Search

Seed orchards' parental reproductive success is often assessed through surveys of seed-and pollen-cone production (reproductive investment). Although the reliability of this approach has been questioned, its speed and ease made it the method of choice for providing approximate estimates for the genetic quality and quantity of seed orchard crops. In this study, reproductive investment data from various female and male phenotypic assessment methods from three seed orchards (lodgepole pine (Pinus contorta Dougl. ex. Loud. var. latifolia Engelm.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and western larch (Larix occidentalis Nutt.)) were compared with reproductive success estimates based on DNA fingerprinting and parentage analyses. The use of reproductive investment as a proxy to reproductive success on estimating seed crop's volume genetic worth and diversity (measured by effective number of parents) was evaluated. Regression analyses indicated that the phenotypic assessment methods reflect the true parental reproductive success and that estimates of seed-and pollen-cone volume production appear to be the most appropriate indicators of female and male reproductive success, respectively. Although the best combination of female-male survey methods produced inflated effective number of parents estimates, the genetic worth estimates were similar to those based on DNA, highlighting their robustness to fertility variation assessment. Resume: Le succes de reproduction des semenciers d'un verger a graines est souvent determine par des inventaires de production des cones seminiferes et polliniferes (investissement dans la reproduction). Quoique la fiabilite de cette approche ait ete remise en question, sa simplicite et sa rapidite en ont fait la methode de choix pour obtenir des estimations approximatives de la qualite genetique et du volume de la production semenciere des vergers a graines. Dans la presente etude, les auteurs ont compare les donnees relatives a l'investissement dans la reproduction obtenues par differentes me-thodes d'evaluation phenotypique de l'effort femelle et de l'effort male aux estimations de succes basees sur l'analyse des empreintes d'ADN et l'analyse de parente dans trois vergers a graines (pin tordu latifolie (Pinus contorta Dougl. ex. Loud. var. latifolia Engelm.), Douglas vert (Pseudotsuga menziesii (Mirb.) Franco) et meleze de l'Ouest (Larix occidentalis Nutt.)). L'emploi de l'investissement dans la reproduction comme indication du succes de reproduction afin d'estimer la valeur genetique du volume de la production semenciere et sa diversite (evaluee par le nombre effectif de parents) a aussi ete evalue. Les analyses de regression ont indique que les methodes d'evaluation phenotypique refletent le succes parental reel de reproduction et que les estimations du volume de production de cones seminiferes et polliniferes semblent etre les indicateurs les plus appropries du succes reproducteur femelle et male. Meme si la meilleure combinaison des methodes de determination de l'effort femelle et de l'effort male produisaient des estimations gonflees du nombre effectif de parents, les estimations de la valeur genetique etaient similaires a celles qui etaient basees sur l'ADN, mettant en evidence leur robustesse relativement a l'evaluation de la variation de la fertilite. [Traduit par la Redaction], Introduction Forest tree recurrent selection programs attain their goals through two distinctive streams, namely breeding and production. Breeding with its classical three steps, crosses, testing, and selection, leads to the [...]

Aegilops tauschii, the D genome donor of wheat (Triticum aestivum L.), has strong seed dormancy and genes controlling the trait may be used to improve resistance of cultivars to pre-harvest sprouting (PHS). Thus, this research project was initiated to identify dormancy genes from Ae. tauschii-derived synthetic hexaploid wheat (SHW). Four permanent segregating populations, developed by crossing four SHW lines with a common wheat line, were grown under field conditions to evaluate dormancy with threshed seeds (kernels) and/or intact seeds on the spike from 2006 to 2008. Significant genotypic and year effects on both kernel and on-spike seed dormancy were detected in each population, with heritability estimates of about 0.4 (0.32-0.48) across the years. Seeds on the spikes were much more dormant than kernels, suggesting the presence of germination inhibitors in the covering tissues. Significant correlations between kernel and on-spike seed germination percentages were detected in all populations; the estimated correlation coefficient (r) was greater for genotypic (0.80) than for phenotypic (0.63) or environmental (0.51) components. Thus, available SHW lines could be an alternative source of dormancy genes for enhancing resistance of wheat cultivars to PHS. doi: 10.2135/cropsci2009.11.0645

