| Rice was moderately sensitive to the salinity and alkaline stress. Salinity and alkaline soils causeserious effects and leads to reduction in rice production. The genetic studies of salt-alkaline toleranceis critical to improve the rice yield potential in the salinity and alkaline soils, and enlarge the riceplanting area, and ensure the food safety in the rice planting area. It is also important to the improvepeople's life and the environment. However, the most of researches were focused on the genetic studiesand detection of quantitative trait loci (QTLs) for the salinity tolerance, there were few reports on QTLsof alkaline tolerance detected in rice.The recombinant inbred line (RILs) population derived from the cross between "Yiai 1", which washighly tolerant to salt-alkaline and "Lishuinuo", which was sesitive to salt-alkaline, was used to detectQTLs for salinity and alkaline tolerance in rice, which could be used in the fine mapping for salinity andalkaline tolerance and MAS in rice breeding.1. Under the salinity stress with 1.5% NaCI, the germination percentage (GP) and relative GPshowed a continuous but partial distribution to lower or higher phenotypic values. Under the saltstress with 0.5% NaCI solution, the dead leaf rate and dead seedling rate at the seedling stage showed acontinous and near normal distribution. Under the alkaline stress with pH 8.7, the dead leaf rate atdifferent growth period showed a continous and near normal distribution, while the dead seedling rateshowed a continous but partial distribution to lower value with 2-3 peaks. These traits associated withsalt-alkaline tolerance were quantitative traits controlled by several main effect genes and minor genes.2. Three QTLs correlated with the germination percentage (GP) and relative GP when treated 7days under salinity stress were detected, respectively, which explained variation were less than 7.32%,which were minor genes. Five QTLs for germination rate and eight QTLs for relative germinationpercentage were detected when germinated 7 days under salinity stress, among which qSGP3associated with relative germination percentage had the largest explained variation, it was 9.60%.3. Two QTLs related to dead leaf rate under salinity stress were found, which located onchromosome 4 and 8, respectively. Among them, qSDLR8 explained 15.77% of the observedphenotypic variance, belong to main effect gene. Ten QTLs confferring dead seedling rate weredetected under salinity stress,which located on chromosome 1 (5 QTLs), 3, 4 (2 QTLs), 5, 8. While allof QTLs explained less than 8.8% of the observed phenotypic variance, which all belong to minor effectgenes.4. Seventeen QTLs correlated with dead leaf rate were identyfied during treated for 10d-60d underalkaline stress, which explained 1.11%-7.37% of the observed phynotypic variation, were were minorgenes. Among them, qADLR6-2, qADLR11-1, qADLR1-1 and qADLR8-1 were expressed in more thantwo periods, which were stable QTLs. Only one QTL for dead seedling rate was found under alkalinestress, which explained 6.56% of the observed phenotypic variation.5. Thirteen QTLs correlated with plant height, panicle length, grain numbers were detected under alkaline stress. Among them, qARPH4-2 associated with relative plant height had he largest explainedvariation, was 10.37%.6. qSGP4-1, SDLR4 and qSDSR4-2 controlling germination percentage, dead leaf rate and deadseedling rate, respectively under salt stress was located at the same interval as qADLR4-2 whichcorrelated with dead leaf rate (DLR) under alkaline stress; qSDLR3 related to DLR under salt stress waslocated at the same interval as qADLR3-2 for DLR under alkaline stress; qSDSR1-3 conferring deadseedling rate (DSR) under salt stress was located at the same interval as qADLR1-1 for DLR underalkaline stress, qSDSR8 for DSR under alkaline stress was was located at the same interval asqADLR8-2 correlated with DLR under alkaline stress. There were some correlation between salttolerance and alkaline tolerance.
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