title: Identification of salt-tolerant QTLs with strong genetic background effect using two sets of reciprocal introgression lines in rice.
abstract: Effect of genetic background on detection of quantitative trait locus (QTL) governing salinity tolerance (ST) was studied using two sets of reciprocal introgression lines (ILs) derived from a cross between a moderately salinity tolerant japonica variety, Xiushui09 from China, and a drought tolerant but salinity susceptible indica breeding line, IR2061-520-6-9 from the Philippines. Salt toxicity symptoms (SST) on leaves, days to seedling survival (DSS), and sodium and potassium uptake by shoots were measured under salinity stress of 140 mmol/L of NaCl. A total of 47 QTLs, including 26 main-effect QTLs (M-QTLs) and 21 epistatic QTLs (E-QTLs), were identified from the two sets of reciprocal ILs. Among the 26 M-QTLs, only four (15.4%) were shared in the reciprocal backgrounds while no shared E-QTLs were detected, indicating that ST QTLs, especially E-QTLs, were very specific to the genetic background. Further, 78.6% of the M-QTLs for SST and DSS identified in the reciprocal ILs were also detected in the recombinant inbred lines (RILs) from the same cross, which clearly brings out the background effect on ST QTL detection and its utilization in ST breeding. The detection of ILs with various levels of pyramiding of nonallelic M-QTL alleles for ST from Xiushui09 into IR2061-520-6-9 allowed us to further improve the ST in rice.
authors.affiliation: Institute of Crop Sciences, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Lirui
authors.initials: L
authors.lastname: Cheng
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Lijun
authors.initials: L
authors.lastname: Meng
authors.forename: Xia
authors.initials: X
authors.lastname: Hu
authors.forename: Yanru
authors.initials: Y
authors.lastname: Cui
authors.forename: Yong
authors.initials: Y
authors.lastname: Sun
authors.forename: Linghua
authors.initials: L
authors.lastname: Zhu
authors.forename: Jauhar
authors.initials: J
authors.lastname: Ali
authors.forename: Jianlong
authors.initials: J
authors.lastname: Xu
authors.forename: Zhikang
authors.initials: Z
authors.lastname: Li
mesh_terms: D002681:China; D003433:Crosses, Genetic; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D012275:Oryza / Q000235:genetics*; D010679:Philippines; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D040641:Quantitative Trait Loci; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D005819:Genetic Markers; D012965:Sodium Chloride