Characterization of maize germplasm: comparison of morphological datasets compiled using different approaches to data recording

Abstract

Different methods are used to report morphological data to evaluate the eligibility criterion of distinctness for Plant Variety Protection (PVP). We compared morphological data for 152 maize (Zea mays L.) inbred lines generated according to both US (metric data) and EU data (summarized by reference to “note” scores from check inbreds). While modal notes were very similar for US and EU data, on average only 42.8% of the characteristics had identi¬cal scores. Associations among inbreds on the basis of comparisons of single or multiple characteristics were very similar regardless of data type. We conclude that maize morphological data collected according to either of these protocols cannot meaningfully be combined into a single dataset. However, each data type, provided an equivalent mechanism to test for distinctness. These results cause us to more fundamentally question the degree of reliance that should be placed upon morphological data for PVP and other applications, including for the man¬agement of accessions conserved in gene-banks.