The seed coat of soybean [Glycine max (L.) Merr.] cracks under field conditions. This study was conducted to investigate the genetic basis of seed coat cracking using DNA markers. Recombinant inbred lines (RILs) were developed from a cross between a sensitive cv. Nasushirome and a tolerant cv. Enrei. Ninety-five [F.sub.6] RILs (2006) and 92 F7 RILs (2007) with an average of 24 plants per line were grown in the field. Seed coat cracking was promoted by removing the upper 50% of pods at 40 d after anthesis. The degree of cracking of each seed was scored by a cracking index (not cracked, 0, to severely cracked, 4). Cracking index was averaged per plant and, subsequently, per line (average cracking index, ACI). Linkage mapping was performed using 114 simple sequence repeat markers and one morphological trait. The markers were associated with 18 linkage groups spanning 1232 cM. Two quantitative trait loci (QTL) for ACI, crl in molecular linkage group (MLG) Dlb and cr2 in MLG M, were identified. The cr2 QTL was detected only in the [F.sub.6] generation, whereas crl was identified across years and generations. The crl had a logarithm of odds score of 4.78 ([F.sub.6]) and 4.77 ([F.sub.7]), accounting for 27.2 ([F.sub.6]) and 23.5% ([F.sub.7]) of phenotypic variation. The cr1 was not associated with seed size or maturity in [F.sub.8] near-isogenic lines. Therefore, markers around the QTL may be useful for breeding to reduce cracking symptoms without altering seed size or maturity. doi: 10.2135/cropsci2009.08.0440

Seed dormancy, the main factor contributing to preharvest sprouting (PHS) resistance, is a complex trait and is strongly influenced by environmental growth conditions. In this study, three sets of single chromosome substitution lines, including 36 genotypes, in a durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] background with donor chromosomes originating from three wild emmer [T. turgidum L. ssp. dicoccoides (Korn. ex Asch. and Graebn.) Thell.] accessions were grown in nine field environments and evaluated for seed dormancy and PHS resistance. The substitution lines involving chromosome 3A were among the most dormant genotypes. Germination tests indicated that five chromosomes contained genes influencing seed dormancy at a level comparable to 3A. Results from PHS tests showed that PHS was affected by at least eight T. dicoccoides chromosomes including 3A. The chromosomes harboring genes for seed dormancy did not fully correspond with those for PHS resistance. The weak correlations between PHS and dormancy observed in this study indicate that different genes are affecting these traits and they may be differentially influenced by the environment. Nonetheless, our results revealed that genes present on five chromosomes, 2A, 2B, 3A, 4A, and 7B, were found to affect both PHS resistance and seed dormancy. These genotypes thus provide useful resources for further studies on genetic interactions that contribute to the overall phenotypic variation and on genetic dissection of quantitative trait loci underlying PHS resistance. doi: 10.2135/cropsci2009.10.0589

Most of the transcription factors (TFs) responsible for controlling seed development are not yet known. To identify TF genes expressed at specific stages of seed development, including those unique to seeds, we used Affymetrix GeneChips to profile Arabidopsis genes active in seeds from fertilization through maturation and at other times of the plant life cycle. Seed gene sets were compared with those expressed in prefertilization ovules, germinating seedlings, and leaves, roots, stems, and floral buds of the mature plant. Most genes active in seeds are shared by all stages of seed development, although significant quantitative changes in gene activity occur. Each stage of seed development has a small gene set that is either specific at the level of the GeneChip or up-regulated with respect to genes active at other stages, including those that encode TFs. We identified 289 seed-specific genes, including 48 that encode TFs. Seven of the seed-specific TF genes are known regulators of seed development and include the LEAFY COTYLEDON (LEC) genes LEC1, LEC1-LIKE, LEC2, and FUS3. The rest represent different classes of TFs with unknown roles in seed development. Promoter-[beta]-glucuronidase (GUS) fusion experiments and seed mRNA localization GeneChip datasets showed that the seed-specific TF genes are active in different compartments and tissues of the seed at unique times of development. Collectively, these seed-specific TF genes should facilitate the identification of regulatory networks that are important for programming seed development. embryo | transcriptome | mRNA localization doi/ 10.1073/pnas.1003530107

