 h post-inoculation with Phytophthora melonis. After inoculation with P. melonis, in JSH and B80, the number of up-regulated CsWRKY genes was both 25 with 22 commonly up-regulated genes, and there were 22 CsWRKY genes down-regulated in JSH and 23 in B80 with 18 commonly down-regulated genes, and there were eight CsWRKY genes with no or little change in transcript expression in JSH and seven in B80 with four common genes. Among the 55 CsWRKY genes, 17 genes showed significant differences (differences > twofold) in the degree of change of gene transcription level between JSH and B80 from RNA-seq data analysis, and the results validated using real-time PCR showed that there were only six genes (CsWRKY2, 20, 26, 35, 44, 52) out of the 17 that exhibited significant differences (differences > twofold) with four genes (CsWRKY2, 20, 26, 52) consistent with the data from RNA-seq and two genes (CsWRKY 35, 44) inconsistent with the data from RNA-seq. In addition, the six genes were strongly up-regulated after salicylic acid (SA) treatment with five genes (CsWRKY2, 20, 26, 35, 44) up to peak at 12 h and one gene (CsWRKY52) up to peak at 24 h in expression and that four CsWRKY genes (CsWRKY2, 20, 44, 52) out of six were strongly up-regulated with three genes (CsWRKY2, 20, 44) up to the highest point at 24 h and one gene (CsWRKY52) up after methyl jasmonate (MeJA) treatment. Based on the results above, we predicted CsWRKY2, 20, 26, 35, 44 and 52 may be involved in disease resistance of JSH against Phytophthora melonis by SA and (or) JA signaling pathway(s).

Khanal, R., Navabi, A. and Lukens, L. 2015. Linkage map construction and quantitative trait loci (QTL) mapping using intermated vs. selfed recombinant inbred maize line (Zea mays L.). Can. J. Plant Sci. 95: 1133-1144. Intermating of individuals in an F₂ population increases genetic recombination between markers, which is useful for linkage map construction and quantitative trait loci (QTL) mapping. The objectives of this study were to compare the linkage maps and precision of QTL detection in an intermated recombinant inbred line (IRIL) population and a selfed recombinant inbred line (RIL) population. Both, IRIL and RIL, populations were developed from Zea mays inbred lines CG60 and CG102. The populations were grown in two environments to evaluate traits, and inbred lines from each population were genotyped with SSR and SNP markers for linkage map construction and QTL identification. In addition, we simulated RIL and IRIL populations from two inbred parents to compare the precision of QTL detection between simulated RIL and IRIL populations. In the empirical study, the linkage map was longer in RIL as compared with IRIL, and the average QTL support interval was reduced by 1.37-fold in the IRIL population compared with the RIL population. We detected 16 QTL for flowering time, plant height, leaf number, and stay green in at least one recombinant inbred line population. Two out of 16 QTL were shared between two recombinant inbred line populations. In the simulation study, the QTL support interval was reduced by 1.66-fold in the IRIL population as compared with the RIL population and linked QTL were identified more frequently in IRIL population as compared with RIL population. This study supports the utility of intermated RIL populations for precise QTL mapping.

Rahemi, A., Gradziel T.M., Chaparro J.X., Folta, K.M., Taghavi, T., Fatahi, R., Ebadi, A. and Hassani, D. 2015. Phylogenetic relationships among the first and second introns of selected Prunus S-RNase genes. Can. J. Plant Sci. 95: 1145-1154. To identify and evaluate self-incompatible alleles in almonds and related germplasm, DNA from 15 Prunus species was amplified using two degenerate consensus primer pairs flanking first and second S-locus introns (PaConsI-FD EM-Pc1ConsRD and EM-Pc2ConsFD EM-Pc3ConsRD). Twenty-eight amplified PCR products were analyzed by automated sequencer capillary electrophoresis. Sequenced fragments were aligned against available Prunus S-locus sequences in the National Center for Biotechnology Information and S-alleles identities were determined. The phylogenetic relationships between S-alleles in the germplasm studied were determined by the homology between their sequences and dendrograms were obtained for each primer pair. The Maximum Likelihood (homology) ranged from 84 to 100%. Most sequences were similar to cultivated almond (Prunus dulcis) or to the European wild almond (P. webbii). Twenty-six alleles for the first and the second introns were registered in the database in the GenBank. Two sequences of the first and second introns, which were taken from Prunusnairica and had similarity in GenBank, were registered in the database under a common sequence of the first and second intron. Analysis of phylogenetic relationships (dendrograms) among S-alleles from wild almond species as well as S-alleles cluster relations showed most pairs of alleles well supported by bootstrap.

