|Boerma, H roger|
Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/6/2008
Publication Date: 3/17/2009
Publication URL: hdl.handle.net/10113/30025
Citation: Scaboo, A.M., Pantalone, V.R., Walker, D.R., West, D.R., Walker, F.R., Sams, C.E., Boerma, H. 2009. Confirmation of Molecular Markers and Agronomic Traits Associated with Seed Phytate Content in Two Soybean RIL Populations. Crop Science. 49:426-432. Interpretive Summary: Soybean seeds with low levels of phytate are preferred over those with standard concentrations for the production of livestock and poultry fee. Walker et al. (2006) reported that the DNA markers Satt237 and Satt561 are linked to two genetic loci which are associated with the level of phytate in soybean populations descended from the low-phytate mutant CX1834-1-2. A study was conducted to confirm this linkage in independent segregating recombinant inbred line populations derived from crosses between the mutant and the cultivar 5601T or the breeding line S97-1688. These studies confirmed that Satt237 is linked to a major locus on Linkage Group N controlling seed phytate, while Satt561 is linked to another locus on Linkage Group L that has a smaller influence on phytate content. These markers were used to determine which lines carried DNA segments from the mutant parent, and to show that the ones that did had lower levels of phytate irrespective of genetic background and growing enviroment. Confirmation of the tight linkage of these markers to the low phytate genes is likely to benefit soybean breeders who wish to backcross the mutant genes into locally adapted, high-yielding breeding lines in order to develop low-phytate soybean cultivars.
Technical Abstract: The concentration of phytate is an important consideration when analyzing grain for livestock feed rations. Simple sequence repeat (SSR) markers Satt237 and Satt561 were recently found to be linked to quantitative trait loci (QTL) for phytate concentration in soybean [Glycine max (L.) Merr.]. The objectives of this study were to confirm these QTL in independently segregating soybean populations, to compare the effectiveness of marker assisted selection (MAS) with that of phenotypic selection for low phytate, and to evaluate agronomic traits associated with low phytate soybean. The low phytate soybean mutant CX1834-1-2 was crossed with the cultivar 5601T and line S97-1688 to form two F5 derived populations. Satt237 was linked to a major QTL (R2 > 0.10) governing the low phytate trait and Satt561 was linked to a minor QTL (R2 < 0.10), in both populations. The heritability estimate for inorganic phosphorus (Pi) was high (h2 = 0.92), which indicates that selecting individuals with stable Pi phenotypes is readily accomplished in these populations. We found low correlations between seed Pi concentration and height, seed protein concentration, and seed oil concentration (r = 0.26, - 0.19, and 0.17, respectively). These low correlations indicate that selection for low phytate individuals would not adversely impact other important agronomic and quality seed traits. Although MAS with either or both SSR markers was effective in lowering the mean phytate levels in the selected progeny groups, phenotypic selection was found to be more cost efficient and effective in lowering mean phytate levels.