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Hoffman, D. D., Diers, B. W., Hartman, G. L., Nickell, C. D., Nelson, R. L., Pedersen, W. L., Cober, E. R., Graef, G. L., Steadman, J. R., Grau, C. R., Nelson, B. D., del Rio, L. E., Helms, T., Anderson, T., Poysa, V., Rajcan, I., and Stienstra, W. C. 2002. Selected soybean plant introductions with partial resistance to Sclerotinia sclerotiorum. Plant Dis. 86:971-980. Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and Canada in replicated large plots from 1998 to 2000. The PIs in the MG I to III tests in Urbana, IL were evaluated for agronomic traits from 1998 to 2000. The selected PIs also were evaluated with an excised leaf inoculation and petiole inoculation technique. After the 1995 to 1997 evaluations, all but 68 PIs were eliminated because of their susceptibility to Sclerotinia stem rot. In field tests in Urbana, higher disease severity in selected MG I to III PIs was significantly (P < 0.05) associated with taller plant heights and greater canopy closure. All other agronomic traits evaluated were not associated or were inconsistently associated with disease severity. MG I to III PIs 153.282, 189.931, 196.157, 398.637, 417.201, 423.818, and 561.331 had high levels of resistance and had canopies similar to the resistant checks. The resistance ratings from the petiole inoculation technique had a high and significant (P < 0.01) correlation with disease severity in the MG I and II field tests. The partially resistant PIs identified in this study can be valuable in incorporating Sclerotinia stem rot resistance into elite germ plasm.

HS-171 is a large-seeded edamame food-grade soybean genotype [Glycine max. (L.) Merr.] with yellow hilum, low oil, and high protein and sucrose concentrations. It is adapted to the areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity rating of 2.6.

Soybean improvement via plant breeding has been critical for the success of the crop. The objective of this study was to quantify genetic change in yield and other traits that occurred during the past 80 yr of North American soybean breeding in Maturity Groups (MGs) II, III, and IV. Historic sets of 60 MG II, 59 MG III, and 49 MG IV soybean cultivars, released from 1923 to 2008, were evaluated in field trials conducted in 17 U.S. states and one Canadian province during 2010 to 2011. Averaged over 27 MG II and MG IV and 26 MG III site-years of data, the estimated rates of yield improvement during the 80 yr were 23 kg ha yr for MGs II and III, and 20 kg ha yr for MG IV cultivars. However, a two-segment linear regression model provided a better fit to the data and indicated that the average current rate of genetic yield gain across MGs is 29 kg ha yr. Modern cultivars yielded more than old cultivars in all environments, but particularly in high-yielding environments. New cultivars in the historic sets used in this study are shorter in height, mature later, lodge less, and have seeds with less protein and greater oil concentration. Given that on-farm soybean yields in the United States are also increasing at a rate of 29 kg ha yr, it can be inferred that continual release of greater-yielding cultivars has been a substantive driver of the U.S. on-farm realized yield increases.

HS-151 is a lipoxygenase free food grade soybean line (Glycine max. L.) with large seed size, high protein content, yellow hilum, and satisfactory food processing quality. It is adapted to areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity of 2.2 (MG 2.2).

HS-162 is a 7S β-conglycinin α′ and 11S glycinin A4 null food-grade soybean (Glycine max L. Merr.) line with high protein concentration, large seed, yellow hilum, and excellent food processing qual...

HS-161 is a 7S β-conglycinin α′ and 11S glycinin A3 null food-grade soybean line (Glycine max (L.) Merr.) with high protein concentration, yellow hilum, and fair food processing quality. It is adap...

