Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap), is a serious foliar disease in most of the dry bean (Phaseolus vulgaris L.) growing regions. A 4 yr study examined the effects of different sources of infection and seed hydration on CBB development, yield components, and yield in seven resistant or susceptible dry bean lines and cultivars. The five agronomic treatments examined included clean seed, diseased seed, hydrated diseased seed, clean seed with a Xap spray, and diseased seed with a Xap spray. Disease development, the yield components, and yield were strongly influenced by weather conditions. In comparison with the diseased-seed treatment, the use of clean (disease-free) seed reduced the incidence of CBB leaf infection in the susceptible dry bean cultivars, but no similar benefit was observed in the resistant lines and cultivars. During the three dry growing seasons, the seed-hydration treatment increased the incidence of CBB leaf infection compared with the diseased-seed treatment for the susceptible cultivars but not for the resistant lines and cultivars. In the wet growing season, no significant difference in the incidence of leaf infection was observed between the hydrated-seed and diseased-seed treatments in any of the cultivars, possibly because the wet soil conditions promoted pathogen development within the bean plants that year. Seed hydration did not improve seed yield in the dry years, but sometimes decreased it under wet conditions. Therefore, seed hydration cannot be recommended for use in the production of dry beans.

Anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara, is one of the most destructive diseases of dry bean (Phaseolus vulgaris L.) in the world. Between 2005 and 2015, commercial fields of dry beans in Manitoba and Ontario were surveyed to determine the frequency of occurrence of races of the anthracnose fungus. Throughout the study, race 73 was most prevalent in Manitoba and Ontario. However, three anthracnose races not previously reported in Canada also were identified. These three new races and four previously identified anthracnose races were used to screen 52 dry bean cultivars, as well as a mung bean and azuki bean cultivar from Ontario, for their seedling reactions to determine their patterns of race resistance. The dry bean cultivars were classified into a total of 19 resistance spectra based on the pattern of seedling reactions to the seven anthracnose races. The most common resistance spectrum was susceptible to the majority of the anthracnose races and no cultivar was resistant to all of the races. Many bean cultivars produced intermediate anthracnose ratings to races 31 and 105 and tests of 16 dry bean cultivars against those races indicated that all cultivars with intermediate ratings to a specific race were segregating in their seedling reactions and none of the cultivars produced plants with only intermediate anthracnose severity ratings. This study provides new information on the anthracnose reactions of common bean cultivars in Canada, which should be useful for the development of new bean cultivars with durable resistance.

Anthracnose caused by the fungus Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib. has been a major constraint to dry bean (Phaseolus vulgaris L.) production in Manitoba and Ontario, as well as elsewhere in the world. There is a lack of consensus on the length of time the anthracnose fungus can survive on infected crop debris as well as the effectiveness of crop rotation to control the disease under temperate climatic conditions. A multi-year study was established at field sites near Morden, MB and Exeter, ON to examine the survival of C. lindemuthianum on seed, pod and stem tissue samples of infected beans on the soil surface and buried in the soil over different 2-year periods. The survival of the anthracnose fungus was influenced by location, type of infected tissue and burial in the soil. On average, C. lindemuthianum could persist for 18months at Morden and about 9 months at Exeter, which was long enough to serve as a source of primary infection to subsequent crops of dry beans. At both field sites, the anthracnose fungus overwintered longer on infected stems and pods than it did on infected bean seed. The burial of infected bean tissue reduced the viability of C. lindemuthianum in all tissue types compared with samples that remained on the soil surface. A 3-year crop rotation study at Morden in which either a wheat, fallow or bean treatment were grown in the second year, confirmed that the anthracnose fungus could survive long enough under zero-tillage conditions to infect a bean crop in the third year of the study and cause considerable downgrading of the seed. This study demonstrated the importance of tillage and crop rotation in the integrated control of bean anthracnose.