An, D., Bykova, N. V. and Debnath, S. C. 2015. EST-PCR, EST-SSR and ISSR markers to identify a set of wild cranberries and evaluate their relationships. Can. J. Plant Sci. 95: 1155-1165. The cranberry (Vaccinium marcrocarpon Ait.) is a woody, evergreen, perennial vine with great potential for economic and health benefits. Selection and use of genetically diverse genotypes are key factors in any crop breeding program to develop cultivars with a broad genetic base. Molecular markers play a major role in selecting diverse genotypes. One hundred and two wild cranberry clones collected from four Canadian provinces and five cultivars were screened with inter simple sequence repeat (ISSR), expressed sequence tag-simple sequence repeat (EST-SSR) and EST-polymerase chain reaction (PCR) markers to validate the genetic diversity and relationships among them. EST-PCRs (0.54) and EST-SSRs (0.35) generated higher frequency of major alleles than ISSRs (0.08), but ISSRs presented a higher level of polymorphism and greater polymorphic information content and expected heterozygosity than EST-SSRs and EST-PCRs. Combined cluster analysis by the unweighted pair-group method with arithmetic averages (UPGMA) separated the wild clones and cultivars into four main clusters, which was in agreement with the principal coordinate (PCo) analysis. Analysis of molecular variation detected sufficient variations among genotypes within communities and among communities within provinces with ISSR (66 and 36%, respectively), EST-PCR (72 and 34%, respectively) and EST-SSR (72 and 34%, respectively) markers. These values were 71 and 35%, respectively, for combined analysis. Combined use of three types of molecular markers, for the first time in Vaccinium species, detected a sufficient degree of variation among cranberry genotypes, allowing for differentiation and rendering these technologies valuable for genotype identification in a diverse cranberry germplasm and for more efficient parental choice in the current cranberry breeding program.

Li, J., Percival, D., Hoyle, J., Yue, J., White, J., Head, K. and Pruski, K. 2015. Environmental effects on fruit composition of cloudberry/bakeapple (Rubus chamaemorus L.) grown in southern Labrador, Canada. Can. J. Plant Sci. 95: 1167-1175. The composition of fruit collected from three fields located near Lanse'au Clair, Red Bay and Cartwright in southern Labrador, Canada, was analyzed over the 2011 and 2012 growing seasons. Soluble solids, titratable acidity, total phenolics, total anthocyanins, chlorogenic acid, caffeic acid, quercetin-3-glucoside, cyanidin-3-glucoside and ellagic acid were determined after each harvest using standard laboratory procedures. Temperature, precipitation, wind and other environmental factors affected growth and deposition of nutrients in harvested fruit. Soluble solids content (TSS), titratable acidity (TA), total anthocyanin, chlorogenic acid, cyanidin, total phenolic compounds and total anthocyanins of cloudberry fruit were significantly (P<0.05) affected by the combination of the growing season and the location. The TSS, TA and total phenolics were higher in fruits from Cartwright (most northern location) in both seasons compared with the other two locations. The HPLC analysis of compounds showed the ellagic acid and quercetin 3-o-β-D-glucoside contents of fruits were significantly affected by the location and the growing season (higher in 2012 compared with 2011), while contents of chlorogenic acid, caffeic acids, and cyanidin-3-o-β-glucoside were not. To our knowledge this is the most comprehensive study of fruit composition of bakeapple conducted in southern Labrador, Canada.

