Table of Content

10 July 2018, Volume 44 Issue 7

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

A Qualitative and Quantitative PCR Detection Method for Disease-resistant Genetically Modified Rice M12 and Its Derivates

Peng LI,Lin ZHANG,Ji-Ni YE,Shi-Yao HE,Jun-Wei JIA,Ai-Hu PAN,Xue-Ming TANG

Acta Agronomica Sinica. 2018, 44(7):  949-955.  doi:10.3724/SP.J.1006.2018.00949

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In this study, the specific sequence of genetically modified Rice M12 and the endogenous reference gene sps were amplified to construct a T vector as the plasmid pM12 for establishing the qualitative and quantitative PCR detection method of transgenic Rice M12 and its derivates. The qualitative PCR method could specifically quantify the samples of M12 with the detection sensitivity about 100 copies of the rice haploid genome. On the basis of SYBR Green qPCR assay, R ² values of standard curves of M12 and sps were 0.998 and 0.997, the amplification efficiency was 95.3% and 108.4%, respectively. Moreover, the standard deviations (SD) of repeatability ranged from 0.043 to 0.276. The limit of quantification (LOQ) and limit of detection (LOD) were 100 and 10 copies, respectively. The mixed rice sample containing 1.0% gene transforming into rice was exactly quantified by the developed quantitative PCR method, and the quantified bias between the true value and tested value was below 8.0%. In conclusion, these methods can be used for identifying and quantifying M12 and its derivatives.

Construction of DNA Fingerprinting for Brassica napus Varieties Based on SNP Chip

Ren-Xin ZHAO,Sen-Ye LI,Rui-Xing GUO,Xin-Hua ZENG,Jing WEN,Chao-Zhi MA,Jin-Xiong SHEN,Jin-Xing TU,Ting-Dong FU,Bin YI

Acta Agronomica Sinica. 2018, 44(7):  956-965.  doi:10.3724/SP.J.1006.2018.00956

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Using the Brassica 60K Infinium SNP (single nucleotide polymorphism) array, a total of 52 157 SNP markers were obtained by genotyping 33 annual test varieties in 2015-2016 and 187 varieties in 2016-2017. A total of 5374 high quality SNPs were retained after removing SNPs with AA or BB frequency = 0, main gene frequency < 0.80, secondary gene frequency < 0.05, sample loss rate > 0.50, or SNPs that did not show clearly defined clusters. The mean PIC (polymorphism information content) value of selected 5374 markers was 0.27, SNPs with the PIC value >0.25 accounted for 55.94% of total number. Among 5374 SNPs, 5143 corresponded to the A1-A10 and C1-C9 linkage groups, and covered the rapeseed genome. We analyzed 5374 SNPs from 224 samples with softwares like PowerMarker and MEGA, etc. The technical error of the SNP array was 0.36%, when comparing two replicates of eight samples. It was close to the 0.1% technical error announced by Illumina. The NJ (Neighbor- joining) cluster analysis revealed that 97.86% of the tested varieties had a similarity coefficient of less than 93%, 87.88% renewed varieties had a similarity coefficient of greater than 95%, which could be further used as criteria for the varietal specificity and the annual consistency assessment. The 5374 SNP markers screened in this study were highly polymorphic and evenly distributed in the rapeseed genome, and could be used for future variety identification and the construction of DNA fingerprinting.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Efficient Separation and Identification of High Molecular Weight Glutenin Subunits by HPCE

