New host resistances to Pseudocercosporella capsellae and implications for white leaf spot management in Brassicaceae crops

Gunasinghe, Niroshini and You, Ming Pei and Li, Xi Xiang and Banga, Surinder S. and Banga, Shashi K. and Barbetti, Martin J. (2016) New host resistances to Pseudocercosporella capsellae and implications for white leaf spot management in Brassicaceae crops. Crop Protection, 86. pp. 69-76. ISSN 0261-2194

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Abstract

Effective host resistance is the most cost-effective long term prospect for successful management of white leaf spot disease (Pseudocercosporella capsellae) in Brassicaceae. In two separate field trials, 168 genotypes were screened. In the first trial, lines of Brassica oleracea var. capitata (59), B. napus (34), B. juncea (6) and B. juncea containing wild weedy Brassicaceae introgression(s) (14) were arranged; and in the second, Australian historic and current B. napus (45) and B. juncea (10) varieties were screened. There was wide variation in expression of resistance, from complete resistance to highly susceptible as assessed by two disease parameters, viz. (i), Area Under Disease Progress Curve (AUDPC) for percent leaves diseased (values 0 - 221.2) and (ii) Percent Leaf Collapse Index (%LCI) values for leaf collapse due to disease (0 – 38.7). Brassica oleracea var. capitata was overall the most resistant species, while B. juncea the most susceptible with the majority having AUDPC values >75 and B. napus was intermediate. Five B. oleracea var. capitata genotypes were completely resistant, with 0 AUDPC and %LCI values. Pioneer® 45Y22 (RR) ‘Mystic’ and ‘Wahoo’ were also highly resistant, with the least %LCI (<3.7) and AUDPC (< 20) of the Australian B. napus varieties. In contrast, ‘Thunder TT’ (AUDPC -133.6; %CLI - 15.6) and ‘Carbine’ (AUDPC – 73.8; %CLI - 12.5) were the most susceptible lines in first and second trials, respectively. The particularly high susceptibility of newly released B. juncea varieties such as ‘Xceed OasisCL’ highlights the risk of significant losses in such susceptible varieties when deployed in areas with high degree pressure for white leaf spot disease. There was no association between AUDPC or % CLI with year of Australian varietal release, indicating that Australian breeding programs not made improvement for resistance to white leaf spot over the past two or more decades. Resistant varieties identified in this experiment can now not only be utilized in breeding programs to significantly improve overall crop resistance and management of white leaf spot disease, but also directly deployed to lower the severe inoculum load challenging current varieties.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Accepted version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: No Faculty
Date Deposited: 20 Mar 2017 04:59
Last Modified: 27 Feb 2018 06:22
Uncontrolled Keywords: Brassica; white leaf spot; Pseudocercosporella capsellae; resistance; oilseed rape; mustard; cabbage
Fields of Research : 07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
Socio-Economic Objective: D Environment > 96 Environment > 9604 Control of Pests, Diseases and Exotic Species > 960403 Control of Animal Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments
Identification Number or DOI: 10.1016/j.cropro.2016.04.014
URI: http://eprints.usq.edu.au/id/eprint/30729

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