Investigation effect of growth region on essential oil content and quality of ‎inflorescence spathe of some date palm varieties ‎

Inflorescences of date palm (Phoenix dactylifera L.) are encapsulated in a cover known as spathe, containing essential oil. In this study the impact of growth location (Bam and Jiroft) on the essential oil content and composition of date palm varieties (Piarom, Zahedi, Mozafati, and Hallilehie) was investigated. The essential oils were obtained by hydrodistillation and analyzed by GC and GC/MS. Results showed that effect of variety on morphological traits was more than growth location and Mozafati’ and ‘Hallilehie’ varieties showed the highest spathe length (55.06 and 48.80 cm). The highest spathe width was recorded for 'Mozafati’ and ‘Piarom’varieties (11.52 and 10.83 cm), and ‘Zahedi’ variety had the highest spathe number per palm tree (14.83). On the other hand, spathe fresh and dry weight and spathe dry matter yield in Bam (235.30 and 67.66 g/spathe, and 747.906 g/palm tree) were 38%, 48%, and 41% greater than those in Jiroft, respectively. The essential oil per palm tree in Bam (1.246 g) was 2.26 times greater than that in Jiroft (0.551 g). The ‘Mozafati’ variety had the highest spathe fresh weight, dry weight, and dry matter yield. The highest essential oil percentage (0.148-0.168%) belonged to ‘Zahedi’ and ‘Piarom’ varieties. The essential oils of all four varieties in both growth location contained five chemical compounds of 3,4-dimethoxytoluene (58.7-71.2 %), p-methylanisole (4.2-30.0 %), 2,6-dimethoxytoluene (8.6-16.8 %), n-nonanol (0.6-4.1%), and o-vanillin (0.5-2.6%). The studied varieties were divided into two groups in terms of their effectiveness from the growth location. The Hallilehie and Mozafati varieties showed higher relative stability.