Boersma, J. G., Hou, A., Gillard, C. L., McRae, K. B. and Conner, R. L. 2015. Impact of common bacterial blight on the yield, seed weight and seed discoloration of different market classes of dry beans (Phaseolus vulgaris L.). Can. J. Plant Sci. 95: 703–710. Common bacterial blight (CBB) is a seed-borne disease of dry bean (Phaseolus vulgaris L.), causing significant economic loss to growers due to reductions in seed yield and quality and the need to annually purchase disease-free seed. Over the past decade a number of breeding lines and cultivars with resistance to CBB have been developed in several bean market classes including navy, black and cranberry beans. A comparison of three susceptible navy bean cultivars and seven resistant navy, three black and one cranberry bean entries in Manitoba revealed that most resistant navy and black bean lines had significantly reduced the incidence of leaf symptoms and their mean yield losses were reduced to less than 17%, while those of the susceptible lines were as high as 36% under severe disease pressure. Only the weakly resistant navy bean cultivar HR67 and the cranberry bean line F4GR1 failed to substantially reduce CBB symptoms or show a yield advantage. The Simple Sequence Repeat (SSR) marker PVctt001 in combination with Sequence Characterized Amplified Region (SCAR) marker SU91 was associated with a low incidence of CBB symptoms and a reduced yield loss in five navy bean lines, but not in the cranberry bean line F4GR1. Disease symptoms on the pods in the resistant black and navy beans and seed discoloration of navy beans caused by CBB were also significantly reduced by resistance. Seed weights were reduced by 2.1–4.7% in the susceptible cultivars, but there was only a slight or no decrease or no effect on the seed weight of the CBB-resistant lines and cultivars. Generally the magnitude of the reductions in yield was much greater than the impact on seed weight, which suggests that yield losses were caused by a combination of reduced seed weight and the number of seeds per plant.

Pratt timothy (Phleum pratense L.) is an 11-clone synthetic cultivar developed through progeny testing for general combining ability at Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, Charlottetown, Prince Edward Island. Pratt timothy was selected for winter hardiness, plant vigour, plant height, and intermediate maturity (similar to the check cultivar Climax but later than Champ). In Atlantic Canada, Pratt timothy produced more forage than Champ during 3 production years. This cultivar was superior in persistence and re-growth potential with greater production of second-cut herbage.

Conner, R. L., Hou, A., Balasubramanian, P., McLaren, D. L., Henriquez, M. A., Chang, K.-F. and McRae, K. B. 2014. Reaction of dry bean cultivars grown in western Canada to root rot inoculation. Can. J. Plant Sci. 94: 1219–1230. Root rot is an important disease of dry beans (Phaseolus vulgaris) that is caused by a complex of root pathogens. Cultural and fungicidal controls are available to reduce the adverse impact of this disease on seedling emergence, plant growth and yield, but none of these practices are highly effective. The development of disease-resistant dry bean cultivars is considered to be an important component of an integrated management system for root rot control. A 5-yr field study was conducted to identify potential sources of resistance to seedling blight and root rot in dry bean cultivars that are widely grown in western Canada. A total of 37 dry bean cultivars, representing all the bean classes grown in the region, were tested against the root rot pathogens Rhizoctonia solani, Fusarium solani, F. redolens and F. acuminatum. Partial root rot resistance was detected in the navy bean cultivar Navigator and the black bean cultivars Black Violet and CDC Jet. The greatest root rot resistance occurred in the cranberry bean cultivars Etna and Cran 09. Reductions in root rot severity were not consistently associated with greater seedling emergence, which indicates that resistance to seedling blight and root rot may be independent traits. Inoculation with R. solani had the most adverse effect on seedling emergence, while infection by F. solani f. sp. phaseoli resulted in the most severe root rot ratings.