Wei-Dong WANG, Xiang GAO, Dan-Yang ZHAO

Acta Agronomica Sinica. 2018, 44(7):  966-976.  doi:10.3724/SP.J.1006.2018.00966

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High molecular weight glutenin subunit (HMW-GS) is important for processing quality of wheat. High performance capillary electrophoresis (HPCE) is increasingly used in the work of separation and identification due to its advantages of small sample, rapidness and high precision. However, this technique has been seldom used in wheat HMW-GS study and its separation system needs improvement in analytical speed and discernibility. On the basis of HMW-GS identification with SDS-PAGE and molecular markers, an high-efficiency separation system of HPCE was set up using Chinese Spring as the standard. The system components (pH 2.5) were 75 mmol L ^-1 IDA, 0.05% HPMC, and 15% ACN. The electrophoresis parameters were 25 μm of inner diameter of the capillary, 200 nm of detection wavelength, 20 kV of separation voltage, and 30°C of operating temperature. Using mixed injection method, the standard spectrums were obtained for 18 subunits. Their migration order was 1Dy12→ 1Dy10→ 1By9→ 1By8→ 1By18→ 1By16→ 1By20→ 1Bx17→ 1Bx20→ 1Bx13→ 1Bx6→ 1Bx7→ 1Ax2*→ 1Ax1→ 1Dx5→ 1Dx4→ 1Dx3→ 1Dx2, and standard peak time of these subunits was 9.39, 9.69, 10.30, 11.70, 11.89, 12.09, 12.22, 12.36, 12.62, 12.83, 13.08, 13.18, 13.50, 13.73, 14.04, 14.24, 14.46, and 14.73 min, respectively. The relative standard deviation was smaller than 0.2%. The y-type and x-type subunits appeared in the phases of 9.39-12.36 min and 12.36-14.76 min, respectively, between which there was 1Bx17 as the boundary. These results indicate that the HPCE separation system is applicable in rapid identification of HMW-GS in wheat germplasm resources when we simultaneously consider migration order, standard peak time, and HPCE spectrum.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Fine Mapping and Candidate Gene Analysis of Rice Blast Resistance Gene Pi47

Xiang-Yi XIAO,Xue-Tao SHI,Hao-Wen SHENG,Jin-Ling LIU,Ying-Hui XIAO

Acta Agronomica Sinica. 2018, 44(7):  977-987.  doi:10.3724/SP.J.1006.2018.00977

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Continuous mapping and cloning new blast resistance genes provided an important approach for revealing the molecular mechanism of resistance to rice disease and breeding new varieties resistant to rice blast. Previously, the blast resistance gene Pi47 was mapped between SSR markers RM224 and RM2956 on chromosome 11, from a broad-spectrum and durable resistance native cultivar Xiangzi 3150 in Hunan province. In this study, the fine mapping and candidate gene prediction were performed, showing that Pi47 was mapped in an interval of 0.24 cM between CAPS markers S32 and K33 with 171.2 kb on Nipponbare reference genome, and further narrowed in an interval of 67.8 kb between markers SC12 and K33, through background screening to Pi47 monogenic lines and susceptible parent CO39 with six STS markers. Eight genes were predicted in this region on the reference genome, among them two encoded NBS-LRR resistance-like proteins, which probably were Pi47 functional candidate genes. A blast resistance spectrum evaluation, using Pi47 monogenic lines and four near-isogenic lines with the Pik allelic gene Pik, Pikm, Pikh, and Pikp across Pi47 region, revealed that Pi47 shared different resistance spectra with these four alleles. These results shed light on further molecular cloning of Pi47, and the molecular marker will be useful for molecular maker assisted selection to breed new resistant cultivars.