Soybean mutant lines that differ in 11S glycinin and 7S β-conglycinin seed storage protein subunit compositions were developed. These proteins have significant influence on tofu quality. The molecular mechanisms underlying the mutant lines are unknown. In this study, gene-specific markers for five of the glycinin genes (Gy1 to Gy5) were developed using three 11S null lines, two A(4) null Japanese cultivars, Enrei and Raiden, and a control cultivar, Harovinton. Whereas gene-specific primers produced the appropriate products in the control cultivar for the Gy1, Gy2, Gy3 and Gy5 genes, they did not amplify in mutants missing the A(1a)B(2), A(2)B(1a), A(1b) B(1b), and A(3)B(4) subunits. However, ecotype targeting induced local lesions in genomes (EcoTILLING) and sequencing analysis revealed that the absence of the A(4) peptide in the mutants is due to the same point mutation as that in Enrei and Raiden. Selection efficiency of the gene-specific primer pairs was tested using a number of breeding lines segregating for the different subunits. Primer pairs specific to each of the Gy1, Gy2, Gy3, and Gy5 genes can be used to detect the presence or absence of amplification in normal or mutant lines. The Gy4 null allele can be selected for by temperature-switch PCR (TS-PCR) for identification of the A(4) (G4) null genotypes. In comparison to protein analysis by SDS-PAGE, gene-specific markers are easier, faster and more accurate for analysis, they do not have to use seed, and can be analyzed at any plant growth stage for marker-assisted selection.

Phytophthora root rot (PRR) of soybean (Glycine max (L.) Merr.) is the second most important cause of yield loss by disease in North America, surpassed only by soybean cyst nematode (Wrather et al. in Can J Plant Pathol 23:115-121, 2001). Tolerance can provide economically useful disease control, conditioning partial resistance of soybean to PRR. The aims of this study were to identify new quantitative trait loci (QTL) underlying tolerance to PRR, and to evaluate the effects of pyramided or stacked loci on the level of tolerance. A North American cultivar 'Conrad' (tolerant to PRR) was crossed with a northeastern China cultivar 'Hefeng 25' (tolerant to PRR). Through single-seed descent, 140 F2:5 and F2:6 recombinant inbred lines were advanced. A total of 164 simple sequence repeat (SSR) markers were used to construct a genetic linkage map. The percentage of seedling death was measured over 2 years (2007 and 2008) in the field at four naturally infested locations in Canada and China following additional soil infestation and in the greenhouse following inoculation with Phytophthora sojae isolate. A total of eight QTL underlying tolerance to PRR were identified, located in five linkage groups (F, D1b+w, A2, B1, and C2). The phenotypic variation contributed by the loci ranged from 4.24 to 27.98%. QPRR-1 (anchored in the interval of SSR markers Satt325 and Satt343 of LG F), QPRR-2 (anchored in the interval of Satt005 and Satt600 of LG D1b+w), and QPRR-3 (anchored in the interval of Satt579 and Sat_089 of LG D1b+w) derived their beneficial allele from 'Conrad'. They were located at chromosomal locations known to underlie PRR tolerance in diverse germplasm. Five QTL that derived beneficial alleles from 'Hefeng 25' were identified. The QTL (QPRR-1 to QPRR-7) that were detected across at least three environments were selected for loci stacking and to analyze the relationship between number of tolerance loci and disease loss percentage. The accumulation of tolerance loci was positively correlated with decreases in disease loss percentage. The pyramid of loci underlying tolerance to PRR provided germplasm useful for crop improvement by marker-assisted selection and may provide durable cultivar tolerance against the PRR disease.

Daily consumption of cadmium (Cd) contaminated foods poses a risk to human health. Cultivar selection is an important method to limit Cd uptake and accumulation; however, analyzing grain Cd concentration is costly and time-consuming. Developing markers for low Cd accumulation will facilitate marker assisted selection (MAS). Inheritance studies using a threshold value of 0.2 mg kg(-1) for low and high and an F(2:3) population showed that low Cd accumulation in soybean seed is under the control of a major gene (Cda1, proposed name) with the allele for low accumulation being dominant. A recombinant inbred line (RIL) population (F(6:8)) derived from the cross AC Hime (high Cd accumulation) and Westag-97 (low Cd accumulation) was used to identify the DNA markers linked to Cda gene(s) or quantitative trait loci (QTLs) controlling low Cd accumulation. We screened 171 simple sequence repeat (SSR) primers that showed polymorphism between parents on the 166 RILs. Of these, 40 primers were newly developed from the soybean genomic DNA sequence. Seven SSR markers, SatK138, SatK139, SatK140 (0.5 cM), SatK147, SacK149, SaatK150 and SattK152 (0.3 cM), were linked to Cda1 in soybean seed. All the linked markers were mapped to the same linkage group (LG) K. The closest flanking SSR markers linked to Cda1 were validated using a parallel population (RILs) involving Leo x Westag-97. Linked markers were also validated with diverse soybean genotypes differing in their seed Cd concentration and showed that SSR markers SatK147, SacK149, and SattK152 clearly differentiated the high and low Cd accumulating genotypes tested. To treat Cd uptake as a quantitative trait, QTL analysis using a linkage map constructed with 161 markers identified a major QTL associated with low Cd concentration in the seeds. The QTL was also mapped to the same location as Cda1 on LG-K. This QTL accounted for 57.3% of the phenotypic variation. Potential candidate genes (genes with known or predicted function that could influence the seed Cd concentration) like protein kinase, putative Adagio-like protein, and plasma membrane H(+)-ATPase were found to be located in the locus of interest. Of the four SSR markers located in the region, SattK152 was localized in the plasma membrane H(+)-ATPase gene. SSR markers closely linked to Cda1 in seeds of soybean were identified and have potential to be used for MAS to develop low Cd accumulating cultivars in a breeding program.

