A major QTL conditioning salt tolerance in S-100 soybean and descendent cultivars

Abstract

Deployment of salt tolerant cultivars is an effective approach to minimize yield loss in a saline soil. In soybean, Glycine max (L.) Merr., substantial genetic variation exists for salt response. However, breeding for salt tolerance is hampered because no economically viable screening method has been developed for practical breeding. To facilitate the development of an effective screening method for salt tolerance in soybean, the present study was conducted to determine the heritability of salt tolerance and to identify associated quantitative trait loci (QTL). F2:5 lines from the cross of 'S-100' (salt tolerant) x 'Tokyo' (salt sensitive) were evaluated in a saline field in Hyde County, N.C., USA, in 1999 and in a greenhouse located in Raleigh, N.C., USA, in 2001. S-100 and Tokyo are ancestors of popular soybean cultivars released for the southern USA. The visual salt tolerance ratings of the F2:5 lines ranged from 0 (complete death) to 5 (normal healthy appearance). The entry-mean heritability for salt tolerance was 0.85, 0.48, and 0.57 in the field (four replications), greenhouse (two replications), and combined environments, respectively. The genotypic correlation between field and greenhouse ratings was 0.55, indicating reasonably good agreement between the two screening environments. To identify QTL associated with salt tolerance, each line was characterized with RFLP markers and an initial QTL single-factor analysis was completed. These results were used to identify genomic regions associated with the trait and to saturate the selected genomic regions with SSR markers to improve mapping precision. Subsequently, a major QTL for salt tolerance was discovered near the Sat_091 SSR marker on linkage group (LG) N, accounting for 41, 60, and 79% of the total genetic variation for salt tolerance in the field, greenhouse, and combined environments, respectively. The QTL allele associated with tolerance was derived from S-100. Pedigree tracking was used to examine the association between the salt tolerance QTL and flanking SSR marker alleles in U.S. cultivars descended from S-100 or Tokyo through 60 years of breeding. The presence of alleles from S-100 at the Sat_091 and Satt237 marker loci was always associated with salt tolerance in descendants. Alleles from Tokyo for these same markers were generally associated with salt sensitivity in descendent cultivars. The strong relationship between the SSR marker alleles and salt tolerance suggests that these markers could be used for marker-assisted selection in commercial breeding.

Location and transmission of QTL for multiple traits in the pedigree of soybean cultivars

“…Satt515, Satt212 and Satt232 were three QTLs for CFC (Hyten et al 2004; Lee et al 1996a, b, c;Mansur et al 1993), Sat_289, Satt232 and Satt156 were three QTLs for PH (Lee et al 1996a, b, c;Mansur et al 1996;Lark et al 1995), Satt156 was the QTL for both CPC and PM (SoyBase81203828 and Lee et al 1996a, b, c). In addition, Satt312 associated with salt tolerance (Lee et al 2004) was also found in our study.…”

Identification of QTLs associated with salinity tolerance at late growth stage in barley

“…In the last decade, QTLs associated with salinity tolerance have been mapped in rice (Gong et al 1998;Koyama et al 2001;Lin et al 2004), wheat (Quarrie et al 2005;Ma et al 2007), tomato (Foolad 2001), and soybean (Lee et al 2004). In barley, diVerences in salinity tolerance including physiological and agronomical response have been reported, but few researches have been done in genetic analysis.…”

Genetic analysis of salt tolerance in a recombinant inbred population of wheat (Triticum aestivum L.)

“…In the last decade, the development of molecular markers had made possible the genetic analysis of a number of complex traits, even to the extent of allowing the tagging of individual QTL (Yano and Sasaki 1997). Thus salt related QTL have been mapped in tomato (Foolad 2001;Foolad and Jones 1993), barley (Yoshiro and Kazuyoshi 1997), soybean (Lee et al 2004), Arabidopsis (Quesada et al 2002) and rice (Gong et al 1998;Gu et al 2000;Lin et al 1998Lin et al , 2004Zhang et al 1995). In wheat, there is a history of physiological research surrounding response to salinity stress, but genetic analysis is limited.…”