Cytokinin is the plant hormone that regulates cell division, leaf development and senescence, shoot growth, source-sink relationship, and several other processes involved in plant growth and development. In coordination with other phytohormones, cytokinins play a crucial role in gametophyte development, root growth, vascular development, nutrients uptake, and stress response. Cytokinin oxidases (CKX) cleave the cytokinins and inactivate them irreversibly. There are eleven genes in rice genome that encodes CKX, among which OsCKX2 has been identified as negative regulator of grain yield. Grain number 1a (Gn1a) allele of OsCKX2 (containing 16 bp deletion in 5’UTR and 6 bp deletion in exon-1) was associated with the trait high grain number/panicle, while its null allele (with 11 bp deletion in exon-3) improved lodging resistance through increasing the culm diameter along with high grain number per panicle. In this study, we utilized CRISPR/Cas12a multiplex editing method to edit two different exons of OsCKX2 in popular rice cultivar Samba Mahsuri. Several variants of OsCKX2 were generated through identification of transgene free homozygous edited mutant lines. One such mutant named as KAMALA showed significant increase in grain number per panicle and overall yield advantage of >35% over the wild type Samba Mahsuri. In addition, the mutant exhibited stronger culm, earliness and broader leaves. Increased grain yield of Samba Mahsuri without any alteration in grain and cooking quality can pave way for enhancing the yield of several other low yielding cultivars through the deployment of novel variant of OsCKX2.