MASS-PRODUCTION METHOD FOR SEEDLING OF SEED POTATO

• US 20070094754A1
• Filed: 10/24/2006
• Published: 04/26/2007
• Est. Priority Date: 10/24/2005
• Status: Active Grant

• Current Assignee: KOE SAN COUNTY
• Original Assignee: KOE SAN COUNTY
• Inventors: JEONG, Woo-choon
• Granted Patent: US 7,906,703 B2
• Time in Patent Office: Days
• US Class Current: 800/317.2
• CPC Class Codes: A01H 4/005 Methods for micropropagation; Vegetative plant propagation using cell or tissue culture techniques

Abstract

Disclosed is a method of mass producing potato seedlings, comprising collecting growing points of seed potatoes and culturing the growing points in a liquid or solid medium; introducing in vitro plantlets obtained from the culture of the growing points to solid culture; and removing the in vitro plantlets from the solid culture, and planting through stem cutting and acclimatizing the in vitro plantlets in deep flow culture, in which a nutrient solution is circulating. When in vitro-cultured plantlets are planted in DSCAC through stem cutting, and sprouts from the terminal and lateral buds of the plantlets are hardened by gradually increasing light levels from the dark condition, the plantlets have healthy dark-green leaves and a high accumulation of carbohydrates, thereby obtaining potato seedlings having long stems that appear robust but not overgrown, and elastic and short nodes. Upon planting in hydroponic facilities, such potato seedlings have high adaptability to the external environment and thus rapidly, uniformly generate roots in a short time. The rapid root anchoring prevents planted seedlings from withering, leading to death, growing poorly, and the like. The direct planting of in vitro plantlets through stem cutting without a separate acclimatization process shortens the overall production period of potato seedlings by omitting the acclimatization process.

Claims

1. A method of mass producing potato seedlings, comprising:

a culturing step of collecting growing points of seed potatoes and culturing the growing points in a liquid or solid medium;

a solid culture step of introducing in vitro plantlets obtained from the culture of the growing points to a solid culture; and

a deep-flow-stem-cutting-and-acclimatization (DSCA) step of removing the in vitro plantlets from the solid culture and planting through stem cutting and acclimatizing the in vitro plantlets in deep flow culture, in which a nutrient solution is circulating.

2. The method according to claim 1, wherein the growing points of seed potatoes are cultured for a period ranging from 24 to 26 days at 18-22°

C. under 900-1,100 Lux lighting for 18-20 hrs, and 0 Lux for 4-6 hrs in a basic MS medium of pH 5.7-5.8 supplemented with 28-32 g/L of sucrose, or in the medium further supplemented with 7-11 g/L of agar.

3. The method according to claim 1, further comprising performing pathogen testing for the in vitro plantlets after the growing points of seed potatoes are cultured.

4. The method according to claim 1, wherein the solid culture is composed of two sub-steps:

primary shoot subculture and secondary propagation culture.

5. The method according to claim 4, wherein the primary shoot subculture is carried out in a basic MS medium of pH 5.7-5.8, which is supplemented with 7-11 g/L of agar and 70-80 g/L of sucrose.

6. The method according to claim 4, wherein the secondary propagation culture is carried out in a basic MS medium of pH 5.7-5.8, which is supplemented with 7-11 g/L of agar, 70-80 g/L of sucrose, and 0.020-0.035 mg/L of coumarin.

7. The method according to claim 4, wherein the primary shoot subculture and the secondary propagation culture are individually carried out for 25-35 days at 18-22°

C. under 4,000-5,000 Lux lighting for 18-20 hrs, and 0 Lux for 4-6 hrs.

8. The method according to claim 1, wherein the potato seedlings planted in the DSCA step through stem cutting have stems from which all leaves have fallen.

9. The method according to claim 1, wherein the potato seedlings are planted in the DSCA step through stem cutting are cut at node regions at a lower part of stems with a disinfected sharp knife.

10. The method according to claim 1, wherein in the DSCA step, light intensity is gradually increased according to growth phases to thus gradually harden the potato seedlings.

11. The method according to claim 10, wherein the potato seedlings are hardened under gradually increased light levels:

a) 0 Lux for 55-65 hours→

b) 2,100 Lux for 45-55 hours, 0 Lux for 4-8 hours→

c) 3,600 Lux for 35-45 hours, 0 Lux for 4-8 hours→

d) 5,500 Lux for 25-35 hours, 0 Lux for 4-8 hours→

e) 7,000 Lux for 535-545 hours (lighting for 18-20 hours every day for 30 days), 0 Lux for 120-180 hours (dark condition for 4-6 hours every day for 30 days).

12. The method according to claim 1, wherein, in the DSCA step, the supply of the nutrient solution and the interruption of nutrient solution supply are alternately repeated.

13. The method according to claim 12, wherein the nutrient solution is supplied for 30-45 minutes, and the supply of the nutrient solution is interrupted for 90-180 minutes.

14. The method according to claim 12, wherein, when the nutrient solution is supplied, the nutrient solution flows without fluctuation on a surface and is supplied at a constant level.

15. The method according to claim 12, wherein when supply of the nutrient solution is interrupted, the supplied nutrient solution and growth debris are completely discharged, thus exposing stems and roots of potato seedlings to the air.

