Association of common bacterial blight (Xanthomonas axonopodis pv. phaseoli) epidemics with agro ecological factors in Southwestern Ethiopia

Common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli, is an economically important disease of common bean and causes significant yield losses in Ethiopia. A field survey was conducted to understand the spatial distribution, relative importance and association of common bacterial blight epidemics with agro-ecological factors in low and mid-land areas of Southwestern, Ethiopia, during the 2018-19 cropping season. A total 85 bean fields were assessed in four common bean growing districts. High diseases incidence and severity was recorded at Debub Ari (77.6 and 52.7%, respectively) while the lowest was from Male (38.5 and 28.0%, respectively). The associations between disease parameters and agro-ecological factors were analyzed using multiple logistic regression models. Agronomic practices including NPS fertilization, preceding crop, weed management and plant population had highly significant (P<0.0001) association with both disease incidence and severity. Also, altitude, seed source and cropping system significantly (P<0.05) influenced disease severity while cropping pattern showed significant (P<0.05) association with disease incidence in the reduced model. Higher mean disease severity (≥40%) had high probability of association with district, absence of NPS fertilization, poor weed management practice, and preceding crops, than their counter parts. Adequate NPS fertilization increases growth performance of the crop in turn decreases disease intensity, weed serve as alternate host for incoming inoculum and previous crops were source for inocula as well as crop rotation used as reduce inoculum load. Therefore, the present study showed that the disease is a major production constraint of common bean, and suggested proper nutrient and weed management practices, and crop rotation to reduce common bacterial blight in the study areas. Int. J. Agril. Res. Innov. Tech. 11(1): 74-83, June 2021

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Comparison of Seed Transmission and Survival of Xanthomonas axonopodis pv. phaseoli and Xanthomonas fuscans subsp. fuscans in Common Bean Seeds

Plant Health Progress ◽

10.1094/php-2013-0923-01-br ◽

2013 ◽

Vol 14 (1) ◽

pp. 41 ◽

Cited By ~ 1

Author(s):

Y. He ◽

G. P. Munkvold

Keyword(s):

Phaseolus Vulgaris ◽

Common Bean ◽

Bacterial Blight ◽

Disease Incidence ◽

Seed Transmission ◽

Common Bacterial Blight ◽

Phaseolus Vulgaris L ◽

Transmission Frequency ◽

Xanthomonas Axonopodis ◽

Seed Health

Xanthomonas axonopodis pv. phaseoli (Smith) Vauterin (Xap) and Xanthomonas fuscans subsp. fuscans Schaad et al. (Xff) cause indistinguishable symptoms known as common bacterial blight of bean (Phaseolus vulgaris L.). These results confirm a higher disease incidence and seed transmission frequency of Xff compared to Xap and reinforce the need for seed health tests that can differentiate the two species. Accepted for publication 21 August 2013. Published 23 September 2013.

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Mapping genetic factors affecting the reaction to Xanthomonas axonopodis pv. phaseoli in Phaseolus vulgaris L. under field conditions

Genome ◽

10.1139/g01-099 ◽

2001 ◽

Vol 44 (6) ◽

pp. 1046-1056 ◽

Cited By ~ 19

Author(s):

B Tar'an ◽

T E Michaels ◽

K P Pauls

Keyword(s):

Phaseolus Vulgaris ◽

Common Bean ◽

Length Polymorphism ◽

Bacterial Blight ◽

Genetic Factors ◽

Fragment Length Polymorphism ◽

Segregation Ratio ◽

Common Bacterial Blight ◽

Phaseolus Vulgaris L ◽

Xanthomonas Axonopodis

The objectives of the present study were to evaluate the field effects of Xanthomonas axonopodis pv. phaseoli (Xap), which causes common bacterial blight (CBB) on common bean (Phaseolus vulgaris L.), and to identify genetic factors for resistance to CBB using a linkage map constructed with random amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP), simple sequence repeat (SSR), and amplified fragment length polymorphism (AFLP) markers. One hundred and forty-two F2:4 lines, derived from a cross between 'OAC Seaforth' and 'OAC 95-4', and the parents were evaluated for their field reaction to CBB. In the inoculated plots, the reaction to CBB was negatively correlated with seed yield, days to maturity, plant height, hypocotyl diameter, pods per plant, and harvest index. A reduction in seed yield and its components was observed when disease-free and CBB-inoculated plots were compared. The broad-sense heritability estimate of the reaction to CBB was 0.74. The disease segregation ratio was not significantly different from the expected segregation ratio for a single locus in an F2 generation. The major gene for CBB resistance was localized on linkage group (LG) G5. A simple interval mapping procedure identified three genomic regions associated with the reaction to CBB. One quantitative trait loci (QTL), each on LG G2 (BNG71DraI), G3 (BNG21EcoRV), and G5 (PHVPVPK-1) explained 36.3%, 10.2%, and 42.2% of the phenotypic variation for the reaction to CBB, respectively. Together, these loci explained 68.4% of the phenotypic variation. The relative positions of these QTL on the core common bean map and their comparison with the previous QTL for CBB resistance are discussed.Key words: common bean, molecular markers, common bacterial blight.

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Application of Image Analysis in Studies of Quantitative Disease Resistance, Exemplified Using Common Bacterial Blight–Common Bean Pathosystem

Phytopathology ◽

10.1094/phyto-06-11-0175 ◽

2012 ◽

Vol 102 (4) ◽

pp. 434-442 ◽

Cited By ~ 17

Author(s):

Weilong Xie ◽

Kangfu Yu ◽

K. Peter Pauls ◽

Alireza Navabi

Keyword(s):

Image Analysis ◽

Common Bean ◽

Disease Severity ◽

Bacterial Blight ◽

Visual Assessment ◽

Common Bacterial Blight ◽

Genetic Studies ◽

Visual Scale ◽

Quantitative Genetic ◽

Visual Assessments

The effectiveness of image analysis (IA) compared with an ordinal visual scale, for quantitative measurement of disease severity, its application in quantitative genetic studies, and its effect on the estimates of genetic parameters were investigated. Studies were performed using eight backcross-derived families of common bean (Phaseolus vulgaris) (n = 172) segregating for the molecular marker SU91, known to be associated with a quantitative trait locus (QTL) for resistance to common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. fuscans subsp. fuscans. Even though both IA and visual assessments were highly repeatable, IA was more sensitive in detecting quantitative differences between bean genotypes. The CBB phenotypic difference between the two SU91 genotypic groups was consistently more than fivefold for IA assessments but generally only two- to threefold for visual assessments. Results suggest that the visual assessment results in overestimation of the effect of QTL in genetic studies. This may have been caused by lack of additivity and uneven intervals of the visual scale. Although visual assessment of disease severity is a useful tool for general selection in breeding programs, assessments using IA may be more suitable for phenotypic evaluations in quantitative genetic studies involving CBB resistance as well as other foliar diseases.

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