Morphological and molecular cytogenetic characterization of partial octoploid Tritileymus

Abstract

This study used cytological observation, genomic in situ hybridization (GISH), and seed storage protein electrophoresis to characterize a partial octoploid Tritileymus M842-1 derived from Leymusmollis (NsNsXmXm, 2n = 28) and common wheat cv. 7182 (Triticumaestivum L.), and its relationship with alien chromosomes and those from wheat. Mitotic observations showed that the chromosome configuration of M842-1 was 2n = 56 = 28II. Mitotic and meiotic GISH using two different probes for L. mollis and Psathyrostachys huashanica indicated that M842-1 contained 14 Ns genome chromosomes from L. mollis, which formed seven pairs of uniform bivalents, and confirmed the genomic composition as AABBDDNsNs. The separation of seed storage protein by polyacrylamide gel electrophoresis indicated that M842-1 expressed some L. mollis-specific glutenin and gliadin bands. The seeds of M842-1 were as large as those of wheat cultivars, while they also had a long spike and were covered with wax on the leaves and stems. Disease screening demonstrated that M842-1 was immune to stripe rust, highly resistant to powdery mildew, and moderately susceptible to wheat scab during the adult plant stage. This study demonstrated that the partial octoploid Tritileymus M842-1 could serve as a donor source in wheat breeding programs for the introduction of novel variation to promote high yield and disease resistance.