Life Cycle and Phenological Growth Stages in Endangered Fritillaria raddeana Regel Using BBCH Scale in Its Natural Habitat, Northern Khorasan Province, Iran

Studying the phenology of valuable native plants which are on the verge of extinction, is very important and effective for better introduction and protection of them. Fritillaria raddeana is one of the native bulbous plants with ornamental and medicinal value in Iran. The aim of this study is to investigate the phenological stages of the F. raddeana as a first step to protect it and later to introduce it. In a natural habitat, in northern Khorasan province, Iran, six zones were selected at a distance of 1000 m from each other and five plants were selected and coded in each zone. To provide a standardized phenological description of the species, this study used the BBCH (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) scale. In total, from sprouting to winter rest, six main principal stages were described for sprouting, leaf development, inflorescence emergence, flowering, fruit development, fruit maturity, senescence and beginning of dormancy stages and within them, 15 secondary growth stages were described. Data were collected once a week in the course of the vegetative season and with a 30-day interval during the dormant season for two consecutive years (2015-2017). Additionally, we measured some traits of plant growth. During the first year, sprouting and subsequent leaf development began in late March and the inflorescence emerged in the middle of April. The full bloom occurred in the first half of May and then seed formation (in the late of May). The summer dormancy was triggered in late spring. During the second year of study (2016-2017), the results showed the growing stages start with a delay of 5-8 days compared with the previous year. In addition, T-test results showed the means of studied growth plant traits such as leaf number, plant height, flower stem length, flower number, and flower diameter were significantly higher in the first year than in the second one (p≤ 0.05). The differences of the phenology and studied variables between both years were related to different temperature and rainfall conditions. This narrow relationship with climatic conditions can imperil F. raddeana growth under the scenario of climate change.