Harker, K. N. 2013. Slowing weed evolution with integrated weed management. Can. J. Plant Sci. 93: 759-764. For millennia, weeds have slowly evolved in response to ever-changing environments and crop production practices. Weeds are now evolving much more quickly due to consistently repeated cropping systems and intense herbicide selection pressures. Weed resistance to herbicides now threatens cropping system sustainability in several industrialized nations. Integrated weed management (IWM) provides opportunities to reduce selection pressure for weed resistance while maintaining current crop yields. Combining optimal IWM tactics that discourage weeds by minimizing disturbance (no till, direct-seeding), adopting diverse crop rotations, and attempting to preclude resource acquisition by weeds are encouraged. New research knowledge on practical IWM systems is available, but despite current and looming threats of major weed resistance, most crop producers will require greater incentives than those currently available to more-fully adopt IWM systems in the near future.

He, J.-F., Goyal, R., Laroche, A., Zhao, M.-L. and Lu, Z.-X. 2013. Effects of salinity stress on starch morphology, composition and thermal properties during grain development in triticale. Can. J. Plant Sci. 93: 765-771. Triticale is a man-made cereal crop developed from a cross between wheat and rye. It has excellent agronomic traits for starch production on arid and semi-arid lands. This study investigated the effects of salinity stress on the alterations of starch morphology, composition and physicochemical properties during triticale grain development. Three triticale varieties (AC Certa, AC Ultima and Blue Alta) were treated with three levels of NaCl solutions (50, 100 and 200 mM), termed low salinity stress (LSS), moderate salinity stress (MSS) and high salinity stress (HSS), respectively. Reduction in seed weight and starch content were observed under salinity stress; the values decreased by 9-42% under MSS and 18-51% under HSS. MSS and HSS favored an increase of amylose synthesis and accumulation in triticale starch. Triticale starch synthesized under salinity stress showed a decreased population of small granules and an increased ratio on A-type to B-type granules. MSS and HSS decreased the peak temperature and increased the starch enthalpy, and an inverse relationship between salinity stress and a range of starch gelatinization temperature was also observed. This is the first report demonstrating that starch morphology, composition and thermal properties in triticale grains can be significantly affected by salinity stress.

Kapanigowda_, M., H., Perumal, R., Aiken, R. M., Herald, T. J., Bean, S. R. and Little, C. R. 2013. Analyses of sorghum [Sorghum bicolor(L.) Moench] lines and hybrids in response to early-season planting and cool conditions. Can. J. Plant Sci. 93: 773-784. Early-season cold tolerance in sorghum contributes to emergence, seedling establishment, and early vegetative growth, and reduces damping-off diseases under chilling conditions. The objectives of this study were to identify cold-tolerant sources and to evaluate and optimize rapid screening techniques under a controlled environment. Field studies involving 48 genotypes, representing phases of the hybrid development process (landraces, elite and advanced breeding lines, recombinant inbred lines (RILs) and hybrids were conducted with early and normal planting dates in 2011 at Hays and Colby, Kansas. Studies under controlled environments were conducted at both locations using 18 genotypes that differ for emergence index (EI) and 30 d after emergence (DAE) shoot biomass based on field studies during 2011. Significant differences among the genotypes were recorded for all seedling traits (emergence percentage, EI, shoot biomass, plant height, and leaf number measured 30 DAE), and agronomic traits (days to 50% flowering, panicle exsertion, panicle length, and plant height at maturity). Eight advanced breeding lines: ARCH10731, ARCH10732, ARCH10736, ARCH10737, ARCH10738, ARCH10739, ARCH10744 and ARCH10749 and one RIL (RTx430/SQR-2) were found to be potential sources of cold tolerance with early EI, higher biomass and relatively early flowering. These genotypes are free from tannin, which helps to increase the feed grain efficiency of livestock, and hence were selected for test hybrid evaluation to assess fertility status, combining ability and yield performance. Significant correlation was observed between EI and biomass during early planting, which indicated that late-emerging genotypes produced greater biomass (30 DAE) compared with early-emerged genotypes. Significant correlation between growth chamber and field study for EI offers a potential and fast preliminary high-throughput screening technique for identification of cold-tolerant sorghum.