Quantitative trait loci (QTL) with different bio-functional roles may occur simultaneously in QTL analysis. Categorizing these QTL by their functional roles is imperative for choosing markers suitable for marker-assisted selection and gene searching. The feasibility of the QTL categorization is discussed in the context of QTL analysis for chemical concentration in seed grains. Our simulated QTL analysis under simple, hypothetical histo-developmental and genetic models shows that, based on the concentration scores taken by conventional methods such as near-infrared transmittance spectroscopy (called score C), a gene can be detected as a QTL even though it has no role in the synthesis or storage of the objective chemical. Such QTL, called nominal QTL, will not be useful as a target of marker-assisted selection for a high chemical harvest. When QTL patterns obtained with score C are compared with those obtained with a modified score, score C x grain weight (called score D), nominal QTL can be distinguished and QTL can be categorized into two groups of functional categories, that is, QTL that control the size of tissues and QTL that control the rate of chemical synthesis. When QTL patterns are evaluated across multiple chemicals, QTL in each group can be distinguished by their functional charges. doi: 10.2135/cropsci2009.01.0015

Seed dormancy provides a strategy for flowering plants to survive adverse natural conditions. It is also an important agronomic trait affecting grain yield, quality, and processing performance. We cloned a rice quantitative trait locus, Sdr4, which contributes substantially to differences in seed dormancy between japonica (Nipponbare) and indica (Kasalath) cultivars. Sdr4 expression is positively regulated by OsVP1, a global regulator of seed maturation, and in turn positively regulates potential regulators of seed dormancy and represses the expression of postgerminative genes, suggesting that Sdr4 acts as an intermediate regulator of dormancy in the seed maturation program. Japonica cultivars have only the Nipponbare allele (Sdr4-n), which endows reduced dormancy, whereas both the Kasalath allele (Srd4-k) and Sdr4-n are widely distributed in the indica group, indicating prevalent introgression. Srd4-k also is found in the wild ancestor Oryza rufipogon, whereas Sdr4-n appears to have been produced through at least two mutation events from the closest O. rufipogon allele among the accessions examined. These results are discussed with respect to possible selection of the allele during the domestication process. domestication | preharvest sprouting | quantitative trait locus doi/10.1073/pnas.0911965107

Timing of germination is presumably under strong natural selection as it determines the environmental conditions in which a plant germinates and initiates its postembryonic life cycle. To investigate how seed dormancy is controlled, quantitative trait loci (QTL) analyses has been performed in six Arabidopsis thaliana recombinant inbred linepopulations by analyzing them simultaneously using a mixed model QTL approach. The recombinant inbred line populations were derived from crosses between the reference accession Landsberg erecta (Ler) and accessions from different world regions. In total, 11 delay of germination (DOG) QTL have been identified, and nine of them have been confirmed by near isogenic lines (NILs). The absence of strong epistatic interactions between the different DOG loci suggests that they affect dormancy mainly by distinct genetic pathways. This was confirmed by analyzing the transcriptome of freshly harvested dry seeds of five different DOG NILs. All five DOG NILs showed discernible and different expression patterns compared with the expression of their genetic background Ler. The genes identified in the different DOG NILs represent largely different gene ontology profiles. It is proposed that natural variation for seed dormancy in Arabidopsis is mainly controlled by different additive genetic and molecular pathways rather than epistatic interactions, indicating the involvement of several independent pathways. recombinant inbred lines | quantitative trait loci analyses | near isogenic lines | transcriptome analyses doi/10.1073/pnas.1000410107

