Diversity and heritability of morphophysiological traits and essential oil of Oliveria decumbens vent in Iran

Oliveria decumbens Vent. (Apiaceae) is a valuable medicinal plant in the western regions of Iran.It sun controlled harvesting in natural habitats has increased the risk of extinction of this species. In order to investigate the diversity of 25 populations, an experiment was conducted using 18 morphphysiological characteristics and percentage of essential oil in a randomized complete block design (RCBD) with three replications. Populations were planted in the research farm of Shahid Beheshti Dezfoul Company. Samples were collected at their full flowering phase and morphophysiological characteristics and were recorded in mid-June of 2016. The results of the analysis of variance were showed a variation among populations in terms of these characteristics, by calculating genetic and environmental variances, changes in most traits including, stem leaf length, stem leaf width and stem leaf width/length, umbellule diameter, the dry and wet weight of 100 umbellule and chlorophyll a/ b were determined by genetic factors. The general heritability were showed the percentage of essential oil, umbellule number in plant andthe dry weight of 100 umbellule were 0.91, 0.51 and 0.77, respectively. The correlation between characteristics and stepwise regression exhibited the greatest impact of the flower texture on essential oil production and the dry weight of 100 umbellule. Based on the factor analysis results, the three main factors justified 78.6% of the total variation among the characteristics. The biomass of the plant was the first factor followed by the percentage of essential oil and flower weight as the second and third factors, respectively. Based on the cluster analysis results, the populations can be divided into 5 groups. The third and fifth groups exhibited a great potential for cultivation, due to the highest average percentage of essential oil and maximum number and dry weight of 100 umbellule in a plant. Moreover, the populations in cluster 1 and 4 alternatively have the greatest genetic distance from each other which can be exploited in crossover and production of synthetic seeds.