Controlled environment system and method for rapid propagation of seed potato stocks

Abstract

A computer controlled environment system and method are used to provide the optimum environmental and nutritional conditions for the growth and development of seed potato cuttings for the initiation and development of tubers that can be used as the seed source for further multiplication under field conditions as seed potato stock. Use of a controlled environment system and method that provides optimum cultural conditions results in rapid growth and development of the potato cutting so as up to six crops of tubers can be harvested in a calendar year.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode presently contemplated of carrying out the invention.

In the drawings:

FIG. 1 is a block diagram of an environmental monitoring and control system for propagating seed potatoes;

FIG. 2 is a fragmentary, perspective, broken away view of a controlled environment chamber used in the system of FIG. 1;

FIG. 2A is a sectional representation of a portion of the chamber in FIG. 2;

FIG. 3 is a more detailed block diagram of the computer control system for FIG. 1;

FIG. 4 is a block diagram of a lighting system used in connection with the chamber in FIG. 2;

FIG. 5 is a block diagram of an atmospheric humidity system used with the chamber of FIG. 2;

FIG. 6 is a block diagram of a nutrient and water delivery system used in the chamber of FIG. 2; and

FIG. 7 is a representation of the process for propagating seed potatoes using the system of FIG. 1.

Claims

1. A plant growing system for developing potato plants that produce minitubers comprising: at least one automatically controlled environment chamber means for holding and supporting growth of potato plants over an entire life cycle, the chamber means including temperature, humidity and light sensor means, a lighting means for establishing light and dark periods of exposure having a number of fluorescent lamps located above the potato plants and separated therefrom by a substantially transparent divider, an air temperature means including an air conditioner for creating a variable temperature uniformly throughout the chamber means, an atmospheric humidity means, a nutrient and water delivery means for fertilizing and irrigating the potato plants, and a computer means for automatically and continuously monitoring and controlling the lighting, air temperature, atmospheric humidity and nutrient and water delivery means;whereby the system enables development of both tissue culture plantlets that produce mother plants, and stem cuttings from the mother plants into minitubers; andthe computer means periodically records environmental parameters in the chamber means.

2. The system of claim 1, wherein the chamber means is defined by a housing having a top panel, a bottom panel, a back panel, opposite end panels, a substantially transparent acrylic divider panel spaced beneath the top panel, a perforated drain pan spaced above the bottom panel for supporting trays of the potato plants and a movable door arrangement at a front portion thereof, the housing forming a light cap for holding the fluorescent lamps therein and a plurality of ventilating fans on the back panel and the front portion, a plant growing area between the divider and the drain pan for holding the trays of potato plants in a single layer, and a drain area located between the drain pan and the bottom panel.

3. The system of claim 2, wherein the temperature, humidity and light sensors are located in the plant growing area.

4. The system of claim 1, wherein the computer means controls the percentage of fluorescent lamps that are turned on during the light periods of exposure.

5. The system of claim 2, wherein the chamber means includes control panel means having signal processing module means in communication with a temperature control relay, a humidity control relay, a water and nutrient supply relay and a light control relay for providing electrical power to the fluorescent lamps, the air conditioner, the fans, and pumps in the humidity means and water and nutrient means.

6. The system of claim 5, wherein the computer means responsive to the module means provides a record at a selected point in time of the air temperature in the plant growing area, the percent of relative humidity of the air in the plant growing area, the light level immediately below the divider panel, an indication whether the lights are on or off, and an indication of whether the pumps are on or off.

7. The system of claim 1, wherein the computer means causes air temperature to be maintained at 50-86 degrees F., and causes relative humidity to be maintained at 47%-100%.

8. A method for developing potato plants that produce minitubers comprising the steps of: a) providing at least one automatically controlled environment chamber means for holding and supporting growth of potato plants over an entire life cycle, the chamber means including temperature, humidity and light sensor means, a lighting means for establishing light and dark periods of exposure having a number of fluorescent lamps located above the potato plants and separated therefrom by a substantially transparent divider, an air temperature means including an air conditioner for creating a variable temperature uniformly throughout the chamber means, an atmospheric humidity means, a nutrient and water delivery means for fertilizing and irrigating the potato plants, and a computer means for automatically and continuously monitoring and controlling the lighting, air temperature, atmospheric humidity and nutrient and water delivery means; andperiodically recording status of various environmental parameters in the chamber means;b) placing uncovered stem cuttings from mother potato plants within trays supplied with a solid growth medium inside the chamber means in a single layer;c) culturing the stem cuttings in the chamber means into minitubers by automatically controlling monitoring and recording the duration and intensity of the lighting, air temperature as a function of time during the light and dark periods, the percentage of humidity as a function of time, and the duration and frequency of aqueous nutrients according to set points established in the computer means as compared with inputs from the sensor means; andd) harvesting the minitubers within 56-64 days of culturing.

