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Conyza spp. are broadleaf weeds that occur in many crops but are also common in non-crop systems such as roadsides and railways. Conyza have selected for glyphosate resistance along railway tracks in southern Spain due to the misuse of this herbicide and the high seed dispersal rate of these species. Twenty-three samples of the genus Conyza (11 Conyza canadensis and 12 Conyza bonariensis) were collected from the margins of railways in different routes of the Andalusia railway network running adjacent to nearby crop fields. The glyphosate resistance level of Conyza populations was evaluated through GR50 (herbicide rate causing 50% growth reduction) and resistance factor (RF) values in every population collected. The highest GR50 were 1851.2 g a.e. ha-1 (RF = 52.53) in C. canadensis (Malaga–Cordoba route) and 1972.4 g a.e. ha-1 (RF = 35.20) in C. bonariensis (Seville–Cordoba route), and the lowest were 46.9 g a.e. ha-1 (RF = 1.33) in C. canadensis (Seville–Cordoba route) and 23.2 g a.e. ha-1 (RF = 0.41) in C. bonariensis (Seville–Cordoba route). The results showed that, among all the C. canadensis populations collected, 18.2% were glyphosate-resistant (RF > 10), 45.5% showed a tendency to develop resistance (RF = 2.5–5), and 36.4% were susceptible (RF < 2.5). Of the 25% of C. bonariensis populations that had resistance to glyphosate, 16.7% had moderate resistance (RF = 5–10) and 58.3% were susceptible. This study found that there are already glyphosate-resistant Conyza spp. along the railway network in southern Spain. This could lead to possible seed exchange between the railway and adjacent places. Therefore, it is vital to consider the railway network when planning control measures against resistance.
Aldehyde dehydrogenases (ALDHs) encode a class of enzymes that dehydrooxidize aldehydes into corresponding carboxylic acids, which are involved in the growth and development of plants and in the response to various biological and abiotic stresses. In this study, we identified 27 ALDH genes in the Chinese cabbage genome and grouped them into 10 different families. Chromosomal mapping revealed that, except for one gene distributed on Scaffold, the remaining 26 genes were unevenly distributed on 10 chromosomes of Chinese cabbage. Based on a comparison of the homologous relationship between BrALDHs and ALDH genes in Arabidopsis thaliana, duplicated patterns of the ALDH gene family in Chinese cabbage were analyzed. The exon–intron structures, conserved protein motifs, and phylogenetic relationship with ALDH in six other species were also predicted and analyzed. Finally, we used available RNA-Seq data and real-time quantitative PCR to analyze the expression of ALDH genes in different tissues of Chinese cabbage including the roots, stems, leaves, flowers, and siliques. The results showed the tissue specificity and differential expression in different tissues of BrALDHs. The analysis of ALDH gene transcriptome data of Chinese cabbage under different stress conditions (cold, heat, drought, and salinity) showed that the response levels of different genes varied under different stresses, suggesting the function of some genes in these processes. Details of the ALDH gene family in Chinese cabbage has enriched studies on the ALDH gene family in plants and animals and is crucial for understanding ALDH function during plant growth and development.
A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha-1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.
‘Honeycrisp’ apple trees are highly prone to biennial bearing and predisposed to bitter pit. The hypothesis that tank mix sprays of ethephon (ETH), naphthaleneacetic acid (NAA), and 1-aminocyclopropane carboxylic acid (ACC) combined with calcium chloride (CaCl2) can mitigate these production problems was tested in a 3-yr study. Mature ‘Honeycrisp’ trees were treated with either three or six summer applications of 150 mg L-1 ETH or 5 mg L-1 NAA, all tank-mixed with and without CaCl2, or two or five applications of 150 mg L-1 ACC (without CaCl2). Treatments were applied at 10-d intervals and initiated between 21 and 26 June. All treatments had little effect on enhancing return bloom of ‘Honeycrisp’. NAA, ETH, and CaCl2 all influenced fruit maturity and quality at harvest to varying degrees and across years. Fruit treated with NAA were firmer compared with untreated fruit in 2 out of 3 yr, whereas overall, fruit treated with six sprays of ETH had lower fruit firmness and were more mature. NAA had less influence on fruit quality attributes at harvest than did ETH, and decreased pre-harvest fruit drop (PFD). PFD increased with ETH in 1 out of 2 yr, whereas ACC and NAA both decreased PFD in 1 out of 2 yr. Overall, ETH and NAA, with or without CaCl2, had significant but inconsistent effects on fruit quality and maturity, all dependent on the year and number of applications. Adding CaCl2 decreased fruit firmness in 2 out of 3 yr.
