The present investigation involves the meiotic studies on two species of Pouzolzia (family Urticaceae) from western Himalayas, India. Both the species uniformly revealed chromosome count of 2n=26 which is first ever chromosome report for Pouzolzia pentandra (Roxb.) Benn. on worldwide basis and first chromosome report for Pouzolzia hirta (Blume) Hassk. from western Himalayas. This is also the first report of cytomixis in P. hirta. In addition to bridge formation and extra chromatin material, chromosome stickiness was the most frequent meiotic chromosomal anomaly found in both the species. In spite of abnormalities there was no adverse effect on pollen fertility. Morphological analysis of P. pentandra revealed the existence of two morphotypes.

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Hybridity, genome differentiation and relationship were investigated in an interspecific F1 hybrid (2n=45) artificially produced between Chrysanthemum latifolium (Shih) H. Ohashi et Yonek. (formerly: Ajania latifolia Shih) (2n=36) and C. grandiflorum Ramat cv. ‘Red Betty’ (2n=54) by FISH (fluorescent in situ hybridization) and GISH (genomic in situ hybridization) using 5S, 45S and total genomic DNA labeled probes. Seventy-three hybrid seedlings were successfully produced only in vitro. FISH on the chromosomes of the hybrid had 11 signals of 45S rDNA sites, while five and six signals of the 5S rDNA were detected. GISH distinguished approximately 27-yellow-colored chromosomes were hybridized with the probe of C. latifolium and 18 redcolored were not, which could be characteristics of C. grandiflorum cv. ‘Red Betty’. Nine out of the 27 chromosomes were common homologous chromosomes of the two genomes. The 18 red-colored chromosomes, which isolated by GISH without using blocking DNA, might come from a distantly related ancestor of C. latifolium.

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In this study the chromosome counts of 12 populations belonging to Achillea aleppica DC. growing in the West of Iran are reported and nine populations were selected for karyotype analysis. Results showed that the studied populations had the basic chromosome number x=9 with ploidy levels ranging from 2x to 6x, while two populations with the chromosome number 8x were determined. The B chromosomes were observed in some of the populations. A low frequency of chromosomal bridge/lagging chromosomes was observed in the all specimens. Length of chromosomes ranged from 3.74 to 10.34 μm. The karyotype formula was 14m+4sm or 13m+5sm in the populations with chromosome number 18, and 56m+10sm+6st or 50m+18sm+4st in the populations with chromosome number 72, respectively. The further karyological studies on the basis of symmetry showed that the most of the studied populations have relatively high symmetrical karyotype (2A), and only a population showed asymmetric karyotype (2B).

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Assessment of the cytogenetical and biochemical studies in two varieties of Stevia rebaudiana Bertoni were performed. The effect of EMS (ethyl methane sulphonate) on mitotic, meiotic analysis and amount of sugar contents were analysed indicating that EMS caused various mitotic and meiotic abnormalities as well as sugar contents were enhanced. Significant dose dependent increase in total soluble sugars, reducing sugars and non-reducing sugars were recorded.

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The study provides cytological and biochemical changes (estimation of oil) by inducing chemical mutagen. Various abnormalities were observed after treatment in two species of Cymbopogon. Cymbopogon martinii var. Motia was noted as sensitive and Cymbopogon flexuosus as resistant in two generations. Percentage of oil was slightly higher after treatment with EMS in both the species of Cymbopogon.

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Most of the species of the Morus are diploid having 28 chromosome, but a few species, namely, M. tiliafolia Makino, Morus cathyana and M. nigra L., are higher polyploidy. Chromosome number varies from 2n =28 to 2n = 308 with ploidy level from x to 22x. In the present study two diploid mulberry varieties namely, Kollegal and DD have been analyzed for both mitotic meiotic studies. Based on the somatic chromosome number, ploidy level, chromosome configuration and other meiotic behavior x = 14 have been considered as basic number of the genus. Meiosis showed marginal differences. Various meiotic abnormalities like occurrence of one large chromosome, stickiness and loose association of chromosomes at metaphase I, unequal separation at anaphase I, laggards, precocious movement and unequal separation of chromosomes at anaphase II, have been observed. The low pollen fertility and seed set may be due to irregular chromosomal pairing and separation rather than due to genic or physiological causes.

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