Method for increasing seed yield in a plant, the method comprising disruption of endogenous AHP6 gene in cells of the plant, wherein said disruption inhibits expression and/or activity of a product of said endogenous AHP6 gene compared to a corresponding control plant lacking such a disruption, wherein the endogenous AHP6 gene encodes for an AHP6 protein which is a member of the structural family of histidine phosphotransfer kinase/transferase proteins and lacks a histidine at a position corresponding to the position Asn83 of SEQ ID No. 1, and wherein the endogenous AHP6 gene comprises or consists of: (a) a nucleic acid encoding an AHP6 protein comprising the amino acid sequence of SEQ ID No. 1, 12; (b) a nucleic acid encoding an AHP6 protein comprising an amino acid sequence having a sequence identity of at least 70% through the entire amino acid sequence of SEQ ID No. 1 or 12; (c) a nucleic acid comprising the nucleic acid sequence of SEQ ID No. 2, 3, 4, 13 or 14; or (d) a nucleic acid comprising a nucleic acid sequence having a sequence identity of at least 90% through the entire nucleic acid sequence of SEQ ID No. 2, 3, 4, 13 or 14; wherein the method further comprises the step of introducing into the plant genome the disruption of at least one endogenous CKX gene, wherein the at least one CKX gene is: - an endogenous CKX1 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No.5; - an endogenous CKX2 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No.6; - an endogenous CKX3 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 7; - an endogenous CKX4 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 8; - an endogenous CKX5 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 9; - an endogenous CKX6 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 10; or - an endogenous CKX7 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No.11. (a) a nucleic acid encoding an AHP6 protein comprising the amino acid sequence of SEQ ID No. 1, 12; (b) a nucleic acid encoding an AHP6 protein comprising an amino acid sequence having a sequence identity of at least 70% through the entire amino acid sequence of SEQ ID No. 1 or 12; (c) a nucleic acid comprising the nucleic acid sequence of SEQ ID No. 2, 3, 4, 13 or 14; or (d) a nucleic acid comprising a nucleic acid sequence having a sequence identity of at least 90% through the entire nucleic acid sequence of SEQ ID No. 2, 3, 4, 13 or 14; wherein the method further comprises the step of introducing into the plant genome the disruption of at least one endogenous CKX gene, - an endogenous CKX1 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No.5; - an endogenous CKX2 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No.6; - an endogenous CKX3 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 7; - an endogenous CKX4 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 8; - an endogenous CKX5 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 9; - an endogenous CKX6 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No. 10; or - an endogenous CKX7 gene encoding for a CKX protein having cytokininoxidase/dehydrogenase activity comprising an amino acid sequence being identical to or having at least 70% identity through the entire amino acid sequence of SEQ ID No.11.