Identification of rice mutants tolerant to salt stress via evaluation biochemical, quantitative and molecular

To evaluate biochemically in different time course in rice mutants (M9) (seedling stage) under NaCl stress, a split factorial experiment was conducted based on randomized complete block design with 3 replications in the greenhouse of Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT), during 2019. The main factor included sampling time (3, 6 and 9 days after stress) and sub-factors included salinity stress in three levels of NaCl (0, 4 and 8 ds/m (saline water + paddy soil)) and rice genotypes (14 mutants (M9), 2 susceptible controls of Sepidrood, IR29 and 2 controls tolerant of Dailamani, Nonabokra). Then, the yield per plant and STI index were evaluated as factorial. Analysis of variance showed that the main and the interaction effects were significant for all traits at 1% probability level. At the time of sampling (9 days after stress) and salinity of 8ds/m, proline concentration in tolerant genotypes increased and malondialdehyde content in tolerant genotypes decreased. Four genotypes at salinity 8ds/m had higher yield than Dailamani. In these genotypes, increasing proline and decreasing malondialdehyde at higher times increased yield. 4 genotypes showed higher stress tolerance index and 3 genotypes showed lower yield loss than Dailamani. Considering the biochemical properties effective in salinity stress, it is possible to suggest these genotypes (G1, G4 and G8) which at 8ds/m  with yield of 2.36, 2.36 and 2.41 (gr) respectively, compared to Dailamani (1/54 gr) They had higher yields and can be used as promising saline-tolerant lines in saline fields.