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Common bean (Phaseolus vulgaris) is an annual legume crop that is grown worldwide for its edible dry seeds and tender pods. Marsh spot (MS) of the seeds is a physio-genic stress disease affecting seed quality in beans. Studies have suggested that this disease involves a nutritional disorder caused by manganese deficiency, but the inheritance of resistance to this disease has not been reported. A biparental genetic population composed of 138 recombinant inbred lines (RILs) was developed from a cross between an MS resistant cultivar ‘Cran09’ and an MS susceptible cultivar ‘Messina’. The 138 RILs and their two parents were evaluated for MS resistance during five consecutive years from 2015 to 2019 in sandy and heavy clay soils in Morden, Manitoba, Canada. The MS incidence (MSI) and the MS resistance index (MSRI) representing disease severity were shown to be both highly correlated heritable traits that had high broad-sense heritability values (H2) of 86.5% and 83.2%, respectively. No significant differences for MSI and MSRI were observed between the two soil types in all five- (MSI) or four-year (MSRI) data collection, but significant correlations among years were observed despite MS resistance was moderately affected by year. The MSIs and MSRIs displayed a right-skewed distribution, indicating a mixed genetic model involving a few major genes and polygenes. Using the joint segregation analysis method, the same four major genes with additive-epistasis effects showed the best fit for both traits, explaining 84.4% and 85.3% of the phenotypic variance for MSI and MSRI, respectively. For both traits, the M1, M2, M3 and m4 acted as the favorable (resistant) alleles for the four genes where M and m represent two alleles of each gene. However, due to epistatic effects, only the individuals of the M1M2M3M4 haplotype appeared to be highly resistant, whereas those of the m1m2m3M4 haplotype were the most susceptible. The m4 allele significantly suppressed the additive effects of M1M2M3 on resistance, but decreased susceptibility due to the additive effects of m1m2m3. Further quantitative trait locus (QTL) mapping is warranted to identify and validate individual genes and develop molecular markers for marker-assisted selection of resistant cultivars.

Low seed protein content in soybeans [ Glycine max (L.) Merr.] grown in Western Canada can result in soybean meal that does not meet the 48% protein standard. The objectives of this study were to quantify seed composition, agronomic differences between Eastern and Western Canada-grown soybeans, and to determine the yield cost of raising Western soybean protein. Twenty high-to-low protein, including one non-nodulating, genotypes were grown at two locations in Eastern Canada, and eight locations in Western Canada from 2018 to 2021 to determine seed protein, seed composition, and agronomic traits. Over all environments, genotype seed protein ranged from 36.8% to 46.9% with 35.0% for the non-nodulating line. Average seed protein was significantly higher in Eastern Canada (41.6%) compared with Eastern Prairie (39.3%) and Prairie sites (39.7%). There are not separate east–west mega-environments for seed protein in Canada; a high protein genotype is high protein across Canada. With an increase of seed protein by 1%, seed yield dropped by 45.3 kg ha−1 in Eastern Canada, 53.1 kg ha−1 in the Eastern Prairie, and 78.4 kg ha−1 in Prairie sites. In Western Canada, plants were taller but lower yielding with fewer and smaller seeds, and produced lower fixed nitrogen protein yield compared with Eastern Canada. Seed protein quality, quantified with the 11S:7S ratio, was higher in Western Canada compared with Eastern Canada. Plant breeders and growers may need to select higher protein genotypes at the cost of lower yield, if the soybean industry is unable to exploit the protein quality advantage in Western Canada.

Soybean ( Glycine max L.) is the most important legume crop in the world and provides protein and oil for human consumption and animal feed. Cold and waterlogging or flooding are abiotic stress that are commonly encountered during soybean germination in short-season growing conditions in the Northern latitudes. Imbibition of cold water during the germination disrupts the cell membranes and increases leakage of their contents and makes seeds vulnerable to biotic stress. The cold tolerance is associated with the ability of cells to avoid or repair the damage to their membranes and organelles, restoring membrane function and metabolism, and managing the reactive oxygen species generated during the process. Excess moisture impedes aerobic respiration by oxygen deprivation and increases the likelihood of soil-borne diseases further reducing the germination rate. Tolerance to waterlogging is associated with mechanisms that slow down the rate of water uptake and help maintain efficient anaerobic metabolism. The quantitative trait loci mapping, transcriptomics, and proteomic studies have revealed several genes and pathways that likely play a role in seed response to cold and waterlogging stress. This review discusses the effects of cold and waterlogging on soybean seed germination at the physiological level, describes the molecular mechanisms involved, and provides an overview of soybean waterlogging and cold tolerance research. The methodologies commonly used to study the molecular mechanisms controlling tolerance to waterlogging and cold stress are also reviewed and discussed.