Mu, P. and Li, Z. 2013. Correlation analysis and QTL mapping of osmotic potential injaponicarice under upland and lowland conditions. Can. J. Plant Sci. 93: 785-792. In order to reveal the genetic basis of differences in osmotic potential (OP) of japonica rice under various water regimes, a recombinant inbreed line (RIL) population including 120 plants derived from a cross between an upland japonica rice IRAT109 and a paddy japonica rice Yuefu was used in this study. A complete genetic linkage map with 201 simple sequence repeat (SSR) molecular markers was constructed. Osmotic potentials of the RIL population and their parents were measured pre-dawn and at mid-day under lowland (no soil water stress) and upland (soil water stress) conditions. Significant correlations between osmotic difference (ODl) and (ODu) and index of drought resistance (IDR, based on relative yield in upland and lowland treatments) was found under lowland and upland conditions. Quantitative trait loci (QTL) associated with osmotic potentials and osmotic differences under lowland and upland conditions were detected by using the software QTL MAPPER version 2.0. Twelve additive QTL and 10 pairs of epistatic QTL for OP and OD were detected. Three additive QTL and a pair of epitatic QTL for IDR were also obtained. There were more Q×E QTL and epistatic QTLs under upland conditions than under lowland conditions, indicating that the genetic pattern was more complex under upland conditions than under lowland conditions. Two QTL near RM493-RM1287 on chromosome 1 and RM332-RM1124 on chromosome 11 were found to have a high general contribution of over 10% and may be the key QTL controlling osmotic potential. These results reveal that osmotic potential is a quantitative trait controlled by both additive and epistatic QTL, which are mainly distributed on chromosomes 1, 2, 8 and 9.

Schellenberg, M. P., Biligetu, B. and Wei, Y. 2013. Predicting seed germination of slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] using thermal and hydro time models. Can. J. Plant Sci. 93: 793-798. Slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] is a native caespitose grass used for forage production and reclamation. The objective of this study was to quantify seed germination requirements of slender wheatgrass using thermal and hydro time models. Slender wheatgrass, San Luis, had a base temperature (T_b) of 9.48°C, and required 946.8°C h to reach 50% of seed germination. Seed germination of San Lius occurred at a temperature range of 10-30°C, with the highest germination rate being achieved at 20°C, and the highest final germination percentage being achieved at 25°C. At 20 and 25°C, San Luis had a hydro time constant of 61 MPa h, and a median base water potential of approximately 1.0 MPa, but the germination had low uniformity in reduced water potentials. Final germination was reduced at or lower than -0.6 MPa. Compared with many other cool-season native grasses of Northern Great Plains, a relatively warm temperature would be necessary for uniform seedling establishment of this grass. In reclamation seeding, the seedling emergence could reach the highest level at a temperature of 25°C.

Thompson, D. J. 2013. Yield and nutritive value of irrigated tall fescue compared with orchardgrass: in monocultures or mixed with alfalfa. Can. J. Plant Sci. 93: 799-807. Orchardgrass (Dactylis glomerata L.) is commonly grown for irrigated forage production in interior British Columbia. Tall fescue [Schedonorus phoenix (Schop.) Holub.] is also adapted to the area but no comparative trials have been reported. Three varieties of each grass species were grown in monocultures or in mixtures with alfalfa at three irrigated sites throughout southern interior British Columbia. Study objectives included comparing the forage yield and nutritive value of the following groups: (1) tall fescue and orchardgrass monocultures, (2) tall fescue and orchardgrass mixtures with alfalfa and (3) grass-alfalfa mixtures with monocultures. In monoculture, tall fescue yield was 9% greater than orchardgrass (significantly greater yield at 3 of 6 site-years), though forage nutritive values were similar. Mixtures of the two grasses with alfalfa had similar yields, but those containing tall fescue had superior nutritive value. Alfalfa contributed a greater percentage to total yield and had higher survival when mixed with tall fescue. Tall fescue is a viable alternative to orchardgrass for irrigated forage production in monoculture and may be more suitable for mixtures with alfalfa. Our findings demonstrate a functional diversity effect; grass-alfalfa mixtures over-yielded the mean of the alfalfa, orchardgrass, and tall fescue monocultures by 12%.

