Optimization of in vitro propagation and tuberization of potato (Solanum tuberosum L.) using apical meristem

Abstract

Highest frequency of shoot induction (3.33%) from meristems was occurred in the Smart variety on the media containing 5 mg l⁻¹ GA₃ + 0.5 mg l⁻¹ BAP + 0.5 mg l⁻¹ NAA and 6 mg l⁻¹ GA₃ + 0.5 mg l⁻¹ BAP + 0.5 mg l⁻¹ NAA whereas, no. of branch per plant and average shoot length were higher at 6 mg l⁻¹ GA₃. the Smart variety responded well in rooting (20%) and 4% of the inoculated meristems of this variety produced shoots with an average shoot length of 1.48. Other two varieties viz. Natura and Laura did not respond at all to shoot formation from inoculated meristems. Maximum rooting (80%) was noticed in the variety Smart on the medium containing GA₃- 2.0, BAP- 1.0 and NAA- 0.5 mgl⁻¹. Plantlets formed in vitro from the variety Smart were multiplied clonally by shoot buds. 5 mgl⁻¹ GA₃ + 0.1 mgl⁻¹ NAA was found better in highest shoot length (91.45 mm) and root length (35.28 mm). Shoot buds of different positions in plant body were also investigated for in vitro clonal multiplication. In all respects, apical buds show better performance. The highest shoot length was 64.26 mm observed in apical bud whereas, the lowest in axillary bud - 4. Highest root length and healthy plants were also found in apical bud. Percentage of survivability of microtuber producing plants also increased with the increase of sucrose concentration. Best survival rate and average diameter of tuber per plant was found at 10% sucrose. Minituber production on direct field showed best performance. It was observed that after 30 days, maximum shoot length per plant (188.87 mm) was found on the direct field whereas the lowest shoot length per plant (69.32 mm) was on sand. Lowest weight of tuber per plant was recorded on the substrates containing coconut dust. The highest weight of tuber was found in direct field. In case of, Average diameter of tuber per plant, 25% soil+ 75% coconut dust showed minimum result and on the other hand, in direct field, large size of tubers were found.