Indirect organogenesis and assessment of somaclonal variation in plantlets of Vanilla planifolia Jacks

The low genetic variability of vanilla (Vanilla planifolia Jacks.) makes it susceptible to pests and diseases, which leads to a decrease in production. The genetic variability can be broadened by using in vitro plant tissue culture techniques. The use of indirect morphogenic routes allows increasing the percentage of somaclonal variation in regenerated plantlets. The objective of this research was to establish a protocol for indirect organogenesis in V. planifolia aimed at broadening the genetic base of the crop. A friable callus was induced from immature seeds grown in the dark, using MS medium supplemented with 2.27 μM thidiazuron (TDZ). Subsequently, 6.8 shoots per callus were regenerated in MS medium supplemented with 8.88 μM benzyladenine (BA). One hundred per cent rooting of regenerated shoots was achieved when MS medium was used with no plant growth regulators. Last, rooted plantlets were acclimatized in a greenhouse. A 91 % survival rate was observed. Molecular analyses on regenerated plantlets revealed the existence of a 71.66 % genetic polymorphism. Furthermore, morphological variation was confirmed by the presence of variegated individuals in regenerated plantlets. The proposed protocol can be useful in subsequent vanilla genetic improvement works.