Abstract
A major quantitative trait locus (QTL) modulating soybean (Glycine max) branch angle was identified by linkage analysis using two bi-parental mapping populations with and without pedigree from wild soybean (Glycine soja). Soybean branch angle is a critical architectural trait that affects many other traits of agronomic importance associated with the plant's productivity and grain yield and is thus a vital consideration in soybean breeding. However, the genetic basis for modulating this important trait in soybean and many other crops remain unknown. Previously, we developed a recombinant inbred line (RIL) population derived from a cross between a domesticated soybean (Glycine max) variety, Williams 82, and a wild soybean (Glycine soja) accession, PI 479,752, and observed drastic variation in plant architecture including branch angle among individual RILs. In this study, one of the RILs possessing extremely wide branch angle (WBA) was crossed with an elite soybean cultivar (LD00-3309) possessing narrow branch angle (NBA) to produce an F2 population composed of 147 plants and F2-derived F3 families for inheritance analysis and QTL mapping. We found that branch angle is controlled by a major QTL located on chromosome 19, designated qGmBa1 and that WBA-derived from the wild soybean accession-is dominant over NBA. This locus was also detected as a major one underlying branch angle by QTL mapping using a subset of the soybean nested association mapping (SoyNAM) population composed of 140 RILs, which were derived from a cross between a landrace, PI 437169B, possessing WBA and an elite variety, IA3023, possessing NBA. Molecular markers located in the QTL region defined by both mapping populations can be used for marker-assisted selection of branch angle in soybean breeding.
Highlights
Plant architecture is defined as the three-dimensional organization of the plant body
This locus was detected as a major one underlying branch angle by quantitative trait locus (QTL) mapping using a subset of the soybean nested association mapping (SoyNAM) population composed of 140 recombinant inbred line (RIL), which were derived from a cross between a landrace, PI 437169B, possessing wide branch angle (WBA) and an elite variety, IA3023, possessing narrow branch angle (NBA)
One population is composed of 147 F2 plants and F3 families derived from a cross between an NBA high-yielding soybean line LD00-3309 – one of the founder lines used to develop the soybean nested association mapping (SoyNAM) population, and a typical WBA recombinant inbred line 1890 (RIL1890) selected from a RIL population derived from a cross between a G. soja accession PI 479752 and an intermediate branch angle (IBA) soybean cultivar Williams 82 (Swarm et al 2019)
Summary
Plant architecture is defined as the three-dimensional organization of the plant body. For above-ground plant parts, this includes plant height, branch/tiller pattern, and the shape and position of leaves and reproductive organs (Reinhardt and Kuhlemeier, 2002) Among these architectural traits, branch, tiller, and/or leaf angles are key determinants of canopy structure which directly affects light interception, photosynthetic efficiency, planting density, and plant productivity and grain yield in many crops (Burgess, 2019). Canopy architecture is often determined by distinct factors among different species In cereal crops such as maize, sorghum, rice, and wheat, the canopy structure is primarily determined by leaf angle – the inclination between the leaf blade midrib and the vertical stem, and upright plant architecture with erect leaves has been identified to be a key component in the development of high-yielding cultivars (Pendelton et al 1968; Lu et al 2007; Khush, 2013; Truong et al 2015; Mantilla-Perez et al 2017). Given that the genetic mechanisms underlying branch/tiller/leaf angles differ greatly among different crops as revealed in the cereals, it is essential to understand the genetic basis of these traits in individual crops
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
