RELATIONSHIPS BETWEEN PLOIDY VARIATIONS AND ORGANOGENIC POTENCY IN LONG-TERM CALLUS CULTURES OF ASPARAGUS OFF.
For clonal propagation of asparagus cultivars and selected parent plants for F1-hybrid seed production organogenic and dedifferentiated callus lines originating from meristem explants have been established over a great number of subculture steps (up to R = 45 – 55). Whereas the dedifferentiated strains of the genotypes under control lost their ability for regeneration of callus born shoots, in organogenic lines however the regeneration rate could be stabilized at a high level. The conversion of callus cells to meristematic cells is accompanied by protein deposition and accumulation in the vacuols. These storage proteins are used for subsequent synthesis of cytoplasm. Cytogenetical studies of the DNA-content in nuclei of callus cells showed that in cultures with high regeneration potency mostly 2C-nuclei existed, whereas in non organogenic callus peaks at 4C and 8C phases could be found. For the evaluation of the somaclonal variability the ploidy and the type of andromonoecism in the callus born asparagus plantlets are investigated. According to provisional results among a great number of progenies only one tetraploid plant was found.
Reuther, G. and Becker, U. (1987). RELATIONSHIPS BETWEEN PLOIDY VARIATIONS AND ORGANOGENIC POTENCY IN LONG-TERM CALLUS CULTURES OF ASPARAGUS OFF.. Acta Hortic. 212, 143-149