Genome editing for enhancing production and productivity of maize in India

Abstract

Maize is the third most important crop in India being cultivated in 10.2 million hectares of land. In India, maize is mainly a rainfed crop with nearly 80% area under rainfed ecology, where the productivity is very low and is affected mainly by drought stress due to long dry spells. Therefore increasing maize yield in said ecology is a major challenge. Furthermore, it is estimated that an additional ~10 million tonnes of maize kernel would be required by 2025-26 to achieve the E20 target (20% bioethanol blending of petrol) envisaged by the government. Taken together, it is imperative to develop high-yielding as well as climate-resilient Indian maize genotypes for yield enhancement and sustainability. In this endeavor, genome editing tools should be employed to develop such genotypes rapidly. Here we enlisted four target genes (KRN2, RAVL1, ABH2, and DST) which are major regulators of key biological functions such as kernel row number per plant, leaf inclination angle imparting the erect leaf phenotype, drought, and salt tolerance. It is expected that knocking out these genes would improve overall yield by increasing kernel numbers per ear, plant population per unit area, as well as confer tolerance to drought and salinity. Besides, an erect leaf phenotype that is suitable for high-density planting will also contribute to drought tolerance by reducing transpiration water loss, improving photosynthesis rate, and resource use efficiency. With these interventions, it is expected that maize grain yield would be improved and thus help in addressing the twin challenges of feed and fuel security.