Introgression of bread wheat chromatin into tall wheatgrass via somatic hybridization

Regenerates were obtained following somatic hybridization between tall wheatgrass (Agropyron elongatum) and bread wheat (Triticum aestivum cv. Jinan177) protoplasts. Two lines (CU and XI) were self-fertile in the first (R₀) and subsequent (R₁ and R₂) generations. The phenotype of each R₁ population was uniform. All CU progeny were phenotypically similar to the tall wheatgrass parent, while XI progeny had thinner, smoother and softer leaves. Cytological analysis showed that more wheat chromatin was present in the hybrid callus than in the R₁ and R₂ plants, and that some intercalary translocations of wheat chromosome segments were retained in the R₂ generation. AFLP profiling confirmed the presence of wheat DNA in the introgression lines. Analysis of the high molecular weight glutenin subunit content of derived seed identified three novel subunits, not present in either the wheat or the tall wheatgrass parent. Microsatellite-based profiling of the chloroplast genome of the introgression lines suggested that only chloroplast sequences from the tall wheatgrass parent were present. The specifically inherited phenomena and possible application of these hybrids are discussed. Haifeng Cui and Zhiyong Yu were contributed equally to this article.