Conner, R. L., Chang, K. F., Hwang, S. F., Warkentin, T. D. and McRae, K. B. 2013. Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot. Can. J. Plant Sci. 93: 473–482. Aphanomyces root rot, caused by Aphanomyces euteiches Drechs., is a serious disease of peas (Pisum sativum) that can severely reduce seed yield, and few effective control measures are available. The development of pea cultivars with tolerance or partial resistance to Aphanomyces root rot is generally considered to be one of the best options to reduce yield loss. A 4-yr field study was conducted at disease-free sites and at an Aphanomyces root rot site to compare the responses of cultivars and lines in the presence and absence of Aphanomyces root rot, identify breeding lines with tolerance and to evaluate the effects of tolerance on plant growth, disease severity and yield. At the Aphanomyces root rot site, a second test was established in which the phosphite fungicide Phostrol™ was applied as a soil drench treatment to the pea cultivars and lines. Aphanomyces root rot reduced seedling emergence, biomass production and yield in the susceptible pea genotypes. However, line 00-2067 consistently produced relatively high yields at all the field sites. At the Aphanomyces root rot site, yield was closely associated with plant vigour and shoot weight. Small, but significant, differences (P<0.05) in disease severity were observed between susceptible cultivars and tolerant lines indicating that the lines producing high yields at the Aphanomyces root rot site are tolerant rather than partially resistant. The root/shoot weight ratio was very low in the tolerant lines, indicating that even though their root systems were reduced and severely damaged by root rot, they were still able to produce high yields under favourable conditions for the disease. Drench application of the fungicide Phostrol™ did not significantly reduce root rot severity or improve the performance of any of the pea cultivars or lines.

Conner, R. L., Gossen, B. D., Hwang, S. F., Chang, K. F., McRae, K. B. and Penner, W. C. 2012. Field assessment of partial resistance to mycosphaerella blight in Pisum subspecies accessions. Can. J. Plant Sci. 92: 289–296. Mycosphaerella blight, caused by Mycosphaerella pinodes (Berk. & Bloxam) Vestergr., the teleomorph of Ascochyta pinodes Jones, is an important foliar disease of field pea in the major production areas of the world. Partial resistance to mycosphaerella blight has been reported in some field pea cultivars, but, at best, they are only moderately susceptible. A 3-yr field study was conducted to evaluate the mycosphaerella blight reactions of 28 accessions from a number of subspecies of Pisum sativum L. and one accession of P. fulvum Sibth. A few of the accessions carried mutations for the genes af, tl, and st that affect the morphology of the leaflets, stipules and tendrils. Reactions to mycosphaerella blight were characterized based on the mean of the severity ratings taken on the two final assessment dates before the crop matured and also on the change in mycosphaerella blight severity between these two dates. In many of the accessions, severity ratings were similar to that of the moderately susceptible check cultivar, CDC Peko, while a few had high severity ratings similar to those of the susceptible check cultivars. The accession PI 512079, which has small stipules, branched petioles with many leaflets but no tendrils, had the lowest ratings for mycosphaerella blight severity. Four other accessions exhibited the smallest change in mycosphaerella blight severity at the end of the growing season. Differences in leaf morphology likely influenced the change in disease severity, since all the semi-leafless and leafless accessions had smaller changes in mycosphaerella blight severity than the susceptible check cultivars. In a detached leaf assay with two isolates of Mycosphaerella pinodes (Berk. & Bloxam) Vestergr., the smallest lesions formed on PI 512079, but otherwise the results failed to show a relationship with the observed severity values in the field trials.

Papadopoulos, Y. A., McElroy, M. S., Fillmore, S. A. E., McRae, K. B., Duyinsveld, J. L. and Fredeen, A. H. 2012. Sward complexity and grass species composition affects the performance of grass-white clover pasture mixtures. Can. J. Plant Sci. 92: 1199–1205. The productivity of managed permanent pastures is closely associated with the species composition of seeded mixtures. Ecological theory suggests that increasing plant species' diversity will result in higher productivity, resilience, and resistance to invasive species. To better understand the relationship between sward species composition and pasture productivity, mixtures of four common pasture grass species, timothy (Phleum pratense L.), Kentucky bluegrass (Poa pratensis L.), reed canarygrass (Phalaris arundinacea L.), and meadow fescue (Festuca pratensis L.), were seeded in 2004 in binary (two-grass), tertiary (three-grass), and quaternary (four-grass) combinations with white clover (Trifolium repens L.). Plots were rotationally grazed for 5 yr, with yield determined in the first post-establishment year (2005) and in 3 subsequent production years (2007, 2008, and 2009). Mean dry matter yield (DMY) increased appreciably from post-establishment (3801 kg ha−1) to the production years (6613 kg ha−1). Contrasts revealed significantly higher DMY production in quaternary mixtures versus less complex plots in production years. Repeated measure analysis found significant quadratic trends in DMY for plots containing bluegrass and timothy, showing different patterns of growth between the respective mixtures. Principal component analysis (PCA) of averaged yields over the production years revealed a strong association between seeded grass growth and DMY. This relationship between DMY and seeded grass growth was strongest in swards containing a combination of timothy and bluegrass. In general, the growth of unseeded grasses and forbs increased in mixtures with large proportions of timothy and reed canarygrass. In spite of the fact that mixtures containing timothy and bluegrass were shown to produce high DMY, it appears the aggressiveness of bluegrass suppressed the yield potential of timothy. White clover yields and unseeded grasses/forbs were both significantly lower in mixtures containing bluegrass. Also, the PCA revealed a favourable compatibility between meadow fescue and white clover growth, while bluegrass appears to suppress meadow fescue growth. Results show that species complexity increases sward productivity over the long term, and that the presence of two grass species, in particular (timothy and bluegrass), has considerable influence on DMY.

