Molecular cytogenetic characterization and stripe rust response of a trigeneric hybrid involvingTriticum,Psathyrostachys, andThinopyrum

Abstract

Trigeneric hybrids offer opportunities to transfer alien traits into cultivated wheat. In this study, a new trigeneric hybrid involving species of Triticum , Psathyrostachys , and Thinopyrum was synthesized by crossing Triticum aestivum L. (wheat) – Thinopyrum intermedium (Host) Barkworth & D.R. Dewey amphiploid Zhong 3 with wheat – Psathyrostachys huashanica Keng ex Kuo amphiploid PHW-SA. Crossability of the two amphiploids was 19.74%, and the fertility of the hybrid was 16.20%. The mean meiotic configuration of the trigeneric hybrid (2n = 56) was 13.06 I + 17.24 IIring + 3.73 IIrod + 0.28 III + 0.04 IV. GISH analysis indicated that the trigeneric F1had seven P. huashanica chromosomes and seven Th. intermedium chromosomes. The mean chromosome numbers of F2, F3, and F4progenies were 2n = 49.24, 2n = 48.13, and 2n = 46.78, respectively, a gradual decrease. GISH analysis revealed that most F2and F3plants had 2–10 Th. intermedium chromosomes and 0–4 P. huashanica chromosomes. In the F4progenies, 1–7 Th. intermedium chromosomes were labeled, but no P. huashanica chromosomes were detected. It seems that Th. intermedium chromosomes are more likely than P. huashanica chromosomes to be transmitted to the progenies. The stripe rust response of PHW-SA was expressed in the F1and some F2and F3progenies. The trigeneric hybrid could be a useful bridge for transfering P. huashanica and Th. intermedium chromosomes to common wheat.