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Title: FIRST REPORT OF RUST ON SAFFLOWER IN OMAN

Author
item DEADMAN, M. - SULTANATE OF OMAN
item AL SAADI, A. - SULTANATE OF OMAN
item AL JOHDAMI, S. - SULTANATE OF OMAN
item Aime, Mary

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2004
Publication Date: 2/1/2005
Citation: Deadman, M.L., Al Saadi, A.M., Al Johdami, S., Aime, M.C. 2004. First report of rust on safflower in Oman. Plant Disease 89:208.

Interpretive Summary: Rust fungi cause diseases on a wide range of crop plants and trees throughout the world. Accurate knowledge about the distribution of these fungi is important for preventing the spread of the diseases they cause. In addition, as crop plants are grown in new places, it is essential to determine if the diseases are also present. In this research a rust fungus that occurs on safflower is newly detected in the Sultanate of Oman. Although known in Egypt and Iran, this rust on safflower has never before been reported from this country. Because the Middle East is the center of diversity for safflower, plant germplasm from Oman will be screened to determine variability in response to rust infection. This research will be used by plant quarantine officials and plant pathologiststo determine the spread of and resistance to the disease caused by this rust on safflower.

Technical Abstract: Safflower (Carthamus tinctorius L.) is a minor, but culturally important crop in Oman. Although the crop is not grown commercially in Oman, the Middle East region is recognized as a center of diversity for safflower (1). The production of oil from safflower has potential in Oman where the crop is very productive. Recently, samples have been collected showing typical symptoms of rust disease, subsequently identified as Puccinia carthami Corda. A voucher specimen has been deposited in the U.S. National Fungus Collections, BPI863557; a voucher sequence of the nLSU ribosomal DNA has been deposited in GenBank AY787782. Numerous chestnut brown pustules covered both sides of the leaf surface and yielded typical urediospores and teliospores of the pathogen, the teliospores being produced most abundantly towards the end of the growing season. Urediospores are globose, measuring 25'm in diameter on average. Two-celled teliospores are chestnut-brown, minutely verrucose, with a single, depressed germ pore in each cell. Thus far, only the leaves of affected plants showed rust pustules. Given also the diversity of safflower in Oman a germplasm collection programme has been initiated and this will be screened to determine the variability in response to rust infection. Some previous authors have considered P. carthami as conspecific with other rusts that infect various members of the Cardueae, such as P. calcitrapae var. centaureae (DC.) Cummins; however we consider these to be separate species.