Study of morphological charecteristics of different Achillea nobilis, A. biberestini and A. filipendula populations at two irrigation intervals

To evaluate effect of two irrigation intervals on morphological charecteristics of different Achillea nobilis, A. biberestini and A. filipendula populations, a field experiment was arranged on the base of factorial experiment in a randomized complete block design with three replications. Experimental factores were irrigation intervals (7 and 14 days) and Achillea nobilis, A. biberestini, A. filipendula populations. The irrigation intervals were applied from the time of plants establishment in the field until the plant yield recorded. The results showed that responses of A. nobilis, A. biberestini and A. filipendula species and populations to irrigation intervals were different. Among three studied species, drought had less impact on plant morphology characteristics of A. filipendula populations. Seven populations of A. nobilis were grouped in three groups. Populations in the group I had higher plant height, yield and flowering time. Polulations group III showed higher crown diameter, flower diameter, stem number and flower number, however shorter full flowering time, indicating favorable production potential of populations group III in semi-arid regions. Accoring to the results of this study, irrigation intervals longer than 14 days are not recommended in geographic conditions similar to Karaj for the A. nobilis, A. biberestini and A. filipendula. Considerable diversity among the populations of studied species indicated the potential of these species in breeding programs in dry and semi-arid regions.