Effects of drought stress on seed yield and yield components in drought tolerant synthetic cultivars and ecotypes of fennel (Foeniculum vulgare Mill.)

Effects of drought stress on seed yield and yield components in fennel genotypes was evaluated at research field of college of Aburaihan, University of Tehran, Iran during 2013. Experiment was carried out in split plot arrangement based on a randomized complete block design (RCBD) with three replications. Normal irrigation and drought stress treatments were assigned to main plots and fennel genotypes including two drought tolerant synthetic cultivars (early and medium maturity synthetic cultivars) and their four elite parents (Fasa, Meshkinshahr, Fozveh and Hashtgerd) were randomized in subplots. Analysis of variance showed that effects of drought stress on number of umbels, number of umbellate, seed yield and biological yield were significant. Drought stress reduced all measured traits and seed yield (40%) was affected the most. Result showed significant differences among the genotypes for all of the studied traits. Mean comparison of the genotypes showed that the highest seed yield belonged to Fozveh (1125 kg/ha) in normal condition and lowest seed yield belonged to Fasa (434 kg/ha) under drought stress. Early and medium maturity synthetic cultivars had the highest seed yield in drought stress conditions. Stress tolerance score (STS) for genotypes were calculated. Early and medium maturity synthetic cultivars with the highest amounts of STS were introduced as the best genotypes with drought tolerant. Finally based on the results, the cultivars in environments with variable climate, especially water shortage, can produce satisfactory yield.