Toivonen, P. M. A. 2015. Comparison of I_AD and starch-iodine indices at harvest and how they relate to post-storage firmness retention in Ambrosia™ apples over three growing seasons. Can. J. Plant Sci. 95: 1177-1180. Starch-iodine index and I_AD values were recorded for Ambrosia™ apples at harvest and compared with firmness retention after controlled atmosphere storage. The starch-iodine index correlated with firmness retention only in 2012. Harvest I_AD values were associated with firmness retention in all years. Seasonal differences in temperature patterns were possible factors affecting the starch-iodine index. I_AD was more consistent between seasons for monitoring maturity.

Zhang, C. J., Lim, S. H., Kim, J. W., Song, J. S., Yook, M. J., Nah, G., Valverde, N. E. and Kim, D. S. 2015. Quantifying herbicide dose-response and resistance in Echinochloa spp. by measuring root length in growth pouches. Can. J. Plant Sci. 95: 1181-1192. The aim of the presented study was to develop a bioassay for rapid diagnosis of herbicide dose-response and resistance in Echinochloa. Pre-germinated seeds of Echinochloa spp. were incubated in growth pouches (18 cm×16.5 cm) containing herbicide solutions in a range of concentrations. Shoot and root lengths were measured after 6 d of incubation. Dose-responses estimated by measuring root lengths in the growth pouches were well-described by the log-logistic dose-response model and similar to those estimated by a whole-plant assay. Accurate dose-response curves were successfully generated for several herbicides with different modes of action, suggesting that the growth pouch method can be used for herbicide bioassays. The suitability of the growth pouch method for rapid diagnosis of acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor resistance in Echinochloa spp. was also tested. For cyhalofop-butyl, resistant and susceptible biotypes were discriminated at 180-300 mg a.i. L^-1 and 80-120 mg a.i. L^-1 for barnyardgrass (E. crus-galli) and late watergrass (E. oryzicola), respectively. For penoxsulam, the discriminatory dosage was 350-500 mg a.i. L^-1 for barnyardgrass and 650-1000 mg a.i. L^-1 for late watergrass. The method was further used to identify late watergrass biotypes resistant and susceptible to two other ALS inhibitors, azimsulfuron and bispyribac-sodium. Our results show that the growth pouch method can be reliably used in herbicide dose-response studies and to diagnose herbicide resistance in Echinochloa spp., with significant time and cost savings compared with conventional whole-plant assays.

Nurse, R. E., Darbyshire, S. J. and Simard, M.-J. 2015. Impact of post-anthesis glyphosate on woolly cupgrass seed production, seed weight and seed viability. Can. J. Plant Sci. 95: 1193-1197. Herbicides are generally applied at early stages of crop and weed growth to protect crop yield. Few studies have evaluated the effect of late (post-anthesis) applications of glyphosate as a management option to limit the seed production of weed escapes, such as woolly cupgrass (Eriochloa villosa). We propagated woolly cupgrass under greenhouse conditions and then applied three glyphosate treatments post-anthesis including: (1) an untreated control; (2) 900 g a.e. ha^-1; and (3) 1800 g a.e. ha^-1. Terminal inflorescences were collected 21 d after glyphosate application, and seed production, seed weight and embryo viability were assessed. Post-anthesis glyphosate applications did not influence seed production, but reduced seed weight and viability by 50 and 96%, respectively. Therefore, glyphosate applied just before the woolly cupgrass inflorescence begins to emerge from the leaf sheath (as late as the R1 stage in soybeans) is an effective strategy to manage woolly cupgrass reproduction and stop viable seeds from entering the soil seed bank or other dispersal pathways.

