The progeny of nucleus seed is called

The progeny of the nucleus seed is called Breeder seed.
This is the hundred percent genetically pure seeds with physical purity produced by the original breeder from basic nucleus seed stock.
Breeder seed is produced by or under the direction of the plant breeder who selected the variety. During breeder seed production, the breeder or an official representative of the breeder selects individual plants to harvest based on the phenotype of the plants.
A pedigree certificate is issued by the producing breeder.