The son of a man accused of kidnapping and raping a European backpacker at his farm in South Australia's Coorong region has testified against his father during his District Court trial.

Key points: Gene Bristow's son has given evidence as a prosecution witness today

Gene Bristow's son has given evidence as a prosecution witness today He told the court he was not aware of any farmhands ever being employed at their property

He told the court he was not aware of any farmhands ever being employed at their property He said he rarely went into the pig shed which was not visible from their house

Gene Charles Bristow, 54, is on trial in Adelaide's District Court after pleading not guilty to charges of kidnapping, rape and indecent assault.

He is accused of luring a 24-year-old woman to his property at Meningie in February, 2017 after responding to an advertisement she posted on the website Gumtree looking for farm work.

Prosecutors allege that once she arrived at the 40-hectare property, he shackled her with chains in an old pig shed and threatened to shoot her if she tried to leave.

Defence lawyer Nick Healy previously told the court the woman was employed to work as a farmhand on Mr Bristow's property and helped him look after cattle.

Mr Healy argued the woman agreed to camp in the shed and was never held there against her will.

On Tuesday, the accused's 22-year-old son, David Bristow, who lived on the farm with his parents at the time, gave evidence as a prosecution witness.

He told prosecutor Michael Foundas he was not aware of any farmhands ever being employed by the farm or staying at the property.

Q: "Had a farmhand ever been employed on the farm?" Mr Foundas said. A: "Never," David Bristow replied. Q: "Were you aware whether anyone had ever advertised for a farmhand to work on the farm in the past?" A: "Never." Q: "Was there enough work in February, 2017 that actually required the assistance of a farm hand?" A: "Absolutely not."

Chains found at the bottom of a well

The court heard police found chains, allegedly used to restrain the backpacker, at the bottom of a well on the property.

David Bristow told the court he had never seen the chains before and that they had no legitimate use on the farm.

David Bristow gave evidence as a prosecution witness in court today. ( ABC News )

He also disputed his father's claims that the cable ties the backpacker alleges were used to bind her wrists were actually used to restrain calves so they could administer eye drops.

David Bristow told the court they would "absolutely not" use cable ties to bind a calf's legs because it would hurt them.

He said he and his mother rarely went inside the pig shed where the backpacker was allegedly held and that it was not visible from their house.

David Bristow's 19-year-old partner, who lived at the farm at the time, also gave evidence as a prosecution witness.

She told the court on the day the accused allegedly abducted the backpacker he told her he was attending a job interview in Murray Bridge.

The trial also heard from a friend of Mr Bristow's, his neighbour and investigating officers.