Optimal culture environment for anther-derived callus, embryo, and regeneration of strawberry ‘Jukhyang’

Abstract

This study investigated the optimal culture conditions of anther-derived callus induction according to heat shock treatment, culture medium, and the concentration of myo-inositol, AgNO3, and Fe-EDTA. We also explored the optimal culture conditions for the regeneration of haploid-derived plants, made by using anther-derived callus, according to the concentration of Murashige and Skoog (MS) medium and rhizosphere temperature. The highest callus induction rate by heat shock treatment was found when incubated at 32 °C for 24 h. Of the three kinds of culture medium used (MS, Lichter [NLN], and Gamborg B5), NLN showed the highest callus induction rate. The addition of 100 mg L−1 of myo-inositol showed a higher callus induction rate in all three media compared with treatments without myo-inositol addition. When AgNO3 was added, the highest callus induction rate was 71.4% at a concentration of 25 mg L−1. Fe-EDTA showed the highest callus induction rate of 51.0% when 100 mg L−1 was added. The 0.5-fold concentration of MS medium exhibited the highest regeneration rate (92.7%). To improve the acclimation efficiency and growth of the regenerated plants in vitro, the growth and survival rates of the regenerated plants were examined by adjusting the rhizosphere temperature to either 25 ± 2 °C or 18 ± 2 °C. The survival rate was 62.5% in both rhizosphere temperature treatments. However, the rhizosphere temperature of 25 ± 2 °C showed significantly higher shoot and root growth than treatment at 18 ± 2 °C. Summarizing the results of this study, embryogenic callus was most effective when cultured in a NLN medium supplemented with 100 mg L−1 Myo-inositol, 25 mg L−1 AgNO3, 75 mg L−1 Fe-EDTA for 24 h heat shock treatment at 32 °C. And the regeneration rate of anther-derived callus induced in the above conditions was highest when regenerated in × 0.5 MS medium. In addition, the regenerated plant had the highest growth and survival rate when acclimated in a growth chamber where the rhizosphere temperature was adjusted to 25 ± 2 °C.