Mapping QTLs related to salinity tolerance of rice at the young seedling stage

Abstract

Using a population of recombinant inbred lines of the 164 genotypes derived from a cross between ÔMilyang 23Õ (indica) and ÔGihobyeoÕ (japonica) in rice (Oryza sativa L.), salt tolerance was evaluated at a young seedling stage in concentrations of 0.5% and 0.7% NaCl. Mapping quantitative trait loci (QTLs) related to salt tolerance was carried out by interval mapping using Qgene 3.0. Two QTLs (qST1 and qST3) conferring salt tolerance at young seedling stage were mapped on chromosome 1 and 3, respectively, and explained 35.5-36.9% of the total phenotypic variation in 0.5% and 0.7% NaCl. The favourable allele of qST1 was contributed by ÔGihobyeoÕ, and that of qST3 by ÔMilyang 23Õ. The results obtained in 0.5% and 0.7% NaCl for 2 years were similar in flanked markers and phenotypic variation.

Screening, Inheritance and Linkage Marker Analyses of Salt Tolerance in Mutated Scented Japonica Rice (Oryza sativaL.)

“…Thirtyone F 3 lines derived from the F 2 salt-tolerant plants were used to evaluate the genotypes of F 2 plants. We found that the SM61 mutated salt-tolerance gene, ST8, is located on chromosome 8, different from those previous QTL regions previously discovered on chromosome 1, 3, 4, 5, 6, 7, 9, 10 and 12 (Zhang et al, 1995;Lin et al, 1998;Gong et al, 1999;Prasad et al, 2000;Koyama et al, 2001;Lin et al, 2004;Ren et al, 2005;Lee et al, 2007;Sabouri and Sabouri, 2008). By applying MAS techniques to the gene we have identified as responsible for conferring salttolerance, the results of our study could be used to improve salt tolerance of japonica scented rice.…”

“…The materials in our study were different from those in the other reports investigating RIL and DH lines (Zhang et al, 1995;Lin et al, 1998;Gong et al, 1999;Prasad et al, 2000;Koyama et al, 2001;Lin et al, 2004;Ren et al, 2005;Lee et al, 2007;Sabouri and Sabouri, 2008) since the latter derived from crosses between a salttolerant indica and a salt-susceptible parent (Prasad et al, 2000;Lin et al, 2004;Ren et al, 2005) or from two parents without salt-tolerance (Lee et al, 2007). To our knowledge, this is the fi rst study using mapping materials originating from a salt-tolerant japonica line and a salt-susceptible indica variety.…”

“…Most QTLs related to salt-tolerance were located in a similar region on chromosome 1 (Gong et al, 1999;Koyama et al, 2001;Lin et al, 2004;Ren et al, 2005). Identification of new QTLs related to salt tolerance through marker-assisted selection (MAS) should be useful in rice breeding programs (Kaushik et al, 2003;Lin et al, 2004;Lee et al, 2007).…”

“…Lin et al (2004) detected eleven QTLs that define the survival period of seedlings, as well as the traits of the shoots and roots in relation to salt tolerance in rice under salt stress on chromosomes 1, 4, 6, 7 and 9. Lee et al (2007) mapped two salt tolerance QTLs at the young seedling stage on chromosomes 1 and 3. Sabouri and Sabouri (2008) found nine QTLs for chlorophyll content, root length, root dry weight and ion exchange on chromosomes 1, 3, 4, 7, 9 and 10, which increased salt tolerance at the seedling stage.…”

“…QTL map studies on salttolerance provide information towards the improvement of plant breeding under saline conditions. In previous studies (Zhang et al, 1995;Lin et al, 1998;Gong et al, 1999;Prasad et al, 2000;Koyama et al, 2001;Lin et al, 2004;Ren et al, 2005;Lee et al, 2007;Sabouri and Sabouri, 2008), the location of QTLs for salt tolerance in rice was examined by using molecular markers. Zhang et al (1995), Lin et al (1998), Gong et al (1999) and Prasad et al (2000) found QTLs involved in salt tolerance of rice on chromosome 7, 5, 1 and 6.…”