Seed yield and essential oil content of fennel influenced by genetic variation and genotype × year interaction

Abstract

Common fennel (Foeniculum vulgare Mill.) is an important medicinal plant with considerable geographical distribution in Iran. Variation in eighteen populations of fennel collected from different regions of Iran and two European accessions was evaluated based on agro-morphological traits, ISSR markers, seed yield and essential oil content. Accessions were planted in the field and studied for two consecutive agronomic years. The analysis of data on all 20 accessions showed that mean squares of genotypes, years, and genotype×year interaction was significant for most of the traits indicating wide variation for the studied traits in the fennel accessions influenced by the environment. Coefficients of genotypic variability revealed high genetic variation for seed yield per plant and harvest index suggesting the possibility of improving seed yield by means of selection particularly in the first year. Seed yield per plant had positive correlations with the number of effective umbels per plant and 1000-seed weight as yield components. Cluster analysis based on agro-morphological traits classified populations into 4 major groups in the first year. Similarly the UPGMA (unweighted pair group method with arithmetic mean) dendrogram obtained from ISSR molecular data based on SM (simple matching) classified populations into four groups. Agro-morphological and ISSR data matrices were not correlated and did not correspond to the geographical variation of the populations. In general, the results of this research showed that there was a considerable genetic variation in terms of seed yield and the other agronomic and molecular traits among accessions and depending on the objectives, this variation may be utilized to select superior genotypes for medicinal purposes and in plant breeding programs.