The ditelosomic lines of common wheat are invaluable tools for mapping genes. They have been bred in a single cultivar Chinese Spring (CS), but CS ditelosomics 7DL has not yet been developed. We started to produce CS ditelosomic 7DL by backcrossing Canthatch ditelosomic 7DL to CS. After eight backcrosses, several ditelosomic lines were developed. These lines were examined with chromosome constitution, were test-crossed with ditelosomic 7DS and were also analyzed by electrophoresis for alpha-amylase isozymes. Three of the ditelosomic lines turned out to be truly ditelosomic for 7DL.
Key words: aneuploid, ditelosomics, 7DL
Introduction
Hexaploid bread Wheat, Triticum aestivum (2n=6x=42), possesses an ability to tolerate the addition or deletion of chromosomes. An array of aneuploid series were produced in Chinese Spring (CS) wheat (Sears 1954; Sears 1966; Sears and Sears 1978). Up to date, 36 telocentric lines for 1AS, 1AL, 1BS, 1BL, 1DS, 1DL, 2AS, 2BS, 2BL, 2DS, 2DL, 3AS, 3AL 3BS, 3BL, 3DS, 3DL, 4AS, 4AL, 4BS, 4DS, 4DL, 5AL, 5BL, 5DL, 6AS, 6AL, 6BS, 6BL, 6DS, 6DL, 7AS, 7AL, 7BS, 7BL and 7DS have been maintained as ditelosomics, and five lines for 2AL, 4BL, 5AS, 5BS and 5DS have been maintained as ditelomonotelosomics (Furuta and Nishikawa unpub). These lines are invaluable tools for allocating genes and markers to specific chromosomes and chromosome arms. However, one line CS ditelosomics 7DL, hag not yet been developed (Friebe et al. 1996), although a ditelosomic line 7DL has been established in Canthatch(Can) wheat.
In order to produce CS ditelosomic 7DL, we performed successive backcrosses of Can ditelosomic 7DL to CS. From selfling the BC8 plants, 20 ditelosomic lines were developed. We examined the obtained lines to know whether they possessed a pair of telocentric chromosome 7DL, by observing the somatic chromosome constitution and the meiotic chromosome pairing in the progeny from a cross with ditelosomic 7DS. We also conducted electrophoresis for alpha-amylase isozymes, some of whose gene loci are on the chromosome arm 7DL.