Mitogen-activated protein kinase (MAPK/MPK) is a group of serine-threonine protein kinases that are activated by different extracellular stimuli. To explore the function of MAPK in wheat infected with powdery mildew, a new wheat germplasm N9134 was used to obtain the full-length MAPK gene and the MAPK sequence was used to identify its prokaryotic expression and subcellular localisation. Wheat MAPK was obtained by homologous gene cloning and designated as TaMAPK10-like. The open reading frame of TaMAPK10-like was 1638 bp, which coded a deduced protein of 545 amino acids. Phylogenetic analysis revealed that TaMAPK10-like was most closely related to MAPK10-like of Aegilops tauschii at the protein level. It had high nucleotide similarity with the reported MAPK gene in A. tauschii, Sorghum bicolor, and Setaria italica, and had features typical of MAPK family genes. Subcellular localisation showed that TaMAPK10-like was mainly located in the cytoplasm along the microtubules, and a small number were located in the cell membrane and the nucleus. A pMD-MAPK10-like fusion expression vector was constructed and the TaMAPK10-like fusion protein was 70 kDa. The expressions of protein in bacteria were best obtained using 0.5 mmol L-1 isopropyl β-d-1-thiogalactopyranoside at 37 °C for 12 h. These results provide the basic data for further understanding the biological function of the TaMAPK10-like gene.
Drought is a major yield-limiting factor in maize production. Osmotic stress was applied to two maize inbred lines with polyethylene glycol 6000 treatments. Proteins from the leaves were analyzed by two-dimensional gel electrophoresis and peptide mass fingerprinting at two time points, 24 and 48 h after osmotic stress. Thirty-five proteins were differentially expressed between control and treatment groups in the two maize inbred lines. In ‘Qi319’, a drought-tolerant inbred line, there were five up-regulated proteins at 24 h and 13 up-regulated and one down-regulated protein at 48 h. In drought-sensitive line ‘Zheng58’, 10 proteins were up-regulated at 24 h, while six proteins were up-regulated at 48 h. The 35 proteins were subjected to mass spectrometry and 17 proteins were successfully identified. These proteins were classified into six categories: photosynthesis-related, energy and metabolism, signaling pathways, protein synthesis, defense-related, and unclassified.
Trees of six recently released hazelnut (Corylus avellana) cultivars (Eta, Gamma, Jefferson, Sacajawea, Theta, and Yamhill) were grown at five locations in southwestern British Columbia to evaluate female receptivity and pollen shed timing, disease resistance, and nut yield. The overlap of female receptivity and pollen shed of mating-compatible cultivars equaled or exceeded that reported elsewhere. Following 4–6 yr of field growth without fungicides at sites adjoining eastern filbert blight (EFB)-infected orchards, EFB symptoms were absent from four cultivars (Eta, Gamma, Theta, Yamhill), negligible on Jefferson, and substantial on Sacajawea. Two additional potential diseases, Phomopsis sp. and Phytophthora sp., were observed on several trees at multiple farms. Yields varied by cultivar and farm, averaging 2.9 kg per tree of sixth-leaf Jefferson and 1.0 kg per tree of fourth-leaf Yamhill; the highest yield per tree observed was 9.3 kg for fifth-leaf Jefferson. These data, the first describing flowering and yield of these cultivars from operational orchards and the only such data from British Columbia, demonstrate the potential for new hazelnut cultivars even where pressure from eastern filbert blight is high. Also revealed are two potential emergent diseases for which growers need to remain vigilant.
The objective of this study was to explore the changes in leaf nitrogen (N) and phosphorus (P) content, physiological processes, growth, and resource-use efficiency in a rapeseed cultivar under drought and (or) high temperatures. The two-wk-old plants were grown under controlled growth chamber conditions and subjected to individual or combined water (well-irrigated, 88% ± 4% field capacity vs. drought, 46% ± 5% field capacity) and temperature (control, 23 °C/17 °C vs. high temperatures, 26 °C/25 °C) regimes for 10 d. The measured response parameters were [N], [P], and their total content in leaves, photosynthetic rate (Asat), stomatal conductance (gs), intercellular CO2 concentration (Ci), mitochondrial respiration (R), intrinsic water use efficiency (WUEi), photosynthetic N use efficiency (PNUE), relative growth rate of the root (RGRr) and shoot (RGRs), leaf area, and dry matter accumulation in the plant. Drought significantly decreased [N], [P], and their total content in leaves, Asat, gs, Ci, RGRr, RGRs, leaf area, dry matter accumulation in the root, shoot, and whole plant, and PNUE, but significantly increased R and WUEi. Drought-induced reduction in growth or Asat was mainly attributed to a decreased Ci due to stomatal closure, while reduction in gs and leaf area appeared to be a drought-adaptive mechanism. High temperature stress alone had no negative impact on physiological and growth parameters, indicating an enhanced thermal stability of the cultivar, which was diminished at combined drought and high temperature stresses. We therefore conclude that the thermal stability of the cultivar in terms of growth was compromised under simultaneous occurrence of drought and high temperature stresses.
