KAMALA , a genome edited rice variety with improved yield by finetuning cytokinin oxidase activity released in India

Abstract Increasing yield is of major importance for Asian and African food security. Knock out mutants in the rice cytokinin oxidase gene CKX2 had shown potential for yield improvement. Here we explored whether subtle changes in CKX2 activity by editing FAD and cytokinin binding site sequences could improve the Indian mega-variety Samba Mahsuri. Knock out and single mutants in FAD and cytokinin binding sites induced by CRISPR/Cas12a caused moderate yield increases. Among 80 CKX2 alleles, five lines with in-frame mutations in both FAD and cytokinin binding domains produced even higher yield. One line, KAMALA , showed superior agronomic performance in 18 field locations (irrigated and rainfed ecologies) over three seasons in trials conducted by AICRPR (All India Coordinated Research Project on Rice), with an average 19% grain yield increase, early maturity, complete panicle emergence, and unaltered grain quality. KAMALA was registered as the first genome-edited variety ready for cultivation by Indian farmers.