Assessment of seedling traits of rice landraces under different saline conditions

Salinity is one of the major abiotic stresses affecting rice growth and yield worldwide. In rice, the most critical stages which affect salinity at a greater level are germination, vegetative and reproductive stages.It is very important to know the genotypic variation among landraces under saline conditions at the seed germination stage to reduce the harmful effect of salinity. The present study conducted on Petri plate was mainly for assessing germination, relative water content and seedling parameters of eleven rice landraces with check landrace Pokali under three different salt concentrations (75mM, 125mM and 150mM). Two-way ANOVA gave the variations among the genotypes, treatments and their interactions. The present study showed that Mundan, Odiyan, Muttadan, Kallimadiyan and Vellimuthu had less percentage reduction in growth parameters at the germination stage. Odiyan and Mundan showed less percentage reduction in fresh weight (36.09%) and  shoot length (25.61%) respectively, in relative water content  (10.70% and 16.07%, respectively) at higher concentrations of salinity (150mM) compared to control. Pokali, Chembakam and Odiyan showed good germination parameters under three different saline treatments compared to other genotypes. Biplot analysis showed 65.4% variation between the treatments, whereas the variation between the genotypes was around 13.3%. Screening of landraces for salinity tolerance at the seed germination stage is the most reliable method to identify the salt tolerant line at the early seedling stage. The present study can be used for further screening programme at the vegetative stage for the identification of potential salt tolerant lines to improve breeding and gene introgression studies.