Nitrogen Use Efficiency in Rice under Abiotic Stress: Plant Breeding Approach

Abstract

Nitrogenous fertilizer has remarkably improved rice (Oryza sativa L.) yield across the world since its discovery by Haber-Bosch process. Due to climate change, future rice production will likely experience a wide range of environmental plasticity. Nitrogen use efficiency (NUE) is an important trait to confer adaptability across various abiotic stresses such as flooding, drought and salinity. The problem with the increased N application often leads to a reduction in NUE. New solutions are needed to simultaneously increase yield and maximize the NUE of rice. Despite the differences among flooding, salinity and drought, these three abiotic stresses lead to similar responses in rice plants. To develop abiotic stress tolerant rice varieties, speed breeding seems a plausible novel approach. Approximately 22 single quantitative trait loci (QTLs) and 58 pairs of epistatic QTLs are known to be closely associated with NUE in rice. The QTLs/genes for submergence (SUB1A) tolerance, anaerobic germination (AG, TPP7) potential and deepwater flooding tolerance (SK1, SK2) are identified. Furthermore, phytochrome-interacting factor-like14 (OsPIL14), or loss of function of the slender rice1 (SLR1) genes enhance salinity tolerance in rice seedlings. This review updates our understanding of the molecular mechanisms of abiotic stress tolerance and discusses possible approaches for developing N-efficient rice variety.

Phenotyping Rice Germplasm Associated With Salinity Tolerance Under Hydroponics System

“…Among abiotic stresses, salinity is the second most destructive constraint on rice production after drought, affecting approximately 1 billion hectares of land worldwide (Fageria et al, 2012). Rice is relatively more sensetive to salt stress in seedling and early vegetative stages (Lutts et al, 1995;Mondal et al, 2020) and later at the reproductive phage (Singh et al, 2010). Sodium chloride (NaCl) is dominant in saline soils among many salt contaminants and is readily soluble in water to yield toxic ions like sodium (Na + ) and chloride (Cl -).…”