9. The method of claim 8, wherein the mother plants providing the stem cuttings are separately cultured inside the chamber means from tissue culture plantlets for about 4 weeks.

10. The method of claim 8, wherein the step of culturing the stem cuttings is preceded by the step of immersing a lower part of the stem cuttings for 15 minutes in a solution containing 20 ppm of indole-3-butyric acid, 380 ppm of 1-napthaleneacetic acid, 400 ppm of thiamin hydrochloride, and 1000 ppm of KH2PO4 to stimulate root development by the cuttings.

11. The method of claim 8, wherein the growth medium of step b) includes a 1:2:1 rooting material mixture of peat, coarse horticultural vermiculite and perlite, and the stem cuttings are spaced at 2 inch center in the trays.

12. The method of claim 8, wherein the step of culturing the stem cuttings in the chamber means includes the steps of: maintaining an air temperature of 68-72 degrees F. during a light period of 12 hours and an air temperature that does not exceed 68 degrees F. during a dark period of 12 hours for a first week throughout which the stem cuttings are illuminated at a low level in which one-third of the fluorescent lamps are on, for a second week at a medium light level in which two-thirds of the fluorescent lamps are on and for a third week at a full light level in which all fluorescent lamps are on; andmaintaining an air temperature of 65-71 degrees F. during the light period and an air temperature of 47-53 degrees F. during the dark period for about five weeks following the third week of culturing.

13. The method of claim 8, wherein the step of culturing the stem cuttings in the chamber means further includes the steps of: maintaining a relative humidity level during the first five days of at least 80 percent during both the light and dark periods;maintaining a relative humidity level during the next five days of at least 70 percent during both the light and dark periods; andmaintaining a relative humidity level thereafter for the next 46-54 days of at least 50 percent.

14. The method of claim 13, wherein the steps of culturing the stem cuttings in the chamber means further includes the step of: providing basic foliar applications of a nutrient solution at six hour intervals during the light period and once during the dark period with each application having a 20 second duration.

15. The method of claim 14, wherein the nutrient solution consists of Ca(NO3)2.4H2O, 590 mg; KNO3, 253 mg; MgSO4.7H2O, 246 mg; KH2PO4, 150 mg; K2SO4, 68 mg; H3BO3, 1.4 mg; MnCl2.4H2O, 1.0 mg; CuSO4.5H2O, 0.04 mg; ZnSO4.7H2O, 0.1 mg; MoO3, 0.008 mg; Iron chelate (14% Fe2O3), 50 mg; per liter of distilled water, adjusted to a pH of 5.5 with 0.1 N H2SO4.

16. The method of claim 14, wherein the step of culturing the stem cuttings in the chamber means further includes the step of: providing enhancing foliar applications of 20 ppm ancymidol and 10 ppm of kinetin during the third and fourth week.

17. The method of claim 9, wherein the culturing of tissue culture plantlets in the chamber means includes the steps of: maintaining an air temperature of 74-80 degrees F. during a light period of 16 hours and an air temperature that does not exceed 68 degrees F. during a dark period of 8 hours for a first week throughout which the plantlets are illuminated at a low level in which one-third of the fluorescent lamps are on, for a second week at a medium light level in which two-thirds of the fluorescent lamps are on, and for third and fourth weeks at a full light level in which all fluorescent lamps are on.

18. The method of claim 9, wherein the culturing of tissue culture plantlets in the chamber means includes the steps of: maintaining a relative humidity level during the first five days of at least 80 percent during both the light and dark periods;maintaining a relative humidity level of at least 60 percent during both the light and dark periods for about 22-25 days.

19. The method of claim 9, wherein the steps of culturing the tissue culture plantlets in the chamber means further includes the step of: providing basic foliar applications of a nutrient solution at six hour intervals during the light period and once during the dark period with each application having a 20 second duration.

20. The method of claim 19, wherein the nutrient solution consists of Ca(NO3)2.4H2O, 590 mg; KNO3, 253 mg; MgSO4.7H2O, 246 mg; KH2PO4, 136 mg; K2SO4, 68 mg; H3BO3, 1.4 mg; MnCl2. 4H2O, 1.0 mg; CuSO4.5H2O, 0.04 mg; ZnSO4.7H2O, 0.1 mg; MoO3, 0.008 mg.; Iron chelate (14% Fe2O3), 50 mg; per liter of distilled water, adjusted to a pH of 5.5 with 0.05 N H2SO4.