Abstract:Jing2416, an elite maize inbred line, was developed by the Maize Research Center of Beijing Academy of Agricultural and Forestry Sciences. Based on the theories of "Pyramiding of Elite lines from the same Heterotic Group" and "High-density, Large-group, Strict-selection", Jing2416 was selected from the back-crossing population ((Jing24 × 5237) × Jing24). Jing2416 represents many merits, such as early maturity, fast dehydration, high tolerance to various diseases, drought and heat, high adaptability, high yield and general combining ability. By taking use of the elite breeding line Jing2416, twenty-one commercial hybrid varieties have been officially approved by national or provincial regional trials. Especially, the hybrid varieties of Jingnongke 728, NK718, MC121 and MC812 showed outstanding agronomical performance, and each of them has been planted over 67 thousands of hectares every year in China. The variety Jingnongke 728 has been accepted as the first mechanized harvesting varieties, as well as the control variety in mechanized-harvesting trials in Huanghuaihai region of China. Jing2416 as a founder inbred line has been used by several key projects and breeding platforms, such as national maize improved varieties, national maize industry technology system, national key research and development project of China, etc.

Abstract:The resistance of 116 wheat varieties collected from the wheat-producing area of Huang-Huai to Fusarium pseudograminearum (Fp) and F. graminearum (Fg) was evaluated by means of artificial inoculation indoors at seedling stage and single flower instillation inoculation at heading stage in the field. Indoor evaluation results showed that none of the varieties were imunne or highly resistant against Fp and Fg. Against Fp, 3 varieties (2.59% of the total) were moderately resistant, 10 varieties (8.62% of the total) were susceptible, and 103 varieties (88.79% of the total) were highly susceptible. Against Fg, 23 varieties (19.83% of the total) were moderately resistant, 50 varieties (43.10% of the total) were susceptible, and 43 varieties (37.07% of the total) were highly susceptible. Field evaluation results showed that against Fp, 6 varieties (5.17% of the total) were resistant, 10 varieties (8.62% of the total) were moderately resistant, 62 varieties (53.45% of the total) were moderately susceptible, 34 varieties (29.31% of the total) were susceptible, 4 varieties (3.45% of the total) were highly susceptible. Against Fg, 1 variety (Sumai 3) (0.86% of the total) was resistant, 2 varieties (Tunmai 127 and Xinmai 208) (1.72% of the total) were moderately resistant, 37 varieties (31.90% of the total) were moderately susceptible, 49 varieties (42.24% of the total) were susceptible, and 26 varieties (22.41% of the total) were highly susceptible. The tested varieties showed different patterns of resistance against Fp and Fg in different stages, with relatively fewer varieties resistant against Fp than against Fg treated with artificial inoculation indoors in seedling stage, and relatively fewer varieties resistant against Fg than against Fp treated with single flower instillation inoculation in the field in heading stage.

Abstract:The millet variety Huangjinmiao represents yellow leaves at the seedling stage and recovered green leaves at the later stages. In this study, we attempted to decipher the physiological and genetic basis of the yellow-leaf seedling phenotype of cv.Huangjinmiao. The leaf color of cv. Huangjinmiao from yellow to green was observed at the booting and heading stages. The dynamic analysis showed that the contents of both chlorophyll a and b at the seedling stage were lower in cv. Huangjinmiao if compared to those of the control plants. At the heading stage, the chlorophyll a became no detectable difference, whereas the chlorophyll bremained significantly lower in cv. Huangjinmiao. The chloroplast ultrastructure showed lower number of chloroplasts and stacked thylakoids, and lower thickness of the stacked thylakoids in cv. Huangjinmiao extensively at the seedling stage but at the heading stage.The accumulative results clearly indicated a compromised biosynthesis of chlorophyll that occurs in cv. Huangjinmiao. The net photosynthetic rate of cv. Huangjinmiao was statistically lower than that of the control lines. The segregation analysis sing a F2 segregation population suggested a recessive-inherited single gene which manipulates the yellow-seedling phenotype. The preliminary mapping suggested that the causal gene was localized on chromosome 8 of Setaria italica. In conclusion, this study laid a good foundation for future high-resolution mapping and functional analysis of the causal gene. Moreover, the application potential of the yellow-leaf color of cv. Huangjinmiao as a phenotypic marker in breeding has been discussed.