Jefferson, P. G., Selles, F., Zentner, R. P., Lemke, R. and Muri, R. B. 2013. Barley yield and nutrient uptake in rotation after perennial forages in the semiarid prairie region of Saskatchewan. Can. J. Plant Sci. 93: 809-816. Alfalfa (Medicago sativa L.) is the most common perennial forage legume grown for hay and pasture in the semiarid Brown soil zone of the Canadian prairies. Perennial forages often are not recommended for inclusion in annual crop rotations due to lower grain yields and drier soils following forage stand termination, but this is based on research results from 50 yr ago. Three replicated experiments consisting of three grasses [slender wheatgrass (Elymus tracycaulus), intermediate wheatgrass (Elytrigia intermedia), and Dahurian wildrye (Elymus dahuricus)] grown in monoculture and in mixture with two alfalfa varieties (cv. Beaver or cv. Nitro) were terminated and seeded to barley (Hordeum vulgare ‘Harrington’) for 2 consecutive crop years at Swift Current, Saskatchewan. Soil water content was lower after the alfalfa-grass mixtures compared with the grass monocultures, even during a wet growing season. Barley yield and N concentration in the grain were significantly greater following Beaver alfalfa/grass mixture compared with grass monoculture in 3 and 4 of 6 site years, respectively. N uptake by the barley crop (grain and straw) was also significantly greater following Beaver alfalfa/grass mixture than following grass monoculture in all 6 yr. Both barley grain yield and N uptake after intermediate wheatgrass (grown in monoculture) were lower than after Dahurian wildrye or slender wheatgrass in 3 of 6 yr. The use of alfalfa and a short-lived grass species in hay and pasture mixtures in the Brown soil zone when grown in rotation with annual crops may indeed result in lower grain yields in the short term than continuous annual cropping systems, but the inclusion of alfalfa will provide a N benefit to the subsequent grain crop thereby enhancing yield and possibly its market value.

Hu, D-L., Chen, Q-Z., Zhang, C-J., Wang, Y., Zhang, B-J. and Tang, C-M. 2013. Identification of cottonSKP1-like geneGhSKP1and its function in seed germination and taproot growth in tobacco. Can. J. Plant Sci. 93: 817-825. The SKP1 (S-phase kinase-associated-protein1) protein, a key component of the SCF (SKP1-CUL1-F-box protein) ubiquitin ligase complex, has been reported to play many important roles in many organisms, including regulation of ubiquitin-mediated protein degradation, seed germination, taproot growth and auxin signaling, though no study of this gene in cotton has been performed. In this study, a SKP1 gene was isolated from upland cotton (Gossypium hirsutum L.) using the rapid amplification of cDNA ends (RACE) method and was named Gossypium hirsutumSKP1 (GhSKP1). The cDNA sequence of GhSKP1 was 813 bp containing a 474 bp open reading frame, encoding a protein of 156 amino acids with a predicted molecular weight of 17.63 kDa. The deduced amino acid of GhSKP1 had a conserved SKP1 domain. GhSKP1 expression was tested in all organs of cotton plants, and the strongest expression was observed in stamens and radicles that have actively dividing cells. Overexpression of the full-length GhSKP1 cDNA in tobacco caused delayed seed germination and shortened taproots. Our results suggest that the presence of functional conservation between GhSKP1 and SKP1 in plant developmental processes may exist.

Endo, J., Takahashi, W., Yokoyama, M. and Tanaka, O. 2013. Induction of gene expression for systemic acquired resistance in tobacco by 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid (KODA). Can. Plant Sci. 93: 827-830. The reaction of 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid (KODA) with (-)-norepinephrine (NE) generates the flowering inducer FN1 of duckweed Lemna paucicostata, although KODA and NE themselves do not promote flowering. We examined the effects of FN1, KODA, and NE on the induction of gene expression for systemic acquired resistance (SAR) in tobacco (Nicotiana tabacum) leaves and found that KODA induces the expression of SAR related genes.

Khadivi-Khub, A. and Naderiboldaji, M. 2013. Predicting models for mass and volume of the sweet cherry (Prunus aviumL.) fruits based on some physical traits. Can. J. Plant Sci. 93: 831-838. There are instances when it is desirable to determine relationships among fruit physical attributes. For example, fruits are often graded on the basis of size and projected area, but it may be more economical to develop a machine which grades by mass or volume. Therefore, the relationships between mass/volume (either mass or volume) and other physical attributes of fruit are needed. In this study three Iranian cultivars (Mashhad, Siah Mashhad, Siah Daneshkadeh), of sweet cherry were selected and the various models for predicting mass/volume of sweet cherry from its dimensions, projected areas, and volume/mass were established. The models were divided into three classifications: (1) single and multiple variable regressions of sweet cherry dimensions, (2) single and multiple variable regressions of projected areas and (3) estimating sweet cherry mass/volume based on its volume/mass. Moreover, some physical characteristics, such as dimensional characteristics, true density, bulk density, and porosity were determined with common methods. Results revealed that mass modeling based on minor diameter, three projected areas, and the measured volume are the best models. The highest determination coefficient in all the models was obtained for mass modeling based on measured volume as R² = 0.93. At last, mass modeling from an economic standpoint was recommended as the most reliable modeling.

