Morphologic variability in Portuguese Mentha cervina accessions

Abstract

M. cervina is traditionally used in Alentejo to flavor fish and fish soups, as well as for its medicinal properties. In Portugal it is a rare species, occurring in river banks and other damp and wet places, which require a longer flooded period that is characteristic of the Natura 2000 priority habitat 'temporary deep ponds' (3130 pt5). This study was based on 30 accessions from backyards and natural habitat collected during 2002-2003 in the Alentejo region. Further collections in natural habitat were achieved in 2005, accounting a total of 17 accessions from natural habitat. From each sample, 15 plants were observed, during 2 years growing seasons. Data from 33 morphological descriptors were submitted to multivariate principal components analysis (PCA) and cluster analysis. High morphologic variability in the species is confirmed by its high statistical difference between accessions on most of the morphologic descriptors. The initial list of 33 morphologic descriptors was reduced to a proposal list of 14 descriptors, measuring plant architecture features, productivity indicators and also phenology descriptors: plant height, biomass, basal leaf length (cm), basal leaf width (cm), inflorescence 1st leaf length (cm), inflorescence 1st leaf width (cm), number of days for flowering (date), main stem length (cm), main stem diameter - basal, main stem diameter - below inflorescence, main stem - number of nodes below inflorescence, main stem - number of branches below inflorescence, number of flowers in half of the 1st verticillaster, number of flowered verticillasters. A list of selected accessions with high crop production potential is also presented.