ROLE OF BIOLOGICAL HARDENING IN ENHANCING THE SU RVIVAL OF IN VITRO RAISED POTATO PLANTLETS

Abstract

The experiment entitled “Role of biological hardening in enhancing the survival of in vitro raised potato plantlets” was conducted at the Plant Tissue Culture Laboratory, Department of Horticulture, University of Agricultural Sciences, GKVK, Bengaluru, Karnataka, during 2025 to 2026. Biological hardening is an important step in potato micropropagation, as plantlets are highly susceptible to moisture stress and environmental changes during transfer from in vitro to ex vitro conditions. The study aimed to evaluate the effectiveness of beneficial microbial bioagents, applied individually and in combination with glycerol, in improving the survival and growth of micropropagated potato plantlets of cv. Kufri Himalini. The bioagents used were Pseudomonas fluorescens, Bacillus subtilis and Trichoderma viride, along with 0.5 per cent glycerol as an anti transpirant. Plant survival was recorded during the first, second and third weeks, while plant height, internodal length and root length were assessed initially and after three weeks. Among the treatments, T10 (P. fluorescens+ T. viride + 0.5 % glycerol) performed best, recording 83.33 per cent survival, 19.03 cm plant height, 2.05 cm internodal length and 10.83 cm root length after three weeks. The second-best treatment, T5 (P. fluorescens + T. viride), recorded 80.00 per cent survival, 18.17 cm plant height, 2.02 cm internodal length and 10.07 cm root length. The third-best treatment, T6 (T. viride + 0.5% glycerol), recorded 76.67 per cent survival, 17.13 cm plant height, 2.01 cm internodal length and 9.53 cm root length after three weeks. In contrast, the control recorded the lowest survival (56.67 %) and plant height (14.47 cm). The findings indicate that the combined application of P. fluorescens, T. viride and glycerol is a promising approach for improving the acclimatization, survival and establishment of micropropagated potato plantlets.