New Zealand Journal of Crop and Horticultural Science abstracts

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Promising genetic resources for resistance to powdery mildew in chestnut rose (Rosa roxburghii) and its relatives in China

X. Wen

National Key Laboratory of Crop Genetic Improvement
Huazhong Agricultural University
Wuhan 430070, People’s Republic of China
Guizhou Key Laboratory of Agricultural Bioengineering
Guizhou University
Guiyang 550025, People’s Republic of China

Q. Xu
Q. Cao
X. Deng

National Key Laboratory of Crop Genetic Improvement
Huazhong Agricultural University
Wuhan 430070, People’s Republic of China
email: xxdeng@mail.hzau.edu.cn

Abstract Chestnut rose (Rosa roxburghii) shows promising prospects both in fruit exploitation and ornamental plant genetic improvement. Powdery mildew is the most destructive fungal disease of this species and its relatives. The infection date, disease duration, peak disease indexes (PDI), and area under the disease progress curve (AUDPC) values were used to rate the resistance to powdery mildew disease in seven genotypes of chestnut rose and their eight relatives. R. sterilis, R. kweichonensis, R. laevigata, R. lucidissima, and R. chinensis were free from powdery mildew, whereas R. multiflora var. multiflora and R. multiflora var. cathayensis were the most susceptible to this disease. Of the genotypes from R. roxburghii, ‘Guinong No. 6’ exhibited a significantly high level of resistance with striking brown necrotic lesions in its leaves, whereas ‘Guinong No. 5’ and ‘Guinong No. 2’ showed the most susceptibility. The resistance ratings identified by AUDPC were significantly correlated with those characterised by PDI. Therefore, it is suggested that the latter is used in the resistance ratings because of its simplicity.

Keywords powdery mildew; relatives; resistance; chestnut rose; Rosa roxburghii

New Zealand Journal of Crop and Horticultural Science, 2006, Vol. 34: 183–188
0014–0671/06/3402–0183      © The Royal Society of New Zealand 2006
H05105; Online publication date 27 April 2006. Received 9 September 2005; accepted 18 January 2006

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