Improving micropropagation conditions for adult-phase shoots of chestnut

Abstract

SummaryThis study aimed to optimize chestnut micropropagation by defining the best explant type for the shoot multiplication stage and by determining a root induction treatment, to balance rooting rate and plantlet quality, and maximize overall survival after transfer to soil. Shoot cultures of Castanea sativa and C. sativa x C. crenata were established in vitro using shoot tips and nodes from shoots forced on stump sprouts, epicormic shoots and crown branches collected from adult trees. The most productive explant type for subculturing was the basal nodal segment, especially when callus tissue was left on the subcultured basal segment. Although rooting capacity was significantly increased when a 7 d 3 mg 1−1 IBA treatment was combined with an initial 5 d dark period, the latter caused severe shoot necrosis. Acceptable rooting frequencies were achieved by a 24 h, 25–50 mg 1−1 IBA treatments without darkness, and for some clones were enhanced by addition of 1% activated charcoal to the root proliferation m...