The most widespread dietary problem in the world is mineral deficiency. We used the nicotianamine synthase (NAS) gene to increase mineral contents in rice grains. Nicotianamine (NA) is a chelator of metals and a key component of metal homeostasis. We isolated activation-tagged mutant lines in which expression of a rice NAS gene, OsNAS3, was increased by introducing 35S enhancer elements. Shoots and roots of the OsNAS3 activation-tagged plants (OsNAS3-D1) accumulated more Fe and Zn. Seeds from our OsNAS3-D1 plants grown on a paddy field contained elevated amounts of Fe (2.9-fold), Zn (2.2-fold), and Cu (1.7-fold). The NA level was increased 9.6-fold in OsNAS3-D1 seeds. Analysis by size exclusion chromatography coupled with inductively coupled plasma mass spectroscopy showed that WT and OsNAS3-D1 seeds contained equal amounts of Fe bound to IP6, whereas OsNAS3-D1 had 7-fold more Fe bound to a low molecular mass, which was likely NA. Furthermore, this activation led to increased tolerance to Fe and Zn deficiencies and to excess metal (Zn, Cu, and Ni) toxicities. In contrast, disruption of OsNAS3 caused an opposite phenotype. To test the bioavailability of Fe, we fed anemic mice with either engineered or WT seeds for 4 weeks and measured their concentrations of hemoglobin and hematocrit. Mice fed with engineered seeds recovered to normal levels of hemoglobin and hematocrit within 2 weeks, whereas those that ate WT seeds remained anemic. Our results suggest that an increase in bioavailable mineral content in rice grains can be achieved by enhancing NAS expression. activation tagging | bioavailability | hemoglobin | metal homeostasis doi/10.1073/pnas.0910950106

Seed development in plants involves the coordinated growth of the embryo, endosperm, and maternal tissue. Several genes have been identified that influence seed size by acting maternally, such as AUXIN RESPONSE FACTOR2, APETALA2, and DA1. However, given the lack of gain-of-function effects of these genes on seed size, it is unclear whether their activity levels are limiting in WT plants and whether they could thus be used to regulate seed size in development or evolution. Also, whether the altered seed sizes reflect local gene activity or global physiological changes is unknown. Here, we demonstrate that the cytochrome P450 KLUH (KLU) regulates seed size. KLU acts locally in developing flowers to promote seed growth, and its activity level is limiting for seed growth in WT. KLU is expressed in the inner integument of developing ovules, where it non-cell autonomously stimulates cell proliferation, thus determining the growth potential of the seed coat and seed. A KLU-induced increase in seed size leads to larger seedlings and higher relative oil content of the seeds. Genetic analyses indicate that KLU acts independently of other tested maternal factors that influence integument cell proliferation. Thus, the level of KLU-dependent growth factor signaling determines size in ovules and seeds, suggesting this pathway as a target for crop improvement. Arabidopsis/clonal analysis/cytochrome P450/seed growth doi/10.1073/pnas.0907024106