Borja-Bravo, M., García-Salazar, J. A. and Skaggs, R. K. 2013. Mexican fresh tomato exports in the North American market: A case study of the effects of productivity on competitiveness. Can. J. Plant Sci. 93: 839-850. The North American market for fresh tomatoes (Lycopersicon escolentum Mill.) involves a complicated web of bilateral trading relationships between the United States, Mexico and Canada. Trade in fresh tomatoes between the three countries has changed significantly in recent years. In particular, Mexico's share of total US fresh tomato imports from all countries decreased from 93 to 88%, while Canada's share of US fresh tomato imports increased from 3 to 11% between 1996 and 2009. Mexico's declining competitive position in the US fresh tomato market is also evidenced by the fact that the Mexican share of combined Mexico-Canada exports to the United States decreased from 97% to 89% between 1996 and 2009. A spatial and inter-temporal model was used to analyze the impact of increased Mexican tomato yields on the North American fresh tomato market. Results indicate that for the average year between 2005 and 2008, 20% higher yields would have resulted in a 15.1% increase in Mexico's tomato production and a 28.9% increase in fresh tomato exports from Mexico to the United States. As a result of higher Mexican tomato sector productivity, Canadian and US producers' shares of the US fresh tomato market would decrease and Mexico's would increase from 35.0 to 41.9%. The model shows that Mexico's share of US fresh tomato imports from both Mexico and Canada would grow from 88.1 to 90.3% as a result of the increased productivity. These results lead to the recommendation that increasing yields of this important export crop are key to maintaining and increasing the North American market competitiveness of Mexican-produced fresh tomatoes.

Byker, H. P., Soltani, N., Robinson, D. E., Tardif, F. J., Lawton, M. B. and Sikkema, P. H. 2013. Occurrence of glyphosate and cloransulam resistant Canada fleabane (Conyza canadensisL. Cronq.) in Ontario. Can. J. Plant Sci. 93: 851-855. Canada fleabane is the second documented glyphosate-resistant (GR) weed species in Ontario, Canada. In 2010, the first eight GR Canada fleabane populations were identified in Essex County. In 2011 and 2012, an expanded survey was conducted to identify the occurrence of GR and cloransulam-resistant populations in Ontario. Seed was collected from field weed escapes in the early fall and sprayed in the greenhouse with 900 g a.e. ha^-1 of glyphosate at the 10-cm rosette stage. Ninety-three and 54 additional sites were confirmed in 2011 and 2012, respectively. There are now 155 sites with confirmed GR Canada fleabane in Ontario in the counties of Elgin, Essex, Haldimand, Huron, Kent, Lambton, Middlesex, and Niagara region. Twelve and seven sites were identified with multiple resistant Canada fleabane (glyphosate and cloransulam) in 2011 and 2012, respectively in Elgin, Essex, Kent, Lambton, and Middlesex counties. This is the first survey documenting the occurrence of glyphosate-resistant and multiple resistant (glyphosate and cloransulam) Canada fleabane in Ontario and its distribution.

Main, D. C., Sanderson, K. R., Fillmore, S. A. E. and Ivany, J. A. 2013. Comparison of synthetic and organic herbicides applied banded for weed control in carrots (Daucus carotaL.). Can. J. Plant Sci. 93: 857-861. The necessity to reduce environmental impact and control the increasing cost of production has many carrot growers seeking new methods of crop management. This research evaluated the potential of applying herbicides in 30-cm bands over the carrot row in combination with between-the-row cultivation to control weeds. Linuron applied in a 30-cm-wide band over the row and linuron applied broadcast provided effective weed control and comparable yield. Clove oil and citrus oil gave slightly better weed control and yield than acetic acid and flaming at the late seeding date. This study demonstrates that acceptable weed control with minimal impact on yield can be achieved with the use of synthetic and organic herbicides applied as a 30-cm-wide band over the row combined with between-row cultivation. This method of weed control provides a 66% reduction in herbicide applied per hectare compared with a broadcast application.

