Comparison of Genotypic and Expression Data to Determine Distinctness among Inbred Lines of Maize for Granting of Plant Variety Protection

The Union Internationale pour la Protection des Obtentions Vegetales (UPOV) currently relies on morphological characteristics to evaluate distinctness, uniformity, and stability (DUS) as eligibility requirements for the granting of Plant Variety Protection (PVP). We used 10 maize (Zea mays L.) inbred lines, including both unrelated and closely similar pairs, representing three heterotic groups to compare abilities of morphological, ribonucleic acid (RNA) transcription, metabolomic, and single nucleotide polymorphism (SNP) data to distinguish inbred lines. We used the range of variability and robustness as important factors to determine distinguishing power of each methodological approach. Using an index that ranged from 0 to 100 (useless to the perfect ideal), index scores for each methodology were: metabolomics (0), RNA transcription (18.2), morphology (19.6), and SNPs (35.7). The ability to distinguish among genotypes using RNA transcription expression data was concordant with SNP data for genotypes that were up to 97.2% similar according to SNPs. The SNP data alone could provide the basis for a determination of distinctness among inbred lines of maize with use of morphological, physiological, or agronomic performance data as supplementary information, if needed.