Plant distributions are in part determined by environmental heterogeneity on both large (landscape) and small (several meters) spatial scales. Plant populations can respond to environmental heterogeneity via genetic differentiation between large distinct patches, and via phenotypic plasticity in response to heterogeneity occurring at small scales relative to dispersal distance. As a result, the level of environmental heterogeneity experienced across generations, as determined by seed dispersal distance, may itself be under selection. Selection could act to increase or decrease seed dispersal distance, depending on patterns of heterogeneity in environmental quality with distance from a maternal home site. Serpentine soils, which impose harsh and variable abiotic stress on non-adapted plants, have been partially invaded by Erodium cicutarium in northern California, USA. Using nearby grassland sites characterized as either serpentine or non-serpentine, we collected seeds from dense patches of E. cicutarium on both soil types in spring 2004 and subsequently dispersed those seeds to one of four distances from their maternal home site (0, 0.5, 1, or 10 m). We examined distance-dependent patterns of variation in offspring lifetime fitness, conspecific density, soil availability, soil water content, and aboveground grass and forb biomass. ANOVA revealed a distinct fitness peak when seeds were dispersed 0.5 m from their maternal home site on serpentine patches. In non-serpentine patches, fitness was reduced only for seeds placed back into the maternal home site. Conspecific density was uniformly high within 1 m of a maternal home site on both soils, whereas soil water content and grass biomass were significantly heterogeneous among dispersal distances only on serpentine soils. Structural equation modeling and multigroup analysis revealed significantly stronger direct and indirect effects linking abiotic and biotic variation to offspring performance on serpentine soils than on non-serpentine soils, indicating the potential for soil-specific selection on seed dispersal distance in this invasive species. Key words: environmental heterogeneity; Erodium cicutarium; invasive species; multigroup analysis; phenotypic plasticity; seed dispersal; serpentine soils; structural equation modeling.

Phytate is an important antinutritional component of legume seeds, which chelates minerals that are essential to the human diet such as iron and zinc. Phytate levels are often correlated with total seed phosphorus (P). The objective of this research was to evaluate quantitative trait loci (QTL) for seed P and phytate content in an inter-gene pool (G2333 x G19839) recombinant inbred line population of common bean (Phaseolus vulgaris L.) planted at medium and high levels of soil P in randomized complete block experiments. Seed P and phytate content were quantified with spectrophotometric methods based on acid digestion with molybdenum blue and Wade reagents, respectively, and net seed P and net phytate content were calculated on a per-seed basis using seed weights for each experiment. Total seed P varied from 2.8 to 6.1 g [kg.sup.-1] and phytates varied from 0.29 to 1.78% across fertilization levels. A total of six QTL were found for total or net seed P, while three were found for percentage or net seed phytates. The QTL for seed P and percent phytates were located independently on linkage groups B2 and B11 vs. B6, respectively. Meanwhile, the QTL for net seed P or phytate content were related to seed weight QTL on linkage groups B6, B7, and B10, with one additional net phytate QTL on B5. The results suggest that bean plants can adapt to different initial supplies of P and that seed P and phytate levels in common bean can be modified through plant breeding.

To investigate the genetic factors underlying a major quantitative trait locus (QTL) contributing to low seed stachyose content in two separate populations derived from soybean [Glycine max (L.) Merr.] line PI200508, the recently released 'Williams 82' whole genome shotgun (WGS) sequence was exploited for candidate gene discovery. The physical interval containing a low stachyose QTL from PI200508 was identified in the WGS, and screened for areas that could be exploited for linkage mapping purposes. Microsatellite sequences designed in these areas were used to develop new markers, creating tighter linkage with the QTL. Examination of the Williams 82 sequence in this interval and the corresponding glyma0.1b gene model, available through the Phytozome website (http://www.phytozome.org), revealed one candidate gene with significant homology to previously characterized galactosyltransferase genes from Arabidopsis, pea, and cucumber. Sequencing of the annotated coding region for this gene revealed a single unique sequence polymorphism between PI200508, and lines exhibiting wild-type expression of stachyose content. The mutant phenotype appears to have arisen from a 3 bp deletion, and is easily distinguished from the wild-type allele via a marker presented in this study. This mutation-specific marker explained 88 to 94% of the phenotypic variation for seed stachyose content, and 76% for seed sucrose content, traits that exhibited a strong negative correlation in this study (p < 0.01).

