There is increasing interest in growing apple cultivars (Malus domestica Borkh.) of European origin for the production of hard cider in Canada; however, little is known about their susceptibility to fire blight (FB). FB can spread rapidly through apple (and pear) orchards causing extensive tree mortality and economic loss. Twenty-eight promising cider cultivars were evaluated over a 7 year period, and in their seventh year of production they were severely naturally infected by an Erwinia amylovora outbreak causing FB. Herein, we report the bloom and harvest dates and tree mortality that developed largely as secondary shoot blight in the summer of 2021. Overall, the cultivars could be classified according to relative susceptibility to FB, based on percentage tree mortality after 7 years: Enterprise (0%); GoldRush and Porter’s Perfection (<20%); Binet Rouge, Kingston Black, Cline Russet, Dabinett, Grimes Golden, Frequin Rouge, Crimson Crisp®, Cox Orange Pippin, and Muscadet De Dieppe (20%–40%); Calville Blanc d’Hiver, Bramley’s Seedling, Yarlington Mill, Michelin, Bulmers Norman, Stoke Red, Golden Russet, Breakwell, Esopus Spitzenberg (50%–90%); Brown Snout, Medaille d’Or, Michelin, Brown’s Apple, Sweet Alford, Tydeman Late, Ashmead’s Kernel, and Tolman (90%–100%). This study highlights the importance of selecting FB tolerant cider cultivars and following best management orchard practices to reduce the spread and prevent infection, which can be achieved by using FB-resistant rootstock, controlling rootstock suckers, FB prediction models, and limited use of antibiotics, biologicals, and careful nitrogen application to regulate tree vigor.

The stomatal complex on the surface of maize leaves is closely related to photosynthesis and transpiration, and the study of maize stomatal phenotypes and the discovery of their regulatory genes are of great importance for the breeding of high-quality and high-yielding maize. In this study, rapid scanning electron microscopy was used to obtain images of the abaxial stomata of 457 maize inbred lines with extensive genetic variation, and stomata density was obtained by counting. The results of correlation showed that stomata density was significantly correlated with leaf width, and Analysis of variance found that there were significant differences (P value < 0.05) in stomata density among different leaf width and 100-grain weight. The highest stomata density was found in the inbred lines with wide and short leaves and higher 100-grain weight. Furthermore, genome-wide association analysis was performed using a mixed linear model. It showed that eight SNPs significantly associated with stomata density were obtained, which could explain 35.507% of the phenotypic variation. Among these, four SNPs on chromosome 5 were tightly linked, mainly formatting two haplotypes, CTTA (0.636) and TCCG (0.330). Twelve genes with functional annotation were identified within 100 kb upstream and downstream of the eight SNPs. One gene, GRMZM2G068277, which had been shown to be involved in plant mitotic processes and exhibited high expression at the leaf base, was therefore the most likely candidate gene for stomata density. The results presented here could provide references for further cloning of functional genes related to stomata density.

This study provides a detailed report on the physicochemical, bioactive components, and volatile profiles of diverse sour cherry (Prunus cerasus) cultivars to identify the cultivar(s) containing high health-promoting components. Physiological characteristics (fruit weight, size dimensions, moisture, color attributes, total soluble solids, pH, titratable acidity, maturity index, nutritional bioactive components (total phenolic, total anthocyanin content, and total flavonoids), antioxidant activity, and volatile profile of 10 sour-cherry cultivars, consisting of dark red Morello type and clear fruit flesh Amarelle type, were studied. The total phenolic content was in the range of 123.24–289.91 mg gallic acid equivalent/100 g FW (fresh weight), total flavonoids (1340.23–2831.91 mg quercetin equivalent/100 g FW), and total anthocyanins (225.43–485.66 mg cyanidin-3-glucoside equivalent (CGE)/100 g FW) in different sour-cherry cultivars, showing significant diversity in such health-promoting compounds. In vitro antioxidant activity assessed by ferric reducing antioxidant potential was observed in the range of 658.18–1483.37 mg Trolox equivalent (TE)/100 g FW and by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) at 384.36 and 931.85 mg TE/100 g FW. A total of 10 phenolic components, including five hydroxycinnamic acids, three flavonoids (flavanols), and one anthocyanin, have been identified and quantified by high-performance liquid chromatography. Hydroxycinnamic acids represented 40%–60% of total phenolic components, while flavonoids and anthocyanins amounted to 20% each in total phenolic composition. The volatile profile of sour-cherry cultivars revealed that aldehydes, alcohols, ketones, esters, monoterpenes, acids, sugars, and hydrocarbons were the predominant volatiles present in sour cherry.

