Treatments affecting maturation and germination of American chestnut somatic embryos

The effects of amino acids, abscisic acid (ABA), polyethylene glycol (PEG), and elevated sucrose were tested on the maturation and germination of American chestnut (Castanea dentata) somatic embryos. Somatic embryos from three lines were matured over an eight week period through a two-stage process. After maturation, somatic embryos were randomly divided into three groups to measure dry weight/ fresh weight ratios, starch levels, and germination rates. Prior to transfer to germination medium, somatic embryos received a four week cold treatment. While some treatments with amino acids, elevated sucrose, PEG or ABA increased either dry weight/fresh weight ratios, starch content or both, only addition of 25 mM l-asparagine significantly increased germination rate and taproot length, and this response was only obtained with one of the three lines tested. Six plants survived the transfer to potting mix, acclimatization to greenhouse conditions and field planting.