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 submetacentric. However, in the progeny of TAI-27 a pair of chromosomes had become small chromosomes in the two morphologically different plants. Fluorescence in situ hybridization (FISH) technique was used to analyze the two different plants. The observations indicate that a pair of small chromosomes in one variation line are from wheatgrass. In another variation line, a pair of small chromosomes are also from wheatgrass, while another pair of wheatgrass chromosomes have substituted the wheat chromosomes. TAI-27 and its variant lines showed a high level of resistance to barley yellow dwarf virus (BYDV). The possible explanation for such a variation and the potential use of the variant lines were discussed briefly.