Of 87 short-season soybean cultivars evaluated for reactions to three races (1, 3, and 5) of Phytophthora sojae Kaufmann and Gerdemann, 29 showed resistance to at least one of the three races. These resistant sources may be used for pyramiding Rps genes and deployment of P. sojae resistant soybean cultivars in Canada. Key words: Soybean, Glycine max, phytophthora root and stem rot, Phytophthora sojae

A possible solution to stability problems is to genetically reduce the content of linolenic acid in soybean seed. RG10 is a low linolenic acid line (< 25 g/kg) produced by ethyl methane sulfonate (EMS) treatment of the low linolenic acid EMS mutant line C1640. The objective of this study was to determine the molecular basis of the low linolenic acid trait in RG10. Sequence analyses of mutant RG10 and wild-type OX948 ω-fatty acid desaturase (Fad3) genes showed that the low level of linolenic acid in RG10 is likely a result of mutations in two Fad3 genes. A mutation in the Fad3A gene introduces a stop codon in exon 6 that would prematurely terminate translation and a second mutation in the 5' splice site of intron 5 of the Fad3B gene may result in abnormal mRNA splicing products. Both mutations would result in a non-functional enzyme. Molecular markers developed for these mutations should simplify and accelerate introgression of the RG10-based low linolenic acid trait into elite soybean cultivars.

Broad tolerance to phytophthora root rot (PRR) caused by Phytophthora sojae has become an important goal for the improvement of soybean (Glycine max) because of the rapid spread of races that defeat the available resistance genes. The aim of this research was to identify the location of quantitative trait loci (QTL) in ‘Conrad’, a soybean cultivar with broad tolerance to many races of P. sojae. A PRR susceptible breeding line ‘OX760-6-1’was crossed with Conrad. Through single-seed-descent, 112, F2 derived, F7 recombinant inbred lines (RILs) were advanced. A total of 39 random amplified polymorphic DNA bands (RAPDs) and 89 type 1 microsatellite (simple sequence repeat; SSR) markers were used to construct a genetic linkage map. In the greenhouse, RILs were inoculated with four P. sojae isolates (three from China and one from Canada). Disease was measured as the percent of dead plants 20 days after germination in P. sojae inoculated vermiculite in the greenhouse. Three QTLs (QGP1, QGP2, QGP3) for PRR tolerance in the greenhouse were detected using WinQTLCart 2.0 with a log-likelihood (LOD) score 27.14 acquired through permutations (1,000 at P ≤ 0.05). QGP1 (near Satt509) was located at linkage group F and explained 13.2%, 5.9%, and 6.7% of the phenotypic variance for tolerance to the JiXi, JianSanJiang and ShuangYaShan isolates, respectively. QGP2 (near Satt334) was located in a different interval on linkage group F and explained 5.1% and 2.4% of the phenotypic variance for JiXi and ShuangYaShan isolates, respectively. QGP3 was located on linkage group D1b + W (near OPL18800/SCL18659) and explained 10.2% of the phenotypic variance for Woodslee isolate. QGP1 and QGP2 appeared to be associated with PRR tolerance across a range of isolates but QGP3 was active only against the Woodslee isolate. At Woodslee and Weaver (in Ontario) in 2000, the interval associated with QGP3 explained 21.6% and 16.7% of phenotypic variance in resistance to PRR, respectively and was referred as QFP1. The identified QTLs would be beneficial for marker assistant selection of PRR tolerance varieties against both China and North America P. sojae races.

