Identification Of Wheat-Agropyron Cristatum 7P Addition Lines/Translocation Lines And Genetic Analysis Of Grain Weight Traits

Agropyron cristatum(L.)is mainly distributed in harsh environments.It carries biotic and abiotic stress resistance traits and multiple floret trait.A.cristatum becomes an important gene source of wheat improvement.In this study,wheat-A.cristatum 7P derived lines were identified by means of molecular markers and molecular cytology.At the same time,based on the corresponding genetic populations,the traits of increasing thousand-grain weight(TGW)on the 7P chromosome was located.1.Combing the method of molecular cytogenetics,specific molecular markers and wheat 660 K SNP gene array technology,we analyzed wheat-A.cristatum 7P addition lines and revealed their chromosome composition in the four addition lines.By using cluster analysis of genotype and comparing their agronomic traits,we revealed the genetic relationship among four addition lines.Finally,according to the SNP variation in different 7P chromosome,four lines were divided into two groups,one group included II-5-1 and 5038,and another group included 5043 and 7-7.The results showed that at least two addition lines from the same homologous group should be produced and preserved to maintain the genetic integrity of polyploid wild relatives.2.A total of 27 translocation and deletion lines produced by irradiation were identified by using specific molecular markers and cytogenetics methods.In the irradiation offspring of wheat-A.cristatum 7P addition line II-5-1,there are 27 lines contained partial 7P chromosome fragments were identified in the study,included one deletion line and 18 translocation lines and 8 complex types translocation lines with two 7P chromosome segments.3.The physical bin map of A.cristatum chromosome 7P was constructed by using A.cristatum EST-STS markers.We use 44 translocation and deletion lines as DNA templates,a total of 157 STS markers were screened.As a result,the chromosome 7P was divided into 40 segments including 19 segments on long arm and 21 segments on short arm.4.In order to further map high TGW gene on A.cristatum chromosome 7P,combined with above fine physical map,we completed the trait investigation of segregation populations of the translocation and deletion lines in S1,S2 and S3 segments,the results showed that higher TGW gene was mapped on 7PS-1 chromosome bin.5.One spontaneous translocation line 7-20 was isolated in backcrossing progenies by means of cytogenetical approach.The identification indicated that the line 7-20 was a whole arm translocation of 7PL.7AL by using specific molecular markers and non-denaturing fluorescence in situ hybridization(ND-FISH)assays.This spontaneous translocation line 7-20 showed the effect of reducing plant height,but its grain number per spike was decreased.