Belfry, K. D., McNaughton, K. E. and Sikkema, P. H. 2015. Weed control in soybean using pyroxasulfone and sulfentrazone. Can. J. Plant Sci. 95: 1199-1204. Pyroxasulfone and sulfentrazone are new herbicides currently being evaluated for weed control in soybean [Glycine max (L.) Merr.] in Ontario, Canada. Seven experiments were conducted over a 3-yr period (2011 to 2013) at Ridgetown and Exeter, Ontario, to evaluate weed management using pyroxasulfone, sulfentrazone and their tank-mixes relative to the industry standard, imazethapyr plus metribuzin. Tank-mixing pyroxasulfone and sulfentrazone provided up to 97, 46, 60, 100 and 71% control of common lambsquarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), green foxtail [Setaria viridis (L.) Beauv.], Powell amaranth [Amaranthus powellii (S.) Wats.] and velvetleaf (Abutilon theophrasti Medic.), respectively, at 2 wk after treatment. Control with pyroxasulfone and sulfentrazone was improved when tank-mixed, relative to application of each herbicide separately. Although control was variable across weed species, no difference in control was identified between pyroxasulfone plus sulfentrazone and imazethapyr plus metribuzin. Soybean yield was up to 2.7, 2.4 and 2.9 t ha^-1 for pyroxasulfone, sulfentrazone and pyroxasulfone plus sulfentrazone application, yet imazethapyr plus metribuzin provided the highest yield (3.3 t ha^-1). This research demonstrates that pyroxasulfone plus sulfentrazone may be used as a valuable weed control option in soybean; however, weed community composition may limit herbicidal utility.

Gasura, E., Setimela, P. S. and Souta, C. M. 2015. Evaluation of the performance of sorghum genotypes using GGE biplot. Can. J. Plant Sci. 95: 1205-1214. In spite of sorghum's drought tolerance, it is largely affected by genotype×environment interaction (GE), making it difficult and expensive to select and recommend new sorghum genotypes for different environments. The objectives of this study were to examine the nature of GE for sorghum grain yield, to identify superior sorghum genotypes for sorghum production environments and determine ideal testing locations for future breeding activities in Zimbabwe. The grain yield of 20 sorghum genotypes from Seed Co. Pvt. Ltd. were evaluated for 2 yr (2011/2012 and 2012/2013 cropping seasons) at five locations in different agro-ecological zones of Zimbabwe. Combined analyses of variance showed significant differences for genotypes (P<0.01), environments (P<0.001) and genotype×location (P<0.01). Genotype×environment variance component was seven times greater than that of genotypes. Genotype×environment interaction was attributed to the variability in the predictable biotic and abiotic factors associated with the different locations. The genotype main effect plus GE biplot showed that the experimental sorghum genotypes W07, W09, W05, G06 and OP46 were high yielding and stable, and possessed other desirable agronomic traits. The most discriminating and representative location was Rattray Arnold Research Station.

Du, G.-H., Liu, F.-H. and Rowland, G. 2015. Fiber cell development and fiber yield of flax (Linum usitatissimum L.) affected by the seasonal temperature pattern. Can. J. Plant Sci. 95: 1215-1220. Three fiber flax cultivars ‘Ariane’, ‘Argos’ and ‘Viking’ were cultured in growth chambers under three seasonal temperature patterns (STPs) [parabolic (P), anti-parabolic (AP) and quasi-horizontal (QH) configurations]. The effect of STP was studied on fiber cell development and on fiber yield. The results indicated that, compared with the quasi-horizontal seasonal temperature pattern (QH-STP), the size of fiber cell cavity (SFCC) and fiber content (FC) decreased under parabolic seasonal temperature pattern (P-STP). However, the size of fiber cell (SFC) and SFCC decreased, but the number of fiber cells per bundle (NFCB) increased under anti-parabolic seasonal temperature pattern (AP-STP). Moreover, there was a significant positive correlation between fiber weight (FW) and width of fiber bundle (WFB), also between FC and NFCB. Considering the response of fiber flax cultivars to the different STPs, ‘Ariane’ had smaller SFC and SFCC, thinner thickness of fiber cell wall (TFCW) under AP-STP, and smaller SFCC and thicker TFCW under P-STP than under QH-STP, while ‘Argos’ had smaller SFC and SFCC, and higher NFCB under AP-STP, and smaller SFC under P-STP than under QH-STP. However, STPs had little effect on the fiber cell development of ‘Viking’. All three cultivars had high FC under AP-STP than under P-STP. These observations indicate that the fiber cell development and fiber yield of flax were related to the STP and suggest that AP-STP are the most favorable temperature conditions for fiber flax growth.

