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Spotted knapweed is a prohibited noxious weed that is primarily controlled with auxinic herbicides. A population collected from a managed rangeland in East Kootenay, BC, was highly resistant to both clopyralid and picloram, with R/S ratios of >25 600 and 28, respectively. This is the first report of resistance in spotted knapweed.
Nine preplant herbicides were tested for the control of glyphosate-resistant (GR) Canada fleabane in corn. At eight weeks after treatment (WAT), the herbicides that resulted in the greatest control and least amount of density and biomass of GR Canada fleabane were dicamba/atrazine (99%), mesotrione atrazine (97%), saflufenacil/dimethenamid-p (97%), and dicamba (94%).
The T and W1 loci determine color and anthocyanin content in soybean hypocotyls. In purple hypocotyls, the anthocyanins were: A1, a delphinidin-type anthocyanin; A2 made of two unresolved peaks: peonidin 3,5-di-O-glucoside and a delphinidin-type anthocyanin; and A3, accounting for >90% of the total, was malvidin 3,5-di-O-glucoside. A single peak, peonidin 3,5-di-O-glucoside, was observed in the bronze hypocotyls.
KEYWORDS: weed biology, proso millet, Panicum miliaceum L., weed/crop, intraspecific variation, global distribution and history, biologie des mauvaises herbes, millet, plante cultivée/envahissante, variation intraspécifique, répartition dans le monde et histoire
Proso millet, Panicum miliaceum L. (Poaceae), has been a crop in Asia and Europe for 10 000 years and for over 300 years in Canada, where it is grown for grain, rescue crops, birdseed, forage, and recently for swath grazing. Crop-like biotypes have escaped from cultivation throughout Canada, but these infestations were generally temporary. Probably the first persistent, weedy biotype in Canada (Quebec) has large, dormant, dark red seeds. Its eradication has been attempted for many years. In the 1970s, a worse problem, a black-seeded biotype with many weedy attributes, including shattering as seeds ripen and strongly dormant seeds distasteful to many birds, spread across southern Ontario and became labelled as noxious. Concurrently, it was described as the worst weed in the US Corn Belt. In the 1980s, Canadian studies revealed infestations of other weedy biotypes, differing in seed colour and other attributes. Panicum miliaceum is an extremely variable species world-wide. Since the late 1990s, weedy proso millet has declined dramatically after the adoption of newer herbicides, particularly glyphosate. This development may lead to increases in cultivated proso millet, especially where climate change favours short-season crops grown under drier conditions.
Six field trials were conducted over a two-year period (2014, 2015) to determine the level and consistency of glyphosate-resistant (GR) Canada fleabane control with glyphosate plus saflufenacil plus a third tankmix partner. GR Canada fleabane interference reduced soybean yield 73% compared with the weed free control. At 4 and 8 weeks after application (WAA), glyphosate plus saflufenacil provided 99% and 88% control of GR Canada fleabane respectively, and at 8 WAA, reduced GR Canada fleabane density by 96% and biomass by 89%. Glyphosate plus saflufenacil plus dicamba improved the control of GR Canada fleabane to 100% and 97% at 4 and 8 WAA, respectively. At 8 WAA, glyphosate plus saflufenacil plus amitrole reduced GR Canada fleabane density and biomass 99% and 97%, respectively. At 8 WAA, glyphosate plus saflufenacil plus dicamba at 300 or 600 g a.i. ha-1 reduced GR Canada fleabane biomass 97% and 98%, respectively. Tank-mixing dicamba with glyphosate plus saflufenacil applied pre-plant improved control of GR Canada fleabane; however, this caused 14% and 46% crop injury at 2 and 4 WAA, respectively. Soybean yield for saflufenacil alone and saflufenacil tankmix treatments were similar to the weed free control, with the exception of dicamba (600 g a.i. ha-1).
MicroRNAs (miRNAs) are a class of endogenous, single-stranded, approximately 21 nt in length, non-coding RNAs which play critical roles in plant biological and metabolic processes. Although numerous miRNAs have been identified in many plant species, miRNAs still remain totally unknown in Ribes nigrum. In the study, two miRNAs (rni-miR5021 and rni-miR5185) were firstly identified in Ribes nigrum using an expression sequence tag (EST)-based comparative genomics approach. Subsequently, transgenic analysis suggested that these putative MIR genes encoding rni-miR5021 and rni-miR5185 were able to generate their corresponding miRNA in vivo. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis indicated that the expression patterns of the MIR genes varied among blackcurrant tissues, and the two mature miRNAs showed higher accumulation in fruits than other tissues. Finally, 47 targets were predicted for the two miRNAs, which are involved in response to stresses and other plant biological processes. These findings will facilitate future studies on the functions and regulatory mechanisms of miRNAs in Ribes nigrum.
