Identification of QTL for increased fibrous roots in soybean

Abstract

Drought stress adversely affects soybean at various developmental stages, which collectively results in yield reduction. Unpredictable rainfall has been reported to contribute about 36% to variation of yield difference between the rain-fed and irrigated fields. Among the drought resistance mechanisms, drought avoidance in genotypes with fibrous roots was recognized to be associated with drought resistance in soybean. Plant introduction PI416937 was shown to possess fibrous roots and has been used as a parent in breeding programs to improve soybean productivity. Little information is available on relative contribution and chromosomal location of quantitative trait loci (QTL) conditioning fibrous roots in soybean. To identify the genomic locations and genetic bases of this trait, a recombinant inbred line population was derived from a cross between PI416937 and 'Benning'. To detect associated QTLs, phenotypic data were collected and analyzed for 2 years under rain-fed field conditions. The selective genotyping approach was used to reduce the costs and work associated with conducting the QTL analysis. A total of five QTLs were identified on chromosomes Gm01 (Satt383), Gm03 (Satt339), Gm04 (Sct_191), Gm08 (Satt429), and Gm20 (Sat_299), and together explained 51% of the variation in root score. Detected QTLs were co-localized with QTLs related to root morphology, suggesting that fibrous roots QTL may be associated with other morpho-physiological traits and seed yield in soybean. Genetic dissection of the fibrous roots trait at the individual marker loci will allow for marker-assisted selection to develop soybean genotypes with enhanced levels of fibrous roots.

Genetic variants in root architecture-related genes in a Glycine soja accession, a potential resource to improve cultivated soybean

“…Despite the narrow genetic base of cultivated soybeans [4], previous root mapping studies [36,37] successfully used intra-specific mapping populations to map root QTLs in soybean. A recent study [38] used a mapping population developed between the cultivar Jingdou23 and a semi-wild cultivar, ZDD2315, to identify genes and their regulation that control seedling coarse root traits.…”

Identification of Novel QTL Governing Root Architectural Traits in an Interspecific Soybean Population

“…soja ) to create a BC2F4-derived population of BILs to map QTLs for root traits. Other studies [5, 39–40] used only intra-species ( G . max × G .…”

“…Drought resistance in plants is achieved by three different mechanisms: drought escape, avoidance, and tolerance [4]. Plants that utilize the avoidance mechanism endure drought by balancing turgor through increased rooting depth, better root architecture, and increased hydraulic conductance [5]. The intrinsic ability of the plant roots to extract water from deeper soil profiles enables plants to maintain optimal water relations, as well as carbon assimilation, under drought stress [6].…”

“…Soybean QTL studies that focused on root traits utilized crosses between G . max parental genotypes [5, 38, 39, 40]. But QTL alleles from exotic soybean germplasm have been reported by several researchers [34, 35, 41] to influence the seed yield in soybean.…”

A New Simple Method for Improving QTL Mapping Under Selective Genotyping

“…Many economically and biologically important traits, such as flowering time, fruit size and shape, crop (meat) yield or quality, growth in height and weight, plant stress and disease resistance, survival time, blood pressure, and body mass index in human, can be obtained at relatively low cost, and QTL mapping of these traits by using selective genotyping can be managed to be more cost effective than that by using complete genotyping. Consequently, although genotyping cost has been dropping recently, selective genotyping has been still widely employed in QTL mapping for improving these traits and understanding their genetic basis in several plant and animal species (Abdel-Haleem et al 2011;Lu et al 2013;Miller et al 2013;Fontanesi et al 2014;). The keyword search using Google Scholar also reveals that selective genotyping remains popular and is more frequently used in genetics studies in recent years.…”