| Induced translocations in wheat F. C. ELLIOTT Agronomy Department, Washington State College Pullman, Washington, U.S.A. Studies of the X-ray induced translocation of stem rust resistance from Agropyron elongatum, 2n=70, to common wheat have been extended. There was no obvious segregation for morphological characteristics nor were there appreciable diffefences in metaphase I associations within or between the X3, X4, and X5 generations of the rust-resistant stock grown simultaneously in 1956. Nearly all plants were 2n=42 although an occasional monosomic plant or one with an isochromosome was found . At least three interchanges were involved in differentiating the karyotype of the rust-resistant stock from the sus- ceptible parent variety Idaed as revealed in cytological studies of the F1 hybrid between the rust-resistant stock and Idaed. Some progress was made during the year in the transfer of bunt resistance from an octoploid involving A. elongatum to the susceptible T. compactum variety Elgin through induced translocation and backcrossing. Of the octoploid wheats assembled last season the following crossed most readily with those involving Agropyron elongatum x common wheat :
F0 Seeds of various octoploid combinations have been irradiated in numerous ways and the X1 hybrids will be studied in the summer of 1957. (Received May 3, 1957) |