The low-phytate (LP) trait in plant seeds offers important nutritional and environmental benefits for food and feed uses. Mutants with reduced phytate content are commonly produced by chemical mutagenesis, as is the case for soybean [Glycine max (L.) Merr.] line CX1834. Quantitative trait loci (QTL) for LP in CX1834 have previously been reported, however the genetic basis for this trait has not been identified. In this study, we examined several possible chromosomal map locations for the LP mutation in CX1834. After eliminating the myo-inositol phosphate synthase (MIPS) gene family as the location of the LP mutations based on mapping studies, we focused on candidate genes in regions of known low-phytate QTL on linkage groups (LGs) L and N. Using the soybean whole-genome sequence, we identified genes encoding two putative multidrug resistance-associated proteins (MRPs). The sequence of a segment of the CX1834 MRP gene on LG N was compared with sequences from 16 other soybean lines with normal phytate content. A single nucleotide mutation from A to T, resulting in substitution of a stop codon for an Arg residue, was detected in the MRP gene on LG N of the low phytate line, but not in the normal counterparts. Further comparative sequence analysis of normal and LP progeny from a cross of CX1834 with V99-3337 (normal phytate) also indicated the A to T substitution in LP individuals, suggesting a mutation in an MRP gene as the possible cause of the low-phytate phenotype.

Many native grasses display seed shattering and other seed production problems. Basin wildrye [Leymus cinereus (Scribn. & Merr.) A. Love] and creeping wildrye [L. triticoides (Buckley) Pilg.] are perennial Triticeae grasses native to western North America. In this study, variation in the number of florets per inflorescence, percent seed set, seed mass, seed shattering, and seed dormancy was measured in clonally replicated multiyear field evaluations of 164 progeny derived from a backcross between a creeping x basin wildrye hybrid and a true creeping wildrye tester. Genomewide quantitative trait locus (QTL) scans detected independent gene effects for all five traits and one pleiotropic QTL, located on Triticeae homeologous chromosome group 6, associated with major seed shattering (43.1% [R.sup.2], 26,9 log of odds likelihood ratio [LOD]) and seed dormancy (24.1% [R.sup.2], 10.6 LOD) effects. We hypothesize that a dominant basin wildrye gene creates an abscission that promotes seed disarticulation but hinders seed development and seed ripening in the creeping wildrye backcross family. Alignments of Leymus chromosome 6 expressed sequence tag markers to the rice (Oryza) genome reveal well-defined correspondence of Leymus wildrye and American wildrice (Zizania palustris L.) seed shatter QTLs.

Stearic acid (18:0) is typically a minor component of soybean [Glycine max (L.) Merr.] oil, accounting for only 2 to 4% of the total fatty acid content. Increasing stearic acid levels of soybean oil would lead to enhanced oxidative stability, potentially reducing the need for hydrogenation, a process leading to the formation of undesirable trans fatty acids. Although mutagenesis strategies have been successful in developing soybean germplasm with elevated 18:0 levels in the seed oil, the specific gene mutations responsible for this phenotype were not known. We report a newly identified soybean gene, designated SACPD-C, that encodes a unique isoform of [[DELTA].sup.9]-stearoyl-ACP-desaturase, the enzyme responsible for converting stearic acid to oleic acid (18:1). High levels of SACPD-C transcript were only detected in developing seed tissue, suggesting that the encoded desaturase functions to enhance oleic acid biosynthetic capacity as the immature seed is actively engaged in triacylglycerol production and storage. The participation of SACPD-C in storage triacylglycerol synthesis is further supported by the observation of mutations in this gene in two independent sources of elevated 18:0 soybean germplasm, A6 (30% 18:0) and FAM94-41 (9% 18:0). A molecular marker diagnostic for the FAM94-41 SACPD-C gene mutation strictly associates with the elevated 18:0 phenotype in a segregating population, and could thus serve as a useful tool in the development of cultivars with oils possessing enhanced oxidative stability.

