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Crop yield is a derivative of the number of plants harvested. In Ghana, soybean fields are mostly sparsely populated with less than the optimum number of plants, a phenomenon that contributes to poor yields of only 46% of the crop's potential in farmers' fields. The low plant population could be the result of the poor quality of the seed planted. Meanwhile, the quality of seed is determined by crop production practices, the environmental conditions of the mother plant, and postharvest handling technologies used. Over 90% of the country's soybean seed comes from the northern part of Ghana, predominantly the Guinea Savannah. In this study, seed lots of soybean genotypes produced within the Savanna Agroecological Zone of Ghana, were evaluated for physical and physiological traits, and the prevalence of seed borne fungi. Results showed that seed lots produced within the zone and stored under ambient conditions have medium-sized (100 to 140 g/1000 seeds) seeds with an average seed weight of 133 g/1000 seeds. The seed lots evaluated had physical purity values higher than the minimum certification standard of 98% for soybean seed in Ghana. Wrinkled seeds were the most dominant component of the seed with visual defects followed closely by seeds that were discoloured, cracked, and those with purple stains. Aspergillus flavus, Aspergillus niger, Chaetomium globosum, Rhizopus sp and Macrophomina phaseolina were the main fungi identified. Furthermore, the seed lots had an average germination percentage of 86%, which is within the acceptable minimum certification standards for soybean seed in Ghana. Though germination and vigour were variable among the seed lots tested, these parameters were not affected by the presence of the fungi species identified and the amount of seed with visual defects. The findings of this study strongly suggest that the low plant density and the resultant poor yields of soybean usually recorded in farmers' fields in Ghana are likely due to suboptimal seeding rates at planting coupled with the low use of good agronomic practices with only a small fraction attributable to poor seed quality. Key words: Soybean, Ghana, fungi, savanna agroecology, viability, vigour, shrivelled seeds, germination, INTRODUCTION Soybean is one of the most widely cultivated leguminous crops across the world, grown for its oil, food and feed. World production is about 176.6 million tons per annum [...]

Genetic linkage maps are used to localize markers on the genome based on the recombination frequency. Most often, these maps are based on the segregation observed within a single biparental population of limited size (n < 300) where relatively few recombination events are sampled and in which some genomic regions are monomorphic because both parents carry the same alleles. Together, these two limitations affect both the resolution and extent of genome coverage of such maps. Consensus genetic maps overcome the limitations of individual genetic maps by merging the information from multiple segregating populations derived from a greater diversity of parental combinations, thus increasing the number of recombination events and reducing the number of monomorphic regions. The aim of this study was to construct a high-density consensus genetic map for single nucleotide polymorphism (SNP) markers obtained through a genotyping-by-sequencing (GBS) approach. Individual genetic maps were generated from six [F.sub.4:5] mapping populations (n = 278-365), totaling 1857 individuals. The six linkage maps were then merged to produce a consensus map comprising a total of 16 311 mapped SNPs that jointly cover 99.5% of the soybean genome with only two gaps larger than 10 cM. Compared to previous soybean consensus maps, it offers a more extensive and uniform coverage. Key words: soybean, genetic mapping, consensus genetic map, genotyping-by-sequencing, recombination events Les cartes genetiques sont employees pour positionner des marqueurs sur le genome en fonction de la frequence de recombinaison. Le plus souvent, ces cartes sont fondees sur la segregation observee au sein d'une population biparentale de taille limitee (n < 300) au sein de laquelle un nombre relativement restreint d'evenements de recombinaison sont rencontres et certaines regions genomiques sont monomorphes du fait que les deux parents partagent les memes alleles. Ensemble, ces deux limitations affectent a la fois la resolution et le degre de couverture du genome que conferent ces cartes. Les cartes genetiques consensus permettent de surmonter ces limitations propres aux cartes individuelles en fusionnant l'information obtenue a partir de plusieurs populations en segregation derivees d'une plus grande diversite de parents. Cela permet a la fois d'augmenter le nombre d'evenements de recombinaison et de reduire le nombre de regions monomorphes. Le but de ce travail etait de produire une carte genetique consensus a haute densite a l'aide de polymorphismes mononucleotidiques (SNP) obtenus par genotypage par sequencage (GBS). Les cartes individuelles ont ete generees a partir de six populations [F.sub.4:5] (n = 278-365) totalisant 1857 individus. Les six cartes de liaison ont ensuite ete fusionnees pour produire une carte consensus comptant 16 311 marqueurs SNP qui couvraient plus de 99,5 % du genome du soja et qui ne comptaient que deux intervalles sans marqueurs de plus de 10 cM. Par rapport aux cartes consensus anterieures chez le soja, celle-ci offre une couverture plus complete et plus uniforme. [Traduit par la Redaction] Mots-cles : soja, cartographie genetique, carte genetique consensus, genotypage par sequencage, evenements de recombinaison, Introduction Soybean (Glycine max (L.) Merr.) is a diploid species (2n = 40) that is believed to have been domesticated in eastern Asia 6000-9000 years ago (Sedivy et al. 2017). [...]