A study was made of the effect of atmospheric CO2 enrichment and increased nitrogen availability on primary leaf senescence in sunflower (Helianthus annuus L.). First, markers normally used for monitoring leaf development (dry weight, leaf surface area, protein content, photosynthetic pigment levels, CO2 fixation rate, changes in the enzymes involved in nitrogen metabolism, and plant-tissue oxidative status) were measured in plants grown for 42 days under ambient (400 µL L-1) or enriched CO2 conditions (800 µL L-1), and with two different levels of nitrate supply (10 mM and 25 mM). Second, two-dimensional electrophoresis (2-DE) was used to compare primary-leaf protein profiles (16 and 42 days) in sunflowers grown under ambient or enriched CO2 conditions with elevated nitrate supply. Plants grown under enriched CO2 conditions and with high nitrogen supply displayed faster growth, a higher CO2 fixation rate, and increased activity by antioxidative and nitrogen-metabolism-related enzymes than those grown under elevated CO2 with low nitrogen supply. These findings indicate that CO2 enrichment and increased nitrate availability slow down the induction of senescence, suggesting that senescence may be directly related to leaf C/N ratio. These results enhance our understanding of the sunflower’s response to increased atmospheric CO2 levels, one of the environmental factors favoring climate change.
Broccoli is an important vegetable crop belonging to the genus of Brassica. However, it is often affected by biotic and abiotic stresses that result in large losses in yield and quality. Genetic manipulation has opened the opportunity for germplasm improvement of broccoli. In this study, an efficient shoot regeneration and Agrobacterium-mediated transformation system was established. The optimum medium for shoot induction was selected for three types of explant including hypocotyl, petiole, and peduncle, and up to 90% regeneration frequency was obtained. The transformation procedure was developed with the EHA105 strain, harboring the PUC19 vector, along with the target gene of codA and a hygromycin-resistance gene. Several factors were optimized, including hygromycin concentration for selection and the Agrobacterium density yielding the highest transformation frequency. Among the three types of explants, peduncle explants showed the highest response to this procedure, and the highest frequency of transformation (3.4%) was obtained depending on the analysis of polymerase chain reaction and Southern blot. In conclusion, the present study introduced a reliable system for plant regeneration and genetic transformation with three types of explants for a DH line of broccoli, and peduncle explant resulted in the highest transformation frequency.
KEYWORDS: G × E Interaction, Genetic gain, heritability, selection differential, selection intensity, Triticum aestivum, interaction G × E, Gain génétique, héritabilité, variation due à la sélection, intensité de sélection
While evaluating genotypes for yield in multi-environment tests, the variation can only be observed in the relative yield performance of genotypes across environments. Eighteen (18) wheat genotypes, along with two standard farmer check varieties, were tested under normal and late sowing conditions for yield comparison, heritability, and selection response to understand the causes of G × E interaction and identification of specific desirable traits and genotypes. Analysis of variance showed highly significant differences (P < 0.01) for spikes m-2, seed yield, and harvest index, while significant differences (P < 0.05) were observed for spikelets spike-1 and grains spike-1. The environmental component revealed highly significant differences (P < 0.01) for all traits except for grain weight spike-1, which exhibited significant differences (P < 0.05). However, the G × E interaction showed highly significant differences (P < 0.01) only for harvest index. The better accessions may further be tested for performance under late sowing conditions. The accessions also have potential for utilization in breeding programs for accumulating the genes of interest in genotypes which otherwise failed to perform better in late sowing environments. The selected accessions can be extremely useful for breeding cultivars to fill the gap between cultivars under conditions of very early or very late sowing.
Jun Qin, Ainong Shi, Haizheng Xiong, Beiquan Mou, Dennis Motes, Weiguo Lu, J. Creighton Miller, Douglas C. Scheuring, M. Ndambe Nzaramba, Yuejin Weng, Wei Yang
KEYWORDS: cowpea, Vigna unguiculata, seed antioxidant content, seed colour, single nucleotide polymorphism (SNP), association analysis, dolique, concentration d’antioxydants dans la graine, couleur de la graine, polymorphisme mononucléotidique (SNP), analyse par association
Cowpea (Vigna unguiculata L. Walp.) is an important legume, and the antioxidant content in cowpea seeds has been recognized as a health-promoting compound for humans. The objectives of this study were to analyze the population structure of cowpea collections and to identify single nucleotide polymorphism (SNP) markers associated with the seed antioxidant content and seed coat colour. A set of 1047 SNPs were used to analyze a 369 cowpea core collection from 47 countries. Results indicated that: (1) there were three clusters in the 369 entries; and the germplasm collected from India, South Africa, and the US showed broader genetic diversity; (2) Scaffold7139_14363 and Scaffold29110_4657 were strongly associated with antioxidant content, and C35063613_1497, Scaffold81493_886, and Scaffold84620_6785 were strongly associated with seed coat colour across three models; (3) significant correlations were detected between the seed antioxidant content and black seed colour (r = 0.45) and between seed antioxidant content and red seed coat colour (r = 0.50); and (4) Scaffold42008_191 and C35082838_2258 were associated with both seed antioxidant content and seed coat colour. The SNP markers identified could potentially be used in marker-assisted breeding to accelerate genetic improvement of cowpea for higher seed antioxidant content.
