A novel approach for rapid micropropagation of maspine pineapple (Ananas comosus L.) shoots using liquid shake culture system

Maspine (Ananas comosus L.) is currently the most preferred pineapple variety in Malaysia due to its pleasant aroma and applicability in caning. Large quantities of plant materials are needed to fulfill the market demand which could not be obtained from the conventional breeding method. Hence, in vitro procedure was developed as an alternative method to improve the multiplication rate of this special variety. Sterilized explants were cultured on solidified Murashige and Skoog (MS) medium supplemented with various combinations of 6-benzylaminopurine (BAP) (1 to 5 mg/l) and ∝-naphthaleneacetic acid (NAA) (1 to 5 mg/l) hormones. Pineapple plant cultures required 5 mg/l BAP to significantly increase the shoot development during the in vitro stage. In addition, explants were subsequently sub-cultured on medium with 1 mg/l BAP which produced highest number of proliferated in vitro plantlets. The optimization of the conditions for shoot propagation was carried out in both liquid and solid medium by supplementing with 1 or 5 mg/l of BAP. MS liquid medium supplemented with 1 mg/l BAP produced the highest number of shoots (31) after 4 weeks. The number of shoots formed was increased to 204 after third sub-culture in liquid medium. Shoot proliferation was increased up to nine-fold in liquid medium when compared to the cultures maintained on solid medium. This improved method of Maspine in vitro multiplication will serve as an alternative source of planting materials of this cultivar for subsistence and large-scale pineapple farmers.Key words: Pineapple, in vitro, 6-benzylaminopurine, ∝-naphthaleneacetic acid, liquid medium