Soybean is a typical short-day (SD) plant. It undergoes reproductive growth only when the day length becomes shorter than a critical length. Fourteen major genes/loci affecting soybean flowering and maturity period have been mapped to date. These are E1 and E7 on chr6, E1La, E1Lb, E6, E8,and J on chr4, E2 on chr10, E3 on chr19, E4 on chr20, E9 on chr6, E10on chr8, Dt1 on chr19, and GmAGL1 on chr14. The functional allele of all these genes, except E6, E9, J,and GmAGL1,delay flowering, while the non-functional counterpart accelerates flowering and maturity. The contribution of the E1 gene in delaying flowering is highest. Four nonfunctional/dysfunctional allelic variants of the E1 gene are already known, which accelerates the flowering by 20-25 days and are being used in development of early maturing soybean varieties in many parts of the world. In this study, seeds of the late maturing Indian variety NRC 37 were irradiated with gamma rays to develop an early maturing variety. One early maturing variant was obtained. Molecular characterization of the gene responsible for early flowering proved it to be a non-functional variant of the E1 gene with major deletion. Key words: soybean, flowering gene, early maturity, E1 gene. Le soja est une plante a jours courts typique. Elle initie une phase reproductive seulement lorsque la duree du jour devient plus courte qu'une duree critique. Quatorze genes/locus majeurs affectant la floraison et la maturite ont ete cartographies a ce jour. Ce sont: E1 et E7 sur le chr6, E1La, E1Lb, E6, E8 et J sur le chr4, E2 sur le chr10, E3 sur le chr19, E4 sur le chr20, E9 sur le chr6, E10 sur le chr8, Dt1 sur le chr19 et GmAGL1 sur le chr14. L'allele fonctionnel de tous ces genes sauf E6, E9, J et GmAGL1 retardent la floraison tandis que les alleles non-fonctionnels accelerent la floraison et la maturite. L'impact sur la floraison du gene E1 est le plus grand. Quatre variants alleliques non-fonctionnels/dysfonctionnels du gene E1 sont connus, lesquels devancent la floraison de 20 a 25 jours et ils sont employes dans le developpement de varietes hatives de soja dans plusieurs regions du monde. Dans ce travail, des graines de la variete indienne tardive NRC 37 ont ete irradiees au moyen de rayonnements gamma pour developper une variete hative. Un variant hatif a ete obtenu. La caracterisation moleculaire du gene responsable pour la floraison hative a revele un variant non-fonctionnel du gene E1 lequel presentait une grande deletion. [Traduit par la Redaction] Mots-cles : soja, gene de floraison, maturite hative, gene E1., Introduction Soybean is the leading oilseed crop, with worldwide production of 336.11 million metric tons contributing 57 million metric tons to total vegetable oil production during 2019-2020 (https://www.statista.com/statistics/267271/worldwide-oilseed-production-since-2008/). Soybean production [...]

Abstract: Soybean (Glycine max) is one of the most important crop plants. Wild and cultivated soybean varieties have significant differences worth further investigation, such as plant morphology, seed size, and [...]

