In the present
investigation, the influence of different forms of cytokinins, auxins and
polyamines were tested for mass multiplication and regeneration of cotton.
Initially, for the identification of effective concentration for multiple shoot
induction, various concentrations of BAP, Kin and 2iP along with IAA and NAA
were tested. Among tested concentrations, media fortified with MS salts; B5
vitamins; 30 g/l, glucose; 2.0 mg/l, 2iP; 2.0 mg/l, IAA and 0.7 % agar showed
best response for multiplication of shoot tip explants (20 shoots per shoot tip
explants). In nodal explants, maximum of 18.6 shoots were obtained in the media
fortified with MS salts, B5 vitamins, 30 g/l, glucose, 2.0 mg/l, 2iP, 1.0 mg/l,
0.7 % agar. Effect of different concentrations of polyamines like spermidine
and putrescine were also tested along with the above said multiplication media.
Among the various treatments, 20 mg/l of putrescine showed best response and
the multiple of shoots were increased to 26.5 shoots per shoot tip explants and
24.5 shoots per nodal explants. Elongation of shoots was achieved on multiple
shoot induction medium. Significant number of roots were initiated in the
medium supplemented with MS salts, vitamin B5 and 1BA (2.0 mg/1). The frequency
of root induction was increased by addition of, PVP (10 mg/l) along with root
induction medium and after 2 weeks, the roots reached the maximum length of 22 cm. Further, these
plantlets were hardened by using sand, soil and vermiculate in 1:1:1 ratio. The
hardened plants were transferred to the environmental growth chamber for proper
acclimatization. The hardened plants were then transferred to field for boll
yielding and they exhibited 100% survival.