QTL mapping for flowering time in different latitude in soybean

Abstract

Flowering represents the transition from the vegetative to reproductive phase and plays an important role in many agronomic traits. For soybean, a short day (SD) induced and photoperiod-sensitive plant, delaying flowering time under SD environments is very important and has been used by breeders to increase yields and enhance plant adaptabilities at lower latitudes. The purpose of this study was to identify quantitative trait loci (QTLs) associated with flowering time, especially QTLs underlying the long juvenile (LJ) trait which delays flowering time under SD environments. A population of 91 recombinant inbred lines derived from a cross between AGS292 and K3 was used for map construction and QTL analysis. The map covered 2546.7 cM and included 52 new promoter-specific indel and 9 new exon-specific indel markers. The phenotypic days-to-flowering data were examined in nine environments, including four short-day (SD, low latitude) and five long-day photoperiod (LD, high latitude) environments. For the SD environments, six QTLs were detected. Five of them were associated with the LJ trait. Among the five LJ QTLs, four QTLs may be attributed to the known flowering time genes, including qFT-J-1 for FT5a locus, qFT-J-2 for the FT2a locus, qFT-O for the E2 locus and qFT-L for the E3 locus. This is the first report that the E2, E3, FT2a and FT5a loci may be Sijia Lu, Ying Li, and Jialin Wang have contributed equally to this work. Electronic supplementary materialThe online version of this article (associated with the LJ trait. Under the five LD environments, as expected, qFT-O for the E2 locus and qFT-L for the E3 locus were identified, suggesting that E2 and E3 loci are very important for soybean adaptation in LD photoperiod. Conjoint analysis of multiple environments identified nine additive QTLs and nine pairs of epistatic QTLs, among which most were involved in interactions with the environments. In total, five QTLs (qFT-B2-1, qFT-C1-1, qFT-K, qFT-D2 and qFT-F) were identified that may represent novel flowering time genes. This provides a fundamental foundation for future studies of flowering time in soybean using fine mapping, map-based cloning, and molecular-assisted breeding.

Loss of Function of the E1-Like-b Gene Associates With Early Flowering Under Long-Day Conditions in Soybean

“…E1 , E2 , and E3 have large effects on flowering in a wide range of latitudes, whereas the allelic effect of E4 is rather limited to high latitudes (Yamada et al, 2012; Tsubokura et al, 2013, 2014; Xu et al, 2013; Lu et al, 2015). Among these four soybean genes, E1 has the most marked effect on time to flowering (McBlain et al, 1987; Upadhyay et al, 1994; Tsubokura et al, 2014).…”

“…Despite the conserved roles of CO and COL genes across plant species in photoperiodic flowering, there is no report that any COL genes are involved in the genetic variation of flowering time in soybean. Among the 11 major genes for flowering that have been reported so far ( E1 – E9 and J , reviewed by Cao et al, 2017; E10 , Samanfar et al, 2017), four maturity genes, E1 to E4 , are the main contributors to soybean adaptation to a wide range of latitudes (Liu et al, 2011; Jia et al, 2014; Jiang et al, 2014; Langewisch et al, 2014; Tsubokura et al, 2014; Zhai et al, 2014; Lu et al, 2015; Kurasch et al, 2017; Li et al, 2017). The floral repressor E1 encodes a protein that contains a bipartite nuclear localization signal and a region distantly related to the B3 domain, and is a possible transcription factor that represses FT2a and FT5a expression (Xia et al, 2012).…”

Adapting legume crops to climate change using genomic approaches

“…QTLs have been widely used to identify genes corresponding to flowering time in various legumes such as soybean (Liu & Abe, 2009;Lu et al, 2015;Yamanaka et al, 2001;D. Zhang et al, 2013), mungbean (Isemura et al, 2012;Kajonphol, Sangsiri, Somta, Toojinda, & Srinives, 2012), pigeonpea (Kumawat et al, 2012), chickpea (Gaur, Samineni, Tripathi, Varshney, & Gowda, 2015), and common bean (Blair, Iriarte, & Beebe, 2006;Chavarro & Blair, 2010;González et al, 2016;Tar'an, Michaels, & Pauls, 2002), enabling genomics-based breeding for adaptation traits.…”

Characterization and quantitative trait locus mapping of late-flowering from a Thai soybean cultivar introduced into a photoperiod-insensitive genetic background

“…QTL mapping studies have also revealed the involvement of novel LJ genes, other than j and e6 , in delayed flowering under SD conditions [16, 22, 34]. Liu et al [16] identified QTLs for the variations of flowering time that segregated in different latitudinal environments in a cross between early and late flowering Korean soybean cultivars.…”

“…Of these, two QTLs located in Chr4 and 16 were responsible for the control of flowering under the SD conditions found at lower latitudes. Lu et al [22] reported that two maturity loci, E2 and E3 , and two novel QTLs located in Chr16 that were involved in the variations of flowering time that segregated under SD conditions in a cross between photoperiod-insensitive cultivar AGS292 and the Thai LJ cultivar K3. Furthermore, the QTL mapping in a cross between the LJ cultivars Paranagoiana and PI159925 revealed two QTLs that regulated flowering time under SD conditions, one corresponding to E6 / J , or a linked novel locus, and one located in Chr2 (D1b linkage group) [34].…”