AN INTERCHROMOSOMAL RECIPROCAL TRANSLOCATION IN WHEAT INVOLVING LEAF RUST RESISTANCE GENE LR34

'Thatcher' backcross lines RL6058 and RL6077 have adult-plant leaf rus t resistance and were believed to have Lr34. However, genetic analysis revealed that the genes in the two lines were independent of each oth er. Previous work demonstrated that Lr34 is located on chromosome 7D. The leaf rust resistance gene in RL6058 must be on chromosome 7DS beca use no recombinants were observed between it and gene Lr29, known to b e on chromosome 7DS. It was also linked with Rc3 (30.25+/-2.88%), a ge ne for purple coleoptile on chromosome 7DS. It was independent of Lr19 and NS1 (nonsuppressor mutant), which are located on 7DL. The leaf ru st resistance gene in RL6077 was independent of genes Lr19 and Lr29. T he presence of quadrivalents in pollen mother cells of the RL6058/RL60 77 hybrid indicates that the Lr34 gene in RL6077 may have been translo cated onto another chromosome. Lr34 from RL6058 and RL6077 may have be en combined in four F-3 lines derived from their intercross.