A total of six field experiments were conducted in southwestern Ontario over a 3-yr period (2016, 2017, 2018) to evaluate the efficacy of trifluralin and halosulfuron applied preplant incorporated (PPI) for weed management in white bean. Trifluralin, halosulfuron, and trifluralin + halosulfuron applied PPI caused as much as 2%, 6%, and 8% white bean injury, respectively. Weed interference delayed maturity and reduced white bean yield 56% compared with the weed-free control. Weed interference with trifluralin and halosulfuron applied alone reduced white bean seed yield as much as 35% and 29%, respectively; however, white bean seed yield with the trifluralin + halosulfuron tankmixes was similar to the weed-free control. Trifluralin, halosulfuron, and trifluralin + halosulfuron applied PPI provided 6%–12%, 75%–92%, and 71%–95% control of velvetleaf; 89%–95%, 93%–98%, and 96%–99% control of pigweed species; 5%–18%, 82%–96%, and 90%–97% control of common ragweed; 90%–97%, 81%–97%, and 95%–99% control of common lambsquarters; 23%–43%, 55%–88%, and 83%–96% control of flower-of-an-hour; 4%–25%, 94%–100%, and 95%–100% control of wild mustard; 96%–100%, 18%–45%, and 97%–100% control of barnyardgrass; and 92%–98%, 21%–40%, and 93%–98% control of green foxtail, respectively. Results indicated that low rates of trifluralin tank-mixed with halosulfuron has the potential to control problematic weeds and improve white bean yields in Ontario.

The WRKY family is a specific super gene family in plants that plays a significant regulatory role in abiotic stress in plants. In this paper, the PlWRKY70 gene was cloned by RT-PCR from Paeonia lactiflora ‘Da Fugui’ buds (GenBank accession no. KU891819). The open reading frame of the gene was 936 bp in length, encoding 311 amino acids. The PlWRKY70 gene contained a WRKY domain in its coding region that belonged to the group III WRKY family and was evolutionarily the closest to Paeonia suffruticosa. PlWRKY70 was widely expressed and found at an extremely high level in buds. Moreover, the PlWRKY70 protein was mostly detected in the nucleus. The expression of PlWRKY70 was remarkably influenced by different abiotic stresses with completely different patterns. It could be significantly induced by low-temperature and salt stress, rapidly reaching peak levels after the initial 4 or 8 h of the stress treatment, whereas under waterlogging stress, it was considerably suppressed, dramatically dropping to minimum levels after 2 h of treatment. These profiles suggested that PlWRKY70 was sensitive to low-temperature, salt, and waterlogging stresses in P. lactiflora.

Several quantitative trait loci (QTL) have been identified for Fusarium head blight (FHB) resistance in the cultivar Sumai 3. Wheat breeders need to know which Sumai 3 loci are present in derived lines used as parents for effective marker-assisted selection for genetic improvement. This study was conducted to identify the loci in Sumai 3 derived parents that contribute FHB resistance in breeding populations. Three doubled haploid (DH) populations utilizing Sumai 3 derived parents, ND3085, ND744, and Alsen, were evaluated during 2007 and 2008 in FHB nurseries near Carman, MB, Ottawa, ON and Charlottetown, PE. The percentage of incidence, severity, Fusarium-damaged kernels (FDK), and deoxynivalenol (DON) accumulation were measured, and FHB index calculated. DNA markers at six FHB resistance loci detected in Sumai 3 were evaluated on the populations. For each trait, a t test was applied to means of observations pooled by parental type of each marker to determine which loci contributed to resistance. The alleles at 3BS and 5AS most frequently contributed to Type I and Type II FHB resistance, as well as to reduced FDK and DON in all three populations. Markers revealed resistance on 3BS and 5AS in Alsen, ND3085, and ND744, on 3BSc, 4D, and 6BS in ND744, on 4D in ND3085, and on 6BS in Alsen. In some environments, the susceptible parent Infinity contributed minor QTL on 2D, 3BSc, and 6BS. Likewise, Helios contributed minor QTL on 5AS and 6BS.