Physicochemical, functional, and nutritional properties of flours from six navy bean varieties cultivated in two different locations in Manitoba, Canada were evaluated. The effect of genotype was found insignificant for protein content, ash content, zeta potential, and surface hydrophobicity among physicochemical properties (p > 0.05). For protein content, total starch content, and zeta potential of navy bean flours, environmental factors were found significant (p 0.05). In vitro protein digestibility results varied by genotype. Although in vitro protein digestibility corrected amino acid score values were significantly affected by genotype, environment, and their interactions similar to slowly digestible starch. The current study established a better understanding of the varietal effects of genotype and environment on a wide range of properties of navy bean flours.

This review provides an examination of the marsh spot disease in beans and the roles played by its causal factor, manganese (Mn) deficiency. The discovery of the marsh spot disease, its relation with Mn deficiency, and how it can be treated are discussed. Mn serves as a cofactor and a catalyst in various metabolic processes in different cell compartments, such as the oxygen-evolving complex of photosystem II (PSII) or reactive oxygen species scavenging. Some major quantitative trait loci (QTL) and putative candidate genes associated with Mn content in plants, especially in plant seeds, have been identified. Marsh spot disease in cranberry common bean is controlled by several major genes with significant additive and epistatic effects. They provide valuable clues for QTL candidate gene prediction and an improved understanding of the genetic mechanisms responsible for marsh spot resistance in plants.

Anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara, is one of the most destructive diseases of dry bean (Phaseolus vulgaris L.) in the world. Between 2005 and 2015, commercial fields of dry beans in Manitoba and Ontario were surveyed to determine the frequency of occurrence of races of the anthracnose fungus. Throughout the study, race 73 was most prevalent in Manitoba and Ontario. However, three anthracnose races not previously reported in Canada also were identified. These three new races and four previously identified anthracnose races were used to screen 52 dry bean cultivars, as well as a mung bean and azuki bean cultivar from Ontario, for their seedling reactions to determine their patterns of race resistance. The dry bean cultivars were classified into a total of 19 resistance spectra based on the pattern of seedling reactions to the seven anthracnose races. The most common resistance spectrum was susceptible to the majority of the anthracnose races and no cultivar was resistant to all of the races. Many bean cultivars produced intermediate anthracnose ratings to races 31 and 105 and tests of 16 dry bean cultivars against those races indicated that all cultivars with intermediate ratings to a specific race were segregating in their seedling reactions and none of the cultivars produced plants with only intermediate anthracnose severity ratings. This study provides new information on the anthracnose reactions of common bean cultivars in Canada, which should be useful for the development of new bean cultivars with durable resistance.

In common bean (Phaseolus vulgaris L.), seed storage protein deficiency is associated with increased total cysteine and methionine concentration. The goal of this study was to generate germplasm lines that combine this characteristic with adaptation to short season conditions in Manitoba, Canada. A recombinant inbred line population was developed by crossing the storage protein deficient genotype, SMARC1N‐PN1 with the cultivar Morden003. Two lines, 2‐37 and 3‐84, with a stable protein profile over 2 years at two locations were identified. Like SMARC1N‐PN1, both lines had a significantly higher cysteine concentration than Morden003, by approximately 35%. Methionine levels were elevated by approximately 15%, while tryptophan levels were also increased by approximately 30%. Line 2‐37 had a significant increase in protein quality, as measured by in vitro protein digestibility corrected amino acid score, by approximately 40%, as compared with Morden003. The increased protein quality for this line is attributable to higher levels of total cysteine and methionine, while having an overall reduction in crude protein concentration. Line 2‐37 had a similar seed yield as SMARC1N‐PN1, with a maturity comparable to Morden003. The results of high‐density single nucleotide polymorphism (SNP) genotyping and quantitative trait locus analysis of recombinant inbred lines indicated that variation in cysteine concentration was determined by the phaseolin locus, while variation in methionine concentration was determined by both the phaseolin and lectin loci. SNP markers that track the introgression of phaseolin and lectin deficiency into the Morden003 background were identified and validated.

Anthracnose caused by the fungus Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib. has been a major constraint to dry bean (Phaseolus vulgaris L.) production in Manitoba and Ontario, as w...

AAC Scotty (CFIA registration No. 8374) is a high-yielding cranberry bean (Phaseolus vulgaris L.) cultivar with a large seed size and resistance to races 73 and 105 of Colletotrichum lindemuthianum developed at the Agriculture and Agri-Food Canada Morden Research and Development Centre in Morden, MB. AAC Scotty is adapted to the dry bean producing regions of the Red River Valley with an average maturity of 97 d. AAC Scotty has acceptable cooking and canning quality.

