Chromosomes polymorphisms of Sichuan wheat cultivars displayed by ND-FISH landmarks

Although fluorescence in situ hybridization (FISH) karyotypes of wheat chromosomes have already been widely investigated, more probes are needed to enrich them. Novel karyotype characteristics of 166 common wheat cultivars bred from the hometown of Chinese Spring were revealed using 11 oligonucleotide (oligo) probes derived from nine kinds of tandem repeats. Chromosomes 5A, 3B and 1D showed the highest number (24, 18 and 6) of karyotype variations in A-, B-, and D-genome chromosomes, respectively. According to the FISH karyotypes, the analyzed wheat cultivars were divided into eight clusters that correspond to breeding entities. Thirty and 38 cultivars contain wheat-Haynaldia villosa 6AL.6VS and wheat-rye 1BL.1RS translocation chromosomes, respectively, indicating their high breeding value in Sichuan, China. Additionally, four and three types of 6AL.6VS and 1BL.1RS translocations were observed, respectively. Scarce translocations were detected. 'Neimai' series cultivars contain reciprocal translocations 5AS.3BS/5AL.3BL. Three cultivars contain reciprocal translocations 5BL.5BS-7BL/7BS.7BL-5BS that occurred at high frequency in European wheat cultivars, indicating that the translocation is also adapted to Sichuan environments. These results indicate that some special karyotypes exist in Sichuan wheat cultivars, showing the relationship between karyotype and adaptation. Richer FISH bands of wheat chromosomes were revealed, and this can be used to investigate meiotic recombination conveniently.