Asexual Propagation of Greek Salvia officinalis L. Populations Selected for Ornamental Use

Abstract

Salvia officinalis, commonly known as sage, is highly valued for its medicinal and ornamental properties. In the present work, 12 native sage populations of north-west Greece were evaluated for eight ornamental traits. Populations from the locations of Aristi, Kefalovryso and Igoumenitsa were selected as the best performing and for their preservation and availability in the market, their asexual propagation was investigated by (a) shoot cutting and (b) in vitro techniques. Propagation by cuttings was investigated during the four seasons. Aristi exhibited the highest rooting (65%) in spring with a well-developed root system (4.7 root number and 5.0 cm length) by applying 0.5 g·L−1 Indole-3-butyric acid, potassium salt (K-IBA), established on perlite under a fog system. However, the rooting performance of Aristi spring cuttings was not affected by different substrates of peat:perlite (0:1, 1:1, 1:2 v/v) or rooting systems (mist, fog) tested. Furthermore, the in vitro propagation of the selected sage populations was investigated using shoot tips as explants. After successful disinfection, the effect of Murashige and Skoog (MS) medium in ten different combinations of Indole-3-acetic acid (IAA), 6-Benzylaminopurine (BAP) and Thidiazuron (TDZ) were tested on shoot multiplication. Aristi presented the highest number of newly formed shoots on MS9 (0.1 mg·L−1 IAA and 0.8 mg·L−1 TDZ) and MS5 (0.1 mg·L−1 IAA and 0.8 mg·L−1 BAP) (3.35 and 3.21 new shoots/explant, respectively) with the highest shoot length (2.23 cm and 3.2 cm) and unexpected spontaneous root formation (64%) at MS5. The rooting ability of Aristi microshoots was further investigated in order to enhance their response. Of the three rooting variants tested, optimal rooting formation (100%) was observed on 0.9 mg·L−1 IAA (R3) combined with successful acclimatization (100%). Aristi exceeded the other populations in both the tested propagation systems, thus holding a strong potential for its introduction in the market as a competitive ornamental variety.