‘Conrad’, a soybean cultivar tolerant to Phytophthora root rot (PRR), and ‘OX760-6-1’, a breeding line with low tolerance to PRR, were crossed. F2 derived recombinant inbred lines were advanced to F6 to generate a population through single-seed descent. This population was used to identify quantitative trait loci (QTLs) influencing PRR tolerance in ‘Conrad’. A total of 99 simple sequence repeat (SSR), or microsatellite, markers that were polymorphic and clearly segregated in the F6 mapping population were used for QTL detection. Based on the data of PRR in the field at two planting locations, Woodslee and Weaver, for the years 2000 and 2001, one putative QTL, designated as Qsatt414-596, was detected using MapMaker/QTL. Qsatt414-596 was flanked by two SSR markers from the linkage group MLG J, Satt414 and Satt596. Satt414 and Satt596 were also detected to be significantly (P

Seed-size uniformity is an important grading factor in soya beans affecting value. Currently, it is determined by visual inspection. Image analysis-based seed-size measurements were used to predict size uniformity of soya bean samples. Linear discriminant function models and artificial neural network classifiers were developed to classify samples in two uniformity classes (uniform or not uniform in size) using various size distribution parameters as measures of size uniformity. Both methods of classification performed equally well with an agreement in excess of 84% with the visual assessment of samples.

Soybean [Glycine max (L.) Merrill] seeds contain isoflavones, which have been associated with positive health effects in human adults but a negative effect on infants. Increasing or decreasing isoflavone content in the seed would be desirable; however, it is not known what impact this would have on agronomic and other seed quality traits. The main objective of this study was to determine if isoflavone content in soybean seeds was associated with changes in agronomic and seed quality traits. Recombinant inbred lines (RILs) with high (n = 35), intermediate (n = 35), and low (n = 35) isoflavone content, were selected from three F 4:5 populations grown in 2000 and planted at three locations in southern Ontario in 2002. There were significant differences among populations, environments, and their interaction for isoflavone content. High and low phenotypic classes were significantly different for maturity in all three populations. Despite a positive correlation between yield and isofiavones, several RILs with decreased isoflavone content (970 μg g -1 ) were identified with yields (4222 kg ha -1 ) comparable to high-yielding cultivars. Isoflavone content had minimal effects on oil content, seed quality, and weight. Population 1 showed a significant negative association between isoflavone and protein content, whereas Pop. 2 and Pop. 3 did not. RILs were identified with high isoflavone and protein content ranging from 1746 to 1851 μg g -1 and 431 to 442 g kg -1 , respectively. It was possible to develop soybean with desirable isoflavone content in the seed and superior agronomic and seed quality traits.

To improve oxidative stability of soybean oil and reduce off-flavours, we previously developed low linolenic acid, lipoxygenase-free (LLA.3lx) soybean germplasm. The objectives of this study were to characterize the patterns of inheritance and determine the relationships between the low linolenic acid (LLA) trait derived from the lines RG10 and PI 361088B and seed lipoxygenase nulls (3lx) from a triple null line OX948 that were used to create the new LLA.3lx germplasm. Reciprocal crosses between RG10 and OX948 and between PI 361088B and OX948 were made and populations derived from them were evaluated for their fatty acid profiles and seed lipoxygenases (LX) at the F2, F5 and F6 generations. Both RG10 and PI 361088B contain a single gene that controls linolenic acid (LA) content with alleles acting in an additive manner. No significant cytoplasmic effects were observed on LA content. The LLA trait was highly heritable in both RG10 × OX948 (RO) and PI 361088B × OX948 (PO) crosses and stable in different environments (Belize and Ontario, Canada). The three seed LX were each controlled by single genes, but lipoxygenase 1 (Lx1) and lipoxygenase 2 (Lx2) were tightly linked. No significant correlations were observed between LA content and seed LX. The simple and independent inheritance of LA and seed LX in these crosses should simplify breeding for soybean cultivars that are resistant to oxidative degradation. Key words: Soybean, linolenic acid, lipoxygenase, inheritance, trait relationships

