Characterization of a New Race of Exserohilum turcicum Virulent on Corn with Resistance Gene HtN

Thakur, R P and Leonard, K J and Jones, R K (1989) Characterization of a New Race of Exserohilum turcicum Virulent on Corn with Resistance Gene HtN. Plant Disease, 73 (2). pp. 151-155. ISSN 0191-2917

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Isolates of a new race of Exserohilum turcicum collected from South Texas in 1986 were compared with isolates of race 1 and race 3 in inoculations of seedlings of corn inbred B37 and B37 backcross lines with Ht2, Ht3, and HtN in controlled environment chambers. The new race resembled race 3 except for its virulence on B37 HtN. Race 3 has the virulence formula Ht1, HtN /Ht2, Ht3. The new race is described as race 4 with the virulence formula Ht1/Ht2, Ht3, HtN. Both race 3 and race 4 were virulent on B37Ht3 at 22 C day/18 C night temperatures but were avirulent at 26 C day/22 C night. Leaf disks were cut from lesions of races 3 and 4 on plants grown under different light and temperature conditions and incubated in moist chambers in the laboratory to compare treatment effects on sporulation. For plants grown under full light (647 ?E·m-2·s-1) at 22 C day/18 C night temperatures or 26 C day/22 C night, sporulation was greater on B37 than on B37Ht3 or B37HtN. In lesions from plants grown at reduced light intensity, sporulation on B37 was significantly decreased, but sporulation by races 3 and 4 on B37Ht3 and by race 4 on B37HtN was significantly increased. The resistance of B37Ht2 to race 1 broke down at low light intensity

Item Type: Article
Uncontrolled Keywords: Maize, Northern leaf blight, setosphaeria, Zea mayes
Subjects: Others > Genetics and Genomics
Depositing User: Mr B K Murthy
Date Deposited: 09 Jun 2014 04:07
Last Modified: 09 Jun 2014 04:07
Official URL:
Acknowledgement: UNSPECIFIED
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