Summary Seeds of Capsicum annuum L. var. G-4 Bhagyalakshmi were subjected to 15, 25, 35 kR doses of gamma ray, and 0.8% and 1% ethyl methane sulphonate (EMS). Effects of mutagenic treatments of meiosis viz. chromosomal anamolies, pollen sterility, seed sterility and survival percentage in M2 generation have been reported. EMS was found more effective in inducing meiotic irregularities than gamma ray treatment. A dose dependent increase in meiotic anomalies was obtained with all the mutagenic treatments.Mutations can be beneficially utilized for tailoring better varieties of crop plants. But in general, ionizing radiations and chemical mutagens like ethyl methane sulphonate (EMS) effects a wide range of chromosomal alterations resulting in to abnormal behaviour during meiosis, leading to various degree of sterility. Further, the cytological abnormalities during meiosis has also been regarded as one of the dependable parameters for estimating mutagenic sensitivity of a species. Though considerable work has been done on induced mutation studies in red pepper (Bansal and Dalmirsingh (1972), Han (1974), Auni et al. (1978), Lakshmi and Bapa Rao (1978), Kumar et al. (1986), Meshram et al. (1992)), there was no current report available on physical and chemical mutagen effect on meiosis in the existing promising varieties of Capsicum annuum L. Hence, the present study is undertaken to assess the meiotic consequences of chromosomal aberrations induced by separate and combined application of gamma rays and EMS. Materials and methodsDry seeds of Indian popular chilli variety G-4-Bhagyalakshmi were subjected to mutagenic treatment with gamma rays and ethyl methane sulphonate (EMS). Seeds were irradiated with 15, 25, 35 kR doses of gamma rays from 6°Co source. A second set of seeds were soaked in 0.8% and 1.0% solution of EMS for 12 h at 23 -± 1°C. Another set of seeds were also subjected to combined doses of gamma rays and EMS in the following combinations; i) 15 kR+ 0.8% EMS ii) 15 kR+ 1% EMS iii) 25 kR+ 0.8% EMS iv) 25 kR+ 1% EMS v) 35 kR+ 0.8% EMS iv) 35 kR+ 1% EMS The control seeds were soaked in distilled water for 24 h at room temperature. After treatments seeds were throughly washed and sown in the nursery beds along with control seeds. Forty-five old day seedlings were transplanted in the field. For meiotic studies, young flower buds were fixed in Carnoy's fluid (6 : 3 : 1) for 24 h and then transferred to 70% ethyl alcohol. Squash preparations were made with 2% acetocarmine. Results and discussionsThe pollen mother cells (PMC's) of control plant showed regular 12 bivalent uniformly at

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Karyomorphological analysis of seven Gossypium species belonging to 'A' (G. arboreum, G. herbaceum), 'D' (G. aridum, G. armourianum, G. davidsonii), 'AD' (G. hirsutum, G. barbadense) genome was carried out. All the species invariably shows the basic chromosome number as xϭ13. The chromosome size ranged from 1.1 to 4.7 mm. G. aridum had the smaller mean chromosome length (1.15 mm) while G. barbadense had the larger chromosome (4.7 mm). Karyotypes were of symmetrical type possessing long and short chromosomes in equal proportions. The satellite chromosomes were located in the long arm of one or two metacentric pair. The species varied with regards to number of SAT chromosomes and chromosome carrying secondary constrictions. Cluster analysis was done to group the species. It shows that the cotton species studied falls in to three distinct clusters. Results also revealed that the popular, cultivated American cotton G. hirsutum, and the Egyptian cotton G. barbadense might have originated from the crosses between the Asiatic cotton G. arboreum, G. herbaceum ('A' genome) and the American wild cotton G. aridum, G. armourianum, G. davidsonii ('D' genome). The present finding clearly indicates the genomic differences within the diploid species and between the diploid-tetraploid species of cotton can be utilised in hybridization programmes. Crossing of the species placed in distant clusters are suggested.

Chromosome studies and in situ estimation of nuclear DNA content were carriedout in two different cultivar of Z. officinale Rosc. Somatic chromosome number 2n=22 was found to be constant in both the cultivars. Karyomorphological analysis indicated high heterogenity. DNA content of these two cultivars were highly varied and a correlation could be obtained between the amount of 4C DNA and the total chromosome length. Average packing ratio was workedout from which the relation between the 4C nuclear DNA content and the total chromosome length were established.

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