Comprehensive Genetic Studies on Available Accessions of Stipa Genus
2005
Pur Meydani, A`bbas | Mirza`i Nadushan, Hoseyn | Maddah A`refi, Hasan
This study was carried out to evaluate the cytogenetic properties of 10 native accessions of Stipa collected from different regions of Iran in 1998-2004. The result of chromosome numbering showed the 10 accessions are tetraploid. In general, surveying karyotypic symmetry of accessions is based on chromosome length variation coefficient (C.V), total form percentage (%TF), relative length of shortest chromosome (%S). Analysis of variation showed chromosoms and ecotypes have significant effects on the traits measured (P 0.01). Significant effects of interaction between ecotype and chromosome showed that chromosomal changes is different in the ecotypes. Average lenght of a genome was 41.05 to 53.5 and for single chromosom was 1.85-2.36. Karyotype grouping by Stebbins method showed that most of them placed in B2 cluster so they show assymetry in karyotype. Based on form percentage, relative length of the shortest chromosom and the range of relative length, karyotype number 22 was the most symetric and number 6 was the least symetric karyotype. Chromosomal traits correlation coefficient reduced for long arm length, length of short arm and length ratio of long arm to short arm between accessions, showing the occurrence of structural changes in chromosoms by means of centromer displacement. The cluster analysis on the statistically significant chromosomal traits (length of long arm, short arm and chromosome length), showed that groups have signigicant differences based on the traits cluster analysis devided the genotypes to three groups. Analysis of variance of 15 accession based 8 agronomic trait showed that this accession are significant at 5% probability level (except of node 1,2 interval).
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