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Oral: Host Plant Resistance


Speeding up the discovery of novel sources of leaf rust resistance in wheat
A. RIAZ (1), N. Athiyannan (2), S. Periyannan (3), O. Afanasenko (4), O. Mitrofanova (5), E. Aitken (6), E. Lagudah (3), L. Hickey (2) (1) The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, St Lucia, QLD 4072, Australia

Leaf rust (LR) caused by Puccinia triticina, is among the most important diseases of wheat (Triticum aestivum L.) crops globally. Deployment of cultivars incorporating genetic resistance, particularly the combination of adult plant resistance (APR) and all stage resistance (ASR), is considered to be the most effective and sustainable method to control rust pathogen. While scoring of ASR in the glasshouse is straight forward, identification of APR in the field is often challenging due to varying micro environments. To overcome this, here we report a novel screening procedure that involves application of a rapid phenotyping method performed under accelerated growth conditions (AGC; i.e. constant light and controlled temperature) and effective elimination of known APR genes using linked DNA markers. Using this approach, screening of 300 diverse wheat accessions from the N. I. Vavilov Institute of Plant Genetic Resources (VIR) identified a set of 50 wheat accessions as potential sources for new APR to LR. In the subsequent screening of the subset under field conditions, 13 accessions consistently displayed good levels of APR. Further, in the DNA marker screening of the 300 accessions, 88 were identified to carry known APR genes (Lr34, Lr46 and Lr67). Interestingly, accessions carrying Lr67 were mostly landraces from India and Pakistan, consistent with previous reports about the likely origin of this APR gene. This can accelerate discovery of new sources of resistance.