Induction of polyploidy in wild cotton species (Gossypium armourianum and G. aridum) by colchicine treatment.

摘要

In cotton, wild species generally have inbuilt resistance of desirable genes for biotic and abiotic stresses and possessing useful fibre qualities such as length and strength. Among the antimitotic agent, colchicine is widely used to induce doubling of the chromosomes in plant species. Attempt has been made to increase the ploidy level in two wild cotton species viz., Gossypium armourianum L and G. aridum L to make crosses with tetraploid G. hirsutum L. A dose dependent increase in ploidy level was observed. Significant difference was noticed in induction of polyploidy and plant growth rate that depend on dose of colchicine, duration of the treatments and type of plant material used. Increase in concentration of colchicine or duration of the treatment showed negative effects on seed viability in both the species under study. The colchicine treatment is more effective when the length of hypocotyls is between 4-8 mm. The root meristem of G. armourianum L treated with 0.7 per cent colchicine exhibited more tetraploid cells in 20 h of treatment. Increase in concentration of colchicine with increase in duration leads to chromosomal abnormalities in both the wild species. Among the three methods employed in inducing polyploidy in wild diploid cotton, application of colchicine on seed was more efficient and reliable than application on seedling and stem.