The effects of cultivar, growing location, and year on physicochemical and cooking characteristics of beans (Phaseolus vulgaris) were investigated, and the relationship between these characteristics was determined. Twenty dry bean cultivars and breeding lines were grown at two different locations for two consecutive years (2013 and 2014) in southern Manitoba, Canada. Results indicated that cultivar, growing location, and year had significant effects on seed weight, water hydration capacity, and cooking time of beans. Significant cultivar, location, and year variations in protein, starch, and phytic acid contents in beans were observed. Most of the traits were also significantly affected by the interactions of cultivar × location, cultivar × year, and location × year. Seed weight was negatively correlated with crude protein and ash contents but positively correlated with starch content. Cooking time was negatively correlated with protein, ash, and phytic acid contents but positively correlated with firmnes...

Several bacterial diseases can significantly impact dry bean production in western Canada. The objectives of this study were to assess the incidence of multiple bacterial diseases on dry bean in southern Alberta and to determine the prevalent races causing halo blight (HB) in western Canadian dry bean fields. Field surveys combined with a pathogen isolation component were conducted in 2012–2014 to determine relative frequency of bacterial pathogens. Bacterial pathogens causing HB and brown spot were most commonly isolated from symptomatic tissues, whereas the pathogens causing common blight (CBB) and bacterial wilt were infrequently detected. In order to screen bean breeding lines for resistance to HB, the races of Pseudomonas syringae pv. phaseolicola (Pph) present in western Canada needed to be determined. A total of 114 Pph isolates were recovered from dry bean samples from Alberta, Saskatchewan and Manitoba in 2010–2013. Virulence testing of these isolates on the halo blight dry bean different...

Seed hardness trait has a profound impact on cooking time and canning quality in dry beans. This study aims to identify the unknown genetic factors and associated molecular markers to better understand and tag this trait. An F2:7 recombinant inbred line (RIL) population was derived from a cross between the hard and soft seeded black bean parents (H68-4 and BK04-001). Eighty-five RILs and the parental lines were grown at two locations in southern Manitoba during years 2014–2016. Seed samples were harvested manually at maturity to test for seed hardness traits. The hydration capacity and stone seed count were estimated by soaking the seeds overnight at room temperature following AACC method 56-35.01. Seed samples from 2016 tests were also cooked to determine effect of seed hardness on cooking quality. For mapping of genomic regions contributing to the traits, the RIL population was genotyped using the genotype by sequencing (GBS) approach. The QTL mapping revealed that in addition to the major QTL on chromosome 7 at a genomic location previously reported to affect seed-hydration, two novel QTL with significant effects were also detected on chromosomes 1 and 2. In addition, a major QTL affecting the visual appeal of cooked bean was mapped on chromosome 4. This multi-year-site study shows that despite large environmental effects, seed hardness is an oligo-genic and highly heritable trait, which is inherited independently of the cooking quality scored as visual appeal of cooked beans. The identification of the QTLs and development of SNP markers associated with seed hardness can be applied for common bean variety improvement and genetic exploitation of these traits. Electronic supplementary material The online version of this article (10.1007/s11032-018-0789-y) contains supplementary material, which is available to authorized users.

Balasubramanian, P. M., Mündel, H.-H., Conner, R. L., Chatterton, S. and Hou, A. 2015. AAC Black Diamond 2 dry bean. Can. J. Plant Sci. 95: 437–440. AAC Black Diamond 2 is a high-yielding black bean (Phaseolus vulgaris L.) cultivar with an upright, indeterminate bush growth habit, lodging resistance, shiny black seed coat and improved resistance to seed-borne common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli. AAC Black Diamond 2 was developed at the Agriculture and Agri-Food Canada (AAFC) Research Centre, Lethbridge, AB. AAC Black Diamond 2 is suitable for irrigated production in Alberta and Saskatchewan.

Genetic diversity of dry bean (Phaseolus vulgaris L.) in Canadian breeding programs is low. Cultivars, especially black beans, generally lack resistance to anthracnose. One hundred and fifty-five black bean accessions originating from twenty countries were evaluated for their resistance to races 73 and 105 of Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara, the predominant races of the bean anthracnose pathogen in Canada. Artificial inoculation in growth chambers identified 39 accessions that were resistant to race 73, of which 33 were also resistant to race 105. Only one accession was susceptible to race 73 and resistant to 105. The resistant lines from the collection were also screened with genetic markers closely associated with known anthracnose resistance genes. At least one of the major resistance loci, Co-1, Co-2, Co-3, Co-4, and Co-5, was indicated to be present in all except four accessions. The majority of resistant accessions appeared to carry at least one or two major resistance...

