In vitro morphogenetic competence of basal sprouts and crown branches of mature chestnut.

Basal shoots of five clones of mature chestnut tree (Castanea sativa Mill. and C. sativa x C. crenata Siebold & Zucc.) had a greater capacity for in vitro establishment, multiplication and rooting than crown branches of the same trees. Cultures from basal shoots were more responsive than crown-derived cultures in terms of in vitro reactivity (proportion of the explants with shoot development), the mean number of shoots formed per explant, the length of the tallest shoot in each culture, and the multiplication coefficient (defined as the product of the reactivity and the mean number of shoots per explant). Multiplication coefficients were greatest between subcultures 6 and 12, but subculturing failed to increase the rooting potential of shoots of crown origin. Multiplication and rooting rates were also determined for clones derived from seeds of mature trees. Genotype influenced the in vitro performance of clones of both adult and seedling origins.