Division of Genetics, Indian Agricultural Research Institute, Delhi-12
* Present address: Department of Plant Breeding, Punjab Agricultural University, Ludhiana, Punjab.
1Part of the thesis submitted in partial fulfilment of the degree of Doctor of Philosophy of I.A.R.I., New Delhi.
X-irradiated diploid (2n=20) and autotetraploid (2n=40) Brassica campestris var. toria were studied for induced morphological changes. Tetraploid plants having closed petal and dark yellow flowers were found in the M1 generation. In the M2 and M3 generations, closed petal, semi-closed petal and apetalous plants were also observed in the irradiated tetraploid populations. Tetraploid plant progenies also segregated for normal and yellow seed-coat colour in the M2 and M3 generations. None of these changes were recorded in control or irradiated populations of diploid toria. The possible role of radiation in inducing such changes and the wider phenotypic range in polyploids is discussed.
