Exploration of relationship between fragrant gene and growth performances of fragrant rice (Oryza sativa L.) seedlings under salinity stress.

Abstract

Fragrant rice is associated with poor agronomic traits and low tolerability to salt stress. Present study was conducted to examine the relationship between fragrant intensity of Sri Lankan rice germplasms and their seedling growth under salt stress. It was reported that correct copy of badh2 gene is associated with more salt tolerance than the mutated version of badh2 gene. Fifteen accessions that exhibited different levels of fragrance were selected and they were categorized into four fragrant intensity groups. Rice seedlings were grown under three salinity levels, 0.73 dSm(-1) (control), 4 dSm(-1) and 8 dSm(-1) and their survival percentage, root length and shoot length were measured. A novel formula of Salinity Survival Index (SSI) was derived from survival percentages and analysis of variance revealed that survival index under salinity stress was significantly associated with the fragrant intensity groups of rice. As the fragrant intensity increases, SSI, root length and shoot length decreases. A fragrant accession that were exceptionally salt tolerant were also disclosed. Most of the Sri Lankan fragrant rice germplasms do not possess the predominant badh2.1 fragrant allele. These findings would be useful in rice improvement breeding programs designed for fragrance and salt tolerance.