Robinson, D. E., McNaughton, K. E. and Bilyea, D. 2013. Comparison of sequential preemergence-postemergence and postemergence-alone weed management strategies during critical period of red beet (Beta vulgarisL.). Can. J. Plant Sci. 93: 863-870. Weed management during the first 4 wk after red beet emergence is critical to prevent yield loss. The purpose of this research was to compare weed control and red beet tolerance of postemergence (POST) treatments alone (full, split- and micro-rates of pyrazon plus triflusulfuron) with sequential preemergence (PRE) applications of s-metolachlor followed by these POST herbicide treatments. The experiment was carried out for 4 yr as a randomized complete block with four replications. Of the POST alone treatments examined, control of velvetleaf (Abutilon theophrasti Medik.), redroot pigweed (Amaranthus retroflexus L.), common lambsquarters (Chenopodium album L.) and green foxtail [Setaria viridis L. (Beauv.)] was 98, 86, 97 and 62%, respectively. Much more consistent control of all species (i.e., greater than 96%) was measured where the sequential treatment of s-metolachlor was applied PRE followed by POST split- or micro-rates in all study years. Red beet density and soluble solid levels were not different than the weed-free check in any of the POST or sequential treatments. However, red beet yield in the POST single and split-rate treatments alone ranged from 9500 to 12100 kg ha^-1, and was significantly less than in the weed-free check (19400 kg ha^-1). Yields in the sequential treatments were comparable to the weed-free check. The results of this study confirm that a sequential treatment of PRE s-metolachlor followed by POST split- and micro-rate applications of pyrazon plus triflusulfuron can be safely applied to red beet and control annual weed species.

Soltani, N., Blackshaw, R. E., Gulden, R.H., Gillard, C. L., Shropshire, C. and Sikkema, P. H. 2013. Desiccation in dry edible beans with various herbicides. Can. J. Plant Sci. 93: 871-877. There is little information available on the effect of diquat, carfentrazone-ethyl, glufosinate ammonium, flumioxazin and saflufenacil applied alone or in tankmix combination with glyphosate as harvest aids in dry bean production under environmental conditions of the various production regions in Canada. A total of 11 field trials were conducted over a 3-yr period (2010, 2011, 2012) at Exeter, Ontario, Carman, Manitoba, and Lethbridge, Alberta, to evaluate various harvest-aid herbicides in dry bean. Comparison of leaf, pod and stem visual dry down at 4 and 8 d after desiccation application (DAA) indicated that adding a tankmix partner to glyphosate increased visual dry down of leaf, pod and stem 17, 10 and 15% at 4 DAA and 20, 17 and 14% at 8 DAA, respectively. At 8 DAA, glyphosate (450 or 900 g a.e. ha^-1), diquat, glufosinate ammonium, carfentrazone-ethyl, flumioxazin and saflufenacil provided 13-58, 65-80, 64-71, 12-34, 36-52 and 41-73% dry down of the dominant weeds (AMARE, AMBEL, CHEAL and SETVI), respectively. Diquat, glufosinate ammonium, carfentrazone-ethyl, flumioxazin and saflufenacil tankmixed with glyphosate (450 or 900 g a.e. ha^-1) provided 67-77, 65-71, 22-62, 45-69 and 44-74% weed dry down, respectively. Dry bean yield was not reduced with any of the desiccation treatments. Among desiccant treatments that provided consistent desiccation of dry bean and weeds, saflufenacil had the least environmental impact followed by flumioxazin, glufosinate ammonium and then diquat. Based on this study, diquat, glufosinate ammonium, flumioxazin and saflufenacil alone or in combination with glyphosate (450 or 900 g a.e. ha^-1) provide consistent desiccation of weeds and dry bean.

Wang, M., Tyree, M. T. and Wasylishen, R. E. 2013. Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments. Can. J. Plant Sci. 93: 879-893. Temporal and spatial information about water refilling of embolized xylem vessels and the rate of water ascent in these vessels is critical for understanding embolism repair in intact living vascular plants. High-resolution ¹H magnetic resonance imaging (MRI) experiments have been performed on embolized grapevine stem segments while they were subjected to refilling at two different applied water pressures in order to investigate these important aspects of embolism repair. Magnetic resonance imaging difference images show that vessels located near the bark tend to refill faster than do inner ones, suggesting that vessel position within the cross section of the stem may affect the refilling process within the vessel. An MRI method for determining the water ascent velocity in each individual embolized xylem vessel is presented. At ambient pressure, the water ascent velocity ranges from 0.0090 to 0.60 mm min^-1, but increases to a range of 0.016 to 0.70 mm min^-1 at 9.8 kPa above ambient pressure. A steady-state bubble model that offers analytical solutions of the water ascent velocity in embolized xylem vessels is presented; model calculations show that if other parameters are held constant, water ascent velocity is influenced by vessel diameter and position.

