Evaluating rice for salinity using pot-culture provides a systematic tolerance assessment at the seedling stage

Authors: KAKAR, NAQEEBULLAH - Mississippi State University; JUMAA, SALAH - Mississippi State University; REDONA, EDILBERTO - Mississippi State University; Warburton, Marilyn; K. RAJA, REDDY - Mississippi State University

Submitted to: Rice
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2019
Publication Date: 7/30/2019
Citation: Kakar, N., Jumaa, S.H., Redona, E.D., Warburton, M.L., K. Raja, R. 2019. Evaluating rice for salinity using pot-culture provides a systematic tolerance assessment at the seedling stage. Rice. 12:57. https://doi.org/10.1186/s12284-019-0317-7.
DOI: https://doi.org/10.1186/s12284-019-0317-7

Interpretive Summary: Rice (Oryza sativa L.) is one of the major staple food crops consumed globally, but production has been severely affected by increasing salinity of soil and irrigation water. Since rice is most sensitive to salinity at the seedling stage, it is essential to develop an efficient screening methodology to identify genotypes possessing genes for salt tolerance. The method developed here uses pots of sand to grow seedlings in, but these pots are placed outdoors to allow plants to experience natural weather conditions, as they will do when grown in farmer’s fields. Extreme weather, however, is controlled with the use of a movable shelter. This report found salt tolerant genotypes; although they still need to be confirmed in field studies and tolerance mechanisms identified at the molecular level, information gained from this study will help rice breeders and other scientists in the selection of salt tolerant rice cultivars for use in rice breeding and salinity tolerance research.

Technical Abstract: Background: Rice (Oryza sativa L.) is one of the major staple food crops consumed globally. But rice production has been severely affected by increasing salinity. Since rice is most sensitive to salinity at the seedling, it is essential to develop an efficient screening methodology to identify genotypes possessing genes for salt tolerance. Result: An experiment was conducted to test a new screening technique in pot-culture for salinity tolerance in rice at the seedling stage. This method controls soil heterogeneity by using pure sand as a growth medium and minimizes the unexpected extreme weather conditions by using a movable shelter. Seventy-four rice genotypes were screened at three salinity treatments including high salt stress with electrical conductivity (EC 12 dSm-1), moderate salt stress (EC 6 dSm-1), and control, imposed one week after emergence. Several shoot and root morpho-physiological traits were measured at 30 days after sowing. A wide range of variability was observed among genotypes for measured traits with root traits being identified as the best descriptors under stress conditions. Stress response indices were used to classify 74 rice genotypes; 7 genotypes (9.46%) were identified as salt sensitive, 27 (36.48%) each as low and moderately salt tolerant, and 13 (17.57%) as highly salt tolerant. Genotypes FED 473 and IR85427 were identified as highly salt tolerant and sensitive, respectively. Results of salt stress response indices (SSRI) were further confirmed by principal component analysis (PCA) for accuracy and reliability. Conclusion: Although tolerant genotypes still need to be confirmed in field studies and tolerance mechanisms identified at the molecular level, information gained from this study could help rice breeders and other scientists in the selection of salt tolerant rice cultivars for use in rice breeding and salinity tolerance research.