Abstract:A good-quality two-line male sterile line (Y58S) was crossed with a good-quality maintainer line (M215B) that carry multiple disease resistant genes. The obtained F1 hybrids were crossed with RGD-7S, which is a good-quality and disease-resistant male sterile line at the heading stage, a two-line male sterile line (He-9S) that contained five resistance genes ,Pi-2, Pi-1, Pi-Kh, Xa21 and Xa23 was bred by marker-assisted selection in combination with pedigree breeding. The average incidence rate of leaf blast in the field identification of He-9 S was only 2.5% (83.0% for the susceptible control), and the disease index of leaf blast was only 0.60 (52.9 for the susceptible control). The incidence rate of panicle neck blast of He-9 S was 38.3% (88.5% for the susceptible control) and the disease index of panicle neck blast was 8.0 (62.3 for the susceptible control) . The Frequency of resistance of He-9S in indoor artificial inoculation was 87.5%(6.25 for the susceptible control).Tests for rice blast resistance under greenhouse condition and field conditions showed moderate resistant to rice blast in He-9S. Furthermore, inoculation with three respective isolates (PXO99, ZHE173 and GD1358) showed that the diseased lesion length of He-9S was variable between 0.1-0.4 cm, similarly to the resistant donor parent, M215B, the lesion length of which were 0.1 cm, 0.1 cm and 0.3 cm respectively. On the contrast, the lesion length of both control varieties RGD-7S and Y58S were variable from 1.3 cm to 7.8 cm. Attractively, He-9S showed low fertility conversion temperature (about 23 °C), good versatility, high stigma exsertion rate and excellent rice quality. Up to date, >10 hybridization combinations have been produced by taking use of He-9S. For example, two elite variety Heliangyou 676 and Heliangyou 639, which exhibited moderate growth period ,high yield, good resistance and good stability, had been approved and released to farmers in May 2019 and on June 2020 respectively in Fujian province, and there are more than 3 varieties are in second-year tests or production test. Taken together, this study released an elite sterile line with a predictable potential in breeding for elite rice hybrids.

Abstract:In order to identify and assess salt tolerance of japonica rice germplasm at seedling stage, salt stress treatment, by using Yoshida culture solution containing 125 mmol/L NaCl, was applied for analyzing 165 japonica rice germplasm accessions. Several parameters including salt tolerance score, leaf damage percentage, seedling height, root length, SPAD value, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight as well as shoot water content were measured. The results revealed significant positive correlations between salt tolerance score and relative seedling height, relative SPAD value, relative shoot fresh weight, relative root fresh weight, relative shoot dry weight, relative root dry weight, relative plant dry weight and shoot water content. Meanwhile, salt tolerance score was found to be significantly negatively correlated with leaf damage percentage and relative root-shoot ratio. Principal component analysis (PCA) with 12 evaluation index suggested five major components, with a cumulative contribution rate of 86.473%. With membership functions and index weight method, a comprehensive evaluation value D for objectively assessing the salt tolerance of japonica rice germplasm resources at seedling stage was obtained. Subsequently, five rice germplasm (Bertone, Changbai 26, Yijing 12, Ningzi 629 and Xiaohubandao) showing the top five D value at the seedling stage were selected. Furthermore, cluster analysis assigned 165 japonica rice germplasm into four groups. For examples, salt-sensitive germplasm accessions were mainly found in group-I; the germplasm genotypes showing weak salt-tolerant were resided in group-II; the group-III contained only one salt sensitive cultivar (Suxuan 2); the group-IV was largely consisted of weak salt-tolerant and salt-tolerant germplasm genotypes. Taken together, five parameters including salt tolerance score, relative root length, relative shoot dry weight, relative root dry weight and shoot water content, were deployed as important indicators, in order to identify salt-tolerant japonica rice germplasm at seedling stage. The results gained from this study?provide a theoretical foundation for screening and identifying the salt-tolerant rice germplasm resources.

Abstract:The traits of pod abscission, dehiscence and kernel cracking directly affect the mechanized harvest and processing in peanut. Here, a total of 720 germplasms from all over the world were used to evaluate pod abscission (plant–petiole and petiole–pod bearing points), pod dehiscence and kernel cracking with a numerical method. Both pod dehiscence and kernel cracking were evaluated from three different directions (horizontal, vertical and side). In pod abscission, the plant–petiole dropping force (51.13 lb) was significantly higher than that of the petiole–pod (22.28 lb), with the variations of 13.5 to 98.1 lb and 5.5 to 54.4 lb, respectively. The significant differences on pod dehiscence were detected among three directions. Of these, the side fracturing pod force is the largest, with an average of 10.76 lb, the vertical fracturing pod force is the second (8.04 lb), and the horizontal fracturing pod force is the smallest (7.47 lb). The force of pod abscission was significantly greater in breeding lines if compared to that of landraces, and this case was observed again in germplasms in South China to North China. The side force of kernel cracking was up to 12.59 lb, while the vertical pressure was lower to 8.48 lb. A higher value of kernel cracking was observed in breeding lines to landraces, but the trait of germplasms from different geographical showed no detectable difference. The cracking force of pods and seeds was from horizontal (r = 0.82, p < 0.01) and vertical extrusions (r = 0.97, p < 0.01), respectively. Finally, a total of 17 germplasms with excellent pod abscission, and 25 germplasms with fine dehiscence and kernel cracking characteristics were obtained. This work becomes helpful in design of harvesting and shelling machineries, and provides elite lines in breeding for new peanut varieties.

