Development Of Molecular Markers Linked To The Stripe Rust Resistance Gene YrC591 In Wheat And Application Of Molecular Markers In Wheat Breeding For Resistance To Stripe Rust

Stripe rust (yellow rust), caused by Puccinia striformis f. sp. tritici West., is one of the most important diseases on wheat in all the wheat- growing areas in the world, especially in China. Utilization of resistant cultivars is the most economic, effective and environment-sound way to control the disease. However, rapid reakdown of disease resistance resulted from the use of one or very few simple genes in a large area and then the disease prevailing is the problem puzzled breeders and phytopathologist for many years. Molecular markers linked to resistance gene can be very helpful to solve the problem. The wheat cultivar C591, introduced from India, is resistant to almost all the races of stripe rust in China at present. In this article the bulked segregation analysis (BSA) was used to develop the molecular makers linked to the resistance gene YrC59] in the cultivar. At first, the reaction mix components and RAPD program were optimized. The PCR mix in 25 ii 1 included: template DNA 1 5ng, dNTPs 150 i-i M, MgC12 2mM; Taq DNA Polymerase 1U, random primer 0.4 i-i M. The temperature profile was: 94C5min; then 940C 30secs, 360C 1mm, 0.30C/sec to 560C, 720C 2mm, for 36cycles; at last 720C 7mm. Resistant DNA pool and susceptible DNA pooi were made up respectively from 88 resistant F2 plants and 79 susceptible F2 plants derived from a cross between the susceptible cultivar ingxian 169 and the cultivar 59 1 A total of 544 10-mer random primers had been used to identify the RAPD markers linked to YrC59J gene. One out of three polymorphic DNA fragments, i. e. OPAN-19616 amplified by the primer OPAN- 19, was found closely linked to the gene YrC591. According to the sequences of the DNA fragment OPAN- 1 6I6, a pair of specific primers was designed. By using the specific primers the YrC591 gene can be detected effectively in wheat breeding materials. Development of the SCAR marker for YrC591 gene will promote the use of the resistance gene in wheat breeding for resistance to stripe rust. Combined artificial inoculation and using the SCAR markers linked to Yr8 and YrlO respectively, some plants with Yr8 and YrlO genes or Yr8 and YrC59I genes were gained from the F2 and F3 segregating population of CP93-6-19 X Compair, CP93-17-30 X Compair and CP93- 17-31 X Compair. The results showed that the markers and the technique were usable and reliable.