AAC Whitestar is a high yielding great northern dry bean (Phaseolus vulgaris L.) cultivar with an upright, indeterminate bush (Type IIb) growth habit, large seed size, and partial field resistance to white mould. AAC Whitestar was developed at the Agriculture and Agri-Food Canada (AAFC), Lethbridge Research and Development Centre (LRDC), in Lethbridge, AB. AAC Whitestar is suitable for irrigated wide row production in Alberta and Saskatchewan.

Boersma, J. G., Conner, R. L., Balasubramanian, P. M., Yu, K. and Hou, A. 2013. Marker-assisted dissection of anthracnose resistance in the dry bean cultivar Morden003. Can. J. Plant Sci. 93: 1115–1123. The dry bean cultivar Morden003 is resistant to anthracnose races 73 and 105, the two most prevalent races in western Canada. Previous studies found that Morden003 carried markers OF10530r, SCAreoli and SAS13 that are linked to the Co-1, Co-2 and Co-4 resistance genes on chromosomes Pv01, Pv11 and Pv08, respectively. Morden003 had a reported resistance spectrum similar to three other cultivars that carry the Co-15resistance gene. Using F2and F2:3populations from the reciprocal crosses of Morden003/OAC Rex, we mapped two race-specific resistance gene loci. An examination of known anthracnose resistance and other core markers showed no evidence of resistance being associated with the Co-1, Co-2, or Co-4 loci. Instead, the resistance genes were co-located in the vicinity of the Co-3 locus on Pv04. They were 2 cM apart and flanked by markers SAH181100and BM161. The map generated in this research also showed strong linkage of the anthracnose resistance loci to markers SW12, PVctt001 and SF10, which were associated with the Co-3 and Co-10 loci by previous researchers. A weak, distant linkage of marker SB12 to the Co-3 locus was also detected.

Balasubramanian, P., Mündel, H.-H., Chatterton, S., Conner, R. L. and Hou, A. 2015. AAC Whitehorse great northern dry bean. Can. J. Plant Sci. 95: 175–177. AAC Whitehorse is a high-yielding, early-maturing great northern bean (Phaseolus vulgaris L.) cultivar with an upright, indeterminate bush growth habit, large seed size and partial field resistance to white mould. AAC Whitehorse was developed at the Agriculture and Agri-Food Canada (AAFC) Research Centre, Lethbridge, AB. AAC Whitehorse is suitable for irrigated wide row production in Alberta and Saskatchewan.

This study examined the compositional change of five specialty soybean genotypes, which are low in oligosaccharides, high in oil, high in protein, large seeded or small seeded, along with two commercial cultivars, Jack and Ozark, during seed development and maturation. Seeds were sampled at 7-day intervals from initial seed formation to full maturity for approximately 8 weeks, and analysed for oil, protein, soluble saccharides, and starch. Although there were significant differences among the seven soybean genotypes in their chemical compositions, some compositional changes followed similar trends. Protein content decreased during the first 3–5 weeks after flowering and then gradually increased. Oil was accumulated rapidly during the early stages. The percentage of starch ranged from 6 to 15% in developing seeds, but declined sharply to 0.2–1% at maturity. Sucrose decreased during seed development and maturation, while non-digestible oligosaccharides (raffinose, stachyose, and verbascose) remained at low levels during early stage until 3 weeks before harvest and increased towards maturity. These findings provide valuable information for developing and selecting specialty soybean varieties for specific applications.

With 1 figure and 3 tables Abstract Food-grade soybean has generated tremendous public interests in various soyfoods including tofu, soymilk, natto and edamame because of their nutritional value and health benefits. In this study, genetic diversity and association analysis were performed among 105 food-grade soybean genotypes using 65 simple sequence repeat (SSR) markers distributed on 20 soybean chromosomes. Based on the SSR marker data, the 105 soybean genotypes were divided into four clusters with six sub-groups. A negative correlation was obtained between protein and oil content (r = −0.67). Thirteen SSR markers distributed on 11 chromosomes were identified to be significantly associated with oil content (P = 0.001 and R2% = 14.4–43.5) and 19 SSR markers distributed on 14 chromosomes with protein content (P = 0.001, R2% = 14.3–45.6). Twelve of the SSR markers were associated with both protein and oil QTL (quantitative trait loci). Results from this research will be facilitatory for breeders to select parents for crossing and use marker-assisted selection in food-grade soybean breeding and to map QTL for protein and oil content in soybean.

Diversity of food-grade soybeans is critical for utilization of genetic resources in cultivar development, germplasm enhancement, and end-product commercialization. The objective of this study was to assess seed quality attributes and phenotypic variability among 54 U.S. and 51 Asian food-grade cultivars and breeding lines. The results showed greater genetic diversity of protein content, calcium content, seed hardness, and seed size uniformity than other quality traits in both small- and large-seeded genotypes evaluated in this study. Among the small-seeded soybeans, the U.S. genotypes were more diverse and exhibited higher swell ratio and oil content but lower stone seed ratio and protein content than Asian accessions. Among the large-seeded accessions, U.S. genotypes had higher stone seed ratio and oil content but lower swell ratio and protein content, and were less diverse than Asian genotypes. The characterization of diverse food-grade soybeans will facilitate parent selection in specialty soybean breeding.

