Callus cultures of shoot base and node

The present study was undertaken mainly to test the efficiency of different anthocyanin genotypes and some local varieties of maize in callus initiation and plantlet regeneration. Different explants (seedling root, shoot base, node, endosperm, embryo and glume) were used. Regenerable cultures have been obtained from immature embryos, shoot bases, first nodes and glumes.

Shoot bases of germinated immature embryos and first nodes of 6- to 7-day-old seedlings were inoculated onto Linsmaeir and Skoog's media containing 2,4-dichlorophenoxy acetic acid (2,4-D), and the cultures were placed under diffused light at 26+1 C. Callus was initiated within two weeks of inoculation from shoot base and node. Subcultures were carried for every two weeks, the 6- to 7-week-old calli of the shoot bases were kept for regeneration on LS basal medium devoid of hormones, and nodal calli on LS medium supplemented with 1 mg/l indole 3-acetic acid (IAA) and 1 mg/l Kinetin (KN).

Germinated immature embryo shoot base not only callused more efficiently compared to mature seedling shoot base, but organogenesis resulting in distinct roots and shoots was observed with greater frequency, while only rhizogenesis was observed in the latter. First node callused efficiently on LS medium supplemented with 4 mg/l 2,4-D compared to medium with 2 mg/l 2,4-D. Regeneration into roots and shoots was observed on LS medium with 1 mg/1 IAA and 1 mg/l KN. Callus initiation and plantlet regeneration was more efficient in the 150/2 Ludhiana variety of Dr. A. S. Khehra, for shoot base and heterozygote of bronze-1 and bronze-2 (Bz1 bz1 Bz2 bz2) for node, over other tested varieties.

K. V. Rao, P. S. Prasanna and G. M. Reddy

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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