A comprehensive review on grain legumes as climate‐smart crops: Challenges and prospects

Global food production needs to be doubled by 50% by the middle of 21st century to ensure the food and nutritional security for 9 billion people explicitly in the challenging scenarios such as land degradation, water scarcity and environmental pollution. Climate change is evident worldwide due to exponential rise in atmospheric carbon-di-oxide (eCO2) and temperature (eT). It leads to more complexity in achieving the sustainable food security. Grain legumes are the major sources of dietary proteins with multifaceted impact on ecosystem services. Being the C3 crops climate change (more specifically eCO2) usually has positive impact on physiology and productivity of grain legumes as compared to C4 cereal crops. Grain legumes can allocate the above ground photosynthates into the below ground parts like roots and nodules resulting improvement in plant biomass, rhizospheric activities and higher input (water and nutrients) use efficacy. However, the impact of eT on grain legume is not always favourable. High temperature explicitly in the reproductive phase is extremely deleterious causing flower abortion and abnormal pod filling. Besides, eT impairs the performance of grain legumes because of higher evaporative demand, poor root-microbial association and pest severity. Therefore, both agronomic and genetic interventions must be integrated to raise successful grain legumes and to achieve the targeted yield in the changing climatic conditions. The targeted breeding programmes should be selection of high yielding, biotic stress resistant and abiotic stress tolerant grain legume genotypes that are adapted to eCO2 and eT conditions. Further, integrating the grain legumes with desirable traits to the food production system might impart resilience towards climate change. In this comprehensive review the impacts of climate change (eCO2 and eT) on above and below ground crop growth, productivity, water use efficiency and disease-pest severity are thoroughly discussed. Further, climate smart technologies which make grain legumes as a perfect candidate crop in the future climatic condition are also highlighted.