Oral Presentation Australasian Plant Pathology Society Conference 2025

Development of a robust glasshouse phenotyping methodology to screen common root rot in wheat and barley (119968)

Akhila Dendi 1 , Cassandra Percy 1 , Anke Martin 1
  1. UniSQ, -, Australia

Common root rot is a soil and seed borne disease caused by the hemi biotrophic fungus Bipolaris sorokiniana. It causes dark brown lesions on the outer coleoptile tissue, sub crown internodes and the leaf base. Common root rot has been reported to occur in 39.0% of wheat and 50.5% of barley growing areas of Australia. Although it is estimated to cause an average annual loss of around A$100 million in wheat and barley in Australia, the disease often goes undiagnosed due to a lack of specific above ground symptoms. There is a need to develop resistant and tolerant wheat and barley varieties for managing the yield losses caused by common root rot. To achieve this a standardised inoculation and screening methodology is required. The purpose of this study was to investigate the ability of previously published glasshouse methods, which differ in inoculum type and placement, growth medium and incubation conditions, to induce common root rot. Seven methods were tested including a colonised grain inoculation method, mixing a spore suspension with soil, two seed coat methods using fully grown fungal plates and a spore suspension, a spore suspension root dip method, a sandwich paper method and a test tube method. All methods were assessed compared based on the variation in disease response across different genotypes which range in susceptibility to the pathogen, establishment of strong disease expression in susceptible varieties, ease of method, time and labour required, scalability of the method, germination success and space and maintenance requirements. Preliminary results indicate that mixing soil with a spore suspension was the easiest and most efficient method for screening wheat and barley genotypes for common root rot. The standardised methodologies reported in this research will be important for pathogenicity and virulence testing, testing environmental variables or pathogen interactions and screening of breeding germplasm and varieties against the common root rot pathogen in the future