This study evaluated the effects of pre-plant treatments: deep ripping (DR), fumigation (F), deep ripping plus fumigation (DRF), deep ripping plus hog manure compost (DRC), and deep ripping plus fumigation plus hog manure compost (DRFC) in comparison with a non-treated control (NTC) on shoot and root performance of 'Honeycrisp' apple trees on M.4 rootstocks in an old orchard site with apple replant disease (ARD). Cylindrocarpon spp., Pythium spp., and Pratylenchus penetrans Cobb, all potential agents of ARD, were present in the orchard soil. Fine-root numbers (1 to 2.9 mm diameter) were significantly greater in the DRC and DRFC treatments than the DR treatment. After 6 years, trunk cross-sectional area (TCSA) and yield were largest for the DRFC treatment followed closely by F. The DR treatment had no effect on TCSA, yield, or yield efficiency when applied alone compared with the NTC. Contrast analysis demonstrated that F was significantly better than non-F for yield in all years and TCSA and yield efficiency in 2007. Also, there was a significant interaction between DR and F treatment in 2005 that significantly reduced yield in the DRF treatment. Contrast analysis showed that compost had a significant positive effect on yield in all three production years and TCSA and yield efficiency in 2007. Yield efficiency in the third production year was largest for F, DRC, and the DRFC treatments. Nutrient analysis revealed that soil phosphorus concentrations in compost-treated plots were double those in other treatments. High phosphorus content of compost may have contributed to the amelioration of ARD symptoms. This study found that in 2007, soil fumigation alone, as conventionally used for ARD control, and composted hog manure were equally effective in increasing yield and yield efficiency of apple trees planted in an ARD soil. The DRFC treatment was the overall best treatment in all years.

PurposeThis paper aims to examine the effect of selected calcium salts on the colour, clarity and calcium content of fortified apple juice in extended storage.Design/methodology/approachApple juice was fortified with calcium lactate, calcium lactate gluconate, or anhydrous calcium gluconate and was processed along with an unfortified control juice. The bottled product was stored at 3 and 18°C for 30 weeks, and was assessed for calcium ion concentration, colour and haze. Consumer acceptance of the juices was confirmed using sensory evaluation.FindingsAnhydrous calcium gluconate and calcium lactate gluconate are easily dissolved in apple juice and are as acceptable to consumers as the unfortified control juice. All three calcium salts remain in solution in apple juice after 30 weeks of storage.Originality/valueThe paper shows that, unlike a number of commercially marketed, calcium‐fortified beverages, these calcium salts stayed in solution in apple juice during extended storage. The ease of dissolution of anhydrous calcium gluconate and calcium lactate gluconate make them excellent candidates for commercial processing; their incorporation should cause minimal disruption to existing apple juice production practices.

