Genotyping of Bangladeshi Onion (Allium cepa L.) Germplasm for Male Sterility Using PCR-Based Molecular Markers

Abstract

Increasing onion productivity requires the development of hybrid varieties. Identification of sterile
and maintainer lines is essential for successful hybrid development. This study aimed to identify
cytoplasmic types: fertile (N) or sterile (S) and genotypic conditions at the Ms locus within the
Bangladeshi onion germplasm, including certain mutant lines. The cytoplasmic marker accD was
employed to differentiate between sterile and fertile cytoplasm, while three nuclear molecular
markers (OPT, PsaO, and jnurf13) were used for genotyping the Ms alleles. The findings of the accD
marker indicated that the frequency of fertile (N) cytoplasm was significantly higher than that of the
sterile (S) cytoplasm. The result of nuclear markers also showed that the molecular markers used in
this experiment are not sufficiently effective for accurate genotyping of the Ms locus due to the lack
of linkage disequilibrium, suggesting the need to assess more closely linked markers for improved
results, or the compromised genotypic purity of the collected germplasm may also be the reason of
inconclusive genotyping. Nonetheless, molecular markers have proven highly effective for
distinguishing between S and N cytoplasm. Utilizing these markers for cytotype (N/S) identification in
onions will be helpful for the development of hybrid onions in the future.