EVALUATION OF GENETIC FIDELITY OF IN VITRO PROPAGATED APPLE (MALUS × DOMESTICA BORKH.) ROOTSTOCK MM 106 USING ISSR MARKERS

Abstract

True-to-type clonal fidelity is of paramount concern during micropropagation of crop species. Though, micropropagation has found an important role in propagation of apple rootstocks, commercial propagation may be constrained by the occurrence of genetic variations, especially when cultures are maintained in vitro for a long period. To determine genetic fidelity of micropropagated plants of apple rootstock MM 106 multiplied by enhanced axillary branching method, we screened 24 inter simple sequence repeat markers (ISSR). Of these, 11 primers reproducibly generated a total of 107 distinct bands. Apple rootstock Merton 793 and scion ‘Jonathon’ were analysed along with tissue culture raised progenies of MM 106 as outliers to rule out the possibility that the invariant banding pattern was on account of inefficiency of ISSR primers in detecting variations. The number of bands per primer varied from 5 to 9 with an average of 9.72 scorable bands per primer. Among 83 bands amplified in micropropagated plants of MM 106, 78 bands were monomorphic (93.9%) and 5 bands (6.02%) were polymorphic. The results showed that ISSR markers can be used to gain rapid and precise information about the genetic stability of micropropagated apple rootstock MM 106 and corroborated the fact that the cultures multiplied through pre-existing meristems (axillary branching) may also show genetic instability especially upon extended in vitro cultivation.