QTL Mapping for Adult Plant Resistance to Stripe Rust in Wheat line "Guixie 3"

Abstract Development of cultivars with multiple resistances has proven to be an effective way to prevent diseases in wheat breeding. The Guixie 3 variety (GX3) has shown excellent performance in resistance to stripe rust in field for many years. The purpose of this study was to detect quantitative trait loci (QTL) associated with resistance to stripe rust in the adult plant stage and determine closely linked molecular markers. A population of recombinant inbred lines (n=228) was derived from a cross between the susceptible landrace Mian 96-5 (M96-5) and GX3 variety and evaluated in multiple field studies to elucidate genetic resistance by identifying QTL specifically for stripe rust resistance. A total of 19 QTL located on 12 chromosomes showed resistance to wheat stripe rust when studying phenotypic data from multiple field tests over the course of six years. These chromosomes included 1B (2), 1D (2), 2A (2), 2B (2), 2D (1), 4B (2), 4D (1), 5A (3), 5B (1), 6A (1), 6B (1), and 7B (1). Two stable QTL on chromosomes 2AS (Qyr.gaas.2AS) and 6AS (Qyr.gaas.6AS) were detected in six and five different environments, respectively; both QTL were derived from the GX3 variety. Qyr.gaas.2AS was found to be crucial for increasing adult plant resistance, which may explain the large phenotypic variation of 45.52%. Our results provide theoretical and molecular insight for wheat breeding and suggest the cloning of genes associated with the GX3 variety may be beneficial in future studies.