Plant Disease (2008) 92, 247-252

Xiangming Xu, Jiarong Yang, Vijay Thakur, Anthony Roberts and Dez J. Barbara (2008)
Population variation of apple scab (Venturia inaequalis) isolates from Asia and Europe
Plant Disease 92 (2), 247-252
Abstract: Apple scab, caused by Venturia inaequalis, is one of the most of damaging diseases worldwide on apple and currently is managed mainly by scheduled applications of fungicides. Understanding pathogen population structure is important for breeding and deployment of resistant cultivars. Isolates of V. inaequalis were sampled from a number of cultivars in China, India, and the United Kingdom to estimate differences in pathogen populations. Amplified fragment length polymorphism (AFLP) markers were used to genotype isolates, mostly from China and the United Kingdom. The AFLP data indicated that, overall, there were significant differences in V. inaequalis populations from China and the United Kingdom. Within China, there was no significant differentiation associated with their geographical or cultivar origins. In contrast, populations from four cultivars in two U.K. orchards (monoculture of Gala and a mixture orchard of Bramley, Cox, and Worcester) differed significantly. Furthermore, populations from Gala and Worcester were more homogenous than expected but those from Cox were more diverse than expected. In total, 80 isolates were selected randomly from three countries for virulence testing: 20 from the United Kingdom (10 from Gala and 10 from Cox), 30 from China (10 from Gala, 10 from Fuji, and 10 from Qingquan), and 30 from India (10 from Gala, 10 from Golden Delicious, and 10 from Black Ben Davis); of these 80 isolates, 41, 47, and 59 were inoculated against each of these cultivars in the United Kingdom, India, and China, respectively. The two local cultivars from India (Black Ben Davis) and the United Kingdom (Cox) were more resistant against non-indigenous isolates, particularly those from China, than they were against indigenous isolates; the Chinese local cultivar (Qingguan) showed a higher general level of resistance against isolates regardless of their origin.
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Database assignments for author(s): Xiang Ming Xu

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Venturia inaequalis	Apple (Malus)	United Kingdom
	Venturia inaequalis	Apple (Malus)	India