章丘大葱地方品种'大梧桐'染色体多样性分析OA

Chromosome variation is one of the important genetic factors for crop evolution and breeding selection.The landrace Dawutong is a core germplasm of the national geographical indication cultivar Zhangqiu green onion(Allium fistulosum L.)with significant economic value.However,its chromosome constitution and diversity remain unclear.In this study,its chromosome characteristics were systematically analyzed using ge-nome sequencing and fluorescence in situ hybridization(FISH).The results were as follows.A total of 288 tandem repeat sequence clusters were identified and 15 oligonucleotide probes were designed.According to the signal patterns of these probes,an oligonucleotide probe multiplex containing nine probes were developed for distinguishing chromosomes of Dawutong,and a reference karyotype was constructed.Karyotyping analysis of 33 individual plants revealed that Dawutong had a high degree of karyotype variation among different individu-als.Chr1 to Chr4 each showed one karyotype,while the other four chromosomes contained 14 karyotypes.Chr8 had the most karyotypes(6),followed by Chr7(4),and Chr5 and Chr6 each contained 2 karyotypes.Three polymorphic types(Chr5-1,Chr6-1 and Chr8-1)had the frequency more than 50％,representing the domi-nant ones in Dawutong population.The average rates of chromosome homozygosity,heterozygosity and hetero-geneity were 67.51％,32.49％and 15.91％,respectively.Chr7 had the highest heterozygosity rate as 66.67％,and Chr8 had the highest heterogeneity rate as 27.27％,indicating high genetic diversity of this landrace.These results could provide an important technical support for Zhangqiu green onion germplasm identification,genetic research and improvement.