This study aimed to evaluate the impact of genotypes and tannin levels on the nutritional characteristics of faba bean seeds and their relation to protein molecular structure profiles using Fourier transform infrared spectroscopy (FTIR). Eight genotypes with low tannin (LT, n = 3) and normal tannin (NT, n = 5) levels were studied. Standard methods of analysis and NRC 2001 were used to obtain chemical and energy parameters. The protein molecular spectral study was performed using a spectrometer JASCO FT/IR–4200. Molecular features were analyzed in the mid-infrared region at ∼4000–800 cm⁻¹ and protein-related functional groups were obtained using OMNIC software. Results showed higher (P < 0.01) soluble crude protein (SCP), rapidly degradable protein fraction (PA2), and intestinal digestibility of bypass protein (dIDP) in LT than NT. The slowly degradable protein fraction (PB2) was higher in NT (P < 0.01) compared to LT. Higher absorbance was observed in spectral peaks related to amide I, amide II, and β-sheet in NT (P < 0.05) compared to LT. The area ratio of amide I to amide II and the height ratio of α-helix to β-sheet were higher in LT compared to NT (P < 0.01). This study provides a better understanding of associations between structure and nutritional characteristics in faba bean genotypes with different tannin levels.

Alfalfa (Medicago sativa L.) cultivars developed for improved digestibility by conventional breeding or genetic modification have not been evaluated in eastern Canada. This study compared yield, nutritive value, and profitability of two reduced-lignin genetically modified (GM) cultivars, three conventionally selected for low lignin or high pectin, and one population with improved stem degradability, with two commercially adapted cultivars as controls. Alfalfa was harvested at the early bud (intensive management) or early flower (extensive management) stage of development during the first post-seeding year at three sites and the second post-seeding year at one site. All cultivars/populations had similar annual dry matter (DM) yields, except for the lower DM yield (−20%) of the improved stem degradability population. Conventionally selected cultivars for improved digestibility did not differ from control cultivars for in vitro DM digestibility (IVTD) and neutral detergent fiber digestibility (NDFd). Reduced-lignin GM cultivars, however, had a greater IVTD and NDFd (+10%) and less lignin (−10%) than control cultivars at the same stage of development. Reduced-lignin GM cultivars under extensive management had similar NDFd and greater annual DM yield (+1 to 2 Mg DM ha⁻¹), but reduced total digestible nutrients (−41 to 44 g kg⁻¹ DM), in comparison to control cultivars under intensive management. Using partial budget analysis, the comparison of more digestible GM cultivars to the control cultivars resulted in an increase in annual farm net profits ranging from CAD$7.40 to $79.60 cow⁻¹ year⁻¹ depending on stage of development at harvest. Further investigations are needed to quantify the performance of dairy cows fed cultivars with improved digestibility.

Cyclamen mite is a nearly global pest of strawberry, inhabiting concealed spaces within folded leaves and flower buds emerging from plant crowns. It feeds on new plant tissue causing leaf discoloration and deformation, stunted plants, fruit bronzing and cracking, and yield losses at high population levels. Because ultraviolet-C (UV-C) irradiation is a promising new tool for disease and pest management in strawberry, and because there are few control options for cyclamen mite, we tested the direct, short-term effects of UV-C on cyclamen mite populations in potted strawberry plants in a controlled environment. Results from three experiments showed few differences in cyclamen mite populations on controls versus plants treated with UV-C (0.237 W m⁻¹) for 3 or 4 weeks. In the second experiment, using a different strawberry cultivar and directing the UV-C from above the plant crown only, there was indication of a mild effect that may be due to some direct mortality and/or indirectly to plant defenses. However, longer-term studies will need to be conducted to determine whether pre-infestation exposure to UV-C can enable strawberry plants to better resist or tolerate cyclamen mite populations. Direct mortality did not occur as in previous experiments with pests, like twospotted spider mite, that live primarily on opened leaves.

Multiple herbicide-resistant waterhemp (Amaranthus tuberculatus (Moq.) J.D. Sauer) has limited herbicide options for Iowa row crop production. Soybean (Glycine max (L.) Merr.) cultivars and corn (Zea mays L.) hybrids resistant to 2,4-D, dicamba, and glufosinate have provided more herbicide options for waterhemp management. A probability-based survey of Iowa fields was conducted in fall 2019 wherein waterhemp seeds were collected and their susceptibility to 2,4-D, dicamba, and glufosinate was determined. The average survival of all populations treated with 1× 2,4-D, dicamba, and glufosinate was 17%, 5%, and 4%, respectively. Seven percent of treated populations exhibited ≥50% survival to 1× rates of 2,4-D.

The OAC Union cultivar of soybean [Glycine max (L.) Merr.] is semi-determinate, has large seeds suitable for food-grade purposes, and offers high yield potential with elevated concentrations of seed protein and oil. Additionally, it displays resistance to soybean cyst nematode. OAC Union is developed and recommended for soybean-growing areas in southwestern Ontario with 2800 or greater crop heat units and has a relative maturity of 1.4.

OAC Stirling is a semi-determinate large-seeded food-grade soybean [Glycine max (L.) Merr.] cultivar with high yield potential, high seed protein concentration, and resistance to soybean cyst nematode. OAC Stirling is developed and recommended for soybean growing areas in southwestern Ontario with 3100 or greater crop heat units and has a relative maturity of 2.3.