Screening And Identification Of Progenies Derived From Hexaploid Triticale Resistant To Stripe Rust

Wheat stripe rust is a fungal disease caused by Puccinia striiformis West.f.sp.tritici Eriks.& Henn.,which seriously threatens the safety of wheat production.Innovating disease-resistant germplasms,cultivating and promoting new disease-resistant varieties are the safest,economical and effective measures to control wheat stripe rust.Rye(Secale cereale L.)has many excellent traits and is a valuable resource for genetic improvement of wheat.Introducing good genes from rye into wheat can broaden the genetic base of wheat and improve wheat productivity.Hexaploid triticale is a new species formed by the hybridization of tetraploid wheat and rye.It not only maintains the excellent traits of wheat,but also has the characteristics of rye resistance to diseases and stresses,high protein,and strong adaptability.It is easy to be crossed with common wheat and is an important bridge to transfer excellent genes of rye.Through hybridization of hexaploid triticale and common wheat,our laboratory had created a batch of new triticale germplasms with different traits and outstanding characteristics.In this study,based on the evaluation of disease resistance,the new germplasms derived from hexaploid triticale were comprehensively identified by means of morphology,cytogenetics,and molecular biology.and the following main results were obtained:1.Among the progenies(LCR series)derived from the hexaploid triticale CURRENCY,Sixteen wheat-rye translocation lines resistant to stripe rust were identified.(1)The results of GISH-FISH showed that the long arm of chromosome 2D or the short arm of chromosome 2A of this series of germplasms were translocated with the rye chromosome.Through the identification of specific molecular markers,it was confirmed that the alien segments originated from the long arm of 2R of rye.Among them,LCR3,LCR4,LCR11 and LCR16 were T2DS·2DL-2RL homozygous translocation lines,LCR1,LCR2,LCR5,LCR6,LCR7,LCR9,LCR10,LCR13,LCR14 and LCR15 were T2DS·2DL-2RL and T2RS-2AS ·2AL compound translocation lines.(2)Disease resistance identification and pedigree analysis found that all of LCR series exhibited excellent resistance to stripe rust.Among them LCR3,LCR4,LCR7,and LCR11 were immune.However,the common wheat parents were susceptible.So it was determined that the resistance to stripe rust was derived from rye 2RL,and this chromosome might contain a new generesistant to stripe rust.Moreover,the thousand-grain weight,plant height,tillering and other traits of LCR series were better than their parents Jimai 22,indicating that they were important new germplasms for genetic improvement of wheat.2.Seven new germplasms with excellent agrnomic traits were selected out from the progenies of the compound crosses between hexaploid triticale Shannong 18730 and common wheat.(1)The results of GISH-FISH identification showed that B21627-1 was a wheat-rye translocation line,B21627-3 was a wheat-rye disomic substitution line,and B21628-2-1,B21628-2-2 and B21628-3-1 were wheat-rye translocation lines.Combined with newly established molecular markers and published marker analysis,it was determined that B21627-3 was a 2R(2D)disomic substitution line;B21627-1 was a T2RS-2AS·2AL translocation line;B21627-4 was a T7AS·7AL-2RL and T1DS·1DL-2RL heterozygous translocation line;B21627-5 was a wheat-rye introgression line,and the alien genetic material came from rye 2R.(2)In the identification of stripe rust resistance at the seedling stage,B21627-1 and B21627-5 showed high resistance,and B21627-4 moderate resistance.The 1000-grain weight of B21628 series were higher than that of its parents Shannong 3050 and Shannong 474-1.The 1000-grain weight of B21627-1 was higher than that of its parents Shannong 3050 and Gaoyou 5218.The results provided new germplasms for development and utilization of excellent genes on 2R chromosome,which enriched wheat genetic resources.