Molecular And Cytogenetic Studies On Derivatives Of Wheat-thinopyrum Ponticum

Thinopyrum ponticum(2n = 10x = 70),a wild relative of common wheat,has been frequently used in wheat breeding program because of the strong regeneration capacity and tillering ability,long spike,disease resistance,high protein levels and adaptive capacity.In order toget some intermediate tools materials,morphology,cytological analysis,disease resistance identification,molecular marker technique,and genomic in situ hybridization(GISH)were used to determine the homoeologous group of the substituted and added chromosomes and then agronomic traits evaluation were combined.The main results are as follows:1.A substitution line ES-6,derived from the progeny of the crosses between common wheat cultivar Abbondanza and Triticum aestivum-Th.ponticum partial amphiploid line Xiaoyan784,was characterized by cytological,fluorescence in situ hybridization(FISH),genomic in situ hybridization(GISH)and EST-STS marker techniques.Cytological observations revealed that the configuration of ES-6 was 2n = 44 = 22 ?.GISH analysis showed that the alien chromosomes came from Th.ponticum,but whether from Pseudoroegneria spicata or Thinopyrum bessarabicum should be in further investigation.Three molecular marker in homoeologous group 1 and homoeologous group 5(BF292071,BF291738 and BF483357)confirmed that the introduced chromosomes belonged to homoeologous group 1 or 5.Furthermore,ES-6 showed highly resistance to stripe rust races in adult stages,which was possibly inherited from Th.ponticum.Thus,ES-6,as a stable addition line,can be used for wheat stripe rust resistance breeding program.2.A substitution line ES-7,derived from the progeny of the crosses between common wheat cultivar Abbondanza and Triticum aestivum-Th.ponticum partial amphiploid line Xiaoyan784,was characterized by cytological,fluorescence in situ hybridization(FISH),genomic in situ hybridization(GISH)and EST-STS marker techniques.Cytological observations revealed that the configuration of ES-7 was 2n = 42 = 21 ?.GISH and FISH results showed that ES-7 had two St chromosomes and lacked 5A chromosomes compared to common wheat.The 4A chromosome of ES-7 had small alterations from common wheat.Two EST-SSR markers BE482522 and BG262826,specific to Th.ponticum and tetraploid Pseudoroegneria spicata(2n = 4x = 28),locate on the homoeologous group 5 chromosomes of wheat,could amplify polymorphic bands in ES-7.It was suggested that the introduced St chromosomes belonged to homoeologous group 5,that is,ES-7 was a 5St(5A)disomic substitution line.Furthermore,ES-7 showed highly resistance to mixed stripe rust races in adult stages,which was possibly inherited from Th.ponticum.Thus,ES-7 can be used for wheat stripe rust resistance breeding program.