Marker-assisted breeding for transgressive seed protein content in soybean [Glycine max (L.) Merr.]

Abstract

After two cycles of marker-assisted breeding on three loci, lines with transgressive segregation of 8.22-9.32 % protein content were developed based on four original soybean parents with 35.35-44.83 % protein content. Marker-assisted breeding has been an innovative approach in conventional breeding, which is to be further demonstrated, especially for quantitative traits. A study on continuous transgressive breeding for seed protein content (SPC) in soybean using marker-assisted procedures is reported here. The SPC of the recombinant inbred line (RIL) population XG varied in 38.04-47.54 % under five environments with P 1 of 35.35 %, P 2 of 44.34 % and total heritability of 89.11 %. A transgressive segregant XG30 with SPC 45.53 % was selected for further improvement. The linkage mapping of XG showed its genetic constitution composed of five additive QTL (32.16 % of phenotypic variation or PV) and two pairs of epistatic QTL (2.96 % PV) using 400 SSR markers with the remnant heritability 53.99 % attributed to the undetected collective of minor QTL. Another transgressive segregant WT133 with SPC 48.39 % was selected from the RIL population WT (44.83 % SPC for both parents). XG30 and WT133 were genotyped on the three major additive QTL (Prot-08-1, Prot-14-1 and Prot-19-2) as A 2 A 2 B 2 B 2 L 1 L 1 and A 1 A 1 B 1 B 1 L 2 L 2 , respectively. From WT133×XG30, surprising transgressive progenies were obtained, among which the recombinants with all three positive alleles A 2 _B 2 _L 2 _ performed the highest SPC, especially that of Prot-08-1. The five F 2-derived superior families showed their means higher than the high parent value in F 2:3 and F 2:4 and more transgressive effect in F 2:5:6, with the highest as high as 54.15 %, or 4.82 and 9.32 % more than WT133 and its original high parent, respectively. This study demonstrated the efficiency of marker-assisted procedure in breeding for transgressive segregation of quantitative trait.

Meta-Analyses of QTLs Associated with Protein and Oil Contents and Compositions in Soybean [Glycine max (L.) Merr.] Seed

“…Through these studies, hundreds of loci contributing to the protein and oil contents and compositions of seed have been identified, as well as few molecular markers which have been successfully applied in marker-assisted breeding [5,10,11,12,13]. Of the more than 700 QTLs identified from over 60 studies mapping protein and oil seed contents, only 57 QTLs have been confirmed (available online: ).…”

“…Contents of soybean seed protein [24] and oil [25] have also been previously studied by meta-analysis with 107 and 121 QTLs, respectively. However, in recent years numerous additional QTL mapping studies for these two traits have rapidly accumulated [10,11,12,13,26,27,28,29,30,31,32,33,34,35,36], as well as, QTL studies on the amino acid and fatty acid compositions of soybean seed protein and oil [37,38,39,40,41,42,43]. Thus, with a nearly three-fold increase in the number of QTL available, a new meta-analysis for seed protein and oil contents which includes recent QTLs for seed protein and oil content as well as seed amino acid and fatty acids profiles is timely.…”

Identification of major QTLs and epistatic interactions for seed protein concentration in soybean under multiple environments based on a high-density map

“…Yang and Zhu (2005) and Yang et al (2007Yang et al ( , 2008 published methods that were developed to predict two types of superior genotypes (superior line and superior hybrid) based on QTL effects, including epistatic and Q 9 E interaction effects based on the mixed-model-based composite interval mapping (MCIM) method. Several studies have been performed to identify the Q 9 E effects in various crops by these methods in recent years, including studies of rice (Liu et al 2007;Wang et al 2012), corn Yang et al 2015), soybean (Korir et al 2011;Zhang et al 2015), wheat (Mohan et al 2009;Deng et al 2015), common bean (González et al 2015), cotton (Jia et al 2014), chickpea (Bajaj et al 2015), rapeseed (Xu et al 2015) and groundnut (Ravi et al 2011). These studies implied that the QTLs were greatly affected by the environment.…”

Quantitative trait loci underlying soybean seed tocopherol content with main additive, epistatic and QTL × environment effects

“…Our results showed that QTL interaction epistasis was important for the QTL selection of individual and total Toc content in MAS breeding programme (Tables 5-8). Zhang et al (2015) also verified that the efficiency of MAS for protein content in soybean seed could significantly be improved based on full consideration of the genetic effects of QTL.…”

“…Zhang et al. () also verified that the efficiency of MAS for protein content in soybean seed could significantly be improved based on full consideration of the genetic effects of QTL. Therefore, we believe that the information of QTL genetic effects obtained here was valuable for design breeding programmes that aim to transfer high‐Toc content from “Beifeng 9” to other elite breeding lines.…”