Seeds of Capsicum annuum L. var. G4 were subjected to different concentrations of methyl methane sulphonate (MMS) and diethyl sulphate (DES). The effects of different mutagenic treatments on meiosis, chiasma frequency, and pollen fertility have been studied in M1 generation. Various types of meiotic aberrations such as univalent, multivalent, stickiness, bridge, laggards, cytomixis etc. were observed in all the treatments. However, the MMS treatments proved to be more effective in inducing meiotic aberrations as compared to DES. Moreover, the frequency of meiotic aberrations was at its maximum at metaphase followed by anaphase and telophase stages. As the concentrations increase, reduction in chiasma frequency and pollen fertility was observed in all the treatments and, MMS again was found to be more effective than DES treatments.

Summary Seeds of Capsicum annuum L. cv. Pusa jwala and G 4 were treated with varying concentrations of methyl methane sulphonate (MMS), and the effect of various concentrations of MMS on each stage of meiosis has been studied in M1 generation. Various types of meiotic abnormalities and reduction in chiasma frequency were observed in treated populations. However, MMS treatment were found to be more effective in inducing meiotic abnormalities and reduction in chiasma frequency in Pusa jwala as compared to G 4 . Moreover, a co-linear relationship between increasing concentrations of MMS and reduction in chiasma frequency was also observed. Taking the percentage of meiotic abnormalities and reduction in chiasma frequency as an index of sensitivity of genotype to MMS, Pusa jwala was found to be more sensitive than G 4 . Key words Capsicum annuum, Chiasma frequency, Meiotic aberrations, MMS.Mutagenesis is an important method of inducing variations in a number of plant characters from time to time, and has a great relevance for raising superior plant types in different crop plants. Mutagenesis is a potential tool for the selection of efficient mutagens and their treatment doses are prerequisite for obtaining the potential mutations.Cytological studies are necessary to obtain information regarding the effect of the mutagens and in elucidating the response of various genotypes to a particular mutagen. Chemical mutagens provide a very good tool for creating alterations in the genotypes and enhancing the variability of characters. Keeping in view the economic importance of C. annuum (2n=24), as a vegetable as well as a spice crop, the present study was under taken to asses the effect of MMS on 2 cultivars of C. annuum. Materials and methodsFresh and healthy seeds of C. annuum cv. Pusa jwala and G 4 , obtained from the Indian Agriculture Institute New Delhi, were presoaked in distilled water for 12 h under laboratory conditions and then treated with different concentrations of MMS i.e., 0.01%, 0.02%, 0.03%, 0.04% and 0.05% for 7 h. The controls were maintained separately. After each treatment seeds were thoroughly washed in tap water and sown in earthen pots to raise the M 1 generation. After 30 days of showing, the seedlings were transplanted into the field. At the flowering stage young flower buds were collected and fixed in freshly prepared Carnoy s fixative for 24 h and preserved in 70% ethanol to study the chromosomal behavior at different stages of meiosis in the pollen mother cells (PMCs) of both control and treated plants. Squashes were made in 2% acetocarmine and the data was recorded at each stage of meiosis.

Cytogenetical investigations have been carried out on Hordeum vulgare. Seed of H. vulgare were treated with different concentrations (0.1, 0.2, 0.3, 0.4 and 0.5%) of ethyl methane sulphonate (EMS) and hydrazine hydrate (HZ). The plants in the treated populations showed varying degrees of meiotic irregularities almost at all the mutagenic concentrations. The frequency of meiotic irregularities was found to be more in HZ treatment than EMS. The various types of meiotic abnormalities such as univalents, multivalents, stickiness, precocious movement, stray bivalent, non-orientation, cytomixis, laggard, bridges, unequal separation, micronuclei and disturbed polarities were observed. Taking the percentage of meiotic abnormalities and pollen sterility as an index of effectiveness of a mutagen, HZ treatment was found to be more effective.

This work was done to study the effect of base analogue 5-bromouracil (5-BU) on the medicinal herb, Cichorium intybus. 5-BU induced miss pairing during the DNA replication. The seeds of C. intybus were treated with different concentrations of 5-BU. Variations in some parameters such as seed germination, seedling survival, seedling height, pollen fertility, days to flowering, days to maturity, number of leaves per plant, plant height, and chromosome behavior were studied in M1 generation. A positive correlation between increasing concentrations of mutagen and various cytomorphological characters of C. intybus was observed.