Hodgson-Kratky, K. M. J., Demers, M. N. K., Stoffyn, O. M. and Wolyn, D. J. 2015. Harvest date, post-harvest vernalization and regrowth temperature affect flower bud induction in Russian dandelion (Taraxacum kok-saghyz). Can. J. Plant Sci. 95: 1221-1228. Russian dandelion (Taraxacum kok-sagyz Rodin; TKS) is a promising candidate for introducing natural rubber production into North America; however, a comprehensive analysis of factors that influence flowering is essential for efficient breeding and crop development. The objectives of this study were to determine the effects of fall harvest date (early September, October and November), post-harvest vernalization (0, 4 and 8 wk at 4°C), and greenhouse regrowth temperature [15/13°C or 21/18°C (day/night)] on flower induction. The vernalization requirements (0, 4, 8 and 12 wk at 4°C) to reflower TKS plants were also examined in controlled environments at 21/18°C. Plants harvested in September or October required 4 wk of vernalization and growth at 15/13°C to maximize the percentage of plants with flower buds and minimize the time for flower bud appearance. Those harvested in November flowered quickly and at high frequency with no vernalization and regrowth at 21/18°C. Vernalization was not essential to re-induce flowering; 80-100% of plants flowered regardless of treatment. Various combinations of harvest dates, vernalization periods and regrowth temperatures can be used to maximize flowering in TKS and have a positive impact on germplasm development.

Beres, B. L. and Stevenson, F. C. 2015. Feasibility of bioplastic mulch systems to stimulate early seed germination and plant growth for corn silage hybrids. Can. J. Plant Sci. 95: 1229-1234. A study was conducted at Vauxhall and Lethbridge, Alberta, Canada, in 2006 and 2007 to determine if covering corn (Zea mays L.) seed rows with bioplastic mulch accelerates growth and improves yield. Each site (location by year combination) included all factorial combinations of three seeding rates (64 000, 74 000, and 84 000 kernels ha^-1), two Pioneer^® corn hybrids [39J26 at 2350 corn heat units (CHU), high vigour; and Roundup Ready^® 38K46 at 2775 CHU; low vigour], and seedbed preparation (1), bioplastic mulch covering each seed row, (2) same bioplastic system but removed 3 wk post-planting, or (3) no plastic covering. The use of a bioplastic mulch decreased days to anthesis and silking, and the removal of plastic often decreased days to anthesis a further day or two. Application and subsequent removal of plastic from corn rows always increased corn plant height relative to plots without plastic. However, the use of plastic without removal limited weed control, causing increased weed weight by 0.3-0.5 Mg ha^-1 at the three sites. A yield reduction of 5-9 Mg ha^-1 occurred with plastic mulch vs. no plastic applied or plastic removed at Vauxhall in 2006 (High CHU hybrid) and at Lethbridge in 2007 (both hybrids). Otherwise, yield was not affected with plastic applied vs. no plastic. Removal of the plastic offers accelerated plant growth and proper timing of weed removal, but the feasibility in a corn silage system at recommended sowing dates is questionable due to logistics at planting and increased costs. The system would provide earlier harvest dates for silage or grain systems, which lessens the risk of frost effects in fall.

