VARIATION OF WHEATGRASS CHROMOSOMES IN WHEAT-WHEATGRASS ALIEN ADDITION LINE TAI-27 REVEALED BY FLUORESCENCE IN-SITU HYBRIDIZATION (FISH)

The karyotype of the primary wheat-wheatgrass alien addition line TAI- 27 was 2n = 44 in which all of the chromosomes were metacentric and su bmetacentric. However, in the progeny of TAI-27 a pair of chromosomes had become small chromosomes in the two morphologically different plan ts. Fluorescence in situ hybridization (FISH) technique was used to an alyze the two different plants. The observations indicate that a pair of small chromosomes in one variation line are from wheatgrass. In ano ther variation line, a pair of small chromosomes are also from wheatgr ass, while another pair of wheatgrass chromosomes have substituted the wheat chromosomes. TAI-27 and its variant lines showed a high level o f resistance to barley yellow dwarf virus (BYDV). The possible explana tion for such a variation and the potential use of the variant lines w ere discussed briefly.