Identifying and selecting high-quality seeds is crucial for improving crop yield.  The purpose of this study was to improve the selection of crop seeds based on separating vital seeds from dead seeds, by predicting the potential germination ability of each seed, and thus improving seed quality.  The methods of oxygen consumption (Q) of seeds and the headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were evaluated for identifying the viability of individual seeds.  Firstly, the oxygen consumption technique showed clear differences among the values related to respiratory characteristics for seeds that were either vital or not, and the discrimination ability of final oxygen consumption (Q₁₂₀) was achieved not only in sweet corn seeds but also in pepper and wheat seeds.  Besides, Q_t was established as a new variable to shorten the measuring process in the Q2 (oxygen sensor) procedure, which was significantly related to the viability of individual seeds.  To minimize seed damage during measurement, the timing for viability evaluation was pinpointed at the 12, 6 and 9 h for pepper, sweet corn, and wheat seeds based on the new variables concerning oxygen consumption (i.e., Q₁₂, Q₆ and Q₉, respectively).  The accuracies of viability prediction were 91.9, 97.7 and 96.2%, respectively.  Dead seeds were identified and hence discarded, leading to an enhancement in the quality of the seed lot as indicated by an increase in germination percentage, from 86.6, 90.9, and 53.8% to all at 100%.  We then used the HS-GC-IMS to determine the viability of individual sweet corn seeds, noting that corn seed has a heavier weight so the volatile gas components are more likely to be detected.  A total of 48 chromatographic peaks were identified, among which 38 target compounds were characterized, including alcohols, aldehydes, acids and esters.  However, there were no significant differences between the vital and dead seeds, due to the trace amount volatile composition differences among the individual seeds.  Furthermore, a PCA based on the signal intensities of the target volatile compounds obtained was found to lose its effectiveness, as it was unable to distinguish those two types of sweet corn seeds.  These strategies can provide a reference for the rapid detection of single seed viability.

Deep-sowing is an important method for avoiding drought stress in crop species, including maize.  Identifying candidate genes is the groundwork for investigating the molecular mechanism underlying maize deep-sowing tolerance.  This study evaluated four traits (mesocotyl length at 10 and 20 cm planting depths and seedling emergence rate on days 6 and 12) related to deep-sowing tolerance using a large maize population containing 386 inbred lines genotyped with 0.5 million high-quality single nucleotide polymorphisms (SNPs).  The genome-wide association study detected that 273 SNPs were in linkage disequilibrium (LD) with the genetic basis of maize deep-sowing tolerance.  The RNA-sequencing analysis identified 1 944 and 2 098 differentially expressed genes (DEGs) in two comparisons, which shared 281 DEGs.  By comparing the genomic locations of the 273 SNPs with those of the 281 DEGs, we identified seven candidate genes, of which GRMZM2G119769 encoded a sucrose non-fermenting 1 kinase interactor-like protein.  GRMZM2G119769 was selected as the candidate gene because its homologs in other plants were related to organ length, auxin, or light response.  Candidate gene association mapping revealed that natural variations in GRMZM2G119769 were related to phenotypic variations in maize mesocotyl length.  Gene expression of GRMZM2G119769 was higher in deep-sowing tolerant inbred lines.  These results suggest that GRMZM2G119769 is the most likely candidate gene.  This study provides information on the deep-sowing tolerance of maize germplasms and identifies candidate genes, which would be useful for further research on maize deep-sowing tolerance.

