Production of immature rhizomes by breaking dormancy under low temperature of Gastrodia elata Blume

 

Gastrodia elata Blume is usually planted as immature rhizomes in April and harvested as mature rhizomes in November the following year. 70% of the total production of G. elata in Korea is consumed raw and only 30% consumed after processing. However, the price of G. elata decrease greatly in November due to seasonal high production at. The production of G. elata should therefore preferably be constant all around the year. Thus, this study was conducted to investigate the possibility of a stable production of immature rhizomes by breaking dormancy by low temperature treatment. After harvesting G. elata in the fall, it was planted in the medium (peatmoss 80% + perlite 20%, moisture content 30 ± 2%) and kept at 5 ± 1 °C from week 2 to week 10. Bolting was subsequently induced at 25 ± 1 °C, and produced the seeds of G. elata by artificial fertilization. These seeds were induced to protocorm formation by Mycena spp., and immature rhizomes produced by Armillaria spp. [1]. As the result, the number of days to emergence showed short as the time of low temperature treatment period was elongated, but the emergence rate, peduncle length, the number of valid blooming, the number of valid pod increased. The natural fertilization rate of G. elata was 0.3%, whereas the artificial fertilization rate increased with 70.4% when it was bolting after low temperature treatment for more than 4 weeks at 5 °C. However, it was low compared to that of 90.4% when it was harvested in natural condition of the spring [2]. After seed (10,000˜20,000 seeds per pod) treated by breaking dormancy under low temperature condition, the protocorm formation rate of the germinated seed was from 2.2 to 2.6% and its immature rhizomes formation rate was from 8.7 to 9.5%. Formation of protocorm and immature rhizomes were proportional to the low temperature treatment period. As the results of these experiments, even though formation ratio of protocorm and immature rhizomes from G. elata harvested in the fall is lower than in the spring, it is considerably higher than the natural germination conditions. Thus, a constant year-round production of G. elata would be available due to the application of breaking dormancy technology under low temperature treatment.

Acknowledgements: Rural Development Administration is acknowledged for research fund supporting.

Keywords: Gastorida elata, low temperature, breaking dormancy, immature rhizome.

References:

[1] Park EJ, Lee WY, Ahn JK, Kim ST. A method for in vitro production of diseases-free Gastrodia elata immature rhizomes via sexual propagation. Kor For Res Inst Sourcebook. 2010.

[2] Hong IP, Nam SH, Jung IY, Sung GB, Nam HW, Cheong JC, Park JS, Hur H, Lee MW. Studies on the conditions of seed germination of Gasrodia elata. Kor J Mycol 2004; 32: 39 – 44.