The present study revealed the chromosomal behavior of Trigonella foenum-graecum L. following treatments with gamma (γ) rays, ethyl methyl sulphonate (EMS) and Sodium azide (SA). The treated populations exhibited various meiotic abnormalities such as stickiness, univalents, precocious segregation, laggards, bridges, cytomixis and so on. The frequency of meiotic aberrations increased with the increase in dose/conc. of the mutagens. Maximum frequency of meiotic aberrations was recorded at 400Gy (15.12%) followed by 0.4% EMS (13.04%) and 0.4% SA (10.50%). In general γ-rays induced greater percentage of chromosomal aberrations followed by EMS and SA (γ-rays ⟨ EMS ⟨ SA). Pollen sterility also increased with the increase in mutagenic treatment, maximum sterility being observed at 0.4% EMS (58.01%). The order of effectiveness for pollen sterility was EMS ⟨ γ-rays ⟨ SA. The lower dose/conc. of all these mutagens could be ideal for induction of micro-mutations and enhancement of genetic base in the crop species under consideration.

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Fluorescent banding with chromomycin A3 (CMA) and 4’,6-diamidino-2-phenylindole (DAPI), and fluorescence in situ hybridization (FISH) were employed to investigate the chromosome differentiation in C. melo and C. metuliferus. The chromosome number of 2n=24 was counted in the two species. Average chromosome lengths, total chromosome lengths and ranges in chromosome lengths of the two species were very similar to each other. In spite of the karyomorphological similarity, fluorescent chromosome banding pattern was quite different in each other. Unlike the C. melo, C. metuliferus had unexpected chromosomespecific CMA and DAPI bands, especially in prometaphase. In FISH, two 5S rDNA and four 45S rDNA signals were detected at the ends of chromosomes of C. melo, while two 5S rDNA and two 45S rDNA signals were detected at the ends of chromosomes of C. metuliferus.

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Cytological studies were made in 14 populations of Achillea wilhelmsii C. Koch (Asteraceae) collected in west of Iran. Chromosome numbers in the species varied from 2n=2x=18 in a population to 2n=4x=36 in 13 populations. Thus, two ploid levels on the basis of the basic chromosome number of X=9 were shown during the course of investigation.

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Cytogenetic investigation was carried out to clarify cytogeographic distribution of two cytotypes with different ploidy level, and to speculate chromosomal differentiation of Goodyera foliosa in southwest Japan. All observed individuals in G. foliosa var. foliosa had tetraploid number of 2n=56, while the all individuals in G. foliosa var. laevis had diploid number of 2n=28 and tetraploid number of 2n=56. Total chromosome lengths at metaphases in tetraploids in the both varieties were nearly twice as long as those of the diploids. In G. foliosa var. laevis native to Hiroshima Prefecure, cytogeographic investigation showed that the tetraploid populations were located more west than those of diploids.

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