Drought Tolerance Evaluation of Wheat Germplasm Resources

Long LI,Xin-Guo MAO,Jing-Yi WANG,Xiao-Ping CHANG,Yu-Ping LIU,Rui-Lian JING

Acta Agronomica Sinica. 2018, 44(7):  988-999.  doi:10.3724/SP.J.1006.2018.00988

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Breeding drought-tolerant wheat varieties is an essential strategy to ensure food security in China. Identification of elite germplasm resources and methodological study of drought tolerance evaluation are the keys to improve drought-tolerance breeding efficiency. The drought tolerance of 323 wheat germplasm resources at seedling and adult stages was evaluated using the methods of repeated drought and direct identification in the field, respectively. With the increase of tested times of drought stress, the seedling survival rates declined, whereas the variation coefficients of seedling survival rates and broad-sense heritabilities increased. The drought tolerance coefficient of yield (DTC_GY) showed significantly positive correlation (R ² = 0.609) with drought resistance comprehensive evaluation value (DV), and DV was an effective indicator for distinguishing the vulnerability of yield of different germplasm resources under drought stress. The repeated drought survival rate (DS) at seedling stage had no significant correlation with either DTC_GY or DV. Twenty-eight accessions with high drought tolerance at seedling stage were selected based on DS, 25 and 30 accessions with high drought tolerance at adult stage were screened out based on DTC_GY and DV, respectively. Among which, nine with high tolerance were detected based on both DTC_GY and DV; 21 accessions showed drought tolerance at both seedling and adult stages. This results provide theoretical guidance and basic information for selections of drought-tolerance evaluation methods and elite parents.

Cloning and Expression Analysis of Strong Inducible Promoter P₁₅₀₂-ZmPHR1 Responding to Low Phosphorus Stress in Maize

Rui-Juan YANG,Jian-Rong BAI,Lei YAN,Liang SU,Xiu-Hong WANG,Rui LI,Cong-Zhuo ZHANG

Acta Agronomica Sinica. 2018, 44(7):  1000-1009.  doi:10.3724/SP.J.1006.2018.01000

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ZmPHR1, a member of transcription factor MYB-CC family, enhanced phosphate absorption and improved plant growth when it was overexpressed under low-phosphate conditions. In order to elucidate the transcriptional regulatory mechanism of the promoter of ZmPHR1, its 5′ upstream sequence P₂₂₀₅-ZmPHR1 was cloned from P-efficient maize inbred line 478. The full length of P₂₂₀₅-ZmPHR1 and four sequence deletion fragments in different lengths fused with the reporter gene GUS were transformed into Arabidopsis, respectively. The results of histochemical and quantitative fluorometric GUS assay showed that in the interval from 0 to -1502 bp, the response time and activity of sequence deletion fragments were increased with increasing fragment length. However, the activities were decreased or unchanged when the length of fragments were longer than 1502 bp. It was considered that the interval from 0 to -972 bp was function region and that from -972 bp to -1502 bp was function enhancing region. The results of qPCR analysis in transgenic plants at different time points (0, 1, 2, 3, and 4 days) after P-stress treatment showed that the activities of P₁₅₀₂-ZmPHR1 were influenced by both external signals and internal gene products, having feedback regulation. This study indicates that P₁₅₀₂-ZmPHR1 is a strong inducible promoter responding to low phosphorus stress and its functional activity is regulated by both external and internal phosphate concentration. These fundings provide an ideal promoter for crop improvement under low phosphate conditions and a basis for its application.

Establishment of DNA Molecular Identification for A Sesame (Sesamum indicum L.) Applied Core Collection

Wen-Juan YANG,Yan-Xin ZHANG,Lin-Hai WANG,Xin WEI,Dong-Hua LI,Yuan GAO,Pan LIU,Xiu-Rong ZHANG

Acta Agronomica Sinica. 2018, 44(7):  1010-1020.  doi:10.3724/SP.J.1006.2018.01010

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The establishment and research of sesame applied core collection are significantly effective to facilitate the improvement of breeding techniques and exploration of out-standing genes. A sesame applied core collection, including 131 sesame accessions with 23 application-oriented features such as big seeds, high oil content and high lignan content, was established according to the observation and statistics in four various environments for four years. Based on 32 pairs of SSR primers developed from the sesame genome, we screened out seven pairs of primers, bearing high polymorphism, distinct bands and excellent repetition, using the technique of denatured polyacrylamide gel electrophoresis for detecting SSR The more precise detection technique of capillary electrophoresis with fluorescent SSR markers was utilized simultaneously to analyze the 131 sesame germplasm of applied core collection. Totally 53 polymorphic locations were detected out by using six primer pairs, and the most sensitive primer pair could detect 12 polymorphic locations. Subsequently, the results were shown in the form of numbers combined with English letters. As per the rule that the least primer pairs detect the most sesame germplasm, the combinations of six core primer pairs, namely ZMM1494, ZMM1648, ZMM3037, ZMM2818, ZMM1851, and ZMM1935 effectively distinguishing the 131 sesame germplasm of applied core collection were screened out by ID Analysis 4.0. So that, the simple and easy-applied DNA molecular identifications such as “4A32645(AC017)” were constructed, and the various combinations of primers distinguishing the germplasm within groups were screened out simultaneously. The DNA molecular identifications of character strings, bar code and quick response (QR) codes, easily scanned and recognized by electric gadget, were constructed based on the molecular data of 131 sesame germplasm of applied core collection so as to broaden their application ranges, also provide important technical foundation for the standardization of sesame germplasm and the construction of DNA identification bank of sesame varieties.

