Clone selection from spontaneous germplasm to improve Rosmarinus officinalis L. crop

Many experiences in rosemary (Rosmarinus officinalis L.) cultivation have taken place in different areas, but up to the present the characteristics and adaptability of Sardinia's spontaneous germplasm have not been investigated. The aim of the research was thus to study some good ecotypes selected from spontaneous populations for crop evaluation in warm and dry Mediterranean conditions. Eleven ecotypes were studied in this preliminary stage. A minimal descriptor list was filled in and three-year or older branches were sampled for morphological and biometric determinations. The following measurements were taken: shoot and internode length; number of leaves per internode; leaf width and length; shoot dry weight. The rough powder obtained by leaf drying was used for essential oil content determination. The results showed that shoot length was comprised between 3 and 20 cm and internode number ranged from 9 to 24. Leaf number per shoot was between 29 and 163; and their size varied from 14.6 to 22.0 mm (length) and from 1.2 to 1.8 mm (width). Spring shoot fresh weight was between 0.3 and 2.3 g, while dry matter content of shoot ranged between 41 and 70%. The maximum number of leaves per shoot (over 160) was recorded in S. Antioco 1 ecotype and the minimum (under 30) in Capo Figari. Leaves per cm of shoot were between 6 and 17. Dry leaf powder of different ecotypes had typical colours ranging from brown to deep-green or yellow-green. Essential oil content ranged between 0.8 to 2.6% of the dry powder weight.