Transmission And Variation Of Secale Africanum Chromosomes 2R^afr And 6R^afr In Wheat Background Revealed By Molecular Cytogenetic Identification

Genus Secale belongs to Poaceae,in the tribe Triticeae.As it contains a variety of genes associated with resistance to winter hardiness,drought,many cereal diseases,and high protein content,genus Secale comes to be an important gene source for morphological and biochemical development in wheat breeding.The main study in wheat breeding focus on cultivated rye,while the studies wild Secale species have been relatively few.Secale africanum Stapf.(RafrRafr),is distributed in Africa,especially in South Africa.The plant of S.africanum is short,and has excellent resistance to various diseases.Therefore,it serves as potential source of genes in wheat breeding.This study focused on the exploit of Secale chromosome specific molecular markers,molecular cytogenetic identification and investigation the resistance of disease and agronomic performance of wheat-S.Africanum 2Rafr substitution lines,6Rafr substitution lines and their derived offspring materials.The research results showed as follows:Total 8 primers specific for rye chromosomes 2R and 6R(KU246,KU325,KU228,KU266,KU291,KU400,KU178,KU196)were used for identifying the wheat-S.Africanum 2Rafr substitution lines,6Rafr substitution lines and their derived offspring materials.The preliminary identification showed that both chromosomes 2Rafrand 6Rafrfrom parent materials were simultaneously transmitted to their derived offspring materials,while the lines 201501517,201501520,201501522,201501524 included only 2Rafr.FISH showed that the parent materials were 2Rafr(2D)and a pair of 6Rafr(6D)substitution lines.The mostly offspring materials had 42 chromosomes,including a pair of 2Rafr and a pair of 6Rafr,while the lines 201501517,201501522,201501524,201501968 were 2Rafrsubstitution lines.The line 201501518 was 6Rafr substitution line including one 2Rafr and three 2A.The line 201501520 was substitution line including one 2Rafrand one 2RafrL.The line 201501523 had four 4B chromosomes with absent of 2D.A possible translocation in 2Rafrwas found in line 201501526.This observation of agronomic traits of the wheat-S.africanum substitution lines and their derived offspring materials indicated that LF34 was dwraf,resistance to stripe rust,more tillers,lodging resistance,slender spike,short awn,poor seeds characters,while the lines 201403390,20143391,20143392,20143391 were high,wide spike,long awn,plump seeds,higher TKW.The most offspring materials inherited the superior characters from 2Rafr and 6Rafr,in particulary,the higher TKW,resistance to stripe rust,more tillers,dwraf characters from their wheat-.S.africanum parents..The the results of gibberellin sensitivity analysis of the wheat-S.Africanum substitution lines and their derived offspring materials showed the coefficient of gibberellin sensitivity(GRI)value of wheat-S.africanum 2Rafr substitution lines,6Rafr substitution lines and their derived offspring materials is from 109 to 118.The dwarfing gene located on 2Rafr was gibberellic acid sensitive and the significant effect of shortening the coleoptile was also observed.In conclusion,the novel agronomic traits from S.africanum chromosomes 2Rafr and 6Rafr will be potential useful for wheat improvement through wheat-alien chromosomal manipulation.