Cloning and Functional Analysis of R2R3 MYB Genes Involved in Anthocyanin Biosynthesis in Potato Tuber

Huan TAN,Yu-Hui LIU,Li-Xia LI,Li WANG,Yuan-Ming LI,Jun-Lian ZHANG

Acta Agronomica Sinica. 2018, 44(7):  1021-1031.  doi:10.3724/SP.J.1006.2018.01021

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The anthocyanins biosynthesis is regulated by transcription factors, and R2R3 MYB is the most important transcriptional regulator in plant. In this study, three homologous genes were isolated from tetraploid potato, belonging to R2R3 MYB gene family. The structure and function analysis of the three homologous genes were characterized by bioinformatics analysis, stable tobacco genetic transformation and qPCR assays. The three homologous genes contained R2 and R3 conserved domains, differed in the number of repeats (R) consisting of 10 amino acid sequences, and named as StAN1-R0, StAN1-R1, and StAN1-R3 according to the number of R. The coding proteins are hydrophilic with molecular weight of 28 047.91, 29 458.35, 31 527.60 Da, and isoelectric points (pI) of 6.14, 6.90, and 8.39, respectively. The accumulation of anthocyanin was significantly increased in StAN1-R0, StAN1-R1 and StAN1-R3 overexpressed plants. The leaf color of StAN1-R1-overexpressed plants was dark red with the highest anthocyanin content among the three transgenic events. The qPCR assays showed that exogenous StAN1 genes enhanced the expression of endogenous NtbHLH transcription factor as well as NtCHS, NtCHI, NtF3H, NtF3’H, NtDFR, NtANS, and NtUFGT, involved in anthocyanin biosynthesis in transgenic tobacco leaves. The overexpression of StAN1-R1 resulted in higher expression of NtDFR, NtANS, and endogenous NtbHLH in transgenic tobacco. The results showed that three homologous genes of StAN1 can regulate anthocyanin biosynthesis, among them StAN1-R1 containing one R has the strongest regulatory capacity.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of Lower Leaf Senescence on Carbon and Nitrogen Distribution and Yield Formation in Maize (Zea mays L.) with High Planting Density

Rong-Fa LI,Peng LIU,Qing-Long YANG,Hao REN,Shu-Ting DONG,Ji-Wang ZHANG,Bin ZHAO

Acta Agronomica Sinica. 2018, 44(7):  1032-1042.  doi:10.3724/SP.J.1006.2018.01032

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Increasing the population density accelerates the senescence of lower leaves, affecting carbon (C) and nitrogen (N) partitioning in maize (Zea mays L.), and also influencing N uptake by roots after silking. We used the maize varieties Denghai 661 and Zhengdan 958 in field and soil column experiments to analyse of changed of C and N distribution, root system function and plant dry matter accumulation in high plant density at post-silking. The chlorophyll content and net photosynthetic rate of the ear leaf showed a significant decrease. Compared with CK, Denghai 661, and Zhengdan 958 decreased the photosynthetic translocation from at lower leaves to roots. Root biomass, root length density and root surface area were also negatively affected post-silking. The reduction of root function significantly reduced nitrogen uptake and leaf photosynthetic rate and leading to accelerate leaf senescence process at post-silking. Grain yield decreased 7.61% in Denghai 661 and 8.35% in Zhengdan 958. Zhengdan 958 had earlier leaf senescence, lower leaf area and net photosynthetic rate than Denghai 661, significantly decreasing dry matter accumulation and yield. In conclusion, lower leaf senescence accelerates root senescence, decreases nitrogen uptake, whole plant green leaves area and photosynthetic duration, eventually reduced dry matter accumulation and yield.