Azri, W., Ennajah, A. and Jing, M. 2013. Comparative study of six methods of protein extraction for two-dimensional gel electrophoresis of proteomic profiling in poplar stems. Can. J. Plant Sci. 93: 895-901. Protein extraction is a crucial step in two-dimensional gel electrophoresis (2-DE) analysis of proteins, since it can have significant impact on both the quantity and the quality of protein detection. The present study is a comparison between six previously published protocols of protein extraction (A, B, C, D, E, and F) aiming to determine a suitable method to extract total proteins from poplar stems, a recalcitrant plant tissue. The obtained results revealed that method F (optimized method B), combining detergents (CHAPS, Triton X-100, and low sodium dodecyl sulfate amounts) and chaotropes (thiourea and urea), gave the best solution for the problem of protein solubilization. Method F enabled the detection of more than 300 spots reproducible on the 2-DE gel with pH 4-7 immobilized pH gradient strips and 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, using silver staining. Our results suggest that Method F is expected to have excellent applications in proteomic studies of poplar stems.

Li, S. H., Du, Y.-P., Wu, Z. H.-Y., Huang, C.-L., Zhang, X.-H., Wang, Z. H.-X. and Jia, G.-X. 2013. Excision of a selectable marker in transgenic lily (Sorbonne) using theCre/loxPDNA excision system. Can. J. Plant Sci. 93: 903-912. To generate transgenic lily plants with no selectable marker and improved tolerance to abiotic stress, two vectors were co-transformed into the Lilium oriental hybrid Sorbonne by particle bombardment. The pKSB vector included the Cre/loxp-mediated site-specific cDNA excision system under control of the inducible promoter rd29A, and the pBPC-P5CS-F129A vector carried the P5CS gene, which we hypothesized would improve resistance to drought and salt stresses in transgenic lily plantlets. The presence of the two genes was simultaneously detected by PCR and Southern blotting in two resistant plantlets. The co-transformation rate was 0.16%. Subsequently, inducer expression was tested under varying conditions to optimize the deletion of marker gene. Results from molecular detection assays revealed that maintaining bases of bulblet scales at 4°C for 12 h resulted in an increase in the excision rate, reaching 60%. Expression of P5CS improved resistance to salt stress in transgenic lily plantlets. These results demonstrated the feasibility of using the Cre/loxP-based marker elimination system to generate marker-free transgenic plantlets with improved stress tolerance.

Garriga, M., Parra, P. A., Caligari, P. D. S., Retamales, J. B., Carrasco, B. A., Lobos, G. A. and García-Gonzáles, R. 2013. Application of inter-simple sequence repeats relative to simple sequence repeats as a molecular marker system for indexing blueberry cultivars. Can. J. Plant Sci. 93: 913-921. Chile, the major exporter of blueberries in South America, grows two species commercially, the highbush blueberry (Vaccinium corymbosum L.) and the rabbiteye blueberry (Vaccinium ashei Reade). Considering the increasing demands for this fruit, it is necessary to have reliable methods for genotyping and genetic traceability of the commercially grown cultivars. In this study, an inter-simple sequence repeat (ISSR) marker-based system was established to perform the genetic identification of these cultivars. Ten cultivars of V. corymbosum: ‘Bluecrop’, ‘Bluegold’, ‘Duke’, ‘Elliott’, ‘Legacy’, ‘Misty’, ‘Nelson’, ‘O'Neal’, ‘Sierra’ and ‘Toro’ and three of V. ashei: ‘Climax’, ‘Premier’ and ‘Tifblue’ were analyzed. The sensitivity and reliability of this molecular marker system was compared with identification by simple sequence repeats (SSR). Six ISSR primers were used and high levels of polymorphism among the cultivars (80% of polymorphic loci) were detected, with high repeatability. Using individual primers, distinguishing among cultivars was possible in three cases. However, using pairs of ISSR primers provided greater reliability in cultivar identification. This ISSR-based technology is a simpler, faster, and less expensive alternative to SSRs for genotyping blueberry cultivars and can be used in genetic traceability studies as well as genetic improvement programs.