McNaughton, K. E., Blackshaw, R. E., Waddell, K. A., Gulden, R. H., Sikkema, P. H. and Gillard, C. L. 2015. Effect of five desiccants applied alone and in combination with glyphosate in dry edible bean (Phaseolus vulgaris L.). Can. J. Plant Sci. 95: 1235-1242. Application of dry bean desiccants just prior to crop maturity is common practice by Canadian producers. As dry beans are grown for human consumption it is critical that producers pick desiccants that do not affect crop yield, seed quality, or result in desiccant seed residue levels above accepted levels. In this study the efficacy of glyphosate, diquat, glufosinate, carfentrazone, flumioxazin, and saflufenacil as desiccants was examined for navy, cranberry, pinto, and great northern dry bean. Seed herbicide residues were also tested for each of the dry bean classes tested. Navy, cranberry, pinto, and great northern dry bean yields were not impacted by use of the desiccants diquat, carfentrazone, flumioxazin, or saflufenacil when applied at labelled rates and application timings. Additionally, herbicide residues in seed following application remained lower than maximum residue limits (MRL) established by primary Canadian dry bean export partners. Generally, dry bean colour, irrespective of class, was not altered by desiccant use; diquat and flumioxazin caused minor increases in the degree of red and yellow seed pigmentation for cranberry bean only. Although colour differences were noted using a Chroma meter the differences were slight and would not likely be of economic importance. Application of glyphosate did not affect crop yield, and seed residue levels were below MRLs for navy, pinto, and great northern bean. However, seed glyphosate residue levels were above the MRL for cranberry bean when glyphosate was applied alone or tankmixed with carfentrazone, flumioxazin, or saflufenacil. Seed residue levels were also above listed MRLs for some export countries when glufosinate was applied to navy, cranberry, and pinto bean, although crop yield and seed quality remained unaffected. These findings suggest that growers and contractors should avoid using glufosinate as a dry bean desiccant at least for some markets and that care should be taken when selecting glyphosate as a desiccant, especially for cranberry bean. Across all market classes desiccation progress of bean leaf, stem, and pod tissue was slowest when glyphosate and carfentrazone were used.

Farid, M. and Navabi, A. 2015. N₂fixation ability of different dry bean genotypes. Can. J. Plant Sci. 95: 1243-1257. Common bean (Phaseolous vulgaris L.) is generally known as a weak N₂ fixer compared with other legumes. The availability of genetic variation for N₂ fixation potential of common bean supports the idea that symbiotic nitrogen fixation (SNF) in common bean can be improved through breeding. To assess the potential N₂ fixation of selected common bean genotypes, 12 bean varieties including three Andean and nine Middle American were screened for SNF ability and related traits in controlled environments and field trials in Ontario, Canada. A non-nodulating mutant, R99, was used as the reference plant to estimate nitrogen derived from the atmosphere (Ndfa) through the natural ¹⁵N abundance method. Significant variation was found among the bean genotypes for Ndfa and its related traits. Environmental and genotype by environmental effects significantly influenced Ndfa and its related traits. The three Andean bean genotypes were superior to Middle American genotypes for nodulation ability, while the Middle American genotypes were generally stronger nitrogen fixers in optimum soil moisture conditions. In general, nitrogen fixation was found to be significantly associated with seed yield and carbon isotope discrimination, an indicator of water use efficiency.

Pandey, M., Singh, A. K., DePauw, R. M., Bokore, F. E., Ellouze, W., Knox, R. E. and Cuthbert, R. D. 2015. Coleoptile length, gibberellin sensitivity, and plant height variation of durum wheat in Canada. Can. J. Plant Sci. 95: 1259-1264. Thirty-three durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.] and three hexaploid wheat (Triticum aestivum L.) cultivars and introduced germplasm were evaluated for coleoptile length (CL), gibberellin (GA) sensitivity, and plant height in the laboratory, greenhouse and field. The semidwarf durum cultivars, AC Navigator and Commander, had short CL (<7.0 cm) and were insensitive to GA. All the tall and conventional-height durum had long CL (>9.0 cm) and expressed sensitivity to exogenous GA. The CL was not associated with plant height and seedling dry matter mass among the tall and conventional-height durum genotypes.

