Soybean rust (SBR), caused by Phakopsora pachyrhizi, was first discovered in North America in 2004 and has the potential to become a major soybean [Glycine max (L.) Merr.] disease in the USA. Currently, four SBR resistance genes have been identified but not mapped on the soybean genetic linkage map. One of these resistance genes is the Rpp1 gene, which is present in the soybean accession PI http://200492 The availability of molecular markers associated with Rpp1 will permit marker‐assisted selection and expedite the incorporation of this gene into U.S. cultivars. We compared simple sequence repeat (SSR) markers between ‘Williams 82’ and the BC5 Williams 82 isoline L85‐2378, which contains the Rpp1 resistance allele from the soybean accession PI http://200492, for candidate regions that might contain Rpp1 One candidate region was found with the SSR marker BARC_Sct_187 on linkage group G. A population of BC6F2:3 lines segregating for the Rpp1 resistance locus was genotyped in this region on linkage group G followed by inoculation with the P. pachyrhizi isolate India 73‐1 in the USDA‐ARS Biosafety Level 3 Plant Pathogen Containment Facility at Ft. Detrick, MD. The Rpp1 gene was mapped between SSR markers BARC_Sct_187 and BARC_Sat_064 on linkage group G.

The use of molecular markers to facilitate the introgression of plant introduction (PI) germplasm into elite soybean [Glycine max (L.) Merr.] cultivars will depend on the amount of polymorphism that exists between elite genotypes and PIs. The objective of this study was to assess the simple sequence repeat (SSR) diversity of 39 elite soybean genotypes (Elites) and 40 PIs that were selected for high yield potential. A total of 397 alleles were detected among the 79 genotypes at 74 SSR marker loci. The number of alleles detected among the PIs was 30% greater than that detected among the Elites. There were 138 alleles specific to the PIs that occurred across 60 SSR loci and 32 alleles specific to the Elites that occurred across 27 SSR loci. Average marker diversity among the PIs was 0.56 and ranged from 0.0 to 0.84. Average marker diversity among the Elites was 0.50 and ranged from 0.0 to 0.79. Genetic similarity estimates based on simple matching coefficients revealed more genetic diversity among the PIs than among the Elites. The greatest genetic diversity was between the PIs and Elites. The ability of SSRs to distinguish among elite soybean genotypes and PIs with agronomic merit may assist with the transfer of favorable alleles from PIs into elite soybean cultivars.

Soymilk made from lipoxygenase-free soybeans had less cooked beany aroma, less cooked beany flavor and less astringency and was rated darker and more yellow than that made from soybeans with normal lipoxygenase. Sensory descriptive panelists noted no differences between lipoxygenase-free and normal soybeans for milky flavor, wheat flavor, thickness, chalkiness or aftertaste. Tofu made from lipoxygenase-free soybeans had less cooked beany flavor than that made from normal soybeans. There were no differences in cooked beany aroma, raw beany aroma, raw beany flavor, wheat flavor, astringency, hardness, darkness or yellowness. Native-born Japanese, Chinese and U.S. descriptive panelists differed in responses to flavor, texture and color of soymilk and tofu.

characteristics (Lambert and Tyler, 1999). The lack of development of superior SIR cultivars may be due to There has been limited success over the past 30 yr in the developthe quantitative nature of resistance and to the retention ment of superior soybean cultivars [Glycine max (L.) Merr] with of undesirable PI donor alleles affecting any number insect resistance. Success may be hampered by the quantitative nature of resistance and by linkage drag from resistant plant introduction of traits because of their tight linkage with the insect (PI) donor parents. Soybean insect resistance quantitative trait loci resistance alleles, or QTL. This condition is often associ-(SIR QTLs) have been identified from PI 229358 and PI 171451 ated with the use of nondomesticated germplasm for the by restriction fragment length polymorphism (RFLP) analysis. The introgression of novel alleles and is generally referred to objective of this study was to tag the SIR QTLs from PI 229358 with J.M. Narvel,

The Rxp locus in soybean [Glycine max (L.) Merr.] that conditions reaction to bacterial pustule was mapped by simple sequence repeat (SSR) marker analysis. A population of 116 F4-derived lines from a cross between the resistant parent Young and the susceptible parent PI 416937 was used for mapping. The Rxp locus was mapped 3.9 cM from Satt372 and 12.4 cM from Satt014 on linkage group D2. Linkage associations were confirmed by identifying a close association between the SSR genotype at each locus identified as flanking Rxp and the bacterial pustule reaction of individual lines derived from a population different from the one used for mapping. A molecular pedigree analysis showed that bacterial pustule-resistant cultivars inherited the resistance gene rxp from the ancestral cultivar CNS based on their consistent genotypic pattern at flanking marker loci. Based on the results of the study, marker-assisted selection for rxp would be very effective.