Guar [Cyamopsis tetragonoloba (L.) Taub.] is one of the most important industrial crops due to its richness in gum. Understanding the inheritance of gum content is a key to its successful genetic improvement. Gum content expression is reported to be controlled by additive, dominant, and epistatic effects, and modified by the environment. fg%, a relative gum content calculated by comparing with the gum content of Kinman was used as gum content (%) in this experiment. Reciprocal crosses of two lines of guar, PI 217923 and Lewis, were made to study the heritability of gum content (fg%). fg% of four plant introductions and four commercial varieties were studied in Lubbock in 1999–2002. Estimates of broad-sense heritability (h2 b.s.) of fg% in Lewis × PI 217923 and PI 217923 × Lewis were 75.53 and 52.74%, respectively. Estimates of narrow-sense heritability (h2 n.s.) of fg% were 40.00 and 29.00% for Lewis × PI 217923 and PI 217923× Lewis, respectively. At least one pair of genes were estimated to control the fg% expression in these two crosses. Significant differences of fg% were found among these eight entries. PI 217923 was found to have the highest fg% among the eight entries.

Anthracnose, caused by the seedborne pathogen Colletotrichum lindemuthianum, is a serious disease of dry bean (Phaseolus vulgaris) that can severely reduce seed yield and quality. A 2 year field study examined how seedborne infection (0%, 1%, 2%, 5%, 10%, and 20%) affected seedling emergence, seedling infection, the buildup of anthracnose in the crop canopy, yield, seed mass, and seed discolouration in ‘Navigator’ navy bean and ‘AC Ole’ pinto bean. The incidence of seedling infection was significantly higher in ‘AC Ole’ than it was in ‘Navigator’ resulting in an early establishment of the disease on the pinto bean cultivar. There was a linear increase (P < 0.01) in anthracnose severity within the crop canopy and on the pods with higher rates of seedborne infection in both cultivars. Increases in seedborne infection rates also resulted in a significant decline (P < 0.01) in yield and seed mass. Comparisons of the 0% and the 20% seedborne treatments indicated that severe anthracnose development resulted in ...

Soluble sugar is an important quality trait in food-grade soybeans [Glycine max (L.) Merr.]. Desirable sugars such as sucrose, glucose, and fructose can help improve the taste and flavor of soyfood including tofu, soymilk, and natto; whereas oligosaccharides including raffinose and stachyose are indigestible by humans and animals and often cause flatulence or diarrhea. In this study, 241 plant introductions (PIs) of three maturity groups (MGs) from 28 origins were investigated for seed sugar content including glucose, fructose, sucrose, raffinose, and stachyose. Variation was detected in individual and total sugars in soybean PIs from different origins and MGs. Sucrose and stachyose are the major sugars in soybean seed. The sucrose content ranged from 1.6 to 95.4 mg g ―1 with 13 PIs containing greater than 70 mg g ―1 and 14 PIs having less than 10 mg g ―1 . The stachyose content ranged from 0.2 to 69.6 mg g ―1 with 14 PIs containing less than 10 mg g ―1 stachyose. The high sucrose and low stachyose types are the most valuable for breeding specialty soybeans for soyfood and animal feed. In addition, 30 PIs were identified as having high concentrations of glucose or fructose as major sugars. This new class of high glucose or fructose has not been reported before. While soybean germplasm with unique sugar profiles may be useful for future breeding and genetic research, environmental effects on sugar stability will need to be further investigated.

Seed calcium content is an important quality attribute of specialty soybean [Glycine max (L.) Merr.] for soyfoods. However, analyzing seed for calcium content is time consuming and labor intensive. Knowing quantitative trait loci (QTL) for seed calcium will facilitate the development of elite cultivars with proper calcium content through marker-assisted selection (MAS). The objective of this study was to identify major QTL associated with calcium content in soybean seed. Calcium content was tested in 178 F(2:3) and 157 F(2:4) lines derived from the cross of SS-516 (low calcium) x Camp (high calcium). The F(2:3) lines were genotyped with 148 simple sequence repeat markers in a previous study on seed hardness, and the genotypic data were used in the QTL analysis of the current study. Four QTL designated as Ca1, Ca2, Ca3, and Ca4 on linkage groups (LGs) A2, I, and M were identified by both single-marker analysis and composite-interval mapping, and the QTL accounted for 10.7%, 16.3%, 14.9%, and 9.7% of calcium content variation, respectively. In addition, multiple-interval mapping analysis revealed a significant dominant-by-dominant interaction effect between Ca1 and Ca3, which accounted for 4.3% calcium content variation. These QTL will facilitate the implementation of MAS for calcium content in soybean-breeding programs.

