抄録
Pollen grains of a normal strain were irradiated with ultraviolet light (5.1×103ergs/mm2 average), then pollinated to the pertinent tester plants with recessive marker genes (ws3, lg1, su1, o2, ra1, sh1, wx and c1). The chromatid breaks were estimated by the dominant marker losses that appeared in X1 kernels and in X1 plants. The marker losses occurred at similar rates to those which have been reported so far. The losses of C1, Sh1, Wx on chromosome 9 were analyzed in detail. The results indicate frequent occurrence of interstitial chromosome deficiencies, although they have seldom been reported as yet with ultraviolet light. The points of breakage seemed to be nonrandomly distributed along the chromatid. The relative sensitivity of selected regions of chromosome 9 differed from each other, and the region proximal to Wx gave the highest among four regions examined. A possible key mechanism for inducing chromatid breaks with ultraviolet light was discussed.
