Table of Content

12 August 2019, Volume 45 Issue 8

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Flowering genes in oilseed rape: identification, characterization, evolutionary and expression analysis

WANG Yan-Hua,XIE Ling,YANG Bo,CAO Yan-Ru,LI Jia-Na

Acta Agronomica Sinica. 2019, 45(8):  1137-1145.  doi:10.3724/SP.J.1006.2019.84159

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Flowering is a prerequisite for successful sexual reproduction. Controlling of flowering time is important for crop production in different geographical regions. However, few information regarding flowering genes or their evolution at genome-wide level in Brassica napus has been reported. In this study, identification, characterization, evolutionary and expression analysis of flowering genes in oilseed rape were performed. In total, 1173 flowering-related genes classified into nine types and distributed unevenly on the chromosomes were identified at the genome level of Brassica napus. Compared with Brassica rapa (AA, 2n = 20) and Brassica oleraca (CC, 2n = 18), B. napus (AACC, 2n = 38) showed significantly enlarge number of flowering-related genes due to natural hybridization and chromosome doubling. Selective pressure analysis showed that the autonomous pathway genes had less selection pressure than the genes involved in sugar metabolic pathway, suggesting that some key flowering-related genes are relatively conserved between B. napus and Arabidopsis thaliana. The present study provides more information on the B. napus flowering pathways and sheds light on the evolutionary relationship of flowering-related genes between B. napus and A. thaliana.

Identification and function analysis of AVP1, VHA-a2, and VHA-a3 genes in Brassica napus L.

YAO Jun-Yue,HUA Ying-Peng,ZHOU Ting,WANG Tao,SONG Hai-Xing,GUAN Chun-Yun,ZHANG Zhen-Hua

Acta Agronomica Sinica. 2019, 45(8):  1146-1157.  doi:10.3724/SP.J.1006.2019.84124

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Vacuoles play an important role in regulating plant cell differentiation and growth. AVP1, VHA-a2, and VHA-a3 genes are important carrier elements for regulating the acid-base balance inside and outside the vacuole of plants and the energy provided by ion transport. In this study, nine BnaAVP1, three BnaVHA-a2, and four BnaVHA-a3 genes were identified in Brassica napus genome database and NCBI plant genome annotation database by using the known AVP1, VHA-a2, and VHA-a3 genes of Arabidopsis thaliana as reference sequences. Bioinformatics studies on copy number variation, molecular characteristics, transmembrane domain, conserved motifs, chromosome localization, phylogenetic tree construction, secondary structure and three- dimensional structure prediction of proteins and high-throughput transcriptome sequencing were carried out, indicating that the number of genes of BnaAVP1 and BnaVHA-a3 was significantly higher than that of B. oleracea and B. rapa; the AVP1, VHA-a2 and VHA-a3 proteins of B. napus belonged to a stable protein composed of acidic amino acids. The analysis of evolutionary selection ability showed that after low nitrogen treatment, BnaAVP1 genes were mainly expressed in shoots, and the expression of BnaAVP1 genes was down-regulated in shoots after three hours of low nitrogen treatment, and up-regulated in roots after 72 hours of low nitrogen treatment. BnaVHA-a2 and BnaVHA-a3 genes were expressed in both shoots and roots, while BnaVHA-a2 genes were up-regulated after 72 hours of low nitrogen treatment, and BnaVHA-a3 genes were down-regulated after three hours of low nitrogen treatment. After low phosphorus treatment, the expression of most BnaAVP1 genes was up-regulated in roots, and no difference in shoots. The expression of BnaVHA-a2 genes was almost no difference, and that of BnaVHA-a3 genes up-regulated in both shoots and roots. This result lays a foundation for further study on the biological functions of AVP1, VHA-a2, and VHA-a3 genes in B. napus and the molecular mechanism that AVP1, VHA-a2, and VHA-a3 proteins hydrolyze ATP to provide energy for plant metabolism, and provides references for other species family genetic bioinformatics studies that are known to have large amounts of data.

Cloning and functional analysis of wheat receptor-like kinase gene TaPK3A

SU Qiang,RONG Wei,ZHANG Zeng-Yan

Acta Agronomica Sinica. 2019, 45(8):  1158-1165.  doi:10.3724/SP.J.1006.2019.81017

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Wheat sharp eyespot has become an important limiting factor of wheat production in China. The precondition for wheat sharp eyespot resistant breeding is to study the molecular basis of wheat defense response and to identify effective resistance genes. In this study, a wheat receptor-like kinase (RLK) gene, named TaPK3A, was cloned from sharp eyespot-resistant wheat line CI12633, and the expression and function of the TaPK3A gene were analyzed. TaPK3A contains an open reading frame with 1983 bp length. It encodes a protein kinase that is consisted of 660 amino acids. RT-qPCR analysis showed that the expression of TaPK3A in sharp eyespot-resistant wheat line CI12633 was significantly induced by the pathogen of sharp eyespot (Rhizoctonia cerealis). The TaPK3A gene was expressed in all the tissues, with the highest expression level in the leaves. The expression of TaPK3A was significantly up-regulated by salicylic acid. By means of barley stripe mosaic virus (BSMV) based virus-induced gene-silencing (VIGS), TaPK3A was silenced in CI12633 plants. After R. cerealis (WK207) inoculation, TaPK3A-silenced CI12633 plants displayed a significant decrease in resistance to R. cerealis infection compared with BSMV: GFP-infected CI12633 plants (control). These results suggested that TaPK3A is required for wheat defense response to sharp eyespot.

Effects of over-expression of AtDREB1A gene on potato growth and abiotic stress resistance gene expression

JIA Xiao-Xia,QI En-Fang,LIU Shi,WEN Guo-Hong,MA Sheng,LI Jian-Wu,HUANG Wei

Acta Agronomica Sinica. 2019, 45(8):  1166-1175.  doi:10.3724/SP.J.1006.2019.84166

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Longshu 3 (L3) and its AtDREB1A transgenic line T2 were planted in the pot experiment. The water content of the soil in pots was controlled to 45%-50% of the maximum water holding capacity (FWC) during the flowering stage of the potato. The phenotype, MDA content