Abstract:In this study, 292 sorghum breeding lines were subjected for tests against the infections of greenbug (Schizaphis graminum) and sugarcane aphid (Melanaphis sacchari) at seedling stage and adult stage, in order to identify the parental lines with reliable resistance used for resistance pyramiding in sorghum breeding. As a result, at both seedling and adult stages three genotypes including PB14648-6, PI550607 and Tx2737 represented constantly resistant against the greenbug, while the lines 3765 white B, L27 (powder), R1027 and jiya2 were resistant to sugarcane aphid. Three genotypes Hebeinuo R, Qingkeyang and Tx2737 showed moderately resistant to both greenbug and sugarcane aphid at adult stage. The statistical analysis revealed a very significant difference after 14 days infested by greenbug (p<0.01). The significant differences were observed after 7d (p<0.05) and 10d, 14d (p<0.01) infested by sugarcane aphid. The resistance varieties became visible easily, because the plants showing high-sensitive died or dried up 14 days post infection (dpi). In the identification of aphid resistance at the adult stage of sorghum ,a higher positive correlation (greenbug, 0.844; sugarcane aphid, 0.954) between the average numbers of aphids in adult plant stage, in relative to that at peak growth period was observed. The resistance level at peak growth period could be deployed to reflect that of the adult stage which could be used for the re-identification test for aphid resistance of sorghum.

Abstract:In order to effectively utilize the wheat germplasm introduced from abroad, high molecular weight glutenin subunits composition and quality properties were analyzed for 393 wheat accessions collected from CIMMYT, France, Pakistan and other foreign sources. The results showed that there were 23 types of subunits and 50 types of subunit combinations among the accessions with a high genetic variation and abundant subunits composition types. According to the subunits quality scores, the range of the introduced wheat germplasm was 4-10, with 7.98 as the average, with 74, 76 and 96 accessions (accounting for 62.6% of the total) scored 10, 9 and 8, and containing 8, 2 and 14 subunit combination types, respectively. Besides, 9 accessions were detected to contain new subunits and subunit combination types in this study: F14 (2*, 14*+15*/6*+16*, Null), F33 (2*, 14*+15*/6*+16*, Null), C119 (1, 7*+16*, 5+10), C120 (Null, 7*+16*, 5+10), C125 (2*, 7+8, 5’+10), C51 (2*, 7+9, 5’+10), O13 (2*, 7+16, 2+12) , O17 (2*, 7+16, 2+12) and P27 (2*, 7+18, 2+12). The introduced wheat germplasm on the whole are high in distribution frequency of good subunits, rich in subunit composition types, and may provide resources for utilization and quality improvement breeding.

Abstract:The Zhejiang Team of the Third Nation-wide Survey and Collection of Agricultural Crop Germplasm Resources Project newly collected a total of 51 accessions of local germplasm resources of bottle gourd [Lagenaria siceraria (Mol.) Stand.]. In this study, these accessions were grown and evaluated in the field, with 15 main agronomic traits investigated. The results showed that they were richly varied in many agronomic traits, and through cluster analysis were divided into three groups, among which group I showed excellent comprehensive agronomic properties and could be developed and utilized directly or indirectly. The genotypes of the accessions were identified using 22 core SNP markers, and cluster analysis of the genetic diversity and population structure of these local germplasm resources revealed that they were divided into two groups mainly related to geographical distributions. A comprehensive comparison of the two methods of germplasm clustering analysis showed that it was more accurate and objective to use the molecular marker method to distinguish germplasm resources, when the two methods were not identical. Our results provided a theoretical basis for further research and utilization of these bottle gourd local germplasm resources.

Abstract:The resistance of five parthenocarpic cherry tomato materials against tomoto yellow leaf curl virus disease (TYLCVD) and gray leaf spot disease (GLSD) were identified using pathogen artificial inoculation and molecular markers. The genetic population was constructed using CP28, and the genetic law of parthenocarpy was studied. The ovary development process was observed at two different temperature environment (day/night temperature of 15°C/5°C and 25°C/15°C) using ultra thin paraffin section technology. The TYLCVD and GLSD parthenocarpic cherry tomato germplasm was constructed by regular hybridization and molecular markers. The results showed that no material was resistant to TYLCVD, but CP24, CR3 were resistant against GLSD. Based on the analysis of segregation of the genetic population, we concluded that the parthenocarpic trait of CP28 was controlled by recessive monogene. The paraffin sections showed no ovule in the ovary of tomato plants grown under low temperature (day/night temperature of 15°C/5°C), while some normal developed ovules were observed in tomato plants grown under normal temperature (day/night temperature of 25°C/15°C). Three new parthenocarpic germplasm resistant to both TYLCVD and GLSD were constructed, It laid a foundation for breeding of new cherry tomato varieties with parthenocarpy and multiple resistance.

