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Natural hail can cause significant damage on seed yield and yield contributing traits of canola (Brassica napus L.). Hail damage can be assessed by (i) type of damage such as stand reduction, stem cut-off, and leaf defoliation, (ii) level of damage, and (iii) plant growth stage. In this research, a simulated hail study was performed by applying nonuniform stand reduction treatments on canola grown in North Dakota, USA, over 5 site-years, in 2017 and 2018. The experiment was a randomized complete block design 4 × 5 factorial arrangement with four growth stages, rosette, bolting, 50%, and 90% flowering, when five stand reduction treatments were applied at 0 (control), 25%, 50%, 75%, and 90%. Growth stage and stand reduction were significant for seed yield where yield decreased as stage of treatment progressed and level of stand reduction increased. Regression equations were developed to estimate the seed yield reduction at each growth stage as stand reduction increased. Stand reduction also affected other traits where plant height was reduced as stand reduction increased, whereas 1000-seed weight, primary branches plant-1, secondary branches plant-1, pods plant-1, seed yield plant-1, plant biomass plant-1, and harvest index plant-1 increased as stand reduction increased. As growth stage progressed the number of primary branches plant-1, secondary branches plant-1, pods plant-1, and harvest index plant-1 decreased, whereas 1000-seed weight increased. The findings of differential yield losses by stand reduction will help producers and crop adjusters to assess the severity of hail damage in canola.
This work presents new data on the effects of orchard growing factors on storage quality of Staccato sweet cherries grown in the southern Okanagan region of British Columbia, Canada. Quality attributes, respiration rates, and the mineral contents of Staccato sweet cherries were analyzed. Orchard growing factors such as pruning practices, growing temperature, and relative humidity varied by orchard throughout the region, and consequently, the mineral contents, quality attributes, and respiration rates of the Staccato sweet cherries also varied. Principal components analysis revealed relationships among orchard growing factors, cherry fruit mineral content, and fruit quality data. The content of Ca, Mg, N, P, and K in cherry fruit was correlated with quality attributes such as pitting, pebbling, soluble solids, titratable acidity, dry matter, firmness, and stem pull force. Orchard temperatures and relative humidity also influenced flavour quality attributes and appearance. Orchard management practices resulting in large leaf sizes were generally associated with good flavour quality and appearance. This work provides new data to support improved understanding how cherry quality is affected by orchard growing factors in an integrated analysis.
A soybean trait resistant to sulfonylurea herbicides along with glyphosate (Bolt™ soybean) has been developed. Information is needed to determine herbicide programs for weed control and crop safety in this new multiple herbicide–resistant soybean trait. The objectives of this study were to evaluate weed control and crop safety in sulfonylurea/glyphosate-resistant soybean with herbicide programs, including but not limited to acetolactate synthase (ALS) inhibitors. Field experiments were conducted near Clay Center, NE, USA, in 2016 and 2017. Herbicide programs with multiple sites-of-action including rimsulfuron/thifensulfuron in mixture with flumioxazin, flumioxazin/chlorimuron, pyroxasulfone, chlorimuron/metribuzin, or saflufenacil/imazethapyr plus dimethenamid-P provided 91%–97% control of common waterhemp, velvetleaf, and common lambsquarters. Rimsulfuron and (or) thifensulfuron resulted in 92%–97% control of velvetleaf and common lambsquarters and 81%–87% common waterhemp control at 21 d after pre-emergence (PRE) (DAPRE) herbicide application. Soybean injury was transient and varied from 3% to 11% at 21 DAPRE and 14 d after post-emergence (POST) (DAPOST) herbicide application without causing yield loss. At 30 and 60 DAPOST, 87%–97% velvetleaf control and 92%–98% common lambsquarters control was achieved with herbicide programs tested (PRE, POST, or PRE followed by POST). Common waterhemp control at 30 and 60 DAPOST was not consistent between years. Weed density and biomass reduction were mostly similar to weed control achieved. Untreated control resulted in the lowest soybean yield (1811 kg ha−1) in 2016 compared with 3406–4611 kg ha−1 in herbicide programs.
