studies on cytogenetical specificity of a few masses of cultivated domestic onion in iran

onion is one of the important strategic crop plants of a highly valuable nutritional food source consumed almost around the whole world. thus the genetically oriented studies around the plant are valuable and inevitable. for a following of these studies some onion masses from various regions throughout iran including: kashan white azarshahr red isfahan dorcheh ghom white zanjan gholigheseh yasouj local herssin nishabour ishaghabad yazd abarkoh ramhormoz against two important commercial varieties texas early grano and yellow sweet spanish were taken into consideration. the obtained results were arc signed and then subjected to dmrt analysis and as well to cluster analysis according to ward’s minimum variance method using the cluster procedure of sas computer software. the base chromosome numbers were=8 for the studied masses in which number of chromosomes length of the longest chromosome length of the shortest chromosome longest/shortest length ratio average of long arm/short arm ratio as well as the average of chromosome ratios were recorded. the types of chromosomes were found to be meta centric sub meta centric and sub telo centric. a comparison of the relative length of the shortest chromosome (s %) showed that whereas kashan white and ramhormoz masses had the more symmetric karyotype respectively azarshahr red and herssin were respectively of the lesser symmetric karyotype. a comparison of differences in relative length (drl) revealed that kashan white and herssin masses are of the more symmetric karyotype respectively while ramhormoz and texase erly grano are respectively of a lesser symmetric karyotype. also in this study it was shown that isfahan dorcheh kashan white zanjan gholigheseh yasouj local ramhormoz and nishabour ishaghabad masses carry micro satellites that are similar to those in texas early grano masses’ and yazd abarkoh ghom white herssin and azarshahr red masses possess macro satellites similar to those in yellow sweet spanish masses. according to the dispersion diagram based on a1 (intra asymmetry chromosomal index) and a2 (inter asymmetry chromosomal index) the masses were grouped into two distinct classes as in confirmation with the results of cluster analysis.