Successful plant regeneration was reported from the calli derived from immature embryos, immature tassels and nodal sections of maize (S. J. Molnar et al., MGNL 54:52, 1980; C. A. Rhodes et al., MGNL 56:148, 1982). The present study was mainly aimed at testing the totipotency of glumes of different developmental stages of four genotypes.
Fresh immature tassels of sweet corn, DHM-101, DHM-103 and Ganga-5 were collected from 55, 60 and 65-day-old field grown plants (Kharif season, 1982), and were sterilized with 0.1% mercuric chloride for three minutes. Antherless glumes were inoculated onto Murashige and Skoog's medium supplemented with 2 mg/l 2,4-D. Subcultures were made every three weeks on MS medium with 1 mg/l 2,4-D.
Glumes of sweet corn after two to three weeks of inoculation gave rise to callus, whereas other genotypes responded poorly. Rapidly growing light green friable callus was observed from the base of the glume irrespective of the position of the glume on the tassel. Of the different age groups tested, glumes of 55-day-old plants exhibited greater response of callus initiation (45-50%) compared to others. Rhizogenesis was observed on basal medium devoid of hormones, and complete plantlets regenerated on MS medium supplemented with 1 mg/l IAA and 1 mg/l KN.
Out of the different hormonal combinations and concentrations tested, 1 mg/l IAA and 1 mg/l KN gave high frequency of plantlet regeneration. The specific age of the glume seems to play an important role, both in callus initiation and plantlet regeneration. This finding may be useful in clonal propagation of male sterile lines.
P. S. Prasanna, K. V. Rao and G. M. Reddy
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