Foliar fertilization is a potential strategy to supplement phosphorus (P) requirements when conditions permit. In 2016 and 2017, canola, wheat, and pea were grown in a randomized complete block design trial near Pilger, SK, Canada. Each crop received a total P application of 20 kg P2O5 ha−1, with varying proportions of the P applied as seed-placed monoammonium phosphate (MAP) supplemented with foliar KH2PO4 (0%, 25%, 50%, and 100%) applied prior to anthesis. Under field conditions, yield response decreased as the proportion applied as seed-placed MAP decreased. The 100% foliar-applied P treatment in canola was able to maintain significantly higher yield than the unfertilized control in the absence of seed-placed MAP, indicating some uptake and response. Of the crops evaluated, canola was most responsive to P fertilization. Phytate content ranged from 68% to over 90% of total seed P, with the highest proportions found in wheat grain. Foliar P application had limited effect on phytate and grain iron content, but there appeared to be an inverse relationship between seed-placed MAP and grain zinc concentration that was less evident when P was applied in foliar form. In this study, foliar P application was unable to substitute for seed-placed MAP and overall had a marginal effect on grain yield and P uptake as well as seed nutritional value.
Malting barley is important in western Canada, yet many malting cultivars do not meet malt quality standards, in part due to lodging. Lodging can decrease barley yield and quality thereby reducing the acceptability for malting. In other countries, plant growth regulator (PGR) applications are used to mitigate lodging. Chlormequat chloride (chlormequat), trinexapac-ethyl (trinexapac), and ethephon were tested at five locations over 3 yr in western Canada for their ability to limit lodging, as well as their effects on yield, agronomic traits, and pre-malt quality characteristics. PGR applications occurred between Zadoks growth stage (GS) 30–33 for chlormequat and trinexapac and GS 37–49 for ethephon. Seeding rates of 200, 300, and 400 seeds m−2 of CDC Copeland barley were used to increase the likelihood of lodging. Increased seeding rate decreased tillers per plant, height, days to maturity, kernel protein, and kernel weight. Ethephon increased the number of tillers per plant and decreased plant height, kernel plumpness, and kernel weight. Trinexapac decreased plant height and kernel weight. Days to maturity was investigated across site-years, with ethephon increasing maturity in 60% of comparisons. Trinexapac and chlormequat had limited effects on maturity. Lodging was investigated across site-years, with trinexapac showing the largest number of lodging reductions and scale of reductions. Ethephon reduced lodging in 36% of comparisons, while chlormequat had inconsistent effects. None of the products affected yield or grain protein. The results suggest PGRs may not be the solution to lodging for CDC Copeland barley on the Canadian Prairies; however, trinexapac shows the most promise of the products tested.
The seeds of Cercis chinensis Bunge are important for reproduction and propagation, but strong dormancy controls their germination. To elucidate the causes of seed dormancy in C. chinensis, we investigated the permeability of the hard seed coat and the contribution of the endosperm to physical dormancy, and we examined the effect of extracts from the seed coat and endosperm. In addition, the effectiveness of scarification methods to break seed dormancy was compared. Cercis chinensis seeds exhibited physical and physiological dormancy. The hard seed coat played an important role in limiting water uptake, and the endosperm acted as a physical barrier that restricted embryo development in imbibed seeds. Germination percentage of Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt] seeds was reduced from 98% (control) to 28.3% and 56.7% with a seed-coat extract and an endosperm extract, respectively. This demonstrated that both the seed coat and endosperm contained endogenous inhibitors, but the seed-coat extract resulted in stronger inhibition. Mechanical scarification, thermal scarification, and chemical scarification had positive effects on C. chinensis seed germination. Soaking non-scarified seeds in gibberellic acid (GA3) solution did not promote germination; however, treatment with exogenous GA3 following scarification significantly improved germination. The optimal method for promoting C. chinensis seed germination was soaking scarified seeds in 500 mg·L−1 GA3 for 24 h followed by cold stratification at 5 °C for 2 mo.
