Molecular characteristics and inheritance of a chromosome segment from Psathyrostachys huashanica Keng in a wheat background

Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs) is a valuable genetic resource for wheat improvement because of its high resistance to diseases and high tillering ability. In the present study, a wheat-P. huashanica derived line, designated DH5, was developed. Cytological observations and genomic in situ hybridization analysis suggested that DH5 had a chromosome karyotype of 2n = 42 + Ti (Ti is a small segment chromosome) and that Ti originated from P. huashanica. Ti underwent unequal division in meiotic anaphase I but divided equally in meiotic anaphase II and somatic mitosis. Selfing and backcross results showed Ti could transmitted to offspring through the microspores instead of eggs. Thus, approximately half of the progeny of the DH5 selfing contained one Ti. Molecular methods and fluorescence in situ hybridization confirmed that Ti belongs to P. huashanica 5Ns and that DH5 is a nulli-tetrasome line. Eight pairs of sequence characterized amplified region markers were designed to locate the 5Ns small segment chromosome. Finally, agronomic trait evaluations showed that Ti may not affect DH5 traits, although DH5 produced relatively larger seeds but exhibited relatively shorter plant height. DH5 is a valuable resource for studying the hereditary systems of small segment chromosomes in a wheat background and improving wheat agronomic characteristics.