The R gene of soybean, presumably encoding a MYB transcription factor, controls seed coat color. The gene consists of multiple alleles, R (black), r-m (black spots and (or) concentric streaks on brown seed), and r (brown seed). This study was conducted to determine the structure of the MYB transcription factor gene in a near-isogenic line (NIL) having r-m allele. PCR amplification of a fragment of the candidate gene Glyma.09G235100 generated a fragment of about 1 kb in the soybean cultivar Clark, whereas a fragment of about 14 kb in addition to fragments of 1 and 1.4 kb were produced in L72-2040, a Clark 63 NIL with the r-m allele. Clark 63 is a NIL of Clark with the rxp and Rps1 alleles. A DNA fragment of 13 060 bp was inserted in the intron of Glyma.09G235100 in L72-2040. The fragment had the CACTA motif at both ends, imperfect terminal inverted repeats (TIR), inverse repetition of short sequence motifs close to the 5' and 3' ends, and a duplication of three nucleotides at the site of integration, indicating that it belongs to a CACTA-superfamily transposable element. We designated the element as Tgm11. Overall nucleotide sequence, motifs of TIR, and subterminal repeats were similar to those of Tgml and Tgsl, suggesting that these elements comprise a family. Keywords: CACTA-superfamily transposable element, Glycine max, R gene, seed coat color, soybean. Le gene R chez le soya, lequel code vraisemblablement pour un facteur de transcription MYB, determine la couleur de la graine. Le gene compte plusieurs alleles, dont R (noir), r-m (taches noires ou stries concentriques sur un fond brun) et r (brun). Ce travail a ete realise pour determiner la structure de ce gene chez une lignee quasi-isogenique (NIL) possedant un allele r-m. L'amplification PCR d'un fragment du gene candidat, Glyma.09G235100 a produit un fragment d'environ 1 kb chez le cultivar Clark, tandis qu'un fragment d'environ 14 kb, en plus de fragments de 1 et de 1,4 kb, ont ete obtenus chez L72-2040, une NIL derivee de Clark 63 ayant l'allele r-m. Clark 63 est elle-meme une NIL de Clark et possedant les alleles rxp et Rps1. Un fragment d'ADN de 13 060 pb etait insere dans l'intron du Glyma.09G235100 chez L72-2040. Ce segment presentait un motif CACTA aux deux extremites, des inversions terminales inversees (TIR) imparfaites, une repetition inversee de courts motifs situes pres des extremites 5' et 3', ainsi qu'une duplication de trois nucleotides a l'endroit du site d'integration; toutes des caracteristiques indiquant qu'il s'agit d'un element transposable de la superfamille CACTA. Les auteurs ont nomme cet element Tgm11. Globalement, la sequence nucleotidique, les motifs des TIR et les repetitions subterminales etaient semblables a celles rencontrees chez Tgm1 et Tgs1, ce qui suggere que ces elements forment une famille. [Traduit par la Redaction] Mots-cles : element transposable de la superfamille CACTA, Glycine max, gene R, couleur de la graine, soya., Introduction Transposable elements are DNA fragments that can change their positions in the genome, occasionally resulting in disruption of genes, or variegation of tissues when inserted in genes responsible for [...]

In soybean, asynaptic and desynaptic mutants lead to abnormal meiosis and fertility reduction. Several male-sterile, female-sterile mutants have been identified and studied in soybean, however, some of these mutants have not been mapped to locations on soybean chromosomes. The objectives of this study were to molecularly map five male-sterile, female-sterile genes (st2, st4, st5, st6, and st7) in soybean and compare the map locations of these genes with already mapped sterility genes. Microsatellite markers were used in bulked segregant analyses to locate all five malesterile, female-sterile genes to soybean chromosomes, and markers from the corresponding chromosomes were used on F2 populations to generate genetic linkage maps. The st2, st4, st5, st6, and st7 genes were located on molecular linkage group (MLG) B1 (chromosome 11), MLG D1a (chromosome 01), MLG F (chromosome 13), MLG B2 (chromosome 14), and D1b (chromosome 02), respectively. The st2, st4, st5, st6, and st7 genes were flanked to 10.3 (~399 kb), 6.3 (~164 kb), 3.9 (~11.8 Mb), 11.0 (~409 kb), and 5.3 cM (~224 kb), and the flanked regions contained 57,17, 362, 52, and 17 predicted genes, respectively. Future characterization of candidate genes should facilitate identification of the male- and female-fertility genes, which may provide vital insights on structure and function of genes involved in the reproductive pathway in soybean. Key words: Glycine max, sterility, simple sequence repeat, genetic linkage map, male-sterile female-sterile. Chez le soya, des mutants asynaptiques et desynaptiques presentent des anomalies meiotiques et une reduction de la fertilite. Plusieurs mutants presentant une sterilite male et femelle ont ete identifies et etudies, mais certains de ceux-ci n'ont pas ete situes sur les chromosomes du soya. Les objectifs de ce travail etaient de realiser la cartographie de cinq genes de sterilite male et femelle (st2, st4, st5, st6 et st7) chez le soya et de comparer la position de ces genes avec celle d'autres genes de sterilite deja positionnes. Des marqueurs microsatellites ont ete employes dans le cadre d'analyses de segregants en melange afin d'assigner une position chromosomique aux cinq genes de sterilite male et femelle. Les marqueurs situes sur ces chromosomes ont ete employes sur des populations F2 afin de generer des cartes genetiques. Les genes st2, st4, st5, st6 et st7 ont ete assignes respectivement aux groupes de liaison moleculaires (MLG) B1 (chromosome 11), MLG D1a (chromosome 01), MLG F (chromosome 13), MLG B2 (chromosome 14) et MLG D1b (chromosome 2). Les genes st2, st4, st5, st6 et st7 ont ete assignes a des intervalles de 10,3 (~399 kb), 6,3 (~164 kb), 3,9 (~11,8 Mb), 11,0 (~409 kb) et 5,3 cM (~224 kb); ces intervalles contenaient respectivement 57,17, 362, 52 et 17 genes predits. Une future caracterisation de genes candidats devrait faciliter l'identification des genes de fertilite male et femelle, laquelle fournira un eclairage important sur la structure et la fonction des genes impliques dans la reproduction chez le soya. [Traduit par la Redaction] Mots-cles: Glycine max, sterilite, sequence simple repetee, carte genetique, sterilite male et femelle., Introduction In soybean, asynaptic and desynaptic mutants lead to abnormal meiosis and fertility reduction. This is caused by abnormal pairing of chromosomes during the first meiotic prophase, also known as [...]

