Effect of colchicine-induced polyploidy on some morphological, anatomical, cytological and agricultural characteristics in common sage (salvia officinalis L.) and anatolian sage (salvia fruticosa mill.)

Sage (Salvia spp.) is a medicinal and aromatic plant of high value due to its terpenes and phenolic compounds. Common sage (Salvia officinalis L.) and Anatolian sage (Salvia fruticosa Mill.) are diploid (2n = 2x = 14) species with fewer chromosomes and a smaller genome compared to many plant species. This study was conducted to develop an effective system for producing autotetraploid plants through colchicine treatment in these two economically important sage species cultivated in Turkey and to compare the (2n = 4x = 28) with their diploid parents. Colchicine applications (0, 125, 250, and 500 ppm) for polyploidy induction were applied to both the embryos during germination and the shoot tips during the seedling stage of S. officinalis cv. Elif and S. fruticosa cv. Karık. The nuclear DNA content (pg/2C) was determined by flow cytometry, and 9 autotetraploid plants were identified in S. officinalis and 16 in S. fruticosa; the polyploidisation efficiency was determined to be 15.0% and 12.3%, respectively. In both species, the highest polyploidy induction was achieved by treating seeds with colchicine at a concentration of 250 ppm for 48 hours. Compared to diploid plants, autotetraploid plants showed an increase in stoma and pollen size and an increase in chloroplast number; however, pollen production and viability, growth rate, and biomass yield decreased. In autotetraploid plants, although the size of glandular trichomes carrying essential oils increased, their number (density) on the leaf surface decreased; therefore, the essential oil content remained lower than that of the diploids. According to the weighted scoring results, two diploid (So2x-250/16 and So2x-F/5) and two autotetraploid (So4x-F/1 and Sf4x-250/39) plants received the highest scores. These findings are expected to provide valuable contributions to comprehensive studies on evolutionary plant breeding in sage.