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POSTULATION OF STRIPE RUST RESISTANT GENES IN SOME AUSTRALIAN BREAD WHEAT CULTIVARS AND THEIR RESPONSE TO TEMPERATURE

MAQSOOD QAMAR¹, S. DILNAWAZ AHMAD¹, ASAD HUSSAIN SHAH¹, COLIN R.WELLINGS² AND FARHAT BATOOL³

Abstract: Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is an important constraint to wheat production in cool environments. Six pathotypes (PST) were used to identify resistance genes in 27 Australian spring wheat (Triticum aestivum) cultivars. Postulation of resistance at seedling growth stage showed that most cultivars carried Yr17 alone or in combination with Yr7 and or other undesignated resistance genes. The cultivar H45 carried Yr7 Molecular markers were used to confirm the presence of stripe rust resistant gene Yr17 in these cultivars. The 252-bp  PCR product from primer VENTRIUP was observed in all Australian spring wheat cultivars tested and in positive check Avocet + Yr17 NIL. The molecular marker for Yr17 verified the results from rust testing. The effect of temperature on expression of resistance conferred by Yr17 was also confirmed. Seedlings that possess Yr17 expressed high levels of resistance under higher temperature (15-20^oC). Under lower temperature (12-15^oC) most cultivars possessing Yr17 showed compatible or near-compatible reactions to the pathotype 134 E16 A⁺ (avirulent to Yr17).

¹Department of plant Breeding and Molecular Genetics, Faculty of Agriculture, University of Azad Jammu & Kashmir, Rawalakot

²Plant Breeding Institute Cobbitty, PMB 11, University of Sydney, Australia.

³Department of Biochemistry, University of Karachi, Karachi-75270, Pakistan.

E-mail: batool@uok.edu.pk