Soil-applied broadleaf herbicides for weed management in dry beans (Phaseolus vulgaris L.) in Ontario are limited. Sulfentrazone is an effective broadleaf herbicide with some grass activity and is currently registered for use in soybean and some pulse crops in Canada. If registered for use in dry beans in Ontario, sulfentrazone would provide growers with another mode of action for broadleaf weed control. Five field studies were conducted over a two year period (2014–2015) to determine the tolerance of white beans to sulfentrazone applied pre-emergence (PRE) and if the spectrum of weeds controlled can be expanded by tank-mixing sulfentrazone with a soil-applied grass herbicide. Sulfentrazone (140 and 210 g ai ha-1) was mixed with pendimethalin, dimethenamid-p, s-metolachlor or pyroxasulfone. All the tankmixes evaluated provided good control of green foxtail (Setaria viridis L.), pigweeds (Amaranthus powelli L. and A. retroflexus L.), and common lambsquarters (Chenopodium album L.), but only sulfentrazone pendimethalin had an adequate margin of crop safety. Based on this study, sulfentrazone combined with a grass herbicide provides acceptable control of some grass and broadleaf weed species; however, further research is required to determine if there is an adequate margin of crop safety for weed management in Ontario dry beans.
Cabernet Sauvignon (CS) and Cabernet franc (CF) vines were subjected to two crop levels (full, half) and three harvest dates (earliest to latest; T0, T1, T2) over two vintages. Wines were analyzed for anthocyanins, phenolics, and proanthocyanidins. Crop level increased CS hue (2011–2012), increased CS pH and reduced CS color intensity (2012), and reduced CF hue (2012). Harvest date had a greater effect than crop level, with many treatment interactions. Half crop (2011) increased three CS anthocyanins plus procyanidin B. Extended harvest increased eight compounds. Quercetin and ( )-catechin decreased in T1. Crop reduction (2012) increased malvidin-3-coumarylglucoside and ( )-catechin, but decreased petunidin and delphinidin-3-coumarylglucoside. Harvest date (2012) impacted all but two compounds, with the highest anthocyanin concentrations in T1 wines. Gallic acid, ( )-catechin and resveratrol increased with harvest date, while three phenols decreased. Half crop (2011) increased CF peonidin. Extended harvest increased four phenols while three others decreased. Crop reduction (2012) increased delphinidin-3-acetylglucoside, cyanidin-3-coumarylglucoside and caffeic acid; (-)-epicatechin and p-coumaric acid decreased. Several anthocyanins and phenols decreased between T0 and T2, nine of 13 anthocyanins decreased between T0 and T1, while others decreased from T1 to T2. Gallic acid and ( )-catechin increased with harvest date; (-)-epicatechin, p-coumaric acid, quercetin, and resveratrol decreased.
KEYWORDS: hard white spring wheat, germplasm, marker-assisted selection, fusarium head blight resistance, blé dur blanc de printemps, matériel génétique, sélection assistée par marqueurs, résistance à la brûlure de l’épi causée par Fusarium
WS175 is a hard white spring wheat line with the parentage Snowbird/Sumai3 with a high level of resistance to Fusarium head blight (FHB) that was developed using marker-assisted selection. WS175 contains haplotypes similar to Sumai3 at the loci previously associated with FHB resistance, located on chromosomes 3B, 5A, and 6B. WS175 has similar maturity and protein content, but has lower grain yield, compared to Snowbird. The combination of white seed coat colour and very high level of FHB resistance will make WS175 a valuable parent for the improvement of FHB resistance in white spring wheat breeding programs.
AAC Cameron (BW485) is a hollow-stemmed high yielding spring wheat (Triticum aestivum L.) with good agronomic, disease, and end-use quality characteristics. AAC Cameron is best adapted to the eastern region of the Canadian prairies as represented in the Central Bread Wheat Cooperative (CBWC) Registration Tests in 2011, 2012, and 2013. AAC Cameron was significantly higher yielding than the best check Unity (5%), and 12% higher than 5603HR. AAC Cameron had moderate resistance to leaf rust (Puccinia triticina Eriks.), stem rust (Puccinia graminis f. sp. tritici), and Fusarium head blight (FHB) (Fusarium graminearum), with lower FHB index and deoxynivalenol (DON) content compared to the check cultivars. AAC Cameron expressed resistance to orange wheat blossom midge (Sitodiplosis mosellana Géhin) and common bunt (Tilletia tritici). AAC Cameron showed good lodging resistance (mean = 2.1) despite its tall (mean = 98 cm) plant ideotype. It had significantly higher kernel weight than all check cultivars, whereas maturity and test weight were similar to the check cultivars. AAC Cameron is registered under the Canada Western Red Spring Wheat class for its premium quality attributes.
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