Comparison of Growth Monitoring Index NDVI between GF-1 and MODIS Images in Winter Wheat

Li-Min WANG,Ling-Bo YANG,Jia LIU,Fu-Gang YANG,Bao-Min YAO

Acta Agronomica Sinica. 2018, 44(7):  1043-1054.  doi:10.3724/SP.J.1006.2018.01043

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Crop growth status is one of the major contents of agriculture remote sensing monitoring. For a long time, crop growth status remote sensing monitoring has been mainly based on related vegetation parameters inverted from satellite images, such as normalized difference vegetation index (NDVI), leaf area index (LAI). In this study, we made an attempt to set up a quantitative relation between remote sensing monitored crop growth indices and ground observation indices of actual crop growth, by comparative study of NDVI based on the GF-1 satellite image with resolution of 16 m and the MODIS image with the resolution of 250 m and comprehensive stalk number (CSN), plant height (PH), and leaf chlorophyll concentration (LCC) of winter wheat. GF-1 NDVI had the highest correlation with CSN (R ² = 0.8961), while other indices had relatively low correlation. In contrast, MODIS NDVI had relatively lower correlation with CSN of winter wheat (R ² = 0.4432), and the accuracy in crop growth remote sensing monitoring was relatively low. The average NDVI value of GF-1 pixels within MODIS winter wheat pixels was measured and found to be weakly correlated with MODIS NDVI (R ² = 0.3944). However, the wheat growth monitoring accuracy by MODIS images was improved (R ² = 0.4633) after eliminating the sensor spectral response function difference and scale effects. By ranking the standard deviations of GF-1 NDVI within the MODIS pixels, we found that higher winter wheat growth consistency within MODIS pixels resulted in higher monitoring accuracy of MODIS remote sensing. The NDVI from GF-1 or MODIS image mainly represented CSN, and the NDVI value from higher solution image had a better reflection of actual winter wheat growth. When the winter wheat growth consistency within MODIS pixels was high, the difference of NDVI between MODIS and GF-1 data was small. From the perspective of long term regional growth monitoring, although spectrum and scale normalization can further improve the consistency of monitoring result, the overall accuracy of MODIS NDVI growth monitoring is relatively low. In order to meet the demand of precise monitoring on crop growth, it is necessary to use high-resolution remote sensing data to replace middle- or low-resolution data for crop growth remote sensing monitoring, and take it as the research focus of the business operation of crop growth monitoring.

Fertilizer Response and Its Contribution to Yield of Foxtail Millet under Ridge-furrow Rainfall Harvesting Planting Model in Semi-arid Areas

Xue-Jiao CHEN,Xu-Dong ZHANG,Zhi-Zhong HAN,Peng ZHANG,Zhi-Kuan JIA,Yan-Hao LIAN,Qing-Fang HAN

Acta Agronomica Sinica. 2018, 44(7):  1055-1066.  doi:10.3724/SP.J.1006.2018.01055

