Is it possible to amplify current by the following way?

If you have something that will deliver a given voltage no matter what current is drawn, your reasoning is correct. That's called a voltage source in electrical engineering. The electrical outlets in your house are basically like that. As you plug more things in (add resistors in parallel), you draw more power.

Unfortunately, a solar cell acts more like a current source with a voltage limit. The power drawn from it increases as the resistance increases, until the output voltage is near the limit. So at any given time, there's an optimum resistance to put across the cell to draw the most power.

If you are drying food, then the sun will do that wonderfully on its own, with no solar cells involved. Just use a screen in your dehydrator to keep the bugs off, if any.

Adding another resistor in parallel with an existing resistance will increase the current. This is because the total resistance is now lower than the original resistance. But if I understand you right, let's consider this:

1.) Your panel can only supply so much current. I=V/R works for any value of R since the voltage source is considered ideal. It can supply as much current as you need. In reality, your solar panel can only produce a certain amount of power and thus a finite amount of current. It is energy that will dehydrate the food or whatever it is you are doing. Let's say the panel creates 1kW of power. 1 kW is 1000 Joules/second. We also know that the equation for power in electric circuits can be written as P=V*I. So if you your power from the panel is fixed and you need to increase current, you must decrease voltage accordingly. You cannot get energy from nothing.

2.) If your original resistance (load) is your dehydrator, placing a resistor in parallel with it will increase the amount of current (until the limits of part 1 are reached) that is drawn from the panel, but that extra current will go through the new resistor and the current through your dehydrator will be unaffected.

If you need more amperage you an hook two panels up in a parallel configuration. This will give you the same voltage but twice the amperage. Or, if the limits of your panel have not been reached (i.e. your dehydrator's power consumption has not exceeded that of the panel) but the current is too low, you can boost the voltage. Your dehydrator has some resistance and thus when hooked to a voltage supply will draw current according to I=V/R. Since you cannot change R since it is part of the dehydrator, you can boos the voltage using a stepper circuit.

There is one thing more which called power p=vi so from this relation u can see that voltage and current inversely proportional so for increase the current reduce the voltage if u have constant power source.