Xin, H., Wu, B., Zhang, H., Wang, C., Li, J., Yang, B. and Li, S. 2013. Characterization of volatile compounds in flowers from four groups of sweet osmanthus (Osmanthus fragrans) cultivars. Can. J. Plant Sci. 93: 923-931. Headspace-solid-phase microextraction (HS-SPME) and gas chromatography-mass spectroscopy (GC-MS) were used to characterize the volatiles in flowers of four cultivar groups of sweet osmanthus (Osmanthus fragrans Lour.), including Thunbergii, Latifolius, Aurantiacus and Semperflorens Groups. A total of 72 volatiles were identified. Volatile compounds and their relative contents varied among the four groups or cultivars within each group. Briefly, β-ionone, cis-linalool oxide (furan), trans-linalool oxide (furan) and linalool were the most common volatiles in tested cultivars, while (E)-2-hexenal, (Z)-3-hexen-1-ol and hexanal were abundant in several cultivars. Principal component analysis showed that the Aurantiacus Group was rich in cis- and trans-linalool oxide (furan), whereas the Latifolius group had high levels of (E)-2-hexenal and (Z)-3-hexen-1-ol. Our results contribute to our understanding of the volatile composition and content in flowers from different osmanthus groups and will facilitate development of new osmanthus cultivars to meet requirements of the food and fragrance industries.

Smith, E. G., Kutcher, H. R., Brandt, S. A., Ulrich, D., Malhi, S. S. and Johnston, A. M. 2013. The profitability of short-duration canola and pea rotations in western Canada. Can. J. Plant Sci. 93: 933-940. A long-term field study of canola and pea interval in rotations was used to determine the most profitable canola production systems. The duration between canola crops has been declining with most canola grown more often than the recommended once every 4 yr. Producers could be reducing their long-term profitability if the short-duration canola rotation results in increased disease and lower yield. A field study was conducted from 1998 to 2007 at Scott and from 1999 to 2006 at Melfort in Saskatchewan, Canada, to examine the long-term impact of shorter-duration canola and pea rotations. Canola and pea were grown continuously, or in rotations with wheat or flax for 2, 3, or 4 yr. Two canola types were used, one was a blackleg-susceptible conventional cultivar and the other a blackleg-resistant hybrid. The returns above variable costs for the production systems were determined over the last 4 yr of the study, the period of time when rotation impacts should be most evident in this study. The continuous canola and pea rotations were the least profitable rotations. Blackleg-susceptible canola had higher return when in rotations of 3 or 4 yr, compared with continuous or 2 yr. Blackleg-resistant hybrid canola had statistically similar returns for 2, 3 and 4-yr rotations, which were superior to continuous canola. Even with increased blackleg disease incidence and severity after several years of a short-duration canola rotation, the short-duration canola rotation was more profitable when growing the disease-resistant hybrid. With high canola prices, the returns from the short-duration canola rotations were as high, or higher, than rotations with more years between canola crops. The canola industry must recognize that producers have an economic incentive to use short-duration canola rotations and new systems (disease resistance and rotations) need to be developed within this context.

Arcand, M. M., Knight, J. D. and Farrell, R. E. 2013. Temporal dynamics of nitrogen rhizodeposition in field pea as determined by¹⁵N labeling. Can. J. Plant Sci. 93: 941-950. Assessing the contribution of symbiotically fixed N₂ to soil from pulse crops necessitates a full accounting of the total crop residue N remaining in the field after seed harvest. Below-ground N, including root and rhizodeposit N, comprises an important component of this total plant N balance - without it the N input to soil is underestimated. Under controlled conditions in a greenhouse, N in intact roots and N rhizodeposition were quantified in field pea (Pisum sativum L.) using the cotton-wick ¹⁵N labeling technique. Plants were supplied with ¹⁵N on a continuous basis and harvested at the vegetative stage (nine leaves unfolded), flowering, and maturity. As the plants aged, the ¹⁵N enrichment in the rhizosphere soil decreased, whereas that in the bulk soil increased, suggesting that N released as root exudates comprised a more important proportion of N rhizodeposition in plants at the early vegetative stage compared with mature plants. In mature plants, N rhizodeposition was comprised predominantly of N associated with root turnover. The contribution of N rhizodeposition recovered in soil to the total plant N balance decreased from 17.8% at the vegetative stage harvest, to 12.3% at flowering, and finally to 7.5% at maturity. However, the total amount of root-derived N released to soil by pea increased with plant development. Below-ground N, including N rhizodeposition and N in intact roots contributed 11.3% to the total plant N balance of mature pea.