Cement kiln dust (CKD), a by-product of the cement industry currently being landfilled, may be a beneficial soil amendment. A 2-yr field forage trial compared the effect of surface applications of CKD and lime on forage yield and the concentration and accumulation of N, P, K, Ca, Mg, Mn, Cu, Zn and B in the forage tissue. Seven soil treatments in three blocks were established on three low pH sites: (1) a check plot with neither lime or CKD added; (2) lime application based on the recommendation from soil analysis; (3) lime at 1.5 times the recommended application; (4) CKD applied at the recommended application; (5) CKD at 1.5 times the recommended application; (6) CKD applied on a neutralizing equivalent basis at the recommended application rate; and (7) CKD on a neutralizing equivalent basis at 1.5 times the recommended lime application; equivalence based on CKD’s apparent neutralizing value at 75% that of lime. In 1998, as tissue concentrations of K, Ca, Cu, and Mn increased with CKD application, the concentrations of N, P and Mg decreased, and in 1999, as the concentrations of Ca, K increased, the concentrations of N, P, Mg Mn, Zn decreased. Lime application increased the concentration of Mg (1998) and Ca and Mg (1999). The concentration of the other nutrients either decreased or were not significantly affected. In1998, forage yield and accumulation of Ca, K, Mn, Cu, Zn and B all increased with CKD addition, whereas the accumulation of Mg increased with lime addition. In 1999, forage yield and accumulation of N, P, K, Ca, Cu, Zn and B in the forage tissue all increased with CKD addition. These results were identified by principal component analysis (PCA). Surface applied CKD increased forage yield to a greater extent than lime. It was also a more readily available source of Ca and K than lime.Key words: Cement kiln dust

Summary Fresh strawberries were evaluated through a commercial supply chain, from harvest to immediately prior to retail display. These samples were compared with controls that were refrigerated immediately after harvest and kept at a constant temperature for the same period of time. Temperature data were collected throughout all stages of the supply chain. Moisture and vitamin C (ascorbic acid) contents were determined at selected points of the supply chain using recognised methodology. Significant differences were found in the vitamin C concentrations of fresh strawberries at various stages of the supply chain but not in their moisture content. The ascorbic acid concentration decreased with time spent in the supply chain in all trials but the absolute vitamin C content differed from trial to trial. This result indicates that both pre‐ and post‐harvest factors influence the vitamin C content of fresh strawberries available to consumers on the retail market.

Anthracnose, caused by the seedborne pathogen Colletotrichum lindemuthianum, is a serious disease of dry bean (Phaseolus vulgaris) that can severely reduce seed yield and quality. A 2 year field study examined how seedborne infection (0%, 1%, 2%, 5%, 10%, and 20%) affected seedling emergence, seedling infection, the buildup of anthracnose in the crop canopy, yield, seed mass, and seed discolouration in ‘Navigator’ navy bean and ‘AC Ole’ pinto bean. The incidence of seedling infection was significantly higher in ‘AC Ole’ than it was in ‘Navigator’ resulting in an early establishment of the disease on the pinto bean cultivar. There was a linear increase (P < 0.01) in anthracnose severity within the crop canopy and on the pods with higher rates of seedborne infection in both cultivars. Increases in seedborne infection rates also resulted in a significant decline (P < 0.01) in yield and seed mass. Comparisons of the 0% and the 20% seedborne treatments indicated that severe anthracnose development resulted in yield losses of 27% in ‘Navigator’ and 20% in ‘AC Ole’. These losses are comparable with the extent of yield reductions reported in a previous fungicidal study on anthracnose control in Manitoba. Key words: anthracnose, Colletotrichum lindemuthianum, dry beans, Phaseolus vulgaris, seed transmission. L’anthracnose, causée l’agent pathogène séminicole Colletotrichum lindemuthianum, est une maladie importante des haricots secs qui peut sérieusement en réduire les rendements et la qualité. Une étude sur le terrain, qui s’est échelonnée sur deux ans, a permis d’examiner comment l’infection séminicole (0 %, 1 %, 2 %, 5 %, 10 % et 20 %) influençait l’émergence et l’infection des semis, la prolifération de l’anthracnose sur le feuillage des plants ainsi que le rendement, le poids et la décoloration des semences chez le cultivar de petit haricot blanc ‘Navigator’ et chez celui de haricot pinto ‘AC Ole’. L’incidence de l’infection des semis chez le cultivar ‘AC Ole’ était significativement plus élevée que chez ‘Navigator’, ce qui provoquait la survenue hâtive de la maladie chez le haricot pinto. Il y avait une augmentation linéaire (P < 0,01) quant à la gravité de l’anthracnose sur le feuillage ainsi que sur les cosses affichant des taux plus élevés d’infection séminicole, et ce, chez les deux cultivars. Des augmentations des taux d’infection séminicole entraînent également une baisse significative (P < 0,01) des rendements et du poids des semences. Des comparaisons des traitements séminicoles (0 % et 20 %) ont indiqué que la prolifération massive de l’anthracnose provoquait des baisses de rendement de 27 % chez ‘Navigator’ et de 20 % chez ‘AC Ole’. Ces baisses sont comparables à celles rapportées dans une étude précédente effectuée sur les fongicides et ayant pour but la lutte contre l’anthracnose au Manitoba. Mots-clés : anthracnose, Colletotrichum lindemuthianum, haricots secs, Phaseolus vulgaris, transmission par semence.

