Breeding and micropropagation of Alstroemeria pallida: a source for the development of winter hardy plants

Alstroemeria is a South American genus, represented by about 110 species. Among these species, Alstroemeria pallida is native to the Chilean Andes Mountains and, besides its attractive pink and big flowers, this is a winter hardy species, which is an important character pursued by breeders for garden plants. The aim of this research was to obtain hybrids using A. pallida as a parental line and develop an efficient micropropagation protocol for the hybrids. Fresh pollen was collected in situ from a natural population of several accessions of A. pallida to manually pollinate flowers of several hybrids of the Alstroemeria Breeding Program of the University of Chile. After 14 days, the embryos were rescued and grown under in vitro conditions using ½ strength MS medium supplemented with 30 g L^‑1 of sucrose and 7 g L^‑1 of agar. Successfully grown hybrids were multiplied and the effect of the MS medium (33, 66 and 100% MS), supplemented with different concentrations of BAP (6-Benzylaminopurine) (0.0, 0.5, 1.0 and 2.0 mg L^‑1) was assessed after 9 weeks. A total of 192 crosses were performed and the only successful crossing was achieved using 13B01 (hybrid) × 65B (A. pallida), from where three hybrids were obtained. The statistical analysis showed that there is no interaction between the levels of the MS and BAP factors for the length of the rhizome (cm), shoot length (cm) and explant weight (g). However, there was a combined effect for the production of new shoots, where the treatment supplemented with 33% MS and 1.0 mg L^‑1 BAP showed the highest response, with the production of 6.0 new shoots after 9 weeks. Thus, three promising A. pallida hybrids were obtained and efficiently micropropagated. Further studies should be performed to show the ornamental value and confirm the winter hardy character of these hybrids.