Randhawa, H. S., Graf, R. J., Fox, S. L. and Sadasivaiah, R. S. 2015. AAC Proclaim general purpose spring wheat. Can. J. Plant Sci. 95: 1265-1269. AAC Proclaim is a soft red spring wheat cultivar eligible for the Canada Western General Purpose (CWGP) wheat class. Evaluated in 18 trials grown over 2 yr in the General Purpose Wheat Cooperative Registration trial, AAC Proclaim yielded significantly lower than the CWGP checks, AC Andrew and Pasteur, and was 1 and 5 d earlier maturing, respectively. AAC Proclaim was significantly taller than the checks, but had similar straw strength. Test weight was higher than the checks and kernel mass was similar to AC Andrew. Based on visual assessments and deoxynivalenol testing over 3 yr, AAC Proclaim was rated as resistant to Fusarium head blight. It also expressed resistance to the prevalent races of leaf rust and moderate resistance to the prevalent races of stem rust and loose smut. AAC Proclaim showed susceptibility to infection by stripe rust and common bunt.

Salmon, D. F., Helm, J. H., Graf, R. J., Albers, S., Aljarrah, M., Xi, K., Oro, M., Lohr, S. and Bergen, C. 2015. Pintail general purpose winter wheat. Can. J. Plant Sci. 95: 1271-1276. Pintail is an awnless hard red winter wheat (Triticum aestivum L.) cultivar that was registered in 2012 and is eligible for grades of Canada Western General Purpose (CWGP) wheat. It was developed using wheat × maize-pollen doubled haploid techniques. Evaluated across western Canada from 2008 to 2010 relative to CDC Harrier, CDC Falcon and CDC Ptarmigan, Pintail expressed grain yield ranging from 98.6 to 105.8% of these CWGP wheat checks. Its area of greatest adaptation was in the parkland and semi-arid prairie regions of Alberta and western Saskatchewan, where cold tolerance is a primary concern. Pintail exhibited excellent winter survival, intermediate maturity, medium height and strong straw. Test weight was within the range of the checks, and kernel weight was lower than all of the checks. Pintail displayed moderate resistance to stripe rust, moderate susceptibility to stem and leaf rust, and susceptibility to common bunt and Fusarium head blight. The high yield and awnless spike of Pintail should make it particularly attractive in various livestock feed and forage applications.

Bing, D.-J., Beauchesne, D., McLaren, D. and Vera, C. 2015. AAC Barrhead field pea. Can. J. Plant Sci. 95: 1277-1278. AAC Barrhead is a semi-leafless, yellow cotyledonary field pea (Pisum sativum L.) cultivar developed at Agriculture and Agri-Food Canada (AAFC) Lacombe Research Centre, Lacombe, Alberta, Canada. It is a high-yielding cultivar with excellent standability. AAC Barrhead is resistant to powdery mildew caused by Erysiphe pisi Syd. It has medium maturity and is adapted to all field growing regions in western Canada.

Bing, D.-J., Beauchesne, D., Vera, C. and Balasubramanian, P. 2015. AAC Liscard maple pea. Can. J. Plant Sci. 95: 1279-1281. AAC Liscard is a semi-leafless maple pea (Pisum sativum L.) cultivar developed at Agriculture and Agri-Food Canada Lacombe Research Centre, Lacombe, Alberta, Canada. It is a high-yielding cultivar with excellent standability. AAC Liscard is resistant to powdery mildew caused by Erysiphe pisi Syd. It has early maturity and medium seed size in the maple pea class. AAC Liscard is adapted to the field pea growing regions in western Canada.