Highbush blueberries, cv 'Burlington', were treated with 22, 45, 50, or 60 degrees C water for 15 or 30 s along with an untreated control. Fruit were then stored for 0, 1, 2, or 4 wk at 0 degrees C and 2 or 9 d at 20 degrees C prior to evaluation of microbial population and fruit quality. After 4 wk of storage, the hot water treatment at 60 degrees C resulted in 92% marketable berries, followed by 90% at 50 degrees C, 88% at 45 degrees C, and 83% at 22 degrees C compared with 76% in untreated controls. Decay incidence was reduced to 0.6%, 1.2%, 1.4%, or 2.8% with 60, 50, 45, or 22 degrees C water treatments, respectively, compared with 5.1% in controls following 4 wk at 0 degrees C and 2 d at 20 degrees C. After an additional 7 d at 20 degrees C, decay in fruit treated at 60 degrees C for 15 or 30 s remained at 1.8% and 0.4%, respectively, compared to 37.4% in controls. Weight loss of berries treated with hot water was 0.4% against 3.8% in controls, and shriveled and split berries were also reduced compared to controls (P < 0.001). Aerobic plate count and yeast and mold count were reduced by 0.45 to 0.7 log at 60 degrees C for 30 s. Botrytis cinerea and Colletotrichum sp. were the dominant fungal pathogens causing decay of Burlington blueberries during storage. Hot water treatments also immediately induced an increase in ethanol and reduced fruit titratable acidity and soluble solids content, but had no significant effect on fruit firmness, pH, or most flavor volatile concentrations.

Bruce birdsfoot trefoil (Lotus corniculatus L.) is a 71-clone synthetic variety developed at the Nappan Research Farm, Agriculture and Agri-Food Canada, Nappan, Nova Scotia. Bruce was developed through two cycles of mass selection for plant vigour (top and root growth) and winterhardiness, and one cycle of mass selection for re-growth vigour under grazing. In Atlantic Canada, Bruce produced more forage than the check cultivar Leo during 3 post-seeding years. It was also superior in spring growth with high first-cut herbage yields. Key words: Birdsfoot trefoil, Lotus corniculatus, cultivar description

The effect of burn-pruning on the flora in a natural stand of lowbush b lueberry was studied over a 24-yr period in Newfoundland and Labrador, Canada. Treatments were: not burned and burn-pruned every 2nd, 3rd, or 4th year. A vegetative survey was conducted before burning and periodically in succeeding years. Following statistical analyses, species were grouped according to their response to burning, as follows: those not significantly affected; those eliminated or whose frequency of occurrence was reduced; and those whose occurrence was increased. Initially, burning virtually eliminated Juniperus communis var. depressa, Empetrum nigrum, Cladina rangiferina, Lycopodium clavatum and Pleurozium schreberi, reduced the frequency of occurrence of nine species by 6 to 69%, and increased 13 others by 1 to 2050%. With burning, Polytrichum commune and Fragaria virginiana ssp. glauca, in particular, increased very early in the study to become two of the most prevalent species. Also, except for some initial effects of burning, the lowbush blueberry and some initially prevalent species (Festuca filiformis, Maianthemum canadense, Danthonia spicata, Cornus canadensis and Luzula multiflora var. acadiensis) remained among the most dominant species. Of the species studied, only seven each of those increased or decreased by burning were affected by the burn-pruning cycle. In both groups, the greatest increases or decreases in the frequency of occurrence were obtained with the 2-yr burn-pruning cycle. Key words: Lowbush blueberry, Vaccinium angustifolium, burning, pruning, plant succession, weeds, fire, flora