Fine mapping of the FT1 locus for soybean flowering time using a residual heterozygous line derived from a recombinant inbred line

Abstract

Fine-mapping of loci related to complex quantitative traits is essential for map-based cloning. A residual heterozygous line (RHL) of soybean (Glycine max) derived from a recombinant inbred line (RIL) was used for fine-mapping FT1, which is a major quantitative trait locus (QTL) responsible for soybean flowering time. The residual heterozygous line RHL1-156 was selected from the RILs that were derived from two distantly related varieties, Misuzudaizu and Moshidou Gong 503. The genome of RHL1-156 contains a heterozygous segment (approximately 17 cM) surrounding the FT1 locus but is homozygous in other regions, including three other loci affecting flowering time. A large segregating population of 1,006 individuals derived by selfing of RHL1-156 included two homozygous genotypes for the nearest marker of FT1 whose flowering time differed by 26 days. No continuous range of phenotypes was observed, in contrast to the F2 population, suggesting that a single FT1 locus affected the flowering time in the RHL1-156 line. Linkage analysis revealed that the FT1 locus mapped as a single Mendelian factor between two tightly linked DNA markers, Satt365 and GM169, at distances of approximately 0.1 cM and 0.4 cM, respectively. Our results show that a RHL derived from RILs can be used to fine-map a QTL and that RHLs can be an efficient tool for a systematic fine-mapping of QTLs.

A Major Soybean QTL,qPDH1, Controls Pod Dehiscence without Marked Morphological Change

“…These families originated from RILs derived from a cross between a shattering-susceptible cultivar, Toyomusume, and a shattering-resistant cultivar, Hayahikari (Funatsuki et al, 2005), which is a progeny of a shattering-resistant Thai cultivar, SJ2 (Yumoto et al, 2000). The families were created from two independent residual heterozygous lines (Yamanaka et al, 2005), the marker loci of which were all fixed except for the genomic region around qPDH1 according to the simple sequence repeat (SSR) marker genotype (Funatsuki et al, 2008). The two families had different genetic backgrounds, and the NILs within a family were supposed to be segregated only for the loci in the genomic region around qPDH1.…”

Quantitative trait loci mapping for kernel row number using chromosome segment substitution lines in maize

“…The first set of CSSLs was constructed and employed for the fine-scale mapping of fruit size QTL fw2.2 in tomato (Paterson et al, 1990;Eshed and Zamir, 1995;Frary et al, 2000). Subsequently, many CSSL populations have been reported in a diverse range of plant species, such as rice (Li et al, 2005;Zeng et al, 2006;Marzougui et al, 2012), soybean (Yamanaka et al, 2005), and barley (Von Korff et al, 2004). Szalma et al (2007) constructed a set of ILs in maize to detect QTL underlying maize flowering time, plant height, and ear height, by introgressing chromosome segments of TX303 to the B73 genome.…”

Map-Based Cloning of the Gene Associated With the Soybean Maturity Locus E3

“…However, the development of NILs through repeated backcrossing is time-consuming and laborious (Tuinstra et al 1997). The use of a residual heterozygous line (RHL), as proposed by Yamanaka et al (2004), and which is derived from RIL, is a powerful tool for precisely evaluating QTL (Haley et al 1994). An RHL harbors a heterozygous region where the target QTL is located and a homozygous background in most other regions of the genome.…”