Purity Testing Method for Maize Hybrids Using SSR Markers

In this study, (1)two sets of DNA samples were extracted from ground dry seeds and seedlings respectively and compared for their qualities and suitability for PCR amplification; (2)non-denaturing polyacrylamide gel electrophoresis (PAGE) was evaluated for its usefulness in separating maize SSR amplification fragments; (3)9 SSR primer pairs were screened to search for the SSR loci that are suitable for testing the purities of 4 maize hybrids that lack a reliable laboratory method for purity testing. The results are as follows: (1)DNA samples extracted from ground dry seeds are comparable in quality to those from seedlings and amplified no differently from the later; (2)non-denaturing PAGE can detect a large proportion of variation in SSR allele sizes and thus is useful in hybrid purity testing; (3)Polymorphic SSR loci have been found that could be applied to purity testing of these 4 hybrids. A procedure featuring inexpensive equipment and ease of use has been set up for testing maize hybrid purity using SSR marker.