Four strains ofDolichos lablab Linn. were treated with 0·5 per cent. aqueous solution of colchicine for 6 and 9 hours. Both the treatments were more or less equally effective.
Polyploid plants had bigger, thicker, coarser and dark green leaves. The increase in thickness was due to increase in palisade tissue.
Colchitetraploids had reduced fruit setting with shorter pods which contained fewer seeds. Many empty pods, sometimes with very small deformed seeds, were also found. The seeds in colchitetraploids, although variable in size, were generally bigger and heavier except in strain DL 279. Nearly 40% seeds were shrunken.
The zygotic number of chromosomes in the diploid and tetraploid is 22 and 44 respectively. Meiosis in diploids was regular. In tetraploids different chromosomal configurations from uni- to quadrivalent were seen. Laggards and precocious movements of chromosomes were conspicuous features and were more common in DL1458 and BR19 strains.