Abstract:
A study was conducted on local elite cultivars of American cotton (Gossypium hirsutum
L.) viz., MCU7 and TCH 1569 in order to assess their callusing as well as regeneration
potential. Although six different media compositions were tested for the callusing, results
revealed that the medium MS salts + 0.4 mg/I thiamine HG1 + 2.0mg/lNAA+ 1.0
mg/1 kinetin+30 g/1 glucose + 0.8% agar exhibited successful and faster induction of
calli. After the induction of calli, they were placed on different sub-culture media for
inducing embryogenic calli. However, significant differentiation for the formation of
embryogenic calli was not observed with the media compositions attempted in the
study. As the cotton crop is reported to be recalcitrant for regeneration through somatic
embryogenesis, to know the progress of tissue culture or development of embryogenic
calli, histological studies were carried out using microtomy. The results of
the microtome study clearly revealed the clumping and organisation of large number
of cells into a definite structure irrespective of the genotypes ancl explants. Therefore,
further manipulation or alteration of hormonal/vitamin combinations of media may
induce friable embryogenic calli resulting in mature somatic embryos, which will give
raise to a plantlet. This histological tool experienced as an efficient tool to save the time
in tissue culture by knowing the progress of somatic embryogenesis on the other hand
is also guiding the scientist to switchover to newer media composition in case of nonembryogenesis.