Seven strains of Soybean mosaic virus (SMV) and three independent resistance loci (Rsv1, Rsv3, and Rsv4) have been identified in soybean. The objective of this research was to pyramid Rsv1, Rsv3, and Rsv4 for SMV resistance using molecular markers. J05 carrying Rsv1 and Rsv3 and V94-5152 carrying Rsv4 were used as the donor parents for gene pyramiding. A series of F2:3, F3:4, and F4:5 lines derived from J05 × V94-5152 were developed for selecting individuals carrying all three genes. Eight PCR-based markers linked to the three SMV resistance genes were used for marker-assisted selection. Two SSR markers (Sat_154 and Satt510) and one gene-specific marker (Rsv1-f/r) were used for selecting plants containing Rsv1; Satt560 and Satt063 for Rsv3; and Satt266, AI856415, and AI856415-g for Rsv4. Five F4:5 lines were homozygous for all eight marker alleles and presumably carry all three SMV resistance genes that would potentially provide multiple and durable resistance to SMV.

Soybean (Glycine max (L.) Merr.) seeds with undesirable texture cause processing complica- tions in soyfood production. Seed hardness is an important quality attribute for food-grade soy- beans. The objective of this study was to iden- tify quantitative trait loci (QTLs) associated with seed hardness in soybean. Three generations of F 2 -derived lines (159 F 2:3 , F 2:4 , and F 2:5 lines) from a soft ('SS-516') × hard ('Camp') soybean cross were grown in a replicated test in Fayetteville, AR, in 2003, 2004, and 2005. Pressure-cooked samples from each line were tested for seed hardness using a texture analyzer. A total of 874 simple sequence repeat (SSR) markers were used to screen the parents; 177 out of 236 poly- morphic markers between the parents showed polymorphism in the F 2:3 lines. A linkage map for seed hardness was established using 148 SSR markers, 15 of which were new and added to the current public soybean genetic linkage map. All identifi ed markers were placed on 19 linkage groups (LGs) and covered 1363.7 cM of the soy- bean genome with an average distance of 9.6 cM between markers. Broad-sense heritability was estimated to be 0.56 for seed hardness. Two stable QTLs across environments (Ha1 and Ha2, p < 0.00001) were identifi ed near Satt229 on LG L and Satt531 on LG D1a, respectively, for the average seed hardness over 3 yr. Ha1 had a logarithmic odds score of 6.17 with R 2 = 12.7%; Ha2 had a score of 5.08 with R 2 = 36.1%. A dom- inance-by-dominance interaction was detected between Ha1 and Ha2, explaining 7.9% of the phenotypic variance. Research is under way to confi rm the identifi ed QTLs for soybean seed hardness in multiple populations with different genetic backgrounds.

Soybean mosaic virus (SMV) is a highly destruc- tive viral disease. Three loci with 12 alleles con- ferring SMV resistance have been identifi ed in soybean (Glycine max (L.) Merr.). The objective of this study was to develop polymerase chain reaction-based markers for detecting the candi- date gene 3gG2 at the Rsv1 locus for SMV resis- tance in diverse soybean germplasm. A pair of DNA primers, Rsv1-f/r, was developed from the 3gG2 sequence. This primer pair produced a 341-bp DNA fragment specifi c for soybean cul- tivars containing Rsv1. The same fragment was confi rmed in genotypes containing Rsv1 alleles including 'Kwanggyo' (Rsv1-k), 'Marshall' (Rsv1- m), 'Ogden' (Rsv1-t), PI 96983 (Rsv1), PI 507389 (Rsv1-n), 'Raiden' (Rsv1-r), and 'Suweon 97' (Rsv1-s). The Rsv1-f/r fragment was also ampli- fi ed in genotypes with two-gene combinations (Rsv1Rsv3 and Rsv1Rsv4) but not in genotypes containing only Rsv3 or Rsv4 or in the sus- ceptible genotypes. The primer pair was used to screen for Rsv1 alleles in 97 SMV resistant genotypes. Results showed that 55 genotypes contained the 3gG2 gene, while 17 genotypes carrying the Rsv1-y allele and additional 25 SMV-resistant genotypes carrying Rsv3 or Rsv4 were not amplifi ed a product using the 3gG2 primer pair. Analysis of an F 2 population derived from J05 (Rsv1Rsv3) × 'Essex' (rsv1rsv3) showed a cosegregation between the marker Rsv1-f/r and the Rsv1 allele. Rsv1-f/r was also shown to be linked to simple sequence repeat marker Satt114 on soybean molecular linkage group F with a distance of 5.42 cM. This marker will give breeders a tool for marker-assisted selection and gene pyramiding in soybean breeding for SMV resistance.

