An isolated nucleic acid for inhibiting the running to seed and flowering of a sugar beet plant, characterised in that the nucleic acid comprises a nucleotide sequence that a) contains or comprises a sequence of SEQ ID NO: 1-3 or a partial sequence of SEQ ID NO: 1-3 that comprises at least 20 consecutive nucleotides, or b) is complementary to a sequence of SEQ ID NO: 1-3 or a partial sequence of SEQ ID NO: 1-3 that comprises at least 20 consecutive nucleotides, or c) comprises a sequence of SEQ ID NO: 1-3 or a partial sequence of SEQ ID NO: 1-3 that comprises at least 20 consecutive nucleotides, or includes a complementary sequence thereto in the antisense direction, or d) is at least 90 % identical to a sequence of SEQ ID NO: 1-3 or is at least 90 % identical to a partial sequence of SEQ ID NO: 1-3 with a sequence length of least 100 nucleotides or at least 95 % identical to a partial sequence of SEQ ID NO: 1-3 with a sequence length of 50-99 nucleotides, or e) codes for a protein with the amino acid sequence of SEQ ID NO: 4 or a part of the protein comprising at least 30 consecutive amino acids of SEQ ID NO: 4, or f) codes for a protein with an amino acid sequence from Beta vulgaris which is at least 90 % identical to the sequence of SEQ ID NO: 4 or at least 90 % identical to a sequence segment that comprises at least 50 consecutive amino acids of SEQ ID NO: 4, or g) hybridises with a sequence according to SEQ ID NO: 1-3 or a nucleotide sequence complementary thereto or a nucleotide sequence oriented in the antisense direction thereto under stringent conditions and the hybridising sequences have at least 90 % sequence identity, wherein the stringent conditions are hybridising in 4 x SSC at 65 °C and subsequent repeated washing in 0.1 x SSC at 65 °C for a total of 1 hour. a) contains or comprises a sequence of SEQ ID NO: 1-3 or a partial sequence of SEQ ID NO: 1-3 that comprises at least 20 consecutive nucleotides, or b) is complementary to a sequence of SEQ ID NO: 1-3 or a partial sequence of SEQ ID NO: 1-3 that comprises at least 20 consecutive nucleotides, or c) comprises a sequence of SEQ ID NO: 1-3 or a partial sequence of SEQ ID NO: 1-3 that comprises at least 20 consecutive nucleotides, or includes a complementary sequence thereto in the antisense direction, or d) is at least 90 % identical to a sequence of SEQ ID NO: 1-3 or is at least 90 % identical to a partial sequence of SEQ ID NO: 1-3 with a sequence length of least 100 nucleotides or at least 95 % identical to a partial sequence of SEQ ID NO: 1-3 with a sequence length of 50-99 nucleotides, or e) codes for a protein with the amino acid sequence of SEQ ID NO: 4 or a part of the protein comprising at least 30 consecutive amino acids of SEQ ID NO: 4, or f) codes for a protein with an amino acid sequence from Beta vulgaris which is at least 90 % identical to the sequence of SEQ ID NO: 4 or at least 90 % identical to a sequence segment that comprises at least 50 consecutive amino acids of SEQ ID NO: 4, or g) hybridises with a sequence according to SEQ ID NO: 1-3 or a nucleotide sequence complementary thereto or a nucleotide sequence oriented in the antisense direction thereto under stringent conditions and the hybridising sequences have at least 90 % sequence identity, wherein the stringent conditions are hybridising in 4 x SSC at 65 °C and subsequent repeated washing in 0.1 x SSC at 65 °C for a total of 1 hour.