Resistance gene analog (RGA) screening of mapped disease-resistant genes not only helps to clone these genes but also helps to develop efficient molecular markers for resistance breeding. The present study focused on the PmU region located on chromosome 7A^uL of Triticum urartu, and recently, a nucleotide binding site (NBS)-encoding gene, Pm60, was cloned from the same chromosome arm. In this research, NBS, protein kinase (PK), and ATP-binding cassette (ABC), the three disease resistance-related gene families, were analyzed within PmU region by using informatics tools, and an expression experiment was conducted to verify their functions in vivo. Comparative genomic analysis revealed that 126 RGAs were included on chromosome 7A^uL, and 30 of the RGAs as well as Pm60 were found in the PmU region. Transcriptome database analysis of T. urartu revealed 14 PmU-RGAs with expression data, and three PmU-NBSs exhibited significant changes in expression after inoculation with Blumeria graminis f. sp. tritici (Bgt); TRIUR3_14879 was up-regulated, while TRIUR3_00450 and TRIUR3_06270 were down-regulated. Cluster analysis showed that these three PmU-NBSs were clustered far from the cloned wheat resistance genes. Then, qRT-PCR was performed to investigate the expression of 14 PmU-RGAs and Pm60 after inoculation with Bgt race E09; the results showed that Pm60 was specifically expressed in UR206 which carrying PmU, but not in susceptible UR203; while TRIUR3_14879 was significantly up-regulated and TRIUR3_00450 was downregulated in UR206 after inoculation. These results indicated that PmU is Pm60, and TRIUR3_14879 and TRIUR3_00450 may also be involved in the defense against Bgt.

This research aimed to improve selection of pepper seeds for separating high-quality seeds from low-quality seeds. Past research has shown that seed vigor is significantly related to the seed color and size, thus several physical features were identified as candidate predictors of high seed quality. Image recognition software was used to automate recognition of seed feature quality using 400 kernels of pepper cultivar 101. In addition, binary logistic regression and a neural network were applied to determine models with high predictive value of seed germination. Single-kernel germination tests were conducted to validate the predictive value of the identified features. The best predictors of seed vigor were determined by the highest correlation observed between the physical features and the subsequent fresh weight of seedlings that germinated from the 400 seeds. Correlation analysis showed that fresh weight was significantly positively correlated with eight physical features: three color features (R, a*, brightness), width, length, projected area, and single-kernel density, and weight. In contrast, fresh weight significantly negatively correlated with the feature of hue. In analyses of two of the highest correlating single features, germination percentage increased from 59.3 to 71.8% when a*≥3, and selection rate peaked at 57.8%. Germination percentage increased from 59.3 to 79.4%, and the selection rate reached 76.8%, when single-kernel weight ≥0.0064 g. The most effective model was based on a multilayer perceptron (MLP) neural network, consisting of 15 physical traits as variables, and a stability calculated as 99.4%. Germination percentage in a calibration set of seeds was 79.1% and the selection rate was 90.0%. These results indicated that the model was effective in predicting seed germination based on physical features and could be used as a guide for quality control in seed selection. Automated systems based on machine vision and model classifiers can contribute to reducing the costs and labor required in the selection of pepper seeds.

In order to clarify the main pathogens of tomato Fusarium wilt in Shanxi Province, China, morphological identification, elongation factor 1 alpha (EF-1α) sequence analysis, specific primer amplification and pathogenicity tests were applied to study the isolates which were recovered from diseased plants collected from 17 different districts of Shanxi Province.  The results were as follows: 1) Through morphological and molecular identification, the following 7 species of Fusarium were identified: F. oxysporum, F. solani, F. verticillioides, F. subglutinans, F. chlamydosporum, F. sporotrichioides, and F. semitectum; 2) 56 isolates of F. oxysporum were identified using specific primer amplification, among which, 29, 5 and 6 isolates were respectively identified as F. oxysporum f. sp. lycopersici physiological race 1, race 2, and race 3; 3) pathogenicity test indicated the significant pathogenicity of F. oxysporum, F. solani, F. verticillioides, and F. subglutinans to tomato plant.  Therefore, among these 4 species confirmed as pathogenic to tomato in Shanxi, the highest isolation rate (53.3%) corresponded to F. oxysporum.  Three physiological species, race 1, race 2, and race 3 of F. oxysporum f. sp. lycopersici are detected in Shanxi, among which race 1 is the most widespread pathogen and is also considered as the predominant race.