Abstract:This study attempted to study the genetic diversity of Armeniaca vulgaris var. ansu germplasm provenances. Fifteen qualitative indexes and 25 quantitative indexes of 54 clones were investigated and subjected for cluster analysis, correlation analysis, principal component analysis and stepwise linear regression analysis. The results showed that the phenotypic traits of 54 Armeniaca vulgaris var. ansu clones have a high degree of variation, diverse types and rich genetic diversity. Among them, the average variation coefficient of the 25 quantitative indexes was 18.19%, with the largest variation coefficient on single fruit weight (42.56%). The mean of Shannon-wiener index in quantitative indexes (1.980) was greater than that in qualitative indexes (0.761), the Shannon-wiener index of leaf-form index was the largest (2.082). The Armeniaca vulgaris var. ansu clones were divided into five groups, including: Group Ⅰ contained germplasm resources with high nutlet rate, high kernel rate and special leaf shape; Group Ⅱ, which included germplasm resources with special types of fruit; Group III contained elite lines with potential use in breeding for special nutlet and kernel types; Group IV contained the germplasm with large-nutlet, large-kernel, and high-yield; Group V contained nutlet shell resources. Principal component analysis indicated that the first seven principal components of the 25 quantitative indexes explained 83.31% of the cumulative contribution rate. An elite line No.270 from Huining county of Gansu province represented a highest comprehensive score.By analysis together with stepwise linear regression method, 11 indexes, including branchlet width, leaf length, fruit length, single fruit weight, nutlet length, nutlet width, nutlet thickness, single nutlet weight, kernel width, kernel shape index and nutlet rate, were proposed as important indexes to evaluate phenotypic variations of Armeniaca vulgaris var. ansu clones.

Abstract:Forty-nine mung bean germplasms newly collected from Chongqing in the recent two years were analyzed based on their phenotypic data and evaluated on the resistance to fusarium wilt, which is a most serious disease in Chongqing and surrounding areas. The results showed that the genotypes of mung bean collected in Chongqing were rich in genetic diversity The genetic diversities of quantitative characters were ranked as: Number of pods per plant > Plant height > Node number of main stem > Number of branches > Bottom pod height > Pod width > Pod length > 100-seed weight > Flowering days > Number of seeds per pod > Maturing days > Emergence days, and the genetic diversities of qualitative characters were ranked as: Pod shape > Branching > Trilobate leaf shape > Seed shape > Seed coat glossiness > Growth habit and Podding habit > Mature pod color > Simple leaf shape > Flower color and Main stem hair color > Cotyledon color at emergence > Seed coat color > Young stem color. According to cluster analysis, the 49 genotypes were divided into 5 Groups: Group I of dwarf materials suitable for mechanization, Group II of large-seeded materials, Group III of yellow seed materials, and Group IV and Group V with potential for development of resistance to fusarium wilt. In the three-dimensional scatter diagram, the first three principal components have the 49 genotypes distributed roughly in two regions. The genotypes distributed in Region I were mostly of the erect type, while those distributed in Region II were mostly of the half sprawling type. Among the 49 genotypes, 9 mediumly resistant genotypes, 3 resistant genotypes and 1 highly resistant genotype were identified. This study provides a theoretical and germplasm basis for the development and better utilization of mung bean genetic resources and genes of resistance to fusarium wilt.

Abstract:Under the frame of the Third National Survey and Collection Action on Crop Germplasm Resources, 104 sorghum germplasm resources were collected from 41 counties of Jiangsu from 2016 to 2017. Fifteen agronomic traits were investigated for the genetic diversity analysis of sorghum germplasm resources. The variation types of agronomic quantitative traits of sorghum resources are rich. The significant positive correlation was detected between grain weight and any of plant height, spike length, node number,100 grain weight, heading stage and aboveground fresh weight. The aboveground fresh weight was positively correlated with any of plant height, node number and heading stage, while negatively correlated with stalk length. The cluster analysis suggested seven groups of the sorghum germplasm accessions. Especially, the first group included sweet sorghum accessions, which are used for sugar and forage; the second group included the accessions with a long spike, which are the special materials for craft; the third group showing higher weight of single spike and 100 grains, represented the accessions with the end-use for grain and sugar; the accessions from the fourth group often showed short, few nodes and early maturing, and they are used for grain, forage and craft；the fifth group are wild accessions, which showed lower yield and are potentially are used for grain, forage and craft；the accessions in sixth group,which often showed moderate plant height, spike length, heading stage and aboveground fresh weight, are used for grain, sugar, craftand forage；the accessions in seventh group, often with short plant, high 100 grain weight, bare grain, and early growth period, are used for grain production. Out of that, nine germplasm resources with excellent and special characters were identified. In summary, the sorghum germplasm accessions from Jiangsu Province represented abundant genetic diversity, especially including several excellent germplasm resources with any of high yield, early maturity, ear type and grain weight can be used potentially for breeding and industrial production.

Abstract:From 2015 to 2019, (GXAAS) carried out field survey and collection of crop germplasm resources in 10 counties in Cat Mountain and surrounding areas in Guangxi Province of China. 685 accessions including 296 vegetables, 219 grain crops, 164 cash crops and six fruit trees were obtained, which belong to 57 species of 36 genera in 18 families. Based on the passport information, 511 accessions are local varieties, 172 wild germplasm resources, and two introduced from other provinces of China. Taken together, this work represented a comprehensive analysis of the collected resources, the types, distribution and characteristics of crop germplasm resources in Cat Mountain and its surrounding areas, and provided insights of the protection, development and utilization of crop germplasm resources in the region.

