Maize Genetic Identity

The success of maize hybrids in the field is highly dependent on seed quality. Morphological and biochemical techniques are often incapable of distinguishing between several modern maize inbred lines or hybrids. In contrast, DNA molecular markers are environmentally insensitive and the simultaneous use of multiple markers allows crop quality assurance and quality control with high resolution.

Following the guidelines and recommendations of CIMMYT for quality control and seed identity, our laboratory has developed a panel of SNP markers that map all the chromosomes of the maize genome, and allow us to evaluate the degree of genetic identity of lines and hybrids.

By applying molecular marker based seed tests, in commercial seed production, one can:

  • Confirm whether the selected parental inbred line meets genetic purity standards
  • Find and measure the extent of selfing and outcrossing in hybrid seed lots
  • Determine the genetic variants, segregation and seed mixes in hybrid or inbred line seed production lots.
  • help verify the appropriate hybrids, ensuring that producers and customers receive what they expect.

Maize inbred lines are expected to be highly genetically pure or homogeneous. Theoretically, inbred lines should be at least 95% identical at every locus for every SNP analyzed, while in case of a doubled haploid (DH) line, the homozygosity is expected to be 100%. An inbred line may be considered genetically pure or homogeneous if the proportion of heterozygous loci does not exceed 5%. Any inbred line with more than 5% but less than 15% genetically heterozygous loci requires purification by selection while one with more than 15% heterozygous loci is likely to be contaminated with unrelated genetic material and requires to be either discarded or extensive reselected for the original genotype. In general, inbred lines with more than 95% of genetic purity is acceptable in commercial maize seed production.

Please contact us for more information:

+54 11 4712-5647