Evaluation of karyotypic relationship of several species of Bromus and Genea sections from Bromus genus

Bromus genus is one of the most important rangeland plants which have distributed in wide range of natural areas in our country. The interspecific relationship were evaluated in 45 diploid populations of two sections of Bromus and Genea, with 5 populations of Lolium multiflorum species based on karyotype characteristics. For each population five mitotic cells in metaphase stage were prepared from meristematic cells of root tips in newly germinated seeds. The total length, short arm and long arm length of chromosomes were measured. The centromer index, arm ratio, relative chromatin value, intrachromosomal and interchromosomal asymmetry index and total form percentage of chromosomes were calculated. The karyotypic asymmetry and types of chromosomes were determined. Variance analysis were showed a significant variation (P>0.01) between species and among populations. The populations had a symmetric karyotype which, were placed in A1 and A2 Stebbins’s classes and had a metacentric chromosomes and a few sub-metacentric chromosomes. The species of two sections were separated based on principal component and cluster analysis. The Karyotypic evolution for Bromus section was more from the chromatin value and for Genea section was further by increasing the asymmetry within and between chromosomes. B. briziformis Fisch. & C. A. Mey and B. squarrosus L. had the most karyotypic evolution and B. scoparius L. and B. danthoniae Trin. ex C. A. Mey. had the least karyotypic evolution in Bromus section. B. japonicus Thunb and B. rechingeri Melderis were placed between the two previous groups. B. tectorum L. were showed a karyotypic evolution more than B. sterilis L. and B. sericeus Drobow. in Genea section.