A simple sequence repeat (SSR) marker composed of a tetra nucleotide repeat is tightly linked to a major gene of common bean (Phaseolus vulgaris L.) conferring resistance to common bacterial blight (CBB) incited by Xanthomonas axonopodis pv. phasoli (Xap). This SSR is located in the third intron region of the common bean nitrate reductase (NR) gene, which is mapped to linkage group (LG) H7, corresponding to LG B7 of the bean Core map. Co-segregation analysis between the SSR marker and CBB resistance in a recombinant inbred line (RIL) population demonstrated a tight linkage between the NR gene-specific marker and the major gene for CBB resistance. In total, the marker explained approximately 70% of the phenotypic variation in the population. Because it is co-dominant, this SSR marker should be more efficient for marker-assisted selection (MAS) than dominant/recessive random amplified polymorphic DNA (RAPD) or sequence characterized amplified region (SCAR) markers that have been developed, especially for early generation selection.

The simple sequence repeat (SSR) or microsatellite marker is currently the preferred molecular marker due to its highly desirable properties. The aim of this study was to develop and characterize more SSR markers because the number of SSR markers currently available in tomato is very limited. Five hundred DNA sequences of tomato were searched for SSRs and analyzed for the design of PCR primers. Of the 158 pairs of SSR primers screened against a set of 19 diverse tomato cultivars, 129 pairs produced the expected DNA fragments in their PCR products, and 65 of them were polymorphic with the polymorphism information content (PIC) ranging from 0.09 to 0.67. Among the polymorphic loci, 2-6 SSR alleles were detected for each locus with an average of 2.7 alleles per locus; 49.2% of these loci had two alleles and 33.8% had three alleles. The vast majority (93.8%) of the microsatellite loci contained di- or tri-nucleotide repeats and only 6.2% had tetra- and penta-nucleotide repeats. It was also found that TA/AT was the most frequent type of repeat, and the polymorphism information content (PIC) was positively correlated with the number of repeats. The set of 19 tomato cultivars were clustered based on the banding patterns generated by the 65 polymorphic SSR loci. Since the markers developed in this study are primarily from expressed sequences, they can be used not only for molecular mapping, cultivar identification and marker-assisted selection, but for identifying gene-trait relations in tomato.

The possibility of using random amplified polymorphic DNA (RAPD) markers previously mapped in the common bean PC50/XANI59 population to select for resistance to common bacterial blight (CBB) in different populations was examined. Two out of 02 selected RAPD markers were polymorphic in HR56 and W0633d, the parental lines used in this experiment. Cosegregation analysis of the two polymorphic markers and disease reaction in a recombinant inbred (RI) population derived from HR67/W1744d confirmed that one of the two RAPD markers, BC420900, was significantly associated with a major quantitative trait locus-conditioning resistance to CBB in HR67. This locus accounted for approximately 51) of the phenotypic variation. The RAPD marker was transformed into a sequence characterized amplified region (SCAR) marker and used for selection in a different population derived from ‘Envoy’/HR67. Prediction for resistance to CBB with the BC420.990 SCAR marker was 94.2% accurate in this population. A comparison between marker-assisted selection (MAS) and conventional greenhouse screening showed that the cost of MAS is about one-third less than that of the greenhouse test.

Two Soybean mosaic virus (SMV) G2 isolates, L and L-RB, sharing high-sequence similarly but differing in ability to break Rsv4-mediated resistance in soybean, were investigated. Infectious clones corresponding to these two isolates and their chimeric clones resulting from swapping different regions of genomic cDNA between L and L-RB were constructed. Only L-RB or chimeras containing the middle fragment of L-RB cDNA showed virulence on Rsv4–genotype soybean. Sequence comparison analysis revealed that the middle genomic region of L and L-RB encodes four different amino acids. Point mutagenesis demonstrated that a single amino acid substitution (Q1033K) in the P3 protein determined virulence toward Rsv4 resistance. In addition, six new SMV Rsv4 resistance-breaking isolates, variants of the second passage on Williams 82 infected with the chimeras or mutants noninfectious on soybean carrying Rsv4, were obtained. Sequencing data indicated that these new isolates contain either the Q1033K mutation or a new substitution (G1054R) in P3. Site-directed mutagenesis confirmed the virulence role of the G1054R mutation on Rsv4-genotype soybean. Taken together, these data suggest that P3 of the SMV G2 strain is an avirulent determinant for Rsv4 and one single nucleotide mutation in P3 may be sufficient to compromise its elicitor function.