    The increasing demand for fresh sweet maize (Zea mays L. saccharata) in southern China has prioritized the need to find solutions to the environmental pollution caused by its continuous production and high inputs of chemical nitrogen fertilizers.  A promising method for improving crop production and environmental conditions is to intercrop sweet maize with legumes.  Here, a three-year field experiment was conducted to assess the influence of four different cropping systems (sole sweet maize (SS), sole soybean (SB), two rows sweet maize-three rows soybean (S2B3) intercropping, and two rows sweet maize-four rows soybean (S2B4) intercropping), together with two rates of N fertilizer application (300 and 360 kg N ha^–1) on grain yield, residual soil mineral N, and soil N₂O emissions in southern China.  Results showed that in most case, intercropping achieved yield advantages (total land equivalent ratio (TLER=0.87–1.25) was above one).  Moreover, intercropping resulted in 39.8% less soil mineral N than SS at the time of crop harvest, averaged over six seasons (spring and autumn in each of the three years of the field experiment).  Generally, intercropping and reduced-N application (300 kg N ha^–1) produced lower cumulative soil N₂O and yield-scaled soil N₂O emissions than SS and conventional-N application (360 kg N ha^–1), respectively.  S2B4 intercropping with reduced-N rate (300 kg N ha^–1) showed the lowest cumulative soil N₂O (mean value=0.61 kg ha^–1) and yield-scaled soil N₂O (mean value=0.04 kg t^–1) emissions.  Overall, intercropping with reduced-N rate maintained sweet maize production, while also reducing environmental impacts.  The system of S2B4 intercropping with reduced-N rate may be the most sustainable and environmentally friendly cropping system.   

Potato (Solanum tuberosum L.) is an important staple food and economic crop in many countries.  China has led world potato production in recent years.  To understand the genetic diversity of potato germplasms and to enrich the current gene pool for potato improvement, we made a global collection consisted of 288 potato germplasms from eight countries and the International Potato Center (CIP).  Using SSR and AFLP techniques, we evaluated the genetic diversity and population structure of these 288 potato accessions.  A total of 190 alleles on 20 SSR loci were detected and all of the SSR alleles were polymorphic among these potato germplasms with an average of 9.5 alleles per SSR locus ranging from 2 to 23.  The effective number of alleles per locus (Ne*), Nei’s genetic diversity (H*), and Shannon’s information index (I*) was from (0.1709±0.3698) to (1.6166±0.3414), (0.076±0.1388) to (0.3812±0.1886), and (0.1324±0.1970) to (0.5347±0.1440), respectively, and the mean polymorphic information content (PIC) value was 0.7312.  A total of 988 AFLP alleles were detected by 10 AFLP primer combinations with 983 polymorphic alleles, and 99.49% alleles was polymorphic with an average of 98.3 polymorphic alleles per primer combination ranging from 91 to 116.  The values of Ne*, H* and I* were from (1.5162±0.311) to (1.6423±0.3278), (0.3114±0.145) to (0.3675±0.1121), and (0.4761±0.1792) to (0.547±0.1322), respectively, and the average PIC value was 0.9871.  Bayesian analysis discriminated the accessions into seven subgroup and an admix group.  The majority of accessions from CIP and China were assigned into SG1, SG5, SG6, SG7 and admix group.  Accessions in SG3 were mainly from CIP and two small groups SG2 and SG4 were mainly from northeastern China.  In general, the results obtained from Bayesian statistical analysis, cluster analysis and principal coordinate analysis consistently revealed the lack of geographical differentiation among country-wide collections, indicating germplasm introduction was common for the countries out of potato origin center.  The polymorphic markers and the differentiate genetic lineages found in this study provide useful information for potato improvement and conservation programs.  

This experiment was conducted to study the effect of molasses on the fermentation characteristics of mixed silage ensiled rice straw and vegetable by-products with alfalfa.  Mixture (202 g kg^–1 dry matter (DM)) consisting of rice straw, broccoli residue and alfalfa at the ratio of 5:4:1 was ensiled with three experimental treatments: (1) no additives (control); (2) molasses at 2.5% (M1); (3) molasses at 5% (M2) on a fresh matter basis of mixture, respectively.  All treatments were packed into laboratory-scale silos, and three silos per treatment were sampled on days 1, 3, 5, 14 and 30.  The result showed that the pH value of all mixed silages decreased gradually with the time of ensiling except for the control silage, in which a significant increase (P<0.05) on day 30 occurred.  The lactic acid content increased gradually with the time of ensiling and reached the highest value on day 14, and a marked decrease (P<0.05) was found in the control silage on day 30.  The changes of acetic acid content showed similar pattern with lactic acid content.  A trace amount of propionic and butyric acid contents were found in the three mixed silages during the fermentation period.  Comparing to the control, M1 and M2 treatments improved the fermentation quality of mixed silages as indicated by higher (P<0.05) lactic acid contents and lower (P<0.05) pH and ammonia-N contents.  The Flieg points also showed that M1 and M2 silages were well preserved, whereas the control silage had a bad quality.  Overall, the findings of this study suggested that adding molasses could improve fermentation quality of mixed silage, and M1 was more suitable for practical application.

