Abstract
Rice is the major and dominant cereal food crop in the world. Salinity stress
is the second most abiotic stress next to drought, limiting rice yield. Approximately 953
Mha area of the world is affected by salinity. Genetic improvement of salt tolerance is
an efficient approach to achieving yield gain in salt-affected areas. Although high-yielding salt-tolerant rice varieties are developed, it is difficult to generate tailor-made
adapted varieties through traditional breeding. Hence various crop improvement
approaches are followed, including marker-assisted selection and transgenic technology
apart from classical breeding. Numerous QTLs were identified through the molecular
marker approach, and specifically, Saltol QTL was introgressed into elite lines through
marker-assisted back cross-breeding, and improved salt-tolerant varieties were bred.
Genetic engineering tools are also amply employed whereby the genes underlying
various biochemical/physiological processes such as ion and osmotic homeostasis,
antioxidation, signaling, and transcription-associated with increased tolerance were
characterized, validated, and used to develop salt-tolerant lines of rice. Yet, a clear
relationship between expected gains in salt tolerance in vitro has often not been
observed in the field in terms of grain yield. Hence, an integrated approach involving
molecular breeding and conventional breeding would certainly pave the way to
enhance salt tolerance in rice.