Resistance Of Wheat-wheatgrass No.33 To Wheat Leaf Rust And Its SSR, TRAP Analysis

Wheat leaf rust is an important disease in wheat production,screening and breeding for resistance cultivars are considered to be the most economical,environmental and effective appropriate strategy to reduce damages due to this disease.Therefore,it is an important basis for utilizing the resistance cultivars,and is very reasonably to make clear the constitutes and genetic characteristics of the resistance genes in demestic wheat cultivars and important germplasm.Wheat-wheatgrass No.33 was a germplasm which bred by Northeast Normal University and Jilin Academy of Agricultural Sciences,and derived from 468-6-7 hybriding with Xinshuguang No.1 wheat through the technique of alien addition lines.In 1995,Wheat-wheatgrass No.33 was examined and approved and began to spread.Now,this wheat variety has been grown in many provinces.It was a variety of high-yield,high protein,and multi-resistance to diseases,and play a very important role in wheat breeding and production practice.In this paper,the investigation of resistance to wheat leaf rust of the wheat cultivar Wheat-wheatgrass No.33 was carded out through temperature-sensitive resistance genes postulation,resistance genes of adult postulation, the genetic analysis of resistance,Meanwhile,Marker-assisted Selection,Single Sequence Repeated(or Microsatellite)technique and Target Region Amplified Polymorphism(or TRAP)technique were emploied to located the resistance genes in Wheat-wheatgrass No.33.The main results were as follows:1.Four physiological races of Puccinia triticina were used to postulate temperature-sensitive resistance genes in wheat cultivar Wheat-wheatgrass No.33 by comparison with the infection types of the seven near isogenic lines containing known temperature-sensitive Lr gene.The results showed that Lr18 and other new temperature-sensitive resistance genes might be existed in Wheat-wheatgrass No.33.The result also demonstrated that the temperatre-sensitive resistance is race specific character.2.Adult resistance genes against wheat leaf rust were detected by comparing the infection types on nine Near-isogenic Lines of wheat against wheat leaf rust in Thatcher background and Wheat-wheatgrass No.33 induced by 13 Puccinia triticina races which were previously characterized of avirulent or virulent gene combination postulated result showed that resistance genes such as Lr12,Lr13,Lr14a,Lr14b,Lr22a,Lr22b,Lr34,Lr35 and Lr37 were not present in Wheat-wheatgrass No.33,and another adult resistance genes and unknown resistance gene might exist in Wheat-wheatgrass No.33 at adult stage.3.Thirty-three F₃ families(Wheat-wheatgrass No.33 crossed with the susceptible wheat 'Thatcher')were tested for analysis of wheat leaf rust resistance at seeding stage with specific Puccinia triticina isolate 04-5-32I(Prt code KHDN).The genetic analysis results showed that the resistance of Wheat-wheatgrass No.33 was controlled by one pairs of dominant.4.Microsatellite technique was used to mark the wheat leaf rust resisting genes in Wheat-wheatgrass No.33.Puccinia triticina race of 01-5-X-15A was used to score the resistance in F₃ generation.DNA samples extracted from the F₂ individuals were pooled into two separate groups for Bulked Segregant Analysis(BSA)to identify the molecular markers linked to the resistant genes.406 primer pairs on 21 chromosome of wheat were tested.and one SSR markers wmc474 located on 2B chromosome of wheat generated adout 110bp specific band between the resistant pool and the susceptible ones.The marker closely unliked to resistance gene trait was obtained,and with genetic distance 38cM.It indicated that a deduced unknown resistance gene in Wheat-wheatgrass No.33.and located on 2B.5.TRAP technique was also used to marker in Wheat-wheatgrass No.33.One pair (em8-fix1)of 143 primer pairs,displayed polymorphism in the population of Wheat-wheatgrass No.33,and generated a 438bp band.Pavon76 and fifty near-isogenic lines were tested with the specific primer pairs and found that the same band as in Wheat-wheatgrass No.33 was also present in TcLr3 and Pavon76.The sequenceing results demonstrated the band generated by em8-fix1 in Wheat-wheatgrass No.33 was same as that in TcLr3 and Pavon76.This suggested that a part sequence in TcLr3,and Pavon76 might be contained in Wheat-wheatgrass No.33.6.A series of optimized systems and programmes were established,which were suitable for marking wheat leaf resistance genes with good stability and repeatability. Marker-assisted Selection for leaf rust resistance in Wheat-wheatgrass No.33 was approached by using above STS or SCAR markers,PCR amplification results showed that Wheat-wheatgrass No.33 did not contain Lr1,Lr28,Lr41,however,deduced possessing Lr34.This experiment concluded that the Wheat-wheatgrass No.33 was a cultivar which possessing multiple leaf rust resistance genes especially adult resistance genes.As an important resistsnce cultivar,it can undoubtedly be used as an important breeding materials to prevent the extension varieties from losing disease resisitance.