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A field experiment was conducted under ridge-furrow rainfall harvesting planting model in 2013 (flood years) and 2014 (drought years) to explore the combined effect of planting model and fertilizer level on yield and fertilizer utilization efficiency of foxtail millet. A two-factor randomized block designed pot with two planting models (rainfall harvesting planting model, R; traditional flat planting model, T) and four fertilizer levels (N 270 kg ha ^-1+P₂O₅ 180 kg ha ^-1, H; N 180 kg ha ^-1+P₂O₅ 120 kg ha ^-1, M; N 90 kg ha ^-1+P₂O₅ 60 kg ha ^-1, L; with no fertilizer as control) was used in the experiment. Plant height, leaf area, photosynthetic rate, water and fertilizer use efficiency, and source of yield increase of foxtail millet were analysed. Compared with T, R effectively promoted the photosynthetic physiology and growth of side row of foxtail millet, increasing plant height by 7.1%-23.5%, the top three leaves area by 1.7%-22.7%, P_n (photosynthetic rate) by 10.4%-20.3%, T_r (transpiration rate) by 8.0%-55.9%, and dry matter by 9.8%-30.0% in different fertilization treatments. There was no significantly difference between the middle rows of R and T on the five indexes. R significantly improved water and fertilizer use efficiency. Application of nitrogen and phosphorus fertilizer significantly improved WUE, in flood years H was significantly higher than M and L, in drought years M was significantly higher than H and no significantly difference with L, Fertilizer use efficiency decreased with the increase of fertilization amount, which was significantly higher in L than in M and H in flood years, with significant difference between the treatments of fertilization in drought years. Effect of fertilizer was bigger than that of planting factor in contribution rate to foxtail millet yield. Contribution rate of fertilization increased by 27.8%-49.3% with increasing fertilizer amount in flood years, with significant, difference among treatments while these was no significant difference in all treatments in the drought years (19.2%-23.7%), Contribution rate of planting model was not significantly different between treatments in two years. Therefore, RH in flood years and RM in drought years could be regarded as a better farming management with high yield and high efficiency in semi-arid area of southern Ningxia.

Effects of Long-Term Irrigation and Nitrogen Regimes on Soil Nitrogen Content and Paste Property of Wheat Grain

Sha-Sha LI,Geng MA,Wei-Xing LIU,Juan KANG,Yu-Lu CHEN,Yang-Yang HU,Pan-Pan ZHANG,Chen-Yang WANG

Acta Agronomica Sinica. 2018, 44(7):  1067-1076.  doi:10.3724/SP.J.1006.2018.01067

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Nitrogen (N) and water contents in soil are primary elements affecting grain yield and quality of wheat. For optimizing the water and fertilizer management in high-quality and high-efficiency wheat production, a split-plot experiment was carried out in the long-term fertilization fields in Wenxian county, Henan province in the 2014-2015 and 2015-2016 winter wheat seasons. The main-plot factor was irrigation in three levels (W0 for no irrigation, W1 for 750 m ³ ha ^-1 at jointing, and W2 for 750 +750 m ³ ha ^-1 at jointing + anthesis), and the split-plot factor was N rate in four levels (0, 180, 240, and 300 kg ha ^-1). Yumai 49-198, a medium-gluten variety, was the unique variety used in the experiment. The soil NO₃ ^--N content in the 0-20 cm soil layer was significantly lower, whereas, the amylopectin and starch contents, starch peak viscosity and final viscosity were significantly higher in W1 and W2 treatments than in W0 treatment. Under irrigation conditions, the volume of small starch granule (<5.0 μm) increased as compared with that under W0 condition, with the increase of 3.4% in W1 and 4.8% in W2 in the 2014-2015 wheat season. Nitrogen application improved soil NO₃ ^--N content but negatively affected amylose content and the percentage of small starch granules. Amylopectin and starch contents, peak viscosity, through viscosity, and final viscosity increased with N application ranging from 0 to 240 kg ha ^-1. The correlation analysis revealed positive correlations (P < 0.01) of NO₃ ^--N with starch yield, peak viscosity, through viscosity, and final viscosity. Results showed that under N 240 kg ha ^-1 and W1 condition the nitrate content in topsoil layer was 19.64-20.55 mg kg ^-1 having higher grain yield and good starch property.

