biostudies-literatureZeng JChina Postdoctoral Science FoundationNational Natural Sciences Foundation of ChinaChongqing Postdoctoral Science FoundationChina Postdoctoral Science Special Foundation6758-6772https://www.ebi.ac.uk/biostudies/studies/S-EPMC9629787biostudies-literatureUnknown73(19)Cytokinin is considered to be an important driver of seed yield. To increase the yield of cotton while avoiding the negative consequences caused by constitutive overproduction of cytokinin, we down-regulated specifically the carpel genes for cytokinin oxidase/dehydrogenase (CKX), a key negative regulator of cytokinin levels, in transgenic cotton. The carpel-specific down-regulation of CKXs significantly enhanced cytokinin levels in the carpels. The elevated cytokinin promoted the expression of carpel- and ovule-development-associated genes, GhSTK2, GhAG1, and GhSHP, boosting ovule formation and thus producing more seeds in the ovary. Field experiments showed that the carpel-specific increase of cytokinin significantly increased both seed yield and fiber yield of cotton, without resulting iJournal of experimental botanyCarpel-specific down-regulation of GhCKXs in cotton significantly enhances seed and fiber yield.PMC96297872021T140569cstc2020jcyj-bshX0019U2003209311300392020M673104Liu HDing BZhang JXiao YWang FZhang MLiu RYan XBai WHou LRen HLi XDing XZeng JChen YPei YZhao JfalseCarpel-specific down-regulation of GhCKXs in cotton significantly enhances seed and fiber yield.Cytokinin is considered to be an important driver of seed yield. To increase the yield of cotton while avoiding the negative consequences caused by constitutive overproduction of cytokinin, we down-regulated specifically the carpel genes for cytokinin oxidase/dehydrogenase (CKX), a key negative regulator of cytokinin levels, in transgenic cotton. The carpel-specific down-regulation of CKXs significantly enhanced cytokinin levels in the carpels. The elevated cytokinin promoted the expression of carpel- and ovule-development-associated genes, GhSTK2, GhAG1, and GhSHP, boosting ovule formation and thus producing more seeds in the ovary. Field experiments showed that the carpel-specific increase of cytokinin significantly increased both seed yield and fiber yield of cotton, without resulting i2022-01-01T00:00:00Z2022 Nov2025-04-04T07:45:32.136Z2025-04-04T07:45:32.136ZS-EPMC96297873579265410.1093/jxb/erac303