Abstract
In Crotalaria juncea (n=8) a plant exhibiting partial asynapsis was isolated in the M1 of a combined treatment of 50 kR gamma rays +0.2% EMS. The majority (48.14%) of PMCs at diplotene, diakinesis and metaphase I had 16 univalents. The bivalents in the asynaptic mutant were always rod-shaped with one terminal chiasma. In comparison, controls had on the average 7.08 ring bivalents. The asynapsis is genetically controlled, monofactorially recessive, and it is concluded that chromosome pairing is interrupted at a very early stage. There is a possible correlation between the number of bivalents and the arrangement of the univalents at metaphase I. When there were less than four bivalents, the univalents tended to be polar, and when there were more than four, the univalents were more equatorial in arrangement. The arrangement of univalents was random and apparently not influenced by the bivalents, when their number (4) was exactly half the zygotic number.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Bozzini, A. & Martini, G., 1971. Analysis of desynaptic mutants induced in durum wheat, Caryologia 24: 307–316.
Celarier, R. P., 1955. Desynapsis in Tradescantia. Cytologia 20: 69–83.
Darlington, C. D. & Haque, A., 1955. The timing of mitosis and meiosis in Allium escalonicum. Heredity 9: 117–127.
Dhesi, J. S., Gill, B. S. & Sharma, H. L., 1973. Cytological studies in desynaptic stock in pearl millet, Pennisetum typhoides. Cytologia 38: 311–316.
Gottschalk, W., 1978. Asynapsis and desynapsis. Cell Chrom. Newsl. 1: 19–22.
Gottschalk, W. & Baquar, S. R., 1971. Desynapsis in Pisum sativum induced through gene mutation. Can. J. Genet. Cytol. 13: 138–143.
Henderson, S. A., 1962. Temperature and chiasma formation in Schistoccrea gregaria II. Cytological effects at 40°C and the mechanism of heat-induced univalence. Chromosoma 13: 437–463.
John, B. & Lewis, K. R., 1965. The meiotic system. Springer, Vienna-New York.
Kativar, R. B., 1977. Radiocytogenetic studies in Capsicum. Induced desynapsis. Caryologia 30: 347–350.
Levan, A., 1940. The cytology of Allium amplectans and oscurrence in nature of its asynapsis. Hereditas 26: 352–394.
Magoon, M. L., Ramanna, M. S. & Shambulingappa, K. G., 1961. Desynapsis and spontaneous chromosome breakage in Sorghum purpureosericeum. Indian J. Genet. Pl. Breed. 21: 87–97.
Martini, G. & Bozzini, A. 1966. Radiation-induced asynaptic mutant in durum wheat (Triticum durum). Chromosoma 20: 251–266.
Östergren, O. & Vigfusson, E., 1953. On position correlations of univalents and quasibivalents formed by univalents. Hereditas. 39: 33–50.
Rees, N., 1952. Asynapsis and spontaneous chromosome breaking in Seilla. Hereditas 6: 89–97.
Seetharam, A., Nayer, K. M. D., Aradhya, B. S. & Hanumanthappa, H. S., 1975. An induced asynaptic mutation in finger millet (Elusine coracana Gaert). Cytologia 40: 301–305.
Sharma, R. K. & Reinbergs, E., 1974. Cytogenetic analysis of a desynaptic mutant in barley (Hordeum vulgare L.). Cytologia 39: 77–81.
Singh, R. B., Singh, B. D., Vijai, L. & Singh, R. M., 1977. Meiotic behaviour of spontaneous and mutagen-induced partial desynaptic plants in pearl millet. Cytologia 42: 41–47.
Sree Ramulu, K., 1973. A comparison of the effects of radiation and chemical mutagens on chromosome association and chiasma frequency in diploid Sorghum. Cytologia 38: 615–621.
Srivastava, H. M., 1974. Radiation-induced desynaptic mutant in barley. Cytologia 39: 63–68.
Sybenga, J., 1981. Specialization in the behaviour of chromosomes on the meiotic spindle. Genetics 57: 143–151.
Tyagi, D. V. S. & Das, K., 1975. Studies on meiotic system of some barley mutants induced through alkylating agents. Cytologia 40: 253–262.
Vig, B. K. & Mehrotra, H. N., 1965. Occurrnce of asynaptic chromosomes in Allium odorum. Sci. Cult. 31: 426–427.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Verma, B.C., Raina, S.N. Cytogenetics of Crotalaria VI. Chiasma frequency and position, and univalent behaviour in a (partially) asynaptic mutants of C. juncea . Genetica 58, 65–70 (1982). https://doi.org/10.1007/BF00056005
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00056005