To better interpret summer maize stomatal conductance (g_s) variation under conditions of changing water status at different growth stages, three water stress indicators, soil water content (SWC), leaf-air temperature difference (?T) and leaf level water stress index (CWSI_L) were employed in Jarvis model, which were J_S, J_T and J_C models respectively.  Measurements of g_s were conducted in a summer maize field experiment during the year 2012–2013.  In the insufficient irrigation experiment, three levels of irrigation amount were applied at four different growth stages of summer maize.  We constructed three scenarios to evaluate the performance of the three water stress indicators for estimating maize g_s in a modified Jarvis model.  Results showed that J_T and J_C models had better simulation accuracy than the J_S model, especially at the late growth stage (Scenario 1) or considering the plant recovery compensation effects (Scenario 2).  Scenario 3 indicated that the more environmental factors were adopted, the better prediction performance would be for J_S model.  While for J_T model, two environmental factors (photosynthesis active radiation (PAR), and vapor pressure deficit (VPD)) seemed good enough to obtain a reliable simulation.  When there were insufficient environmental data, CWSI_L would be the best option.  This study can be useful to understand the response of plant stomatal to changing water conditions and will further facilitate the application of the Jarvis model in various environments.

    Onion (Allium cepa L.) is a very important vegetable crop widely cultivated throughout the world. In this study, we measured total anthocyanins and flavonols of onions of three colors. The fresh weight (FW) of total anthocyanins were (29.99±1.19), (9.64±1.30) and (0.75±0.40) mg 100 g^–1 fruit in red, yellow and white onions, respectively. Likewise, the FW of total flavonoids were (111.10±5.98), (36.64±3.59), and 0 mg 100 g^–1 in red, yellow and white, respectively. Four types of anthocyanins (delphinidin 3,5-diglycosides, cyanidin 3,5-diglycosides, cyanidin 3-glycosides and cyanidin 3-(6´´-malonyl)-glucopyranoside) and two kinds of flavonoids (quercetin and quercetin 3-glycosides) were identified in two varieties (red and yellow bulb) of onions by HPLC/DAD-ESI/MS. The total polyphenol contents were also measured by means of Folin-Ciocalteu method. Moreover, all the concentrations of anthocyanins, flavonoids and polyphenols showed significantly positive correlations with antioxidant activities measured by DPPH˙, ABTS˙+ and FRAP assays. This study provided information on anthocyanin and flavonoids compositions that will be useful for onion breeding.

    Plant height (PH) is one of the most important agronomic traits of rice, as it directly affects the lodging resistance and the high yield potential. Meanwhile, PH is often constrained by water supply over the entire growth period. In this study, a recombinant inbred line (RIL) derived from Xiaobaijingzi and Kongyu 131 strains grown under drought stress and with normal irrigation over 2 yr (2013 and 2014), respectively (regarded as four environments), was used to dissect the genetic basis of PH by developmental dynamics QTL analysis combined with QTL×environment interactions. QTLs with net effects excluding the accumulated effects were detected to explore the relationship between gene×gene interactions and gene×environment interactions in specific growth period. A total of 26 additive QTLs (A-QTLs) and 37 epistatic QTLs (E-QTLs) associated with PH were detected by unconditional and conditional mapping over seven growth periods. qPH-2-3, qPH-4-3, qPH-6-1, qPH-7-1, and qPH-12-5 could be detected by both unconditional and conditional analyses. qPH-4-3 and qPH-7-5 were detected in four stages (periods) to be sequentially expressed QTLs controlling PH continuous variation. QTLs with additive effects (A-QTLs) were mostly expressed in the period S3|S2 (the time interval from stages 2 to 3), and QTL×environment interactions performed actively in the first three stages (periods) which could be an important developmental period for rice to undergo external morphogenesis during drought stress. Several QTLs showed high adaptability for drought stress and many QTLs were closely related to the environments such as qPH-3-5, qPH-2-2 and qPH-6-1. 72.5% of the QTLs with a and aa effects detected by conditional analysis were under drought stress, and the PVE of QTLs detected by conditional analysis under drought stress were also much higher than that under normal irrigation. We infer that environments would influence the detection results and sequential expression of genes was highly influenced by environments as well. Many QTLs (qPH-1-2, qPH-3-5, qPH-4-1, qPH-2-3) coincident with previously identified drought resistance genes. The result of this study is helpful to elucidating the genetic mechanism and regulatory network underlying the development of PH in rice and providing references to marker assisted selection.

