EXPLOITATION OF VARYING LIGHT REGIMES AND HIGH SUCROSE CONCENTRATIONS FOR IN VITRO TUBERIZATION IN POTATO: A STEP TOWARDS DISEASE FREE SEED PRODUCTION

Abstract

Potato is the 4^th major vegetable crop in our country but more than 90% of the seed is imported which costs heavy economic burden on the foreign exchange. Further, imported germplasm is not well adapted to local climatic conditions and is vulnerable to different types of diseases. In vitro manipulations have proved their worth not only for the mass multiplication but also for the production of disease free seed of various crop plants. A proficient in vitro micropropagation and tuberization system was established in elite potato cultivars Kuroda and Desiree. In addition to growth hormones, sucrose concentration and light regime appeared to have dominant effect on microtuberization. Maximum number of microtubers was observed in genotype Desiree (2.20±0.20) followed by Kuroda (2.0±0.316) on MS medium augmented with 8% sucrose. Average fresh weight was maximum (0.70±0.063 g) on MS medium augmented with 10% sucrose in genotype Desiree. Likewise, best microtuberization was observed in initial 20 days light (16 hrs light with 8 hrs dark) incubation followed by complete dark incubation. The resultant microtubers were multiplied in pots for the production of minitubers and were tested for disease infestation by ELISA (Enzyme Linked Immunosorbant Assay). The antigen-antibody interaction was detected to be similar to the negative control (0.35-0.528) indicating absence of the viral pathogens. Hence, the developed protocol can be employed for the mass multiplication of disease free seed of elite potato cultivars resulting in reduced dependence on imported seed.