توصيفگر ها :
رازيانه , ژرم پلاسم جهاني , زيرگونه , تنوع ژنتيكي , صفات فيتوشيميايي , كروماتوگرافي گازي , ديرزيستي , خودگشني اجباري , توارث پذيري , تنش رطوبتي , بازيابي پس ازخشكي طولاني
چكيده انگليسي :
Fennel (Foeniculum vulgare Mill.) is one of the most important perennial and drought tolerant medicinal plants. In the first study, 64 fennel genotypes (from 23 different countries) from four subspecies/varieties were evaluated for morphological, agronomic, seed essential oil content, phytochemical traits, and persistence during four years (2015-2018). At the end of the fourth year irrigation was completely stopped for one year, then complete irrigation was restored to evaluate the post-drought recovery of germplasm. High genetic variation was observed among genotypes and subspecies. Based on the GC–MS analysis, trans-anethole, estragole, limonene, and fenchone were major components in the essential oils of the studied germplasm. Compared to other subspecies, the lowest seed yield, essential oil content, post-drought recovery, and the highest persistence, limonene, fenchone, and estragole belonged to ssp. piperitum. This subspecies had positive persistence but other subspecies/varieties had negative one. The results confirmed that piperitum is a different subspecies from the other three studied varieties. Correlation between traits showed that indirect selection is possible to improve seed yield through yield components. Also, the correlation between some essential oil components and post-drought recovery showed that indirect selection for increasing post-drought recovery is possible through phytochemical traits. The classification of genotypes was not completely consistent with their geographic origin. But, the results of classification based on the continents of their origin, support available information on the history of human establishments and the introduction of fennel from Mediterranean gene pools to other regions in ancient times. In the second study, 49 open-pollinated and 30 selfed families, created from the genotypes of the first study, were evaluated in terms of agronomic, morphological, physiological, and phytochemical traits in two environments (normal irrigation and drought stress) during two years (2018 and 2019). Significant genetic diversity was observed between open-pollinated and selfed families for all the evaluated traits, indicating the selection for these traits will be successful. Drought stress decreased most traits, but increased seed essential oil content, harvest index, and proline content. Also, drought stress changed the correlation among traits, compared to normal conditions. Obligatory selfing reduced all traits except the content of trans-anethole, anisaldehyde, gamma-terpinene, and the ratio of chlorophyll a to chlorophyll b under drought stress condition, and the content of trans-anethole, anisaldehyde, proline, the ratio of chlorophyll a to chlorophyll b, and the ratio of total chlorophyll to carotenoid, which may be due to inbreeding depression. Different values of inbreeding depression were observed, which highest was related to plant fresh and dry weight, seed yield per plant, essential oil content, and the number of umbllets per umbel. Based on the estimation of heritability, it was found that the additive function of the genes is an effective factor in controlling the seed yield components. But seed yield is controlled by both additive and non-additive effects. The significant correlation between stress tolerance indexes and some physiological traits confirmed the importance of these traits in improving drought tolerance in fennel.