Root rot caused by Fusarium spp. is prevalent in soybean crops in Alberta, Canada. To mitigate the risk to soybean crops caused by Fusarium spp., nine seed-treatment fungicide formulations were assessed for their efficacy in promoting seedling survival, reducing root rot symptoms, and maintaining yield. Twelve soybean varieties were also assessed for resistance to seedling blight and tolerance to Fusarium root rot. All treatments except Vibrance + Apron XL improved emergence. All the fungicide formulations reduced root rot severity on Fusarium-inoculated soybean seedlings under field conditions and all treatments except Vibrance + Apron XL reduced root rot under greenhouse conditions. Among the varieties, ‘90M01’ showed lower reductions in emergence than all the others except ‘900Y61’ and ‘900Y81’ under field conditions and emergence losses for ‘900Y71’ were greater than all other varieties. ‘LS003RR’ had a lower disease severity rating compared with ‘TH32004R2Y’, ‘27005RR’, and ‘900Y71’. ‘NSC Portage’ had a higher nodulation rating compared with all the other varieties except ‘90M01’. Yield losses were consistently low for ‘TH32004R2Y’ and ‘900Y71’. Under greenhouse conditions, ‘900Y81’ had lower seedling losses compared with all the other varieties except ‘Tundra’ and ‘OAC Prudence’. ‘900Y71’ had a greater loss of emergence than all the other varieties except ‘NSC Portage’ and ‘LS005RR’. ‘900Y81’, ‘OAC Prudence’, and ‘Tundra’ had lower disease severity compared with all the other varieties except ‘TH27005RR’ and ‘900Y61’. Shoot length and dry mass were lower for ‘900Y81’ compared with all the other varieties, while root dry mass was lower for ‘OAC Prudence’ compared with ‘LS005RR’, ‘90M01’, ‘TH29002RR’, and ‘LS003RR’.
The use of drought-tolerant rootstocks is an important strategy in maintaining orchard productivity while meeting the increasing need to conserve water resources. The drought tolerance of two new genotypes, Vineland 1 (V.1) and Vineland 3 (V.3), was assessed along with industry standards to test the hypothesis that differences in water-use efficiency exist among these apple rootstocks. One-year-old, non-grafted nursery liners of M.9, MM.111, V.1, and V.3 were grown in a controlled-environment experiment. Plants of each genotype were maintained water-replete or were subjected to a 9-d controlled dry down and then maintained under water stress conditions for 55 d. Water stress reduced biomass accumulation and trunk cross-sectional area for all four genotypes. The two vigorous genotypes, MM.111 and V.1, increased their root-to-shoot ratios in response to water stress, whereas the root-to-shoot ratios of M.9 and V.3 remained unchanged in their water-replete controls. Genotype V.3 maintained its transpiration at a significantly lower soil water content compared to M.9, MM.111, and V.1. Of the four genotypes, V.3 demonstrated a high tolerance to water stress conditions, and therefore deserves further investigation using grafted apple trees in an orchard study.
Carrot (Daucus carota L.) is a crop with rich nutritional value and is one of the most important economical horticulture crops worldwide. The TEOSINTE BRANCHED 1, CYCLOIDEA, PROLIFERATING CELL FACTORS (TCP) transcription factor (TF) family plays important roles in several physiological processes; However, TCP TFs in carrot are rarely reported. In this study, 36 D. carota TCP (DcTCP) TFs were identified from the carrot genome database. On the basis of phylogenetic relationship with TCP TFs in Arabidopsis, the DcTCP family was divided into two classes, namely class I and class II (including CIN and CYC/TB1 subclass). The number of DcTCP TFs in classes I and II were 22 and 14, respectively. Motif analysis and chromosome location of DcTCP TFs were also conducted. All of the DcTCP genes were distributed on nine chromosomes of carrot. The distribution of TCP TFs in different species indicates that the number of TCP TFs is consistent with plant evolution. Quantitative real-time PCR assay was performed to further understand the expression patterns of DcTCP genes during the development of carrot. The expression levels of DcTCP33 and DcTCP36 increased with the germination of carrot seed. The CIN subclass of DcTCPs (DcTCP1, DcTCP4, and DcTCP5) was primarily expressed in leaf blades, whereas the DcTCP26 gene was mainly expressed in roots. These results can provide potentially useful information about TCP TF identification and help explain the roles of TCP TFs in carrots.
