Phenotypic Plasticity inMentha viridis lavanduliodora

Abstract

Mentha viridis L. cult, lavanduliodora Sacco was characterized by high levels of linalool and linalyl acetate. The same features were found in a F¹ population coming from seed. Phenotypic plasticity, genotypic variability and genotypic variation for phenotypic plasticity were studied by analyzing essential oils distilled from flowering F¹ hybrids during two growing seasons: 1989 and 1990. The oils were analyzed by GC/MS: limonene, 1, 8-cineole, linalool, linalyl acetate, β-caryophyllene, α-terpineol and geraniol were found to be the main compounds and were statistically processed. The linalool/linalyl acetate (R¹) and 1, 8-cineole/limonene (R²) ratios were also calculated and statistically processed. Two-way AN OVA, Clusters Analysis (CA) and Principal Component Analysis (PCA) were used to evaluate genotypic variability and phenotypic plasticity respectively; statistical linkage as well as pattern and structure of terpenes and partition among plants. The results showed high genotypic variability for linalool. Linalyl acetate, R² and geraniol showed high phenotypic plasticity whereas R² and linalool had the greatest genotypic variation for phenotypic plasticity. During 1989 the CA revealed low variability among plants except for one hybrid. On die other hand increased levels of linalyl acetate in this same hybrid during 1990 revealed a greater variability among hybrids. Linalool, linalyl acetate, geraniol and R² were always found to be good discriminators. PCA calculated by pooling 1989 and 1990 data discriminated plants with high levels of linalool from those having linalyl acetate or α-terpineol. The results of this investigation indicated that the evaluation of phenotypic plasticity and genotypic variation can be considered an important tool for selecting plants producing economically important secondary metabolites.