Inhibition of the maize starch branching enzyme IIb (ZmSBEIIb) significantly alters the amylose content and grain yield in maize. Only a few ZmSBEIIb-interacting proteins involved in the starch branching process have been identified, and the understanding of this mechanism is limited. We report here the successful isolation of an Anoctamin protein, ZmSIP, that binds directly to ZmSBEIIb. In our study, the detection of interaction between ZmSIP and different truncated ZmSBEIIb baits in yeast showed that the full-length ZmSBEIIb is essential for binding. The direct protein–protein interaction could also be found in co-transformed tobacco protoplasts. Moreover, knocking out the ZmSIP gene using the CRISPR/Cas9 system could effectively increase the apparent amylose content but maintain the maize kernel weight. Thus, our results suggest that ZmSIP may be involved in the ZmSBEIIb-mediated amylose synthesis pathway through its physical interaction with ZmSBEIIb.
The use of rain shelters in pear cultivation has been shown to improve yields and the appearance and quality of fruit, as well as reduce diseases and pests; however, how rain shelters affect soil chemical properties, soil enzyme activity, and soil microbial diversity remains unknown. Here, we studied pear trees under rain-shelter cultivation and open-field cultivation in the same orchard and compared fruit quality, soil chemical characteristics, soil enzyme activity, and soil microbial diversity. Results showed that rain shelters can significantly (p < 0.05) increase the sugar content (sweetness) of pear fruits and decrease the content of acids. The levels of available phosphorus, available potassium, organic matter, and water in soils under rain shelters were significantly (p < 0.05) lower than in soils in open fields. Rain-shelter treatment increased soil polyphenol oxidase activity and decreased phosphomonoesterase, urease, and sucrase activity. Analysis of microbial carbon-source utilization rates and microbial diversity showed that open-field cultivation is beneficial for microbial carbon-source utilization and microbial diversity in rhizosphere soil. Our study found that rain-shelter cultivation is not beneficial to soil fertility, microbial carbon-source metabolism and utilization, matter cycling, or microbial diversity and that the use of rain shelters may require appropriate nutrient and organic matter supplementation to maintain long-term cultivation of crops; whereas, the effects of environmental factors on open-field cultivation are greater, and more refined water and fertilizer management is required to improve fruit quality.
Herbicide-resistant (HR) crops, specifically glyphosate-, glufosinate-, and dicamba-resistant (HT3) soybean, will offer producers a new weed management option for the control of some HR weeds in soybean. Four field experiments were conducted near Cottam and on Walpole Island, ON, Canada, during 2017 and 2018 to assess the control of multiple-resistant (MR) waterhemp (herbicide groups 2, 5, and 9) in HT3 soybean treated with various herbicide programs. Pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied preemergence (PRE) and followed by (fb) glyphosate postemergence (POST) controlled MR waterhemp at 94%, 66%, and 78%, respectively, in early September. Pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied PRE controlled MR waterhemp 86%–97% when fb glufosinate POST; 100% when fb glyphosate plus dicamba POST; 99%–100% when fb glufosinate plus dicamba POST; and 100% when fb glyphosate plus dicamba POST and fb glufosinate POST2 (before the R2 soybean growth stage) in early September. Reduced MR waterhemp interference with all herbicide programs resulted in an increase in HT3 soybean yield (up to 59%) relative to the weedy control. Results indicate that pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied PRE fb glufosinate POST, glyphosate plus dicamba POST, glufosinate plus dicamba POST, or glyphosate plus dicamba POST fb glufosinate POST2 provides similar and excellent season-long control of MR waterhemp in HT3 soybean.