Abstract:In this study, we investigated the phenotypic diversity of 18 characters on five main natural populations of Paphiopedilum hirsutissimum that were collected from three provinces Yunnan, Guangxi and Guizhou in China. The statistical methods used included nested variance analysis, coefficient of variation, correlation analysis, principal component analysis (PCA) and cluster analysis. The results revealed significant difference at most phenotypic traits among populations if compared to that within populations. The mean phenotypic differentiation coefficient (VST) was 75.18%, indicating that the population diversity was largely contributed by the variation among populations. The average variation coefficient of the 18 phenotypic traits was variable from 6.36%–18.51%, with a higher degree of dispersion. PCA showed that plant height, length of ovary, scape height, length of maximum leaf, diameter of flower and length of synsepal were the main sources of phenotypic variation. Pearson correlation analysis showed that plant height, width of synsepal and width of dorsal sepal were significantly or extremely significantly positively correlated with the majority of plant traits, whereas only the length of synsepal was extremely significantly correlated with geographic factors. Cluster analysis revealed three groups from the five populations, which could be explained by the geographic distribution. This study found that populations of Paphiopedilum hirsutissimum have high genetic diversity, and the variation between populations is much higher than that within the population. The phenotypic diversity indicates that wild Paphiopedilum hirsutissimum populations should be protected as much as possible. Moreover, it is recommended that germplasm is preserved in nurseries and libraries in addition to in-situ conservation, and that an artificial reproduction system is established enhance our conservation efficiency.

Abstract:Virescent mutant was first recognized from the upland cotton. Since its yellow-green phenotype was often found to be associated with the heterosis, this has been used as a phenotypic marker in cotton breeding. By taking use of three virescent mutants 71-7, 62-17 and 115-23, this work generated 33 hybridization combinations in order to genetically localize the underlying functional genes and to identify the elite lines with a potential used for cotton breeding. The genetic analysis suggested that a single recessive genetic locus causing virescent in sprout was present in mutants 71-7 and 115-23, respectively. A single locus with the incomplete dominant mode was detected in virescent mutant 62-17. We generated by backcross breeding approach with virescent marker, nine elite germplasms including male sterile lines, maintainer lines and restorer lines. Moreover, by analysis of comprehensive character of 12 dominant combinations, two lines Y34 and Y26 showed higher value on seed cotton yield and lint yield, and both can be used as new strains of precocious hybrid cotton in early maturing group of Xinjiang for Variety Screening Test. Taken together, this study provided new cotton germplasm resource, which might be used in identification of the functional genes and breeding of elite upland cotton varieties in Xinjiang.

Abstract:Pre-harvest sprouting (PHS) is a frequently-occurring disaster that results in a serious economic loss in rice production. Breeding for PHS-resistant rice varieties has limited worldwide due to the mechanism of PHS that remains unclear. Here, nine independent mutants conferring PHS were identified by screening of an EMS (Ethylmethylsulfone) mutant library, and two of them were subjected for further study. By taking use of whole genome resequencing, SIMM method and HRM technology, two PHS mutant genes (LOC_Os03g08570 and LOC_Os07g10490) were molecularly cloned. LOC_Os03g08570 codes a phytoene desaturase (OsPDS), and LOC_Os07g10490 codes a ζ-carotene desaturase (ζ-carotene desaturase). Both were reported to be involved in the biosynthesis of carotenoid as the precursor of ABA. In summary, our data highlights the critical role of carotenoid that participates in rice dormancy. Further studies of these PHS mutants would allow revealing the mechanism of PHS and breeding for PHS-resistant rice varieties.

Abstract:New virulence races of the wheat leaf rust pathogen emerge continuously, due to frequent mutations in pathogenicity, often resulting in loss of resistance in wheat cultivars originally resistant to leaf rust. So, it is important to develop a specific molecular marker for diagnosis and prediction of wheat leaf rust in the field. On the basis of our previous studies of completing transcriptome sequencing of wheat leaf rust fungus PHNT, in this study we selected candidates of effectors from the wheat leaf rust fungus PHNT transcriptome database, used real-time fluorescence quantitative PCR (qPCR) to detect their expression patterns at different time points after leaf rust fungus infection with wheat, then designed primers according to the sequences of the selected candidates of effectors based on expression differences, conducted PCR amplification using genome DNA of PHNT as templates to screen a specific molecular marker for wheat leaf rust. As a result, a total of 24 candidates of effectors were screened based on the transcriptome database, and 17 expressed significantly difference by qPCR. The PCR results showed that the candidates of effector PTTG-05290 had a specific band of 920bp appearing in the wheat leaf rust fungus PHNT, and the specific band was detected in 25 leaf rust races, but was absent in six rust fungi of wheat stripe rust, bean rust, jujube rust, willow rust, apple rust and reed rust, which indicated that the marker was specific for wheat leaf rust fungus. In addition, the results of qPCR showed that the expression level of PTTG-05290 is 218 times higher at the expression peak (4 dpi) than that at 0 dpi, and the gene could be detected in large quantities at 0.5 dpi. So, the specific molecular marker can be used for the detection and prediction of leaf rust in the field at an early stage, providing a shortcut for the adoption of wheat cultivars of resistance to leaf rust.