Anthocyanin in grapevines, regulated by structural and regulatory genes, determines the colour of grape berries and is a key factor in wine quality. The transgenic approach is a useful strategy for elucidating gene function. However, it is difficult to obtain transgenic fruit trees, including grapevines. Viral vectors offer an effective strategy for overcoming this challenge. In this study, we successfully knocked down the VvMYBA1 gene in ‘Red Globe’ and ‘JiZaoMi’ grape berries via virus-induced gene silencing (VIGS) by vacuum infiltration and silencing efficiencies of 73% and 93%, respectively, were obtained relative to the control. Total anthocyanins content was reduced 1.7- and 2.7-times relative to that in the control in ‘Red Globe’ and ‘JiZaoMi’ grape berries, respectively. The expression levels of VvUFGT and VvDFR were reduced by 80% and 8% and by 72% and 42% relative to the control in ‘Red Globe’ and ‘JiZaoMi’ grape berries, respectively, in the anthocyanin metabolic pathways. Tobacco rattle virus-mediated VIGS was, therefore, successfully established in grape berries. These findings provide direct evidence that VvMYBA1 encodes skin colour in red grape berries and suggest a possible application of VIGS for gene function studies in other fruits.

Gala apple (Malus domestica Borkh.) trees are prone to heavy cropping but respond to chemical fruitlet thinners to reduce crop load and improve fruit quality. Environmental concerns over the fate of the chemical fruitlet thinner carbaryl is widely acknowledged, but crop load management options are limited. In southern Ontario, Gala trees were treated with new thinning compounds or combinations to determine post-bloom thinning efficacy and resulting fruit quality. Treatments included 6-benzyladenine (6-BA) combined with naphthaleneacetic acid (NAA) or abscisic acid (ABA), and 1-aminocyclopropane-1-carboxylic acid (ACC) alone applied at 9 mm in 2014 and 17 mm in 2015. The treatment NAA + 6-BA produced unacceptably small “pygmy” fruit when applied at 17 mm fruitlet diameter. ABA at 150 and 300 mg L^-1 and ACC at 150 mg L^-1, when applied at 17 mm fruitlet diameter, resulted in acceptable fruit set, crop load, and quality results in comparison with the carbaryl thinner in 1 yr. The bioregulators ACC and ABA combined with 6-BA showed commercial potential for thinning Gala fruit but require further evaluation.

Camellia fascicularis is an endangered evergreen ornamental plant with pale yellow flowers. An efficient and reproducible in vitro regeneration method is required for its large-scale propagation and germplasm conservation. In this study, one axillary bud per nodal stem was obtained from C. fascicularis cultured on Murashige & Skoog (MS) medium containing 0.1 mg L^-1 indole-3-acetic acid (IAA) combined with 1.0 mg L^-1 6-benzylaminopurine (BA). Axillary buds from the stem segments were transferred to modified woody plant medium (WPM) supplemented with 3.0 mg L^-1 BA in combination with 0.3 mg L^-1 IAA for multiplication, thereby resulting in a high shoot multiplication rate of 6.8. Multiple shoots were divided into nodal stems and shoot tips and were induced to root. The shoot tips were induced to root by culturing on one-half MS medium supplemented with 2.0 mg L^-1 indole-3-butyric acid (IBA) in combination with 0.3 mg L^-1 α-naphthalene acetic acid (NAA), which resulted in 76.0% rooting efficiency with 2.3 roots per shoot. The optimal hormone ratio for inducing rooting of nodal stems was 1.0 mg L^-1 IBA in combination with 2.0 mg L^-1 NAA, which resulted in 72.7% rooting efficiency with 1.7 roots per nodal stem. These two rooted plantlets were successfully acclimatized and established in a greenhouse.

