Developing genetic stock for yellow and brown rust resistance in Triticum aestivumL. viaImperata cylindrica-mediated doubled haploidy technique

In vitro haploid production followed by chromosome doubling greatly enhances the production of complete homozygous wheat lines in a single generation. This work aimed to develop wheat doubled haploid genetic stock resistant to yellow and brown rust via intergeneric hybridization with Imperata cylindricaand its further characterization. The wheat doubled haploid (DH) line was developed by crossing wheat F1(HS 542/China 84-40,022) with I. cylindrica. This DH-1 was tested against eight races of yellow (110S119, 110S247, 238S119, 78S84, 110S84, 111S68, Tand P) and eighteen races of brown rust (11,12-5, 12-7, 12A, 77, 77-1, 77-2, 77-5, 77-7, 77-8, 77-10, 77A-1, 104-2, 107-1, 108-1, 162-1, 77-9and 104-1) at seedling stage and with mix race of yellow and brown rust in adult plant stage (at Dhaulakuan, Bajaura and Shimla). At the seedling stage, DH-1 showed resistance to all the yellow and brown rust pathotypes except for 77-5race of brown rust. The adult plant response of this DH line also showed resistance to both yellow and brown rust. Based on host pathogen interaction, the DH-1 was postulated to carry leaf rust resistant genes Lr26+ Lr23+ 1 + and yellow rust resistant gene Yr9+ gene. Molecular characterization of the DH line with gene-specific primers showed that the developed DH-1 contains leaf rust resistance genes Lr34, Lr26and Lr32. The DH-1 has semi-spreading growth habit, erect flag leaf attitude, plant height of 94 cm, have scurs and 1000 grain weight of 36 g. The results highlight I. cylindrica-mediated chromosome elimination technique of doubled haploid production as an effective tool for the development of wheat rust resistant lines in the shortest timeframe. This is the first report of genetic stock development for rust resistance in wheat viaI. cylindrica-mediated DH technique.