Soybean [Glycine max (L.) Merr.] seeds contain a high concentration of the isoflavones daidzein and genistein, which are considered to be compounds beneficial to human health. Our objective was to determine the influence of breeding and selection for yield on the isoflavone concentration of short-season cultivars. A collection of 14 historical cultivars released from 1934 to 1992 was grown at Ottawa for 12 yr under identical cultural conditions. Seed samples, taken at harvest, were examined using near-infrared reflectance in conjunction with traditional chemical methods to measure the concentration of daidzein, genistein, and total isoflavones (TIF). A linear regression equation developed based on the changes across time of cultivar release was used to determine the improvement rates for various soybean parameters. Across the 58 yr of breeding history, yield and oil concentration increased by 0.43 and 0.24% per year, respectively, while protein concentration decreased by 0.15% per year. Across the same time period daidzein, genistein, and TIF increased by 1.04, 1.47, and 0.98% per year, respectively. Moderate broad sense heritabilities of 43, 45, and 44% were calculated for the aforementioned isoflavones. Genotype main effects + genotype x environment interaction biplots revealed that recent cultivars with high isoflavone concentration were more prone to environmental influence than older cultivars. In the short-season region, plant breeders should be aware that selecting for higher yield may indirectly select for higher isoflavone concentration.

Soybean [Glycine max (L.) Merr.] seed produced in high-temperature, high-humidity production environments is prone to have substandard germination. Hardseededness, wrinkled seed coats, and infection by Phomopsis Iongicolla Hobbs are all known to affect soybean seed germinability. Ancestors of modern U.S. soybean cultivars may lack the necessary variability to impart high germinability to new cultivars without the introgression of new genetic diversity. The purpose of this research was to identify soybean germplasm possessing positive traits affecting high seed germinability for seed produced under high-temperature environments, such as in the early soybean production system (ESPS) of the midsouthern United States. Seed was produced in the ESPS for 486 U.S. plant introductions (PI), 25 ancestral lines of U.S. cultivars, and four U.S. cultivars at Stoneville, MS, in 2002 and 2003. Standard and accelerated-aging germination percentages, hardseededness, seed coat wrinkling, and incidence of P. longicolla were estimated for each line. Based on the 2002 and 2003 field data, 42 PIs were selected for further testing, along with three cultivars, in two greenhouse temperature regimes (36[degrees] and 42[degrees]C) at Stoneville, MS, in 2005. Standard field germinations for the 25 ancestral lines ranged from 26 to 82%. Sixty-three accessions were identified as having a mean standard field germination of [greater than or equal to] 90%,

The fatty acid composition of soybean [Glycine max (L.) Merr.] seed affects the flavor, nutritional value, and stability of the oil. Increasing oleic acid content in soybean oil would reduce the need for hydrogenation, a process that creates unhealthy trans fatty acids. The objective of this study was to map and confirm the areas of the soybean genome associated with oleic acid content from the soybean line N00-3350 (~583 g [kg.sup.-1] oleic acid) using simple sequence repeat (SSR) markers. An [F.sub.2:3] population of 259 lines from the cross of G99-G725 x N00-3350 was used as a mapping population, and an [F.sub.2:3] population of 231 lines from the cross of G99-G3438 x N00-3350 was used for confirmation. Using single-factor analysis of variance, interval mapping, and composite interval mapping, six quantitative trait loci (QTLs) for oleic acid content were found on linkage groups LG-A1 (Satt211, [R.sup.2] = 4%), LG-D2 (Satt389, [R.sup.2] = 6%), LG-G (Satt394, [R.sup.2] = 13%), LG-G (Satt191, [R.sup.2] = 7%), LG-L (Satt418, [R.sup.2] = 9%), and LG-L (Satt561, [R.sup.2] = 25%) in the G99-G725 x N00-3350 population. All six QTLs for oleic acid were confirmed in the G99-3438 x N00-3350 population. The designations cqOle-001, cqOle-002, cqOle-003, cqOle-004, cqOle-005, and cqOle-006 have been assigned to these confirmed QTLs by the Soybean Genetics Committee. The identification of SSR markers linked to the oleic acid QTLs will facilitate the use of marker-assisted selection (MAS) in soybean breeding programs to increase the oleic acid content in soybean seed.