Elevated carbon supply altered hypericin and hyperforin contents of St. John's wort (Hypericum perforatum L. cv `New Stem') grown in bioreactors

For the high frequency selection of salt-tolerant doubled haploids (DHs) using rice anther culture, the efficiency of anther culture was investigated with different genotype, media condition and NaCl concentrations. The six F₁ hybrids obtained by backcross or three-way cross between indica and japonica differed in salt tolerance. The efficiencies of callus induction and plant regeneration was decreased by NaCl concentration and salt tolerance of donor variety, and those in japonicas were higher than those in indicas. The percentages of callus induction in Gyehwa 5 (japonica, tolerant) and IR61633-B-2-2-1 (japonica, sensitive) were 21.1 and 13.5% on agar medium containing 0.3% NaCl, respectively. The plant regeneration of callus derived from anther floating culture in liquid media was less than that on solid medium. In four F₁ hybrids, the frequencies of high salt-tolerant DHs were 21.4 and 8.9% in 0.3% NaCl medium and the control, respectively. The high frequency of salt-tolerant DHs could be selected in the callus induction medium (0.3% NaCl) and in the combinations crossed with salt-tolerant japonica as the third parent.