Morphological variations among hoary cress (Lepidium draba L.) populations in Iran

In order to investigate morphological traits of hoary cress populations, seeds of 40 populations were collected from different parts of Iran in 2013 and were sown in pots at the same condition. At the end of growth season, fifteen morphological traits were measured. Germination rate and germination percentage were also measured in laboratory. Unweighted pair-group method of arithmetic averages (UPGMA) was performed to determine the individual relationship among populations of hoary cress. Five groups were classified based on the cluster analysis of populations of hoary cress which were mainly in accordance with geographic origins. Populations belonging to the northern latitudes had lower growth due to the decline in average daily cumulative annual radiation and air temperature with increasing latitude. These variations among populations may affect their responsee to specific herbicides. Factor analysis based on PCA revealed that three factors comprise almost 88.97% of total variations that the proportion of the first, second and third components were 67.39%,12.97% and 8.60%, respectively. Fresh and dry above ground and below ground weight, total fresh and dry weight and leaf length possessed the highest positive correlation with the first factor. Leaf width, stem height, silicle width, germination rate and germination percentage possessed the positive correlation with the second factor. Dry weight of aboveground / belowground ratio and number of stem (negative) possessed the highest correlation with the third factor.