| Thinopyrum intermedium(2n=6x=42,JJJSJSStSt),is one of the perennial species related to wheat(Triticum aestivum L.),which is resistant to stripe rust,leaf rust,stem rust,powdery mildew and Fusarium head blight,and has a high tolerance of cold,salt,drought and other stress,with rich genetic diversity.Th.intermedium ssp.trichophorum(2n=6x=42,JJJSJSStSt)is a subspecies of Th.intermedium,its leaves and heads are covered by pubescence.As well as Th.intermedium,it has good resistance to disease and stress,and is a valuable resource for improving wheat through distant hybridization.TE-3,a wheat-Th.intermedium ssp.trichophorum partial amphiploid,was bred by our laboratory,has high resistance to wheat stripe rust,leaf rust and powdery mildew.AS1677 was a wheat-Th.intermedium 1St#2(1D)substitution line derive from hybridization between TE-3 and common wheat cultivar ML-13,which carries resistance to stripe rust and has a Th.intermedium specific high molecular weight glutenin subunit(HMW-GS);wheat-Th.intermedium 1St(1B)4St-4Js(4B)substitution line X479 was originated from cross between TE-3 and common wheat cultivar MY26,which carries resistance to stripe rust.The main contents of this study included:(1)By using ND-FISH and molecular markers,we identified the radiation progenies of AS 1677 and the F2,F3 descendants derived from hybridization between X479 and common wheat MY11,with aim to aetermine the introgression,transmission and translocation of alien chromosomes from Th.intermedium ssp.trichophorum.(2)We evaluated the potential value of these progenies for wheat improvement,by using ND-FISH,molecular markers,disease assessment and A-PAGE.(3)We preliminarily identified the gene(s)for resistance of powdery mildew located on the chromosome 4St-4JS,and two kinds of 1St chromosome derived from AS 1677 and X479 was also compared.The main results are as follows:1.By using multi-color-FISH(mc-FISH)and molecular markers analysis,we identified two translocation lines A425 and A439 which are radiation progenies from AS1677.The translocations in A425 are:3BS-1StL.3BL?1StS.2AS?3BS.2AL?3AS·6BL?6BS·3AL;The translocations in A439 are:3BS-1StL·3BL?1StS·2AS?3BS·2AL?7DS·7DL-1BL?1BS·1BL-7DL.2.By using mc-FISH analysis,we karyotyped F2 and F3 population derived from the hybridization between X479 and MY11,and analyzed the frequency of alien chromosomes in delivery and translocation.The results shows that,many translocations between wheat and 1St or 4St-4JS,1St and 4St-4Js,1St and 1St,4St-4Js and 4St-4JS was obtained,and chromosome 4St-4JS displayed slightly easier transmission than that of 1St in wheat background,while they had similar frequencies of translocation.3.By using mc-FISH,molecular marker,disease assessment of stripe rust and powdery mildew,we analyzed the resistance of stripe rust and powdery mildew in F2 and F3 population derived from the hybridization of X479 and MY11.The result are as follow:(1)Some of lines showed obvious resistance to stripe rust in the field,while others did not at all,we speculated that there is a stripe rust resistance gene in 1St or 4St-4JS.(2)X479 has obvious powdery mildew resistance,the resistance comes from 4St-4JS but not 1St.According to the observation of the translocation line in F2 and F3 populations,we located the powdery mildew resistance on the long arm of 4JS.By using the molecular markers of PCR-based landmark unique gene(PLUG)and intron targeting(IT),we obtained 55 1St-specific markers,and 12 of the showed polymorphism between two types of 1St come from AS 1677 and X479 respectively.5 of the polymorphism 1St-specific markers are concentrated on the terminal regions of the long arm,this suggests that there are some structural variations during the transmission of 1St. |
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