Schwarzauer-Rockett, K., Al-Hamdani, S. H., Rayburn, J. R. and Mwebi, N. O. 2013. Utilization of kudzu as a lead phytoremediator and the impact of lead on selected physiological responses. Can. J. Plant Sci. 93: 951-959. This study was carried out to evaluate kudzu [Pueraria montana var. lobata (Willd.)] in lead phytoremediation. The impact of lead (PbNO₃) concentrations of 100 and 200 mg L^-1 on plant growth, photosynthetic pigments, photosynthesis, and stomatal conductance were evaluated. Additionally, concentrations of phenolic compounds and anthocyanin were determined. The lead was dissolved in 0.142 g L^-1 ethylenediaminetetraacetic acid (EDTA) and an EDTA control treatment was added to evaluate the impact of EDTA on the above selected plant responses. Root accumulation of lead was significantly higher than in the shoot. Kudzu growth in response to the presence of lead and EDTA in the Hoagland's solution was similar to that of the EDTA control, except for plants growing at 200 mg L^-1, which showed significantly lower root dry weight. Total phenolic compounds increased with the presence of EDTA and lead in the Hoagland's solution. Photosynthetic rate, stomatal conductance, chlorophyll a and chlorophyll b, carotenoids, and anthocyanin were not different (P≤0.05) among the treatments, with the exception that carotenoids were significantly higher in plants growing in the presence of EDTA without lead compared with 200 mg L^-1 lead concentration. Kudzu accumulated most of the lead in the root and therefore can be considered as a rhizofiltrator. As kudzu was able to accumulate 1.02% (wt/wt) of lead it can be considered a hyper-accumulator.

Ngosong, C., Halpern, M. T., Whalen, J. K. and Smith, D. L. 2013. Purslane (Portulaca oleraceaL.) has potential for desalinizing greenhouse recirculation water. Can. J. Plant Sci. 93: 961-964. Recirculating fertigation solutions improves the environmental sustainability of hydroponics-based vegetable production in Canada. Purslane is an edible halophyte with proported medicinal benefits that could absorb excess salts from recirculation water. It grew well in hydroponic solutions with up to 1000 mg NaCl L^-1. Greatest Na absorption occurred during earlier vegetative growth.

Tamburic-Ilincic, L. and Smid, A. 2013. OAC Emmy, soft white winter wheat. Can. J. Plant Sci. 93: 965-967. OAC Emmy is a soft white winter wheat (Triticum aestivum L.) cultivar registered for Ontario, Canada. It has high grain yield, with good pastry and biscuit quality and similar resistance to Fusarium head blight (FHB) as the moderately susceptible check Emmit. OAC Emmy is well adapted for the winter wheat growing areas of South Western Ontario.

Legge, W. G., Tucker, J. R., Bizimungu, B., Tekauz, A., Fetch, Jr., T. G., Haber, S., Menzies, J. G., Noll, J. S., Turkington, T. K., Martin, R. A., Choo, T. M., Vigier, B. J., Blackwell, B. A. and Savard, M. E. 2013. Taylor barley. Can. J. Plant Sci. 93: 969-977. Taylor is a hulless two-row spring barley (Hordeum vulgare L.) cultivar with malting quality potential, and is one of the first hulless cultivars to be registered for that purpose in Canada. This line was developed in 2001 from a CDC Freedom/Rivers cross by in vitro selection using three Fusarium derived mycotoxins in the medium of an anther culture system. Taylor was evaluated in the Western Cooperative Hulless Barley Registration Test (2006-2008), and in pilot-scale malting trials (2007-2008), before being registered as HB705 in 2009 with its name changed to Taylor in 2011. In extensive evaluation in Fusarium head blight (Fusarium graminearum Schwabe) nurseries from 2002 to 2011, Taylor consistently showed low deoxynivalenol concentration.

Hampson, C. R., MacDonald, R. A., McKenzie, D.-L. and Walters, W. 2013. SPA493 (Salish™) apple. Can. J. Plant Sci. 93: 979-982. ‘SPA493’ (Salish™) is a new bi-coloured dessert apple from the Agriculture and Agri-Food Canada breeding program at Summerland, BC, Canada. The fruit is crisp and juicy, with balanced flavour and medium to long storage potential. The fruit reaches harvest maturity in early October in Summerland. ‘SPA493’ trees are moderately vigorous, productive, and not subject to biennial bearing or pre-harvest drop.