Seeds of guar black in color are believed to be of low quality. In the present experiment, seeds varying in color were studied to examine the effect of seedcoat color on water uptake, germination, and quantity of seed component. Results showed that the rate of water uptake for black-colored seeds was greater than that of dull-white-colored seeds. Black seeds had a higher germination than that of dull-white-colored seeds. Seedcoat quantity in black-colored seeds was less than dull-white seeds. Endosperm quantity and embryo quantity of black-colored seeds were not significantly different from those in dull-white-colored seeds. The higher water uptake rate and germination in black-colored seeds are likely due to the degeneration of seedcoat. This research suggests that guar seeds black in color may be recommended for planting or gum-extracting purposes with little expected loss in stand or gum yield.

Conflicting theories of inheritance of branching in guar [Cyamopsis tetragonoloba (L.) Taub.] have been reported. In this study, two lines differing in leaf surface and growth habit were used to make reciprocal crosses and form progeny populations in order to study how basal branching is inherited. Parents in the reciprocal crosses were PI 217923, which is an erect type with pubescent leaves that exhibits predominantly zero, but as many as four basal branches; and ‘Lewis’, which is a branching type with glabrous leaves that exhibits from two to ten branches at the base. Parental and progeny populations were evaluated for branching under field-grown conditions. Effect of plant spacing (seeding rate at 1 seed/cm vs. 1 seed/30 cm) on basal branching of PI 217923 and Lewis was studied. Hybrids were identified by erect branching and pubescent leaf surface. F1 plants had erect branching type and pubescent leaves, indicating that erect branching is dominant to basal branching and there is no maternal effect. Chi-square goodness-of-fit analysis revealed that F2 populations segregated in the expected 3:1 ratio (P

Hou, A., Balasubramanian, P., Conner, R.L., Park, S., Yu, K., Kiehn, F.A. and Navabi, A. 2011. Portage common bean. Can. J. Plant Sci. 91: 523–525. Portage (CFIA registration no. 6881) is a high-yielding, early-maturing navy bean (Phaseolus vulgaris L.) cultivar with moderate resistance to common bacterial blight, developed at the Agriculture and Agri-Food Canada, Research Station, Morden, MB, and the Greenhouse and Processing Crops Research Centre at Harrow, ON. Portage is adapted to the dry bean producing regions of Manitoba. Portage has similar cooking and canning quality as the check cultivars.

Balasubramanian, P. M., Hou, A., Conner, R. L., Kiehn, F. A. and Mundel, H.-H. 2011. Carman Black dry bean. Can. J. Plant Sci. 91: 519–521. Carman Black is a high-yielding black bean (Phaseolus vulgaris L.) with an upright indeterminate growth habit (Type 2a) and early maturity. Carman Black was developed at the Agriculture and Agri-Food Canada (AAFC) Research Station, Morden, MB, in collaboration with the AAFC Research Centre, Lethbridge, AB. Carman Black has a black seed coat with an intermediate (matte-shiny) seed luster or glossiness. Carman Black is well adapted to the Red River Valley of Manitoba, with maturity earlier than the check cultivars AC Harblack and CDC Jet.

Polyacrylamide gel electrophoresis (PAGE) was used to study the polymorphism of esterases in Allium cepa L. and A. fistulosum L. Two varieties of each species, an A. fistulosum × A. cepa interspecific F1 hybrid, and (A. fistulosum × A. cepa) hybrid derivatives were analyzed for determination of banding patterns upon staining with α- and β-napthyl acetate substrates of esterase. Complex band patterns were observed. In total, 10 bands were detected between A. cepa and A. fistulosum — five inA. cepa, six in A. fistulosum with only one band common to both species. With the exception of one band unique to A. fistulosum which appeared only when stained with α-substrate, extracts of both A. cepa and A. fistulosum leaf tissue exhibited the same bands when stained with both α- and β-substrates. Bands stained with the different systems are distinguished by color: α-substrate always appeared black, while bands stained to β-substrate are always red. Esterase bands were assigned into 5 presumptive loci of four zones of activity with according to the migration distance of the bands from the front, color of each band upon staining with α- and β-substrates, and segregation observed in crosses and hybrid derivatives. Esterase enzymes detected in this study appear to be monomeric. Polymorphisms were identified between A. cepa and A. fistulosum by esterase banding patterns. Esterase enzymes provide an additional marker in monitoring introgression of foreign germplasm in interspecific onion breeding.