Differences in Physicochemical Properties between Flour and Starch of Wheat Grain

Chun-Yan LI,Wen-Xia ZHANG,Yu-Xue ZHANG,Meng-Hao YAO,Jin-Feng DING,Xin-Kai ZHU,Wen-Shan GUO,Chao-Nian FENG

Acta Agronomica Sinica. 2018, 44(7):  1077-1085.  doi:10.3724/SP.J.1006.2018.01077

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The quality of wheat food products significantly relates to physicochemical properties of starch. Starch components are different between waxy wheat and non-waxy wheat. To realize the different physicochemical properties of flour and grain starch from waxy wheat cultivars (Yangnuomai 1 and Ningnuomai 1) and non-waxy wheat cultivars (Yangmai 16 and Chinese Spring), we tested the pasting and gelatinization properties, thermodynamic properties, swelling power as well as solubility and analyzed the differences between flour and starch. C-type granule (<2 μm) accounted for 96.14% to 97.36% of the total granules among four wheat cultivars, which was the main granule in grain starch. The number percentage of C-type granule in waxy wheat was slightly higher than that in non-waxy wheat. The damaged starch content in grain starch was also lower than that in flour. As compared with flour, grain starch had higher swelling power, transmittance, gelatinization enthalpy (ΔH), degree of retrogradation (DR%), and lower initial gelatinization temperature (T_o), peak temperature (T_p), final temperature (T_c) as well as solubility. Waxy wheat flour had lower damaged starch content, pasting property eigenvalue and degree of retrogradation than non-waxy wheat flour. The α-amylase activity, protein and lipid contents in wheat flour and the added sucrose and sodium chloride all affected the physicochemical properties of wheat flour, which is the main reason causing different physicochemical properties between wheat flour and grain starch.

RESEARCH NOTES

Relationship between Potato Canopy-air Temperature Difference and Drought Tolerance

Bin YU,Hong-Yu YANG,Li WANG,Yu-Hui LIU,Jiang-Ping BAI,Feng ZHANG,Di WANG,Jun-Lian ZHANG

Acta Agronomica Sinica. 2018, 44(7):  1086-1094.  doi:10.3724/SP.J.1006.2018.01086

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The canopy-air temperature difference can reflect the physiological adaptability of plants under drought stress. In this study, drought tolerant varieties Jizhangshu 8 and Longshu 10, drought sensitive varieties Atlantic and Shepody, and ten potato clones with different drought tolerance levels from Peru International Potato Center were used to measure plant phenotypic traits (plant height, leaf area, leaf fresh weight, normalized difference vegetation index), photosynthetic indexes (photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll content) and the canopy-air temperature difference, and evaluated the drought tolerance under semi-arid and semi-humid environments. The canopy-air temperature difference, transpiration rate and stomatal conductance were most sensitive to drought stress. The canopy-air temperature difference was significantly different among different potato varieties (clones) under semi-arid and semi-humid environments. The drought tolerance coefficient of canopy-air temperature difference showed significantly positive correlations with drought tolerance coefficients of plant phenotypic characters and photosynthetic indexes. The canopy-air temperature difference is an effective indicator to evaluate potato drought tolerance by using infrared thermometers, which could provide a theoretical basis for the research of potato drought tolerance breeding.

Development and Validation of Molecular Marker for Protein Content in Tetraploid Potato Tuber

Hong-Bo SHAN,Jia-Wen SHI,Ying SHI

Acta Agronomica Sinica. 2018, 44(7):  1095-1102.  doi:10.3724/SP.J.1006.2018.01095

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Protein content is one of the most important quality traits in potato. In this study, SCAR8-107, a protein content linked molecular marker, was developed using Atlantic, Dingshu 1, and their F₁ segregation population consisting of 173 individuals by reduced-representation sequencing and bulked segregant analysis. A further testing of marker SCAR8-107 was performed using 74 high protein content individuals, 42 low protein content individuals and some tetraploid varieties, showing the selection accuracy of 90.51% and 72.97% between marker test and phenotyping in segregation population and tetraploid varieties respectively. Pearson’s correlation analysis also showed that the marker SCAR8-107 was significantly correlated to protein content in potato. The SCAR8-107 marker could be used in marker-assisted selection.