Abstract:Translationally controlled tumor protein (TCTP) is an important regulator involved in plant growth and development as well as responses to biotic and abiotic stresses. By taking use of Puccinia triticina isolate-260 and four wheat near-isogenic lines (NILs) that form combinations with different affinity degrees, we investigated the expression of TCTP at transcription and translational levels using RT-qPCR and Western Blotting, respectively. The transcriptional level of TCTP was significantly up-regulated in the incompatible combination, but this was diverse in NILs with Lr gene. No obvious change trend in the affinity combination was observed. Gained from the results of TCTP mRNA and protein levels, the expression of TCTP was found to be modified at both transcription and translation level during the interaction between wheat and Puccinia triticina. It is speculated that it may play a positive role in the defense response of wheat against Puccinia triticina infection. This will lay the foundation for further research on the function and mechanism of TCTP.

Abstract:Abiotic stress such as drought stress seriously destabilizes crop production. E3 ubiquitin ligase genes play important role in the development and responses to abiotic stresses. In the present research, TaAIRP2-1B, a gene encoding for a RING finger (really interesting new gene) E3 ubiquitin ligase, was cloned from common wheat (Triticum aestivum L.). To analyze the transcriptional profiles of TaAIRP2-1B, the tissues at heading stage were subjected for RNA extraction, followed by qRT-PCR analysis. The TaAIRP2-1B gene expressed in various tissues, and abundance on expression was detected in the aboveground tissues in relative to that of the roots. This gene was found to be expressed with highest in the peduncle internode and lowest in the 30-60 cm root. Moreover, the expression of TaAIRP2-1B was inducible upon ABA, PEG or cold treatments. We further analyzed overexpressing lines carrying TaAIRP2-1B in Arabidopsis by treated with ABA or drought stress. The germination rate of transgenic Arabidopsis to wild type (WT) was significantly decreased at 0.4 μΜ ABA treatment. ABA treatment was observed with inhibition on root growth. The transgenic lines exhibited significantly higher inhibition degree than WT, indicating that TaAIRP2-1B enhanced the sensitivity of Arabidopsis to ABA during seedlings stage. After drought stress treatment, leaf wilting and yellowing of the transgenic lines were significantly lower than WT, and the water retention rates of transgenic L1, L2 and WT were 73.16%, 73.7% and 69.04%, respectively. These results showed that TaAIRP2-1B enhanced the drought resistance of Arabidopsis, and the water retention rates of transgenic Arabidopsis were significantly higher than that of WT. Therefore, these results suggested an involvement of wheat gene TaAIRP2-1B in response to abiotic stress and may positively regulate the drought resistance through an ABA-dependent pathway.

Abstract:Plants make corresponding measures by modifying the physiological and biochemical processes in respond to heavy metal cadmium stress. Detoxification of reactive oxygen exposure caused by heavy metals serves as one of the important aspects. In this study, the expression of ZmOPR5 in roots and shoots under Cd treatment was analyzed in two inbred lines B73 (Cd tolerant) and Mo17 (Cd sensitive). Moreover, the relative dry matter yield, malondialdehyde (MDA) content, superoxide radical O2-, H2O2, Cd2+ content and Cd2+ transfer coefficient were analyzed. The results showed that ZmOPR5 was inducible in genotypes and tissues by Cd stress. The relative expression of ZmOPR5 was positively correlated with H2O2 content, MDA content, Cd2+ content and transfer coefficient. For examples, the correlation coefficients of ZmOPR5 and above-mentioned traits in roots of B73 were 0.778, 0.879, 0.893 and 0.822, respectively, suggesting that ZmOPR5 might be involved in the process of antioxidant stress induced by Cd stress. The remaining six traits showed phenotypic variations in materials and tissues, and the correlation coefficients of these traits were also different. In B73 roots, the relative expression of ZmOPR5, MDA content, Cd2+ transfer coefficient and Cd2+ content were abundant. We speculated that roots of B73 were able to absorb more Cd2+ thus resulting in the active oxygen burst, while the high expression of ZmOPR5 participated in the scavenging process of active oxygen free radicals. B73, with the higher Cd2+ transfer coefficient and could rapidly transfer excessive Cd2+ in the root system to stems and leaves, and might be stored in the vacuole of leaves in the form of chelates. These results raised an explanation of Cd accumulation and tolerance between maize genotypes, which provides a reference for further analysis of physiological mechanism of ZmOPR5 involved responses to Cd stress in maize.

Abstract:QTL mapping of soybean quality traits can provide a theoretical basis for molecular hybridization breeding. In this study, 113 genetic pairs of SSR primers with polymorphism were used to construct a genetic linkage map with a total length of 1630.95 cM and an average genetic distance of 14.43 cM, covering 19 soybean linkage groups (except B2) of 142 lines of advanced backcross introgression population BC2F7 derived from soybean ‘Zhonghuang 13’ (recurrent parent) × ‘Dongshan 69’ (donor parent). Near-infrared spectroscopy (NIR) and gas chromatography (GC) were used to determine the contents of protein, fat and five major fatty acids in soybean. A total of 33 QTLs were identified using ICIM-ADD in two years. The number of mapped QTL were 5, 2, 6, 11, 4, 3, and 3 for protein (PR), fat (OIL), stearic acid (SA), palmitic acid (PA), linoleic acid (LA), oleic acid (OA), and linolenic acid (LNA), respectively. Sat_003 - Sat_147 were negatively correlated with OA in the two years. Satt523 - Sat_405 were correlated with PA and PR. Staga001 -Satt658 and Satt263 - Satt651 were correlated with OA and SA. Satt228 - att525 were correlated with LA and PR. Satt658 - Satt433 were correlated with LNA and SA. The mapping results have clarified the correlation of quality traits to a certain extent, and have reference significance for the selection of excellent varieties in soybean molecular breeding.

