Role of herbicide-tolerant (HT) rice in the weed management of direct seeded crop: Challenges and opportunities

Food insecurity which has been a global threat, forces researchers to develop crops with increased productivity even under varying climatic conditions. Rice, being a significant staple and strategic crop, helps ensure economic stability, food, and nutritional security globally. It meets 20% of the calorie requirement of people residing all over the world. Lately, rice cultivation and research have been facing hitherto unprecedented difficulties in the context of climate-induced water scarcity and dwindling resources of manpower, arable land, etc. In this regard, direct seeded rice (DSR) as a resource conservation technique is gaining popularity as a potential alternative to conventional transplanting with reduced input requirement, reduced methane and CO2 emission, increased adaptability to climate change, and increased economic returns. The weed menace in DSR prevents it from reaching its fruitful attainment to a significant level. DSR highly depends on herbicide for weed control as manual weeding and other cultural practices are labour intensive which again meets a setback of crop injury (non-selective herbicide) and resistant weeds (selective herbicides). Herbicide-tolerant (HT) rice could be an effective and long-term solution for weed management in DSR. Three HT rice systems, viz., imidazolinones, glyphosate, and glufosinate, have already been developed in this context. This review gives an insight into the need for HT rice in DSR, its production system, limitations, and stewardship guidelines for proper weed management in rice.