Testing Wheat Seedlings for Resistance to Crown Rot Caused by Fusarium graminearum Group 1. G. B. WILDERMUTH, Principal Plant Pathologist, Queensland Wheat Research Institute, P.O. Box 2282, Toowoomba 4350, Australia. R. B. McNAMARA, District Experimentalist, Queensland Wheat Research Institute, P.O. Box 2282, Toowoomba 4350, Australia. Plant Dis. 78:949-953. Accepted for publication 6 June 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0949.

Resistance to crown rot of wheat caused by Fusarium graminearum Group 1 is currently measured in mature plants that have been grown in inoculated soil in the field. This technique is laborious and time-consuming, and a faster technique is desired. Seedlings of different cultivars of wheat were grown in steam-air treated soil inoculated with a band of wheat-barley grain colonized by F. graminearum. Plants were grown at 13, 19, and 25°C; and after 22 days the sheaths of leaves 1, 2, and 3 were rated for the extent of necrotic lesions. At each temperature, this rating was positively correlated with disease ratings of the same cultivars grown in the field. At 25°C, the correlation coefficient between seedling and mature plant ratings of 28 cultivars was 0.78 {P ≤ 0.01). This close relationship gives confidence that seedlings can be used to measure resistance to crown rot. Use of seedlings will speed the selection of resistant progeny in wheat breeding programs where resistance to crown rot is an objective.

Keyword(s): field test, leaf sheaths, seedling test, soilborne disease, wheat cultivars