Comparative study of the Bengal Assam Aus Panel (BAAP) at varying salinity levels in hydroponics for screening salt-tolerant rice genotypes

Abstract Rice is a widely grown crop consumed by millions of people across the globe. However, increasing soil salinity, primarily due to seawater intrusion in coastal areas, inadequate irrigation practices and drainage in inland regions, has made rice growth difficult necessitating the identification of salt tolerant varieties suitable for saline environment. This study aimed to evaluate and identify salt tolerant genotypes using a hydroponic system. A total of 268 genotypes from Bengal Assam Aus Panel (BAAP) were tested under three NaCl concentrations: 75, 150 and 300 mM. The plants were grown up to two leaf stage with three replicates per treatment group and then subjected to salt stress for a week. Principal component analysis and hierarchical clustering was performed to evaluate genetic relationships and genotype responses under salinity stress. Genotype AUS 335 was the best performer for majority phenotypic traits whereas genotype BRRI Dhan 50 was the least performer. Shoot fresh weight showed the highest heritability at 300 mM salinity. Root length and shoot length were highly correlated. PCA and hierarchical clustering grouped genotype into four clusters that are closely related with one another. At 75 mM salinity, sixteen genotypes were identified as tolerant, whereas nine genotypes were tolerant at 150 mM. All the genotypes were susceptible at 300 mM salinity. The genotypes AUS 16, Haiganj Boro-2 and Jagal were tolerant at 75- and 150-mM salt concentrations. Antioxidant analysis revealed changes in concentration of stress coping enzymes. These identified salt tolerant genotypes could be utilized in breeding programs and cultivated in salinity prone areas, thereby ensuring rice productivity and global food security.