. 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: 703Á710. 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 2.1Á4.7% 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. 'une diminution du rendement et d'une de´te´rioration de la qualite´des graines, ensuite, de la ne´cessite´d'acheter chaque anne´e des semences indemnes de la maladie. Au cours des dix dernie`res anne´es, plusieurs ligne´es ge´ne´alogiques et cultivars re´sistants a`la bruˆlure bacte´rienne ont vu le jour dans diverses classes marchandes, y compris celles du petit haricot rond blanc, du haricot noir et du haricot canneberge. La comparaison de trois cultivars sensibles de petit haricot rond blanc a`sept varie´te´s re´sistantes, et at rois cultivars re´sistants de haricot noir ainsi qu'a`un autre de haricot canneberge au Manitoba re´ve`le que la plupart des ligne´es re´sistantes de petit haricot rond blanc et de haricot noir pre´sentent des symptoˆmes foliaires nettement moins e´tendus et une baisse de rendement moyenne infe´rieure a`17 %, alors que la diminution du rendement peut atteindre jusqu'a`36 % chez les ligne´es sensibles, quand la pression de la maladie se fait e´leve´e. Seuls le cultivar de petit haricot rond blanc peu re´sistant HR67 et la ligne´e d...

Boersma, J. G., Conner, R. L., Balasubramanian, P. M., Navabi, A., Yu, K. and Hou, A. 2014. Combining resistance to common bacterial blight, anthracnose, and bean common mosaic virus into Manitoba-adapted dry bean (Phaseolus vulgaris L.) cultivars. Can. J. Plant Sci. 94: 405–415. Resistance to common bacterial blight (CBB) is generally absent in dry bean cultivars. In order to transfer CBB resistance into dry bean cultivars grown in Manitoba, crosses were made between CBB-resistant navy bean OAC Rex and susceptible cultivars Black Violet (black bean), AC Pintoba (pinto bean) and Morden003 (an anthracnose-resistant navy bean). The F1 progeny were back-crossed to the recurrent susceptible parents for four generations and selections were made based on inoculation tests and molecular markers. The BC4F3 populations were evaluated in CBB field disease nurseries for 3 yr at Morden, MB, and Harrow, ON. Three of the 114 BC4F3 navy bean lines were shown to have improved resistance to both CBB and anthracnose, whereas approximately 50% of the lines exhibited strong resistance to anthracnose. Meanwhile, 11 black bean and 7 pinto bean lines were selected with resistance to CBB and four of the seven pinto beans were also putatively resistant to bean common mosaic virus (BCMV). There was good agreement between the presence of molecular markers and field resistance to CBB and anthracnose. The resistant lines recovered in this research possess desirable yield potential and seed characteristics, and can be used in crossing for future dry bean improvement.