BROMUS TOMENTELLUS BOISS آناليز خوشه اي مطالعات فنولوژي ، ريخت شناسي و سيتولوژي گونه

Cluster analysis of phenology, morphology and cytological studies of Bromus tomentellus Boiss

Bromus tomentellus Boiss is a perennial grass belonging to the Poaceae, which grows in wide range of distribution in Iran. This plant was important in rangelands, thus phenology, morphology and cytological study was carried out. In this regards the seeds of the plant belonging to the different areas were provided from the Gene bank around the country. The seeds were grown at glasshouse condition and the characters of morphology and phenology were studied during the vegetation growth. The results obtained from the study of morphology indicated: color of Cellolotic Fibril of base sheath, present or absent of hair and its density, number a. Td length and broad of leaf, culm length, number of tillering branch, spikelet length, spikelet number, upper and lower glumes length, lemma length and seed length are preferred characters. Phenology indicated three different growth stages. The first is vegetati .ʹP growth stage, which takes from March to July. The second is temporary dryness stage, which starts from early autumn to early spring for about 4-5 months. Flowering, seed ripening and seed falling take from April to May, May to June, and June to August , respectively. This research shows that this plant not only hasnʹt 28 chromosomes but also has 42 chromosomes and it is Hexaploid (2n=42, x=7) and classified into two groups based on the karyotype results. One group was consisted of 36 sub-metacentric and 6 metacentric chromosomes, whereas the other type contained 26 sub-metacentric and 16 metacentric chromosomes. Cluster analysis was performed based on the results obtained using UPGMA method and relevant dendrogram was constructed. The dendrogram showed two main clusters and each cluster containing the samples belonging to the same ecological areas. It was concluded that it is probably possible to identify different ecotypes of the species based on the geographical distribution.