The genetic diversity of cowpea was analyzed, and the population structure was estimated in a diverse set of 768 cultivated cowpea genotypes from the USDA GRIN cowpea collection, originally collected from 56 countries. Genotyping by sequencing was used to discover single nucleotide polymorphism (SNP) in cowpea and the identified SNP alleles were used to estimate the level of genetic diversity, population structure, and phylogenetic relationships. The aim of this study was to detect the gene pool structure of cowpea and to determine its relationship between different regions and countries. Based on the model-based ancestry analysis, the phylogenetic tree, and the principal component analysis, three well-differentiated genetic populations were postulated from 768 worldwide cowpea genotypes. According to the phylogenetic analyses between each individual, region, and country, we may trace the accession from off-original, back to the two candidate original areas (West and East of Africa) to predict the migration and domestication history during the cowpea dispersal and development. To our knowledge, this is the first report of the analysis of the genetic variation and relationship between globally cultivated cowpea genotypes. The results will help curators, researchers, and breeders to understand, utilize, conserve, and manage the collection for more efficient contribution to international cowpea research.

Genomic selection is a promising molecular breeding strategy enhancing genetic gain per unit time. The objectives of our study were to (1) explore the prediction accuracy of genomic selection for plant height and yield per plant in soybean [Glycine max (L.) Merr.], (2) discuss the relationship between prediction accuracy and numbers of markers, and (3) evaluate the effect of marker preselection based on different methods on the prediction accuracy. Our study is based on a population of 235 soybean varieties which were evaluated for plant height and yield per plant at multiple locations and genotyped by 5361 single nucleotide polymorphism markers. We applied ridge regression best linear unbiased prediction coupled with fivefold cross-validations and evaluated three strategies of marker preselection. For plant height, marker density and marker preselection procedure impacted prediction accuracy only marginally. In contrast, for grain yield, prediction accuracy based on markers selected with a haplotype block analyses-based approach increased by approximately 4 % compared with random or equidistant marker sampling. Thus, applying marker preselection based on haplotype blocks is an interesting option for a cost-efficient implementation of genomic selection for grain yield in soybean breeding.Electronic supplementary materialThe online version of this article (doi:10.1007/s11032-016-0504-9) contains supplementary material, which is available to authorized users.

Capacitors are widely used in dc links of power electronic converters to balance power, suppress voltage ripple, and store short-term energy. Condition monitoring (CM) of dc-link capacitors has great significance in enhancing the reliability of power converter systems. Over the past few years, many efforts have been made to realize CM of dc-link capacitors. This paper gives an overview and a comprehensive comparative evaluation of them with emphasis on the application objectives, implementation methods, and monitoring accuracy when being used. First, the design procedure for the condition monitoring of capacitors is introduced. Second, the main capacitor parameters estimation principles are summarized. According to these principles, various possible CM methods are derived in a step-by-step manner. On this basis, a comprehensive review and comparison of CM schemes for different types of dc-link applications are provided. Finally, application recommendations and future research trends are presented.

Porcine reproductive and respiratory syndrome virus (PRRSV) is the etiologic agent of porcine reproductive and respiratory syndrome (PRRS), which can evolve continuously by random mutation or intragenic recombination. Here we report the complete genomic sequence of a PRRSV variant with nucleotide acid deletions and insertions in the nonstructural protein 2 (nsp2) gene and a possible recombination event between a modified live virus (MLV) vaccine strain and a prototype Chinese field strain. P orcine reproductive and respiratory syndrome (PRRS) outbreaks occur worldwide and cause significant economic losses in the swine industry (6, 7). Even though modified live virus (MLV) vaccines were shown to provide solid protection against PRRSV infection, there were substantial barriers to the use of MLV vaccines in the field (2, 5). Considering the extensive use of MLV vaccines for preventing and controlling PRRS in mainland China, the appearance of a natural recombination event between a vaccine strain and a field strain is noteworthy.Serum and tissue samples were collected from suspected growing pigs in Guangdong Province in 2011. Infected pigs were about 10 weeks old and displayed symptoms similar to those of original PRRS, including severe respiratory problems, diarrhea, and poor growth. In addition, this disease resulted in a ϳ2.2% mortality rate on this farm. A porcine reproductive and respiratory syndrome virus (PRRSV) field isolate, named GM2, was propagated on Marc-145 cells, and total viral RNA was extracted from the serum and infected cell culture and then used separately for the amplification of the genome. Basically, 16 primer pairs were used to generate overlapping amplicons by reverse transcription-PCR (RT-PCR) as reported previously (8), and 3=-terminal sequences of GM2 were obtained by a 3= rapid amplification of cDNA ends (RACE kit; TaKaRa). The PCR products were cloned into pMD19-T vector (TaKaRa), sequenced three times using an ABI 3730 Sanger-based genetic analyzer, and assembled using DNAStar version 7.0 to obtain the complete genome sequence. The completed sequence showed that, excluding the poly(A) tail, the genomic sequence of GM2 was 15,513 nucleotides in length. Genetic analysis demonstrated that GM2 shared 90.2% genome similarity with VR-2332, but a lower degree of genetic homology (87.7%) was observed than with the representative highly pathogenic PRRSV JXA1 strain. Compared with the VR-2332 strain, 36-amino-acid insertions and two continuous amino acid deletions in the nonstructural protein 2 (nsp2) region of GM2 were found. However, GM2 shared a very low identity with the SP strain (68.8%) and the Japanese strain EDRD-1 (70.5%), which was characterized by similar insertions within nsp2.Recombination events were detected using both Simplot version 3.5.1 (3) and the recombination detection program version 4.1.3 (RDP4) (4). The results indicated that GM2 was a potential recombinant between the MLV RespPRRS/Repro vaccine strain and a recently emerging prototype Chinese field strain, named QYYZ. P...

Water soluble protein content (SPC) plays an important role in the functional efficacy of protein in food products. Therefore, for the identification of quantitative trait loci (QTL) associated with SPC, 212 F(2:9) lines of the recombinant inbred line (RIL) population derived from the cross of ZDD09454 × Yudou12 were grown along with the parents, in six different environments (location × year) to determine inheritance and map solubility-related genes. A linkage map comprising of 301 SSR markers covering 3,576.81 cM was constructed in the RIL population. Seed SPC was quantified with a macro-Kjeldahl procedure in samples collected over multiple years from three locations (Nantong in 2007 and 2008, Zhengzhou in 2007 and 2008, and Xinxiang in 2008 and 2009). SPC demonstrated transgressive segregation, indicating a complementary genetic structure between the parents. Eleven putative QTL were associated with SPC explaining 4.5-18.2 % of the observed phenotypic variation across the 6 year/location environments. Among these, two QTL (qsp8-4, qsp8-5) near GMENOD2B and Sat_215 showed an association with SPC in multiple environments, suggesting that they were key QTL related to protein solubility. The QTL × environment interaction demonstrated the complex genetic mechanism of SPC. These SPC-associated QTL and linked markers in soybean will provide important information that can be utilized by breeders to improve the functional quality of soybean varieties.