Plant breeder agent Plants for Europe has been lobbying the Treasury, through Wealden MP Charles Hendry, to ensure that PVRs were included in the legislation.
The original proposal excluded them, which Plants for Europe director Graham Spencer said was discriminatory because plant varieties are ineligible for patent protection.
"It seems that our lobbying efforts have been successful, although we have reservations," Spencer added.
"As it stands, while the guidance notes say PVRs are included - and one assumes that will be both UK PVRs issued by the PVR Office and Community PVRs issued by the Community Plant Varieties Office - we see no specific mention in the draft legislation," he said.
"This merely refers to the potential for the Government to add to the list of included intellectual property by order. It is not clear when the order will be introduced.
"We have written to our MP to seek clarification from the Treasury, both on the timing of the inclusion of PVRs and the scope - UK only or UK and European rights."