16. The method according to claim 1, wherein, in the DSCA step, the potato seedlings are repeatedly collected from 13-15 days after planting of stem cuttings at time intervals of 6-10 days until nodes are exhausted.

17. The method according to claim 1, wherein the DSCA step is performed with a deep-flow-stem-cutting-and-acclimation-culture (DSCAC), the DSCAC comprising:

a culture panel, in which holes for planting of stem cuttings are arranged, to plant potato seedlings through stem cutting and cultivate the seedlings;

a culture bed, which has a space in which the culture panel is placed, contains a supplied nutrient solution required for the growth of the potato seedlings planted through stem cutting in the culture panel, and has a water outlet for discharging the excessively supplied nutrient solution;

a light source, which is provided at one side of the culture bed and radiates light on potato seedlings planted through stem cutting in the culture panel;

a nutrient solution dispersion and supply tube which is provided at one side of the culture bed and flows and supplies the nutrient solution to a lower part of the culture bed; and

a nutrient solution preparation and supply part which is equipped with a nutrient solution tank, is connected to the nutrient solution dispersion and supply tube and supplies the nutrient solution thereto.

18. The method according to claim 17, wherein, in the DSCAC, the water outlet of the culture bed is provided with a water discharge tube having a slit in a longitudinal direction, and an opening and closing tube having a helical opening and closing part is inserted into the water discharge tube in a separated state against a lower part of the water discharge tube.

19. The method according to claim 17, wherein, in the DSCAC, the culture bed is formed in two layers by a support frame in which the space in which the nutrient solution is held is formed in two layers, the nutrient solution dispersion and supply tube connected to the nutrient solution tank is placed in the space formed at each layer of the support frame, and fluorescent lamps as the light source are arranged in two rows at a lower part of the culture bed formed at each layer of the support frame.

20. The method according to claim 19, wherein a main supply tube is placed in one side of the support frame and is connected to the nutrient solution dispersion and supply tube at each layer to supply the nutrient solution,

the main supply tube has a flow control valve between the nutrient solution dispersion and supply tubes, to control an inflowing amount of the nutrient solution,

the main supply tube is placed in an upright orientation such that it extends to an upper part of the culture bed placed at the uppermost part of the support frame,

the uppermost part of the main supply tube is greater in volume than a lower part, and is coupled with a pressure tube connected to the nutrient solution tank, and

a pressure control valve for controlling the pressure against the main supply tube is placed between the main supply tube and the pressure tube.

21. The method according to claim 17, wherein, in the DSCAC, the water outlet of the culture bed includes a discharge tube which is connected to the nutrient solution tank and recovers the discharged nutrient solution into the nutrient solution tank.

22. The method according to claim 21, wherein a micro-sieving net is placed at a terminal part of the discharge tube to sift sediments or impurities contained in the circulating nutrient solution.

23. The method according to claim 17, wherein, in the DSCAC, one side of the nutrient solution dispersion and supply tube is a T-shaped branch tube into which the nutrient solution is supplied from the nutrient solution tank, and the branch tube has an effusion tube in which a nozzle from which the nutrient solution flows out is formed, and which is horizontally provided at a lower surface of the culture bed.

24. The method according to claim 1, wherein, after the DSCA step, the potato seedlings are subjected to an SSCA step, in which a nutrient solution is sprayed onto the root zone of the potato seedlings through nozzles.

25. The method according to claim 24, wherein the SSCA step is performed in a spraying-stem-cutting-and-acclimation-culture (SSCAC), the SSCAC comprising:

a culture panel in which holes for planting stem cuttings are formed to plant potato seedlings through stem cutting and cultivate them;

a culture bed in an upper part of which the culture panel is supported and which has a spray tube having nozzles spraying in a mist form a nutrient solution required for the growth of the potato seedlings planted through stem cutting in the culture panel, and a water outlet for discharging the nutrient solution that has been sprayed and has flowed down;

a light source which is provided at one side of the culture bed and radiates light on potato seedlings planted through stem cutting in the culture panel; and

a nutrient solution preparation and supply part which is equipped with a nutrient solution tank in which the spray tube of the culture bed is connected to one side and the nutrient solution is stored.

26. The method according to claim 25, wherein, when above-ground portions of the potato seedlings have grown to about 8-12 cm in length, lower leaves other than two to four uppermost leaves are removed with disinfected scissors, and stem descending work is carried out two or three times by descending the stems of potato seedlings below the culture panel.

27. The method according to claim 24, wherein the SSCA step is performed for a period ranging from 32 to 40 days, all lower leaves except for two or three uppermost leaves are removed during the last 5-7 days, and the roots of potato seedlings are cut to remove three quarters thereof and then regenerated.

28. A method of mass producing seed potatoes, comprising:

planting the potato seedlings produced according to the method of claims 1 in hydroponic facilities;

maximizing a number of stolons by carrying out stem descending work for the planted potato seedlings two or three times; and

harvesting potato minitubers formed at the stolons.

29. The method according to claim 28, wherein the potato seedlings planted in hydroponic facilities are 30-40 cm in plant length.