Pengembangan metode organogenesis dan embriogenesis somatik pada nenas (Ananas comosus (l.) Merr.) Serta deteksi dini untuk mereduksi keragaman somaklonal

Abstract

Pineapple is a unique plant belongs to facultative CAM (Crassulacean Acid Metabolism) photosynthesis. It is highly potential to be planted on suboptimal land. Conventionally, it can be propagated from many propagules but their reproductive time is not uniform and this availability is commonly limited in cultivar Smooth Cayenne. Today micropropagation is being used commercially in the pineapple industry abroad but in Indonesia, the industries survive with conventional vegetative propagation because of somaclonal variation. The main goal of the study was to obtain the effective regeneration method of pineapple with high level of seedling production and low level of somaclonal variation, included the artificial seed formation method, the early detection method of somaclonal variation for eliminating undesirable traits during micropropagation, and the method to reduce the level of somaclonal variation during micropropagation. This study was devided into six chapters, included the study of morhogenetic system (with solid and liquid media); direct organogenesis induced by auxin and cytokinin (IAA, IBA, NAA, and BA); indirect organogenesis and somatic embryogenesis induced by 2,4-D, picloram, adenine sulfate, and N-organic compounds; encapsulation and minimal growth induced by paclobutrazol, mannitol, and reduced temperature; morphological and molecular characterization by using RAPD markers; and early detection to reduce of somaclonal variation. Generally, this study has some novelities in the in vitro characterization, the information of the non dead-end mechanism of rooted pineapple explants, the information of the complete events of somatic embryogenesis, the conservation method by minimal growth, and the large number of variants. The result showed that the direct and indirect organogenesis generated high shoot multiplication level. The use of mannitol (4%) was better than paclobutrazol for storing the encapsulated explants for 4 months. The morphological characterization could easily differentiate the normal and the abnormal variants (off-types). The direct organogenesis showed the lower level of variation (1.6%) compare to the indirect organogenesis (2%) and somatic embryogenesis (31.1%). The RAPD analysis strengthened the occurence of somaclonal variation. The use of the new in vitro cultures could reduce somaclonal variation. In conclusion, the direct organogenesis was the effective regeneration method for mass propagation. The morphological characterization of in vitro cultures can be applied as guidance for early detection and elimination of undesirable variants in mass propagation. The in vitro conservation method by mannitol can be applied to store pineapple cultures for medium-term period. The use of the new in vitro population could reduce the level of somaclonal variation.