Cytogenetical Investigation of a Translocation Heterozygote Induced by Gamma Rays in Coriandrum sativum L.

抄録

Seeds of Coriandrum sativum L. (Coriander) cultivar CO-2 were irradiated with different doses (100, 200, 300, 400 and 500 Gy) of gamma rays. During the meiotic analysis of pollen mother cells (PMCs), a plant having segmental exchanges between non-homologous chromosomes was isolated in populations raised from 100 Gy irradiated seeds. This paper documented with structural heterozygosity along with cytological behavior of translocation heterozygote induced and the probable cause of its occurrence in the coriander. Morphologically, the plant was weak with short height in contrary to control and irradiated populations. In the plant cytological manifestation of chromosome configurations at diakinesis and metaphase I revealed the predominance of ring octavalents with tetravalents and bivalents. In a few PMCs, the variable number of associations in the form of multivalents along with univalents and bivalents were also screened out. The induced translocation heterozygote showed unequal segregation of chromosomes, laggards, and bridges along with normal 11 : 11 separation at anaphase I. Furthermore, due to chromosomal anomalies, pollen fertility was declined to 37.36% as an overwhelming adjacent orientation (53.16%). Translocation heterozygotes may provide a source for creating aneuploids with novel gene combinations.