Direct shoot regeneration from mature embryo as a rapid and genotype-independent pathway in tissue culture of heterogeneous diverse sets of cumin (Cuminum cyminum L.) genotypes

A rapid and one-step protocol for direct regeneration of shoots from cumin embryo explants has been developed. Embryo explants with shoot meristems were cultured on shoot regeneration medium for 15-22 d. After embryo culture, shoots were regenerated from the area adjacent to the region between the cotyledons and embryo axis within 2 wk, without any intermediate callus phase. Shoot proliferation and elongation were achieved on shoot regeneration medium without subculture. Among the different combinations of 6-benzylaminopurine, alpha-naphthaleneacetic acid (NAA), and indole-3-acetic acid (IAA) tested, 0.8 mg l(-1) (4.3 mu M) NAA in combination with 0.3 mg l(-1) (1.71 mu M) IAA in the B5 medium resulted in the most efficient direct shoot regeneration. No significant difference was detected for the number of regenerated explants when different heterogeneous endemic varieties were compared. This plant regeneration procedure was applicable to different cumin genotypes and regenerated plants were phenotypically normal.