In soybean, an environmentally stable male sterility system is vital for making hybrid seed production commercially viable. Eleven male-sterile, female-fertile mutants (ms1, ms2, ms3, ms4, ms5, ms6, ms7, ms8, ms9, msMOS, and msp) have been identified in soybean. Of these, eight (ms2, ms3, ms5, ms7, ms8, ms9, msMOS, and msp) have been mapped to soybean chromosomes. The objectives of this study were to (i) locate the msl, ms4, and ms6 genes to soybean chromosomes; (ii) generate genetic linkage maps of the regions containing these genes; and (iii) develop a comprehensive map of all known male-sterile, female- fertile genes in soybean. The bulked segregant analysis technique was used to locate genes to soybean chromosomes. Microsatellite markers from the corresponding chromosomes were used on [F.sub.2] populations to generate genetic linkage maps. The msl and ms6 genes were located on chromosome 13 (molecular linkage group F) and ms4 was present on chromosome 2 (molecular linkage group D1b). Molecular analyses revealed markers Satt516, BARCSOYSSR_02_1539, and AW186493 were located closest to msl, ms4, and ms6, respectively. The msl and ms6 genes, although present on the same chromosome, were independently assorting with a genetic distance of 73.7 cM. Using information from this study and compiled information from previously published male sterility genes in soybean, a comprehensive genetic linkage map was generated. Eleven male sterility genes were present on seven soybean chromosomes. Four genes were present in two regions on chromosome 2 (molecular linkage group D1b) and two genes were present on chromosome 13 (molecular linkage group F). Key words: Glycine max, male sterility, simple sequence repeat, genetic linkage map, male-sterile female-fertile. Chez le soya, un systeme de sterilite male presentant une stabilite environnementale serait un atout cle pour rendre commercialement viable la production de semence hybride. Onze mutants presentant une sterilite male et une fertilite femelle (ms1, ms2, ms3, ms4, ms5, ms6, ms7, ms8, ms9, msMOS et msp) ont ete identifies chez le soya. Parmi ceux-ci, huit (ms2, ms3, ms5, ms7, ms8, ms9, msMOS et msp) ont ete assignes a un chromosome. Les objectifs de ce travail etaient: (i) de situer les genes ms1, ms4 et ms6 sur les chromosomes du soya; (ii) de produire une carte genetique pour les regions contenant ces genes; et (iii) produire une carte complete de tous les genes conferant une sterilite male et une fertilite femelle chez le soya. Une analyse des segregants en composite (BSA pour << bulked segregant analysis >>) a ete employee pour assigner chacun des genes a un chromosome. Des marqueurs microsatellites logeant sur les chromosomes correspondants ont ete examines sur des populations [F.sub.2] pour produire des cartes genetiques. Les genes ms1 et ms6 ont ete assignes au chromosome 13 (groupe de liaison F) et ms4 a ete assigne au chromosome 2 (groupe de liaison D1b). Des analyses moleculaires ont revele que les marqueurs Satt516, BARSOYSSR_02_1539 et AW186493 etaient respectivement les marqueurs les plus proches des genes ms1, ms4 et ms6. Les genes ms1 et ms6, bien que presents sur le meme chromosome, presentaient une segregation independante et sont situes a 73,7 cM l'un de l'autre. En faisant appel a l'information produite au cours de ce travail et des etudes anterieures sur les genes de sterilite male, une carte complete a ete generee. Onze genes de sterilite male sont presents sur sept chromosomes. Quatre genes sont presents au sein de deux regions du chromosome 2 (groupe de liaison D1b)et deux genes sont presents sur le chromosome 13 (groupe de liaison F). [Traduit par la Redaction] Mots-cles: Gycine max, sterilite male, sequences repetees simples, carte genetique, male sterile femelle fertile., Introduction Male and female reproductive structures play an important role in the development of seeds in plants. Mutations in genes involved in development of stamens and (or) pistils can lead [...]