Section 17 allows farmers' privilege. Section 23 provides that the PBRs are exhausted after sale of seed, except when the sold seed is multiplied for commercial purpose. The PBRs are allowed for 25 years in case of trees and vines and for 20 years for any other variety. Section 19 of the Act requires that if the holder of PBR fails to supply the material of reasonable quality, at reasonable price, an appropriate person may be granted license to produce the material' and sell it (compulsory licensing). Compulsory licensing may not apply if the material has no 'direct use .as a consumer product.