A male sterile plant, 79-399-3, was identified from a spring cabbage line 79-399 in 1979. Light-microscopic studies with paraffin section indicated that meiotic division stopped at the tetrad stage. The ratio of male sterile plants to fertile plants in the progenies of test crosses was 1:1 in five experiments conducted in 1982 and 1991–1994. However, some male sterile plants were sensitive and developed a very low number of viable pollen grains. When sensitive male sterile plants were selfed, the progenies segregated into male sterile and fertile plants at a ratio of 3:1. The male sterile plants from selfing of sensitive male sterile plants were propagated by tissue culture and crossed with different inbred lines. From the progenies of the crosses, populations with 100% male sterile plants were observed. The results indicated that homozygous dominant male sterile (MsMs) plants segregated from the selfed progenies. Populations with 100% male sterile plants and stable male sterility were developed as male sterile lines. Several favorable combinations were also selected by crossing the male sterile lines with inbred lines with high combining ability for desirable horticultural characters.

J05 soybean was previously identified to carry 2 independent genes, Rsv1 and Rsv3, for "soybean mosaic virus" (SMV) resistance by inheritance and allelism studies. The objective of this research was to confirm the 2 genes in J05 using molecular markers so that a marker-assisted selection can be implemented. The segregation of F(2) plants from J05 x Essex exhibited a good fit to a 3:1 ratio when inoculated with SMV G1. Three simple sequence repeat (SSR) markers near Rsv1, Satt114, Satt510, and Sat_154, amplified polymorphic DNA fragments between J05 and Essex and were closely linked to the gene on soybean molecular linkage group (MLG) F, thus verifying the presence of Rsv1 in J05 for resistance to SMV G1. The presence of Rsv3 in J05 was confirmed by 2 closely linked SSR markers on MLG B2, Satt726 and Sat_424, in F(2:3) lines that were derived from the SMV G1-susceptible F(2) plants and segregated in a 1:2:1 ratio for reaction to SMV G7. Two closely linked markers for Rsv4, Satt296 and Satt542, segregated independently of SMV resistance, indicating the absence of Rsv4 in J05. These SSR markers for Rsv1 and Rsv3 can serve as a useful molecular tool for selection and pyramiding of genes in J05 for SMV resistance.

The Chinese genebank contains 23,587 soybean landraces collected from 29 provinces. In this study, a representative collection of 1,863 landraces were assessed for genetic diversity and genetic differentiation in order to provide useful information for effective management and utilization. A total of 1,160 SSR alleles at 59 SSR loci were detected including 97 unique and 485 low-frequency alleles, which indicated great richness and uniqueness of genetic variation in this core collection. Seven clusters were inferred by STRUCTURE analysis, which is in good agreement with a neighbor-joining tree. The cluster subdivision was also supported by highly significant pairwise F st values and was generally in accordance with differences in planting area and sowing season. The cluster HSuM, which contains accessions collected from the region between 32.0 and 40.5°N, 105.4 and 122.2°E along the central and downstream parts of the Yellow River, was the most genetically diverse of the seven clusters. This provides the first molecular evidence for the hypotheses that the origin of cultivated soybean is the Yellow River region. A high proportion (95.1%) of pairs of alleles from different loci was in LD in the complete dataset. This was mostly due to overall population structure, since the number of locus pairs in LD was reduced sharply within each of the clusters compared to the complete dataset. This shows that population structure needs to be accounted for in association studies conducted within this collection. The low value of LD within the clusters can be seen as evidence that much of the recombination events in the past have been maintained in soybean, fixed in homozygous self-fertilizing landraces.

Two naturally occurring Arabidopsis mutants, Cape Verde Islands and Monte (Mr-0), with aberrant 12S seed storage protein (SSP) profiles have been identified by SDS-PAGE. In both mutants, one of the 12S globulin bands is missing while a new band of lower molecular mass is present. Tandem mass spectrometry-mass spectrometry (MS/MS) analyses of the mutant peptides have revealed that both are shorter variants of 12S globulin with deletion sites detected within the alpha-subunits of 12S globulin cruciferin B (CRB) and C (CRC), respectively. Sequence analyses of the genomic DNA flanking the deletion sites have demonstrated that both deletions occurred at the genomic level. These two mutants are referred to as CRBDelta12 and CRCDelta13 with the delta sign indicating a deletion and the number indicating amino acids deleted. Alignment of these two mutant sequences with that of soybean A3B4 subunit, for which the crystal structure was determined recently, have revealed that the CRCDelta13 deletion is located in a hypervariable/disordered region, and will probably not affect the structure of the hexameric globulin. The CRBDelta12 deletion, however, is located in a binding region that is thought to be important for the hexamer formation. However, CRBDelta12 appears to accumulate normally as judged by its band intensity relative to the other SSP subunits on the protein gels. Thus it seems that the seed can, to a certain extent, tolerate some mutations in its storage proteins.