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Genetic mapping of soybean seed protein QTLs

Watcharin Soonsuwon, University of Nebraska - Lincoln

Abstract

Soybean is used as vegetable oil and a high protein meal for humans and livestock. However, there is an inverse relationship between seed protein and oil, resulting in difficulty when trying to simultaneously improve both traits. The purpose of this study was to discover new high protein QTLs that may be more useful than existing QTLs relative to increasing protein content with less adverse effects on oil. Eleven high seed protein (480 g kg-1 or more) germplasm accessions representing maturity groups (MGs) 00, II, III, IV and V, were mated to a high-yielding cultivar with normal seed protein content (420 g kg-1 or less) of the same MG to produce 11 F2:3 populations (of about 240 individuals each) segregating for seed protein content. A selective genotyping approach was used to identify the controlling QTLs for soybean seed protein concentration in these 11 F 2:3 populations. The Illumina Golden Gate SNP assay method, using a 1536-SNP 96-well matrix was used to genotype the 22 high protein and 22 low protein decile F2:3 progenies of each population, with two populations assayed in a single 96-well plate. A t-test, single marker regression, and interval mapping analysis were used to identify candidate QTLs in each population. Seed protein QTLs were identified on chromosomes 3 (LG-N), 6 (C2), 10 (O), 12 (H), 15 (E), 16 (J), 18 (G), and 20 (I). Seed oil QTLs were detected on chromosomes 12 (LG-H), 15 (E), 18 (G), and 20 (I). A new protein QTL was detected on chromosome 10 or LG-O near or at a SNP marker S15265 in the population of PI 408138 C x PI 597387. The additive effect of PI 408138 C parental allele was 8.3 g kg-1 greater protein. This marker was not associated with an oil QTL, as thus may be useful for increasing protein with less impact on oil. The known strong protein QTL was detected on chromosome 20 or LG-I, flanked by SNP markers S13608 and S17070, in a population of PI 340011 x PI 597387. The additive effect of PI 340011 parental allele was a greater seed protein of 9.2 g kg-1, but there was an associated seed oil reduction of -8.6 g kg-1 at the marker S17070. The strongest protein QTL was detected on chromosome 20 or LG-I at marker S26171, in a population of PI 253666 A x PI 206748. The additive effect of PI 253666 A parental allele was a greater seed protein content of 10.5 g kg-1. The marker S15265 was unlinked to an oil QTL. These and other results suggest that the major loci can be used for improving normal protein cultivars in marker-assisted selection (MAS) of soybean breeders. ^

Subject Area

Agriculture, Agronomy|Agriculture, Plant Culture

Recommended Citation

Soonsuwon, Watcharin, "Genetic mapping of soybean seed protein QTLs" (2009). ETD collection for University of Nebraska - Lincoln. AAI3386842.
http://digitalcommons.unl.edu/dissertations/AAI3386842

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