1. Introduction
Ranunculus asiaticus L. is an important cut flower in the Mediterranean area where
its propagation is mostly done by seed (Meynet, 1993). Seed germination occurs during
autumn at a relatively low temperature (below 18OC) and the sprouted plantlets form a
rhizome at the beginning of the warm season. The most profitable flower harvest is
obtained with plants developed from rhizomes planted at the end of the summer. The
higher degree of cut flower production relies to a large extent on the selection of the best
genotypes, currently propagated by seed. Therefore, when a large amount of material is
required, it is difficult to obtain good uniformity both for flower colour and plant vigour
due to plant heterozygosis.
The Ranunculus cut flower market is based on production obtained from seedlings,
or from small (2-3 cm) or large (5-7 cm) rhizomes. Plants grown from large rhizomes
produce commercial flower stalks starting from October-November. Plants grown from
small rhizomes are not able to give a commercial production before January-February,
and plants from seed flower in March-April. Currently, tissue culture production of
Ranunculus is not widespread because of technical difficulties (e.g. sterilization of the
explants, choice of suitable starting material) and the high production cost (Lercari et al.,
1984; Beruto et al., 1989).
The purpose of this research was to evaluate the field performance of the in vitro
plantlets obtained both through axillary bud stimulation and through somatic embryogenesis.
A concomitant evaluation of the phenotypic stability of the ex vitro material has
been carefully canied out.