The objective of this study was to evaluate the effects of low ambient temperature (LAT) and dietary vitamin C (VC) supplementation on pulmonary vascular remodeling (PVR) and the relative expression of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and its receptor 2 (VEGFR-2) mRNA of lungs in 21-d-old broilers. 400 1-d-old male Cobb broilers were assigned randomly to 4 treatments as follows for 21 d: 1) LAT and a basal diet; 2) LAT and a basal diet supplemented with 1 000 mg kg–1 VC (LAT+VC); 3) normal ambient temperature (NAT) and a basal diet; 4) NAT and a basal diet supplemented with 1 000 mg kg–1 VC (NAT+VC). Each treatment was composed of 10 replicates of 10 birds per replicate. Samples of lung were collected after the broilers were killed at d 21. LAT increased the ratio of vessel wall area to vessel total area (WA/TA, %) and mean media thickness in pulmonary arterioles (mMTPA, %) (P<0.05). Dietary VC supplementation decreased mMTPA (P<0.05), but had no effect on the WA/TA. LAT increased (P<0.05) the relative mRNA expression of HIF-1α, VEGF and VEGFR-2, while adding VC to the diet could decrease (P<0.05) their relative mRNA expression. A significant positive correlation existed between the level of VEGF mRNA expression and the value of WA/WT (P<0.05) or mMTPA (P<0.05). These results suggested LAT resulted in pulmonary vascular remodeling, and the increase of HIF-1α, VEGF and VEGFR-2 mRNA expression, and dietary VC supplementation can alleviate pulmonary vascular remodeling in broiler by affecting these gene expression.

Sucrose non-fermenting-1 related protein kinase 2 (SnRK2) is a unique family of protein kinases associated with abiotic stress signal transduction in plants. In this study, a maize SnRK2 gene ZmSnRK2.11 was cloned and characterized. The results showed that ZmSnRK2.11 is up-regulated by high-salinity and dehydration treatment, and it is expressed mainly in maize mature leaf. A transient expression assay using onion epidermal cells revealed that ZmSnRK2.11-GFP fusion proteins are localized to both the nucleus and cytoplasm. Overexpressing-ZmSnRK2.11 in Arabidopsis resulted in salt and drought sensitivity phenotypes that exhibited an increased rate of water loss, reduced relative water content, delayed stoma closure, accumulated less free proline content and increased malondialdehyde (MDA) content relative to the phenotypes observed in wild-type (WT) control. Furthermore, overexpression of ZmSnRK2.11 up-regulated the expression of the genes ABI1 and ABI2 and decreased the expression of DREB2A and P5CS1. Taken together, our results suggest that ZmSnRK2.11 is a possible negative regulator involved in the salt and drought stress signal transduction pathways in plants.

