Title

New techniques for the {\it in vitro\/} culture of {\it Alstroemeria\/} hybrids

Date of Completion

January 1998

Keywords

Biology, Botany|Agriculture, Plant Culture

Degree

Ph.D.

Abstract

Butterfly-type and hybrid-type Alstroemeria hybrids were grown on different media at different concentrations of 6-benzylaminopurine (BA) and 1-naphthalene acetic acid (NAA). BA was necessary to induce rhizome branching and concentrations higher than 0.4 $\mu$M BA did not increase branching. Differences in branching ability between hybrid-type and butterfly-type and within the butterfly-type group suggested that branching strongly depends on genotype. NAA was necessary for rooting in vitro and for survival after transplanting into soil.^ Liquid, shaken cultures of Alstroemeria 'Sweet Laura$\sp\circler$' and 'Redcoat$\sp\circler$' showed that liquid medium did not induce hyperhydricity but increased rhizome branching after 6 and 9 weeks of subculture. Completely submerged and partially submerged liquid static cultures of 'Sweet Laura$\sp\circler$' and 'Redcoat$\sp\circler$' did not induce hyperhydricity although explant survival was only 72.2% and 80.0%, respectively. Survival was higher in 'Sweet Laura$\sp\circler$' than in 'Redcoat$\sp\circler$' and partially submerged explants had 100 and 60% survival, respectively, making partially submerged liquid culture of 'Sweet Laura$\sp\circler$' a valid alternative to semisolid medium.^ Alstroemeria rhizome tips could be split in 2 halves with a horizontal or a vertical cut and were able to regenerate new rhizomes from their axillary buds. Survival of the splits was 85.9 and 80.7% for 'Sweet Laura$\sp\circler$' and 'A30', respectively. Over a period of 12 weeks, rhizome splitting with vertical cut allowed to increase propagules production of 194% for 'Sweet Laura$\sp\circler$' and 213% for 'A30'.^ Axillary meristem tips excised from rhizomes were the best initial explants for meristem culture of Alstroemeria. BA was not essential for rhizome formation, although the use of 8.9 $\mu$M BA significantly increased the number of meristems that did develop into a rhizome. Size affected explant survival and the percentage of alstroemeria mosaic potyvirus (AlMV) that was eradicated. Meristem tips (0.7 mm) and buds (2 mm) had 12.2 and 34.7% survival, respectively, while the rate of AlMV elimination was 73.7 and 14.7%, respectively.^ Virus-free plants produced more floral and vegetative stems, longer floral stems and had higher fresh mass than infected plants. ^