Essential protein (PubMed:23929493). Regulatory subunit of the condensin complex, a complex required for conversion of interphase chromatin into mitotic-like condense chromosomes (By similarity). The condensin complex probably introduces positive supercoils into relaxed DNA in the presence of type I topoisomerases and converts nicked DNA into positive knotted forms in the presence of type II topoisomerases (By similarity). Required for fertility, growth and euchromatin organization, but not for sister chromatid cohesion (PubMed:23929493). Necessary to maintain normal structural integrity of the meiotic chromosomes during the two nuclear divisions of gametogenesis, especially to maintain compaction of the centromeric repeats and 45S rDNA (PubMed:25065716). Seems also involved in crossover formation during meiotic prophase I (PubMed:25065716). Prevents centromeric and pericentromeric heterochromatin repeats association (PubMed:23929493). Contributes to the induction of stress-responsive genes in response to stress treatment (PubMed:16856987). Component of the condensin complex. Associates with the chromosomes throughout meiosis. Present in buds. Mostly expressed at bolting, flowering and during seed formation. Regulated in a cell cycle-dependent manner with an increase during G2 phase, highest levels in the middle of G2 and a drop during mitosis. Homozygous mutants are not viable (PubMed:23929493). Heterozygous mutants exhibit a reduced fertility (PubMed:23929493, PubMed:25065716). Non-structural maintenance of chromosomes condensing subunit (PubMed:23929493). During meiosis, elongated chromosome at metaphase I, stretched centromeric DNA at metaphase I as well as a slight reduction in crossover formation (PubMed:25065716). Reduced expression of stress-responsive genes in the root tip in response to stress treatment (PubMed:16856987). Belongs to the CND1 (condensin subunit 1) family.