Soil erosion can be a serious issue in eastern Canada during the 3–5 wk that it takes for potato (Solanum tuberosum L.) to emerge under the cool, humid climatic conditions with frequent heavy rainfall events. Seeding a fast-growing nurse crop at the same time as the potato crop can hold the soil particles in place, reduce surface crusting, and increase water infiltration. The objective of this study, conducted in Prince Edward Island and in New Brunswick in 2017, was to evaluate the effects of under-seeding potato with barley (Hordeum vulgare L.) and winter rye (Secale cereale L.) on marketable potato yield, nitrate dynamics during the growing season, and soil moisture content. Nurse crop growth was terminated mechanically (hilling), with a selective herbicide, or with a nonselective herbicide. Yield increases ranging from 9% to 91% were observed when nurse crop growth was terminated using a nonselective herbicide at both sites. Inconsistent results were obtained when a mechanical method or a selective herbicide were used, with marketable yield reduced at one site and no effect on yield at another site. There was a trend toward higher soil nitrate contents under the control than under the nurse crop treatments, though it was not consistent across sampling times. Results demonstrated that there are circumstances under which nurse crops can be successfully integrated into a potato-based system and provided future hypotheses to test. Potential confounding factors that can impact the nurse crop efficiency are discussed.
Breeding for tolerance to lodging is an objective, but also a challenge, in oat (Avena sativa L.) breeding programs. A widely adopted method to assess breeding lines for tolerance to lodging is based on visual scoring of plant standability (1 = standing upright; 9 = completely lodged). The lack of sufficient lodging pressure due to weather or growing conditions often renders the visual scoring method ineffective. We present an alternative approach that allows selection for tolerance to stem lodging by screening for peduncle strength in the absence of lodging pressure. This approach also provides objective selection of lodging tolerance using a quantitatively measurable plant trait rather than subjective scoring of the lodged plants. Stem structural and mechanical properties of six oat cultivars with varying levels of lodging tolerance were tested at field experiments over 3 site-years under three nitrogen rates. Results suggested peduncle breaking resistance (PBR), measured below the panicle, as a potential selection criterion for stem strength and therefore lodging tolerance. Significant genetic variation among oat cultivars (p < 0.01) was observed for PBR, which was significantly correlated with the strength of all lower internodes in all environments (R2 > 0.73, p ≤ 0.05). This suggests that PBR provides a good estimation of the whole culm strength. Phenotyping of PBR can be easily integrated into breeding programs because of the ease of sampling and rapid measurement.
CDC Credence durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield potential with high grain and pasta color and low grain cadmium. CDC Credence is resistant to leaf, stem, and stripe rusts and common bunt and demonstrated end-use quality suitable for the Canada Western Amber Durum class.
CDC Defy durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield, acceptable time to maturity, test weight, and grain protein concentration. CDC Defy is resistant to prevalent races of leaf and stem rust, has excellent common bunt resistance, and demonstrated end-use quality suitable for the Canada Western Amber Durum class.
CDC Covert durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield with acceptable time to maturity, disease resistance, test weight, and end-use suitability. CDC Covert is resistant to prevalent races of leaf and stem rust, has excellent common bunt resistance, and demonstrated end-use quality suitable for the Canada Western Amber Durum class.
AAC Network is a semi-dwarf hard red winter wheat (Triticum aestivum L.) cultivar that is well adapted across western Canada and eligible for grades of Canada Western Red Winter (CWRW) wheat. It was developed using wheat × maize pollen doubled haploid methodology. AAC Network was evaluated in the Western Canadian Winter Wheat Cooperative registration trials relative to CDC Buteo, Emerson, Moats, and AAC Elevate for 4 yr (2016–2019). Based on 44 replicated trials, AAC Network produced grain yield similar to AAC Elevate, the highest yielding check, with a protein concentration 0.9 units higher. AAC Network had fair to good winter survival, relatively late maturity, short straw with excellent lodging resistance, and high test weight. AAC Network expressed resistance to stem and stripe rust, moderate resistance to leaf rust and common bunt, and intermediate resistance to Fusarium head blight. In addition to increased grain protein concentration, AAC Network showed improvements in gluten strength and flour water absorption, and it maintained the excellent milling yield and low flour ash attributes of the CWRW wheat class.
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