Abstract:To clarify the genetic factor underlying the early flowering in soybean (Glycine max L.) cultivar BeiNong103, F2 segregating population from a cross of cv. BeiNong103 (male) and cv. Haixi13 (female, late-flowering) as well as its derived F2: 5 recombine inbred line population were subjected for analyzing the segregation ratio and the preliminary mapping following the bulked-segregant analysis pipeline. The genetic analysis suggested a single recessively-inherited locus on chromosome 6, which is associated to the early-flowering phenotype in cv. BeiNong 103. The genetic interval, franked by two markers Satt557 and XH2_11, expanded 2 cM which harbors a formerly-identified recessive gene el of E1. The sequence analysis showed a G to C mutation at the 218bp of E1 coding sequence, thus resulting in an amino acid substitution of arginine (AGG) to threonine (ACG) in BeiNong103. Taken together, the single-base mutation of e1 might be the causal agent that underlies the sensitivity of the photoperiod and the early flowering. The elite allele, suggested by the pedigree analysis, is derived from the American variety Century, and might play a role in future improvement of the maturity and plant height characteristics of cultivar in soybean breeding.

Abstract:R2R3-MYB transcription factors are known to play important regulation role in the flavonoid biosynthesis of plants. In this study, a gene FtMYB1 belonging to the R2R3-MYB gene family was cloned from Tartary buckwheat cultivar ‘Chuanqiao No.1’.The FtMYB1 transcription factor was found to exhibit the transcriptional activation activity in yeast, and its expression of FtMYB1 gene was induced by Methyl jasmonate (MeJA) and abscisic acid (ABA) treatment. Overexpressing the FtMYB1 gene in Tartary buckwheat hairy root showed a significant reduction in contents of total flavonoid and rutin if compared with wild type. Furthermore,the expression of FLS and RT1 genes, which encode for flavonol synthetase (FLS) and rhamnosyltransferase (RT) in Tartary buckwheat, respectively, were significantly lower in the FtMYB1 overexpressing hairy roots than that of wild type. Taken together, our results suggested that FtMYB1 may function in inhibition of the flavonol biosynthesis by repressing the expression of FLS and RT1 genes.

Abstract:Glucosinolates are important secondary metabolites in cruciferous vegetables. In various cruciferous crops, glucosinolates and their degradation products may be different, thus rendering their respective special flavors and biological functions. A main glucosinolates in radish, glucoraphenin(RAE) and its degradation product have powerful anticancer activity, whereas oxazolidinone, a degradation product of progoitrin (PRO), a main glucosinolate in Chinese cabbage, is considered to have the side effect of causing goiters. In this study, high performance liquid chromatography (HPLC) was used to analyze the main components and contents of glucosinolates in radish (‘36-2’), Chinese cabbage (‘Chiifu’) and raphanobrassica, a synthetic intergeneric distant hybrid (DH). A total of 13 glucosinolates were identified. The main glucosinolates in radish were glucoraphasatin (RSA) and RAE. The main glucosinolates in Chinese cabbage were PRO, gluconapin (NAP) and glucobrassicin (GBC). The main glucosinolates in the synthetic intergeneric hybrid species were RAE, glucobrassicanapin (GBN), NAP, PRO and GBC. Through the transcriptome analysis comparing DH with ‘36-2’, it was found that there were 14 down-regulated expression and 23 up-regulated expression genes for glucosinolates pathway in DH, among which the radish-specific RsIQD1.1 and RsMYB34.2 were down-regulated, while RsMYB34.1 was up-regulated. Notably, the RsFMOGS-OX2.1 of radish was significantly up-regulated in DH. Through comparative analysis with ‘Chiifu’, it was found that 24 glucosinolates pathway genes in DH were down-regulated and 15 were up-regulated, among which the Chinese-cabbage-specific BrIPMI-SSU3.1, BrIPMDH3.1 and BrMAM3.1 were significantly up-regulated. The expression characteristics of these genes in DH appeared to be related to the change of the composition of glucosinolates. This proved to some extent that distant hybridization may change the component and content of glucosinolates by changing the genetic composition and gene expression of the offspring, which lays a theoretical foundation and technical support for realization of gene exchanges among species by using distant hybrids as a bridge germplasm and creation of new germplasms of high quality in cruciferous crops.

