MOLECULAR CYTOGENETIC ANALYSIS OF LEYMUS-RACEMOSUS CHROMOSOMES ADDED TO WHEAT

Five disomic, two double-disomic, and two ditelosomic addition lines a nd one disomic substitution line derived from the crosses of Triticum aestivum (2n = 6x = 42, AABBDD) x Leymus racemosus (2n = 4x; = 28, JJN N) were identified by C-banding analysis, The homoeology of the added Leymus chromosomes was determined by RFLP analysis. Four of five disom ic addition lines belonged to group 2, 5, 6 and 7 chromosomes of L. ra cemosus; these were designated as 2Lr#1 (NAU516), 5Lr#1 (NAU504, NAU51 4), 6Lr#1 (NAU512), and 7Lr#1 (NAU501). Two additional chromosomes, 1L r#1 and 3Lr#1, were present in double-disomic addition lines 1Lr#1 + 5 Lr#1 (NAU525) and 3Lr#1 + 7Lr#1 (NAU524), respectively. In the disomic substitution line wheat chromosome 2B was replaced by L. racemosus ch romosome 2Lr#1 (NAU551), Two telocentric chromosomes, 2Lr#2S (NAU509) and 7Lr#1S (NAU511), were isolated as dilelosomic addition lines. The study presented here provides the first evidence of homoeology of the added L. racemosus chromosomes with wheat chromosomes using DNA marker s. Our data provide the basis for further directed chromosome engineer ing aimed at producing compensating wheat-L. racemosus translocation l ines.