Identification Of Wheat 2R Addition Lines

Common wheat (Triticum aestivum L., genome AABBDD,2n=6x=42) is a typical representative of allopolyploidy species. Due to the allohexploidization evolution, domestication, and spread of new cultivars, the diversity in common wheat has been largely reduced, thus limited its further genetic improvement. By means of distant hybridization with the aid of chromosome engineering, alien chromosomes or a chromosomes segment can be transferred into common wheat background. This kind wheat with alien genetic material is useful for wheat breeding.In the present study, we analyzed seven F7 lines derived from the wide cross between common wheat and rye (Secale cereale,2n=2x=14, genome RR) on agronomy, cytogenetic and molecular levels. Compared to those of other six sib lines, YYW-102 showed thinner and smaller plants with lower height, less tillers, shorter main spikes, and less spikelet number.The chromosome number for root-tip cell in YYW-102 was 44, thus indicating that it was probable an addition line. At meiotic metaphase I, most of the 44 chromosomes paired into bivalents and thus indicated YYW-102 is stable in cytology. Genomic in situ hybridization (GISH) analysis on YYW-102 proved that a pair of chromosomes were derived from rye.C-banding technology was used for identifying rye chromosome existed in this addition line, Strong telomeric bands were apperead in a pair of short arm of chromosomes, which indicated 2R chromosome may be existed. This result was further proved by RAPD makers specific for 2R chromosome.Combined these results from cytological, C-banding, GISH, RAPD, and gene sequencing for 75Ky-secalin subunit, we concluded YYW-102 was an disomic addition line of rye chromosome 2R.