identification of male sterile (t, s) of fertility (n) cytoplasm by pcr-based molecular markers to access maintainer lines in onion

Purpose: modern onion breeding is almost completely based on the production of hybrid seed . this project was performed to evaluate the effectiveness of marker-assisted selection (mas) in identification of the cytoplasmic types and ms locus in 123 onion accessions. research method: three cytoplasmic markers cob, accd and mk were used to identify the sterility (s) from the fertility (n) cytoplasm and four nuclear molecular markers (opt, psao, jnurf-13 and acskp1) were used for genotyping of ms alleles. findings: the results showed that the two accd and cob markers were quite similar in the detection of the type of cytoplasm with 100% male sterility for male sterile lines and 100% fertility for maintainer lines. the mk marker was able to distinguish t-type cytoplasm as well. based on the results, the frequency of fertility (n) was much more than the frequency of sterility (s and t) cytoplasm found to be 90% in dorche (pop.1), 100% in dorche (pop.2) and kashan based on marker cob and accd and with mk marker, was found to be 80%, 90% and 82% in dorche (pop.1), dorche (pop.2) and kashan, respectively. limitations: in this study, nuclear markers were not successful due to not finding linkage disequilibrium with the ms locus, suggested more markers to be evaluated. originality/value: molecuar markers were very suitable for the indentification of s or n lines. cytotype (n/s) determination of plants by using molecular markers (cob, accd and mk), could easily reduce the population size required for the production of onion hybrid seeds.