Field- and laboratory-based methods of screening salt tolerant genotypes in rice

• Published in: Crop and pasture science Vol. 72; no. 2; pp. 85 - 94
• Main Authors: Gupta, Amber, Shaw, Birendra Prasad
• Format: Journal Article
• Language: English
• Published: CSIRO Publishing 01.01.2021
• Subjects: hydroponic system; NaCl IC50, osmolyte accumulation; salinity stress; salt injury; salt tolerance screening; shoot growth inhibition
• ISSN: 1836-0947; 1836-5795
• DOI: 10.1071/CP20393

Salinity is one of the major abiotic stresses that lead to loss of billions of dollars in crop production worldwide. The growth of rice plant is severely affected and subsequently the yield is generally low in salt affected areas. Salinity affects rice primarily at the early vegetative stage by interfering with biochemical and physiological processes governing its growth and development. This review aims at summarising various morphological, physiological, biochemical, and molecular-based methods that are currently used in screening salt-tolerant rice genotypes at different growth stages with particular emphasis on screening of breeding lines, and also the effectiveness of these methods. Field and laboratory-based methods are described including visual screening of salt-induced injuries as per the IRRI’s standard evaluation system, salt-induced accumulation of ions, changes in the levels of photosynthetic pigments, antioxidant, and image-based visual quantification of injuries, and molecular markers-based screening, which are lengthy and cumbersome. Among these methods currently available, this review highlights IC50 (50% inhibition concentration) estimation of shoot growth inhibition as a rapid and accurate method that can differentiate genotypes with the IC50 difference of only a few mm NaCl for the initial screening of a large number of rice germplasm and breeding lines.