Abstract:Panicum virgatum L. is an important biomass energy plant. Its straw is rich in lignocellulose which can be used as raw material for ethanol production. An investigation on chromosome localization and distribution of 45S rDNA in P. virgatum cultivars with different ploidy would promote the cytogenetic study of the species. In this investigation, chromosome localization of 45S rDNA and karyotype analysis were conducted by fluorescence in situ hybridization using root tips of three tetraploids and six octaploids as materials. The results indicated that there were 36 chromosomes in the somatic nucleus of the tetraploids, which could be divided into nine groups, each with four homologous chromosomes. The karyotype formula of the tetraploids was 2n = 4x = 36 = 32m (SAT) + 4sm, and 45S rDNA was invariably located at one end of chromosome 3. Significant differences in number of chromosomes and location of 45S rDNA signals were found among different octaploid cultivars or different individuals of the same octaploid cultivar. Four types of 45S rDNA distribution in the octaploid cultivars existed. The first type had a strong 45S rDNA signal at the end of both arms of the chromosome. The second type had a strong 45S rDNA signal within one arm of the chromosome. The third type had a strong 45S rDNA signal at the end of one arm of the chromosome. The fourth type had a weak 45S rDNA signal within one arm of the chromosome. The complexity of the models of 45S rDNA signal distribution among different octaploid cultivars or different individuals of the same octaploid cultivar is inferred to be closely correlated to homologous recombination and structure variation of the chromosoms.

Abstract:One of the effective ways to control the damage of stripe rust in wheat is the introduction of stripe rust resistant genes into cultivars to improve their resistance. Molecular marker-assisted selection (MAS) can improve the selection efficiency of target genes in breeding. In order to detect the stripe rust resistant gene Yr69 and verify the validity of molecular marker linked to Yr69, the genotypes of 63 F6 lines derived from Chang 4738/CH7086 and Yannong 999/CH7086 were identified by molecular marker 2AS33,and their resistance to stripe rust were identified with the Pst mixed with CYR32, CYR32 and CYR34. The results showed that 32 lines among the 35 lines derived from Chang 4738/CH7086 had Yr69 and showed resistance to stripe rust, and one line showed resistance to stripe rust without Yr69 being detected; 8 lines among the 28 lines derived from Yannong 999/CH7086 had Yr69, of which 7 lines showed homozygous resistance and one line showed segregation of resistance and susceptibility. Among the total 63 lines, 3 had genotypes inconsistent with phenotypes. It suggested that the marker 2AS33 had a high accuracy of 95.2% and it could be used to detect the Yr69 gene effectively in molecular marker-assisted selection breeding. The 40 resistant lines identified, after yield and adaptability identification, may be entered for regional trials of cultivars directly or as good parents for stripe rust resistance breeding.

Abstract:In order to systematically evaluate the germplasm resources of Pueraria in Guangxi, a total of 283 germplasm resources of Pueraria were collected from 153 villages in 67 towns of 50 counties. The Pueraria germplasm resources were mainly distributed in the north, west and southeast of Guangxi. 44.52% of the collected germplasm accessions were found at the low altitude(100 to 200 meters). By deployment of botanical classification method, the germplasm resources of Pueraria in Guangxi are mainly composed of two species: P.lobata (Wild) Ohwi var. thomsoni (Benth.) van der Maesen and P.lobata (Wild.) Ohwi var. Montana (Lour.) van der Maesen, in which P.lobata (Wild) Ohwi var. thomsoni (Benth.) van der accounts for 62.20% of total accessions, and the morphological difference is more abundant than that of P.lobata (Wild.) Ohwi var. Montana (Lour.) van der Maesen. Excellent germplasm resources of Pueraria, which are suitable for edible, starch processing, medicinal use and flower tea development, have been identified and evaluated. Taken together, the geographical distribution, botanical classification, morphological diversity and utilization value of the collected germplasm resources of Pueraria in Guangxi were evaluated. Moreover, the protection, development and utilization of the germplasm resources were discussed, thus providing reference for the excavation and utilization of the germplasm resources of Pueraria in Guangxi.

Abstract:SNP (single nucleotide polymorphism), as the latest generation of genetic molecular markers, has been widely accepted in multiple research fields. This article focuses on the exploitation and detection of SNP molecular markers and their application in variety identification in crop species. At present, the exploitation of SNP markers mainly relies on the polymorphisms either released in public databases or generated by high-throughput sequencing. The polymorphisms could be detected with the traditional detection method using gel electrophoresis to new high-throughput automated detection technologies. In crop variety identification, it is recommended to use gene chip or genotyping by sequencing (GBS) technology for crops with large sample populations and multiple SNP detection markers, and for which with small sample populations and few SNP detection markers could more flexible, efficient and lower cost by kompetitive allele specific PCR (KASP) or high resolution melting (HRM) typing technologies.

Abstract:Drought is the main environmental stress factor that leads to yield reduction in soybean (Glycine max). The canopy wilting caused by drought stress is the external expression of the water potential status and osmotic-regulation status, which can directly reflect the drought tolerance of soybean. The improvement of drought resistance and grain yield via deploying and incorporating slow-wilting tolerance germplasm has been accepted in practical uses. This article reviews the progress on the physiological and genetic mechanisms underlying slow-wilting in soybean. Breeding for slow-wilting soybean lines/varieties in China was limited largely due to the insufficiency of elite slow-wilting germplasm resources. The suggestions on identification of elite slow-wilting germplasms and cloning of genes underlying the slow-wilting process in soybean are proposed. Thus, this article provides considerable insights to understand the interaction networks between slow canopy wilting and drought resistance and yield, and to guide the breeding of slow-wilting cultivars in soybean.