The physiological and phenotypic response of Salvia aethiopis L. to herbicides

Salvia aethiopis is an aromatic species within the Lamiaceae family, used both as a herb and as an ornamental plant, the yield and quality of which, when cultivated on a commercial basis, is frequently affected by weed infestation. Therefore, the application of herbicide is often required for the commercial production of this spe-cies. Considering which, for the current study, a pot experiment based upon a completely randomized design, with three replications, was conducted to evaluate the physiological and growth response of S. aethiopis to five commonly used herbicides (bentazon, phenmedipham/desmedipham, metribuzin, oxyfluorfen and oxadiargyl). These herbicides were applied at three concentrations (0.75X, 1X and 1.25X where X is equal to the recom-mended dose of herbicide). The data obtained from this study, demonstrated that herbicide application led to an increase in crop damage, minimum fluorescence (F0) and malondialdehyde content (MDA) and a concomitant decrease in the maximum quantum efficiency of PSII (FV/FM), maximum fluorescence (FM), SPAD value, relative water content (RWC), plant height and shoot and root dry weight as compared to the control. However, the level of response/tolerance was dependent upon the specific herbicide and the dose applied. Of the selected herbi-cides, S.aethiopis has shown to display the most tolerance to bentazon. As such, these data indicate that of the herbicides tested, bentazon should be the preferred herbicide used for broad leafed weed control, during the commercial production of this species.