The poor stability and off-flavors of soybean oil and protein products can be reduced by eliminating lipoxygenases from soybean seed. Mature seeds of OX948, a lipoxygenase triple null mutant line, do not contain lipoxygenase proteins. The objective of this study was to determine the molecular basis of the seed lipoxygenase null traits in OX948. Comparisons of the sequences for lipoxygenase 1 (Lx1) and lipoxygenase 2 (Lx2) genes in the mutant (OX948) with those in a line with normal lipoxygenase levels (RG10) showed that the mutations in these genes affected a highly conserved group of six histidines necessary for enzymatic activity. The OX948 mutation in Lx1 is a 74 bp deletion in exon 8, which introduces a stop codon that prematurely terminates translation. A single T–A substitution in Lx2 changes histidine H532 (one of the iron-binding ligands essential for L-2 activity) to glutamine. The mutation in the lipoxygenase 3 (Lx3) gene in OX948 is in the promoter region and represents two single base substitutions in a cis-acting AAATAC paired box. All three mutations would result in the loss of lipoxygenase activity in mature seed. The seed lipoxygenase gene mutation-based molecular markers could be used to accelerate and simplify breeding efforts for soybean cultivars with improved flavor.

Dietary intake of isoflavones has been shown to reduce the risk of several major diseases in humans. Therefore, breeding soybean [Glycine max (L.) Merrill] seeds with desirable isoflavone content would be beneficial to the food and health industries, but the environmental sensitivity of the trait complicates phenotypic selection. The objective of this study was to identify quantitative trait loci (QTL) and epistatic interactions associated with isoflavone contents in soybean seeds. A population of 207 F 4:6 recombinant inbred lines (RILs) was produced from the cross 'AC756' × 'RCAT Angora'. The population was phenotyped at two locations in Ontario, Canada, and genotyped by means of 99 polymorphic SSR markers. A significant genotype X environment interaction was found. Seventeen QTLs were detected (P < 0.01) by single-factor ANOVA. Individual loci explained up to 10.5% (P < 0.0001) of the phenotypic variation. Interval mapping and composite interval mapping identified nine genomic regions (LGs Al, C2, D1a, F, G, H, J, K, and M) associated with isoflavone contents. Some QTL associated with agronomic or seed quality traits mapped to the same regions as those for individual isoflavone contents on LGs Al, C2, F, J, K, M, and N. Twenty-three epistatic interactions were detected for isoflavones. Multiple locus models explained up to 25.0% (P < 0.0001) of the phenotypic variation without epistasis and up to 35.8% (P < 0.0001) with it. The QTL identified in this study could be useful for developing soybean varieties with desirable isoflavone content in the seed through marker-assisted selection (MAS).

Hilum color is useful for identifying soybean [Glycine max (L.) Merr.] cultivars. Tawny-pubescent yellow-hilum genotypes are sometimes described with buff, light brown, or very light brown hila in Canada. This study was conducted to determine whether the yellow hila of tawny-pubescent lines discolor more than grey-pubescent lines, and whether therefore these yellow hila may actually be classified as brown rather than yellow. Seed of tawny- and grey-pubescent yellow-hila isolines in two genetic backgrounds grown in three or four seasons were scored (1, light, to 4, dark) for hilum color by soybean breeders and also classified by the Variety Verification Unit, Canadian Food Inspection Agency. Hilum color was scored darker and non-yellow (2.9 score) for tawny-pubescent lines compared with yellow (1.4 score) for grey-pubescent lines. The effects of year and genetic background were also significant. Generally, non-yellow and yellow hila were found in tawny-pubescent lines while only yellow hila were found in grey-pubescent lines. We propose recognition of a new hilum color, imperfect yellow, conditioned by II, rr, and TT. The hilum color imperfect yellow has been approved by the Soybean Genetics Committee. The color of imperfect yellow hila ranges from yellow to brown depending on the genetic background of the line and environmental conditions.