Vol. 12, Issue 7 (2023)

Rice grown in coast is highly prone to salinity. High salt in plant cell damages the membrane system and thylakoids in chloroplasts and hence affect photosynthetic performance. This can be quantified by assessing Photosystem-II (PS-II) efficiency. However, this technique has not been employed so far to assess salinity tolerance in rice genotypes adapted to salinity in Konkan Coast. Hence, PS-II efficiency in response to salinity, as a potential trait, was considered for optimising screening protocol that can accelerate breeding varieties for salt-affected areas. Experiment was conducted with 20 rice genotypes collected from Regional Agricultural Research Station, Karjat and Khar Land Research Station, Panvel of coastal area including checks as well-known salt tolerant and salt sensitive varieties. Plants were exposed to medium (MSS) and high (HSS) salt stress with electrical conductivity 6 and 9 dSm^-1 respectively with control (3 dSm^-1) (Coastal saline soil with no additional salts) 21 days after emergence. The PS-II efficiency (Fv/Fm) was measured at 6, 24 and 36 hours after imposing salt stress. There was a large variation in salinity tolerance among the rice germplasms as revealed by Fv/Fm. Among 20 rice genotypes CST 7-1, Kala rata, SR 3-9 and Damodar retained high Fv/Fm in medium salt stress condition (6 dSm^-1) and high salt stress condition (9 dSm^-1) as compared to check such as FL478 (salt tolerant) and Karjat 4 (salt sensitive) at different time intervals. This work reveals the potential of PS-II efficiency as a trait for differentiating the responses of rice genotypes to coastal salinity. This can help identify relevant genes essential to develop salt-tolerant varieties.