Development of sequence-characterized amplified region (SCAR) markers for resistance gene Pc94 to crown rust in oat

Abstract

Crown rust, caused by Puccinia coronata f. sp. avenae, is an important disease of oat (Avena sativa). Pyramiding effective resistance from diverse sources is one strategy to provide more durable control of crown rust. The objective of this study was to develop a DNA marker for the resistance gene Pc94 to crown rust derived from the diploid oat Avena strigosa. Amplified fragment length polymorphism generated two DNA fragments that were associated with the resistance gene Pc94 in a F₂ population derived from a cross between the rust-susceptible oat 'Calibre' and a near-isogenic hexaploid oat line, S42, possessing Pc94. One of the fragments was successfully converted into two sequence-characterized amplified region (SCAR) markers linked to the Pc94 gene in the Calibre/S42 F₂ population. Specificity of the SCAR markers to the Pc94 gene was confirmed in three other populations. The estimated distance between the SCAR markers and Pc94 ranged from 0.9 to 3.4 centi-Morgan. These SCAR markers developed for the Pc94 gene will be valuable tools for pyramiding this gene with other resistance genes to crown rust in marker-assisted breeding programs when crown-rust races with the appropriate virulence combinations are not available to detect the genes being introgressed.

Keywords:

• oat crown rust
• resistance gene
• amplified fragment length polymorphism
• sequence-characterized amplified region
• DNA markers