In recent years, subgroup J avian leukosis virus (ALV-J) has been found to frequently infect layers in China. This virus is responsible for economic losses due to both mortality and decreased performance in chickens. In this study, 45-d-old cloned free-range layers were suspected to be infected with ALV and other immunosuppressive diseases because their feathers were unkempt and their growth rate was impaired. To estimate the infection status and determine the source of ALV-J in the flock, 30 cloacal swabs were randomly collected to measure the p27 antigen level by enzyme-linked immunosorbent assay (ELISA). Among the birds that were tested, 87% (26/30) were positive. In addition, 6 anticoagulant blood samples were aseptically collected at random from the flock when the layers were 60 d old. These samples were centrifuged to obtain the leukocytes, which were then used to inoculate chicken embryo fibroblast (CEF) cells for the identification of ALV-J by indirect immunofluorescence (IFA). Of the samples tested, 100% (6/6) were positive. The flock’s production performance was also investigated, and 10 layers were necropsied to evaluate pathological changes at 115 d of age. The flock never laid eggs even though they reached the age of the first laying (110 d). Furthermore, there were pathological changes present, including atrophy of the thymus and bursa of Fabricius, undeveloped ovaries, glandular stomach haemorrhage, and hepatosplenomegaly. Paraffin-embedded sections of intumescent liver and spleen were prepared for antigen localisation using IFA. Positive signals were prevalent in paraffin-embedded sections of the intumescent liver and spleen. Furthermore, provirus DNA was extracted from 4 cloned free-range layers, and 2 paternal parents (HR native cocks), and the gp85 gene of ALV-J was amplified by PCR to analyse the genetic variation. The results of the autogenous variation analysis showed that the 6 strains were 98.5-99.7% homologous. This study indicated that there was persistent infection with ALV-J by dynamic inspection, which seriously reduced the production performance of the flock. In addition, the genetic variation analysis showed that ALV-J in the flock was more likely to have originated from the paternal parent, the HR native cock.

Grain number per spike (GNPS) is a major factor in wheat yield breeding. The development of high GNPS germplasm is widely emphasized in wheat-yield breeding. This paper reported two high GNPS wheat germplasm lines, Pubing 3228 and Pubing 3504, which had a stable and wide adaptability to different ecological regions. By exploring a nested cross design with reciprocals using Pubing 3228 or Pubing 3504 as a common parent and investigating the GNPS phenotypes of F1 hybrids in 2007-2008 and F2 populations in 2008-2009 of different cross combinations, the narrow-sense GNPS heritability was up to 49.58 and 52.23%, respectively. Genetic model analysis predictions suggested that GNPS in Pubing 3228 and Pubing 3504 was mainly controlled by additive genetic effects. Correlation analysis results between GNPS and 1 000- kernel weight (TKW) of F2 populations showed that TKW was not influenced with the increase of GNPS. The good coordination among three yield components of spike number per plant (SNPP), GNPS, and TKW in the F2 segregating population implied that selection of good candidate individuals in breeding programs would be relatively straightforward. Overall, our results indicated that Pubing 3228 and Pubing 3504 are two potential germplasm lines for yield improvement of GNPS in pedigree selection of wheat breeding.

The function of the 3 040 bp sequence at the upstream translation starting site (ATG) of the ZAG2 gene, isolated from the maize genome, was studied. The sequence analysis showed that the sequence contained a typical class C MADS-box gene regulatory element. The 5´ UTR region of the gene contains a 1 299-bp intron that might have important regulatory functions. To study the sequence function, deletion derivatives of promoter-reporter (uidA) gene fusions were generated and transformed into tobaccos. The GUS staining and fluorescence quantification results showed that the GUS activity was detected only in the third and fourth whorl floral organs of the transgenic tobaccos under driving the promoter including the first intron, while detected in all the organs and was stronger under driving the promoter without the first intron. However, the GUS activity was just detected in one whorl of the fourth or third floral organs under driving of the 35S promoter. These results suggested that the first intron of the ZAG2 gene contains functional regulatory elements, which turned out to be important for gene expression in the heterologous systems. Moreover, the GUS activity was decreased when the reporter gene driven by the promoters with 5´-deletions, respectively, from -1 606 to -951 and -951 to -426 nts, which indicates that positive regulatory elements are present in these two sequence stretches.

Agricultural information cooperative services (AICS) are now becoming an important aspect of agriculture informatization. This study offers an ontological conception of the agricultural production process, establishing operational divisions corresponding to both the stages and the fundamental information requirements of the dairy industry production process in China, yielding a process ontology for the dairy industry as well as a business chain model. A framework for a dairy industry information cooperative service system was established, with service functions realized in a prototype system. The resulting agricultural process ontology built on the basis of biological characteristics has advantages as a classification standard for agricultural information; whereas the business chain model based on this agricultural process ontology allows for an effective distribution of agricultural information cooperative services. This study outlines a concept and demonstrates a prototype of a cooperative service capable of integrating diverse online agricultural information relevant to the dairy industry in China.