Abstract:
Exploitation of the full potential of any hybrid requires the possessing of genetically
high-purity seeds. Commercial soybean hybrids have been developed using a cytoplasmic
male sterility (CMS) system. In order to avoid reduction in yield caused by using lowpurity
seeds, development of a simple, rapid, and accurate method for hybrid purity
assessment is of great essence and significance. Therefore, the parental lines of HybSoy 1
to 5 were screened using 160 Simple Sequence Repeat (SSR) makers, of which 8 markers
exhibited polymorphism. A PCR-based assay with these markers detected both alleles of
the parental lines in pure hybrids, proving their heterozygosity, whereas impurities were
identified by the presence of only one parental allele. The confirmation of hybrid purity
indicated that a single polymorphic marker was sufficient for detection of contaminations
of these hybrids from their parents. It was also found that if a hybrid seed lot was
contaminated by another hybrid or its parental lines, two or more appropriate markers
could be used to easily detect such contamination. This method could accurately and
effectively identify the hybrid purity in a predetermined sample of soybean hybrids
constituted by deliberately mixing seeds of parental lines. This is the first report that
demonstrates the utility of SSR markers for assessment of genetic purity of soybean
hybrids.
Keywords: Cytoplasmic male sterility, Genetic purity, Molecular marker, Contamination,
Polymorphism.
