Tissue Culture Variability in Wheat: Callus Induction and Plant Regeneration1

Abstract

Thirty‐nine genotypes of winter wheat (Triticum aestivum L.) were examined for potential use in tissue culture studies. Tissue cultures were initiated from immature embryos approximately 12 days old on a modified Murashige and Skoog medium containing 1.0 mg 2,4‐dichlorophenoxyacetic acid (2,4‐D)/liter. Cultures were maintained on the same medium with 0.5 mg 2,4‐D/liter. Shoots were initiated by reducing the 2,4‐D to 0.1 mg/liter and complete plants were regenerated by transferring to 2,4,‐D‐free medium. Variability was observed among the wheat genotypes tested for callus induction, regenerable callus formation, response to subculture, and plant regeneration potential. Eighteen genotypes were capable of regenerating plants after four subcultures (90 to 125 days). Cultures from five genotypes remained totipotent after 240 days. Tissue cultures derived from ND 7532 and Roughrider remained totipotent for 420 days. Selection ND7532 demonstrated higher percentage of calli induction and regenerable calli formation, faster in vitro growth rates, and higher frequency of totipotent calli than other genotypes. Plant regeneration from tissue cultures derived from immature embryos is predictable and stable when the appropriate genotype is used. Five hundred thirty‐two plants were regenerated from callus tissue in this study and 510 of these produced seed. It appears that the response in tissue culture of cultivated wheat varies with genotype and that lines with good potential can be identified.