Crown rust, caused by Puccinia coronata f. sp. avenae (Pca), is the most important disease and yield limiting factor of oat production in eastern Canada. In this study 101 oat genotypes composed of 51 cultivars and 50 breeding lines from eight oat breeding programs across Canada were evaluated for seedling reactions to six common Pca races, as well as reactions to a bulk inoculum of Pca in greenhouse trials and for adult plant resistance (APR) to natural populations of Pca in field trials in 2014 and 2015. Sixty-six genotypes showed resistant reactions to at least one of the six races; of these, 22 were resistant to all six races. These 22 genotypes also showed resistance to the bulk inoculum at the seeding stage and to the natural populations of Pca at the adult plant stage, suggesting that these current and future oat varieties have effective resistance against the common races and Pca populations in the region. Eleven genotypes, including 12ANS03, AAC Bullet, CFA1213, CFA1306, Idaho, OA1301-1w-3, OA1369-5, OA1370-2, OA1371-2, OA1383-2, and Oscar, were susceptible as seedlings but resistant as adult plants. APR is proven to be long lasting and provides broad-spectrum resistance to Pca populations. The 11 oat genotypes identified with APR in the present study are more desirable as sources of resistance for breeding programs developing durable crown rust resistant cultivars for eastern Canada.

In Canada, clubroot (Plasmodiophora brassicae) disease is managed mainly by planting clubroot resistant (CR) canola (Brassica napus). New pathotypes of P. brassicae have emerged recently, however, which are virulent on most CR canola cultivars. To understand the impact of cultivar rotation on pathotype abundance, greenhouse experiments were conducted in which different canola cultivar rotations were grown in a soil mix containing equal amounts of pathotypes 5X and 3, which are virulent and avirulent, respectively, on CR canola. The rotation treatments included: T1, the same susceptible cultivar planted over four cycles; T2, the same CR cultivar planted over four cycles; and T3, different CR cultivars planted in each cycle. Clubroot severity increased from cycles one to four in all treatments, with the exception of one CR cultivar in T3 that may carry a different source of resistance. Pathogen populations were recovered with a susceptible bait crop and pathotyped on the differentials of Williams plus a CR host (B. napus ‘Mendel’). The percentage of galls classified as pathotype 5X in T1 declined from 50% to 6.7% over the course of the experiment, while galls classified as pathotype 5X increased from 50% to 66.7% in both T2 and T3. Quantitative PCR analysis of the soil with pathotype 5X-specific primers generally confirmed an increase in 5X DNA. The results suggest that continuous planting of CR canola favours a rapid proliferation of virulent pathotypes of P. brassicae, as indicated by the increases in pathotype 5X observed in this study.

The objective of this study was to investigate the effects of storage regime and postharvest 1-methylcyclopropene (1-MCP) treatment timing on softening of ‘Northern Spy’ apples, to determine if ideal firmness for processing could be achieved after storage while at the same time maintaining fruit quality and extending storage life. Over 4 yr of study, ‘Northern Spy’ apples with or without 1-MCP (1 μL L^-1) were held for up to 12.5 mo at 0 °C–1 °C in the following regimes: (1) controlled atmosphere (CA) with or without 2 wk post-storage ambient air; (2) ambient air or CA; (3) CA with up to 6 mo delayed 1-MCP treatment; (4) delayed CA establishment for up to 4 mo; (5) delayed 1-MCP treatment in combination with delayed CA establishment for 1 or 2 mo. 1-MCP treatment at harvest consistently enhanced firmness retention, which remained too high for processing. Delayed 1-MCP treatment allowed more firmness loss but fruit remained firmer than those not treated, and these apples would be acceptable for subsequent processing (∼67–72 N). 1-MCP-treated fruit developed higher incidence of core browning than those not treated, especially after 6 mo of storage. However, this is not a major problem for processing because core tissue is removed. Delayed CA within any regime did not result in apples with firmness values acceptable for processing, while additional air storage for 2 wk at 0 °C after CA had no significant effect. Overall, delayed 1-MCP treatment with no delay in CA provided the most acceptable apple firmness for processing.

AAC Crossfield, an awned hard red spring wheat (Triticum aestivum L.) cultivar, combines high grain yield and good agronomic characteristics with excellent resistance to leaf, stem, and stripe rust. AAC Crossfield is significantly shorter than Conquer and AAC Foray, and has maturity, straw strength, and test weight similar to the check cultivars. AAC Crossfield has improved farinograph stability and is eligible for grade in the Canada Prairie Spring Red wheat market class.