An irrigation study in southern Alberta compared spring-banded nitrogen (N) to spring-banded N plus fertigation at three plant growth stages for spring wheat (Triticum aestivum L.) and canola (Brassica napus L.). Yield and quality impacts were quantified when N fertigation was applied to (i) wheat at the early tillering, flag leaf, and anthesis stages and (ii) canola at the four-leaf rosette, bolting, and early flowering stages. For both crops, fertigation could replace some spring-banded N without an effect on yield. However, the results revealed that for canola grown with a large amount of N, applying it all in the spring often generated higher yields than if an equivalent amount of N was delivered at later stages by fertigation. Canola oil concentration declined marginally (about 1%) from no applied N to the high rate of applied N. The application of more than 60 kg N ha-1 and delayed application each increased wheat protein content. Comparing revenues to costs, fertigation did not improve profit margins for canola growers. When growers applied 90 or 120 kg N ha-1 in the spring, fertigation was financially counter-productive. In contrast, the main benefit to wheat growers from fertigation was higher grain protein, especially with N applied at later growth stages. When protein premiums increase during the growing season, fertigation would facilitate growers to obtain higher net returns than they would otherwise.
Soil salinization is an important threat to wheat growth and production. Previous transcriptome analysis showed that the expression of the betaine aldehyde dehydrogenase (BADH) gene differed significantly between cultivars with strong or weak salinity tolerance. Herein, the BADH gene from the wheat cultivar Dongnongdongmai 1 was cloned and transformed into wild-type Arabidopsis to identify its function in salt tolerance. Root length was calculated at 0, 50, 100, 150, and 200 mmol L-1 NaCl for 7 d. The relative electrolytic leakage (REL), GB content, and BADH activity were measured at 150 mmol L-1 NaCl for 1 and 3 d. It was determined that BADH activity and the GB content of TaBADH-overexpressed transgenic (TaBADHOE) lines were significantly higher than in wild-type lines. Salt stress analysis showed that the root length of TaBADHOE lines 4, 18, and 19 were 0.44, 0.54, and 0.35 cm, respectively, which were significantly longer than the 0.24 cm roots of the wild-type line in the media containing 150 mmol L-1 NaCl for 7 d. In addition, the RELs of transgenic lines 4, 18, and 19 were 0.37, 0.33, and 0.42, respectively, which is significantly lower than the 0.63 of the wild-type line in media containing 150 mmol L-1 NaCl for 3 d. These results demonstrate that TaBADH significantly increased plant salt tolerance, indicating that genetic transformation of TaBADH may be an effective and sustainable breeding method for increasing salt tolerance in wheat cultivars.
Cannabis sativa is usually clonally propagated from plants in the vegetative phase. However, phenotypic traits such as yield and chemical composition can only be assessed in unfertilized plants reaching the end of their life cycle and there are no peer-reviewed methods to propagate flowering plants. In this study, immature (three cultivars) and mature (one cultivar) floral explants were cultured on thidiazuron and shoot development was observed in both the immature and mature explants. This provides the first report of micropropagation from floral tissues in C. sativa and will enable plants to be clonally propagated up to the date of harvest.
AAC Stronghold durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.] is adapted to the durum production area of the Canadian prairies. Averaged over 3 yr, AAC Stronghold yielded significantly more grain than AC Navigator. AAC Stronghold had a protein concentration significantly less than Strongfield but significantly more than Brigade. AAC Stronghold had a plant height significantly shorter than Brigade, Strongfield, and AAC Cabri, with a lodging score significantly less than Strongfield and AAC Cabri. AAC Stronghold has a solid stem, which confers resistance to cutting by the wheat stem sawfly (Cephus cinctus Norton). AAC Stronghold had low grain cadmium concentration and stronger gluten than Strongfield. AAC Stronghold is eligible for grades of Canada Western Amber Durum.
HS-182 and HS-183 are food-grade soybean lines [Glycine max (L.) Merr.] with distinct seed protein profiles and food processing quality. HS-182 is a 7S β-conglycinin α’ and 11S glycinin A4 null with a high protein concentration of 45.7% and good processing quality. HS-183 is a 7S β-conglycinin α’ and 11S glycinin null with a protein concentration of 42.7% and poor tofu processing quality. They are adapted to areas of southwestern Ontario with 3100 or more crop heat units and have relative maturity groups of 2.5 and 2.4, respectively.
AAC Cranford is an early-maturing cranberry dry bean (Phaseolus vulgaris L.) cultivar with high yield, an upright determinate bush (Type I) growth habit, and large seed size. Currently, dry bean cultivars in the cranberry bean market class are only commercially grown in Manitoba and Ontario, primarily due to their late maturity. Therefore, AAC Cranford, with its early maturity and high yield potential, will enable growers to commercially produce cranberry bean in Alberta and Saskatchewan.
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