Screening And Identification Of Saline Tolerant Germplasms In Rice

As the world’s population continues to grow,so does the demand for total food production.Due to drought,salinization,and other reasons,the existing arable land is decreasing.The reduction of arable land seriously threatens food production.Rice is an important food crop,and its growth is seriously threatened by saline stress.Breeding salinetolerant rice can not only expand the rice planting area but also ensure grain yield.In addition,planting saline-tolerant rice can improve the physicochemical properties of local saline land.Screening and identification of saline-tolerant germplasm resources of rice is the first and most important step in the breeding of saline rice varieties.In this study,a screening system for saline tolerance at the seedling stage was established.Then 300 rice germplasm resources were treated with Na2CO3 at the seedling stage.Finally,the saline tolerance of different rice germplasms was evaluated using shoot length and biomass data,and a genome-wide association analysis was performed combined with genotype data.The main results of this study are as follows:According to the phenotypic response of the saline-sensitive cultivar Kongyu131(KY131)and the saline-tolerant cultivar Haidao86(SR86)under different Na2CO3 concentrations,the Na2CO3 concentration suitable for the screening of saline-tolerant germplasms in rice seedling stage was determined as:0.3%,and further,its feasibility was verified with 32 randomly selected rice varieties.The shoot length and biomass data of 300 germplasms under normal and stress conditions were obtained by image processing technology combined with traditional weighing.Thirteen saline-tolerant rice lines were obtained by comparing shoot length data.Based on the relative shoot length data,seventeen saline-tolerant rice lines were obtained.A saline-tolerant rice line was obtained by comparing biomass data.Three saline-tolerant rice strains were obtained by comparing relative biomass values.The phenotypic traits of 300 rice lines were comprehensively evaluated by membership function method.Three rice lines SR86,W132,and W100 were determined to be highly saline-tolerant,of which SR86 and W100 were both from slightly saline land.Based on germplasm screening-related phenotype data combined with germplasm resource genotype data,GWAS analysis was carried out,a total of 278 SNP loci were obtained,of which 31 candidate genes with functional annotation were associated with the significant SNP loci.These gene loci can provide a reference for the molecular breeding of saline-tolerant rice.The highly saline-tolerant and highly saline-sensitive materials screened in this study can provide a reference for the population construction of rice saline tolerance genetic research.The highly saline-tolerant lines can also be used as the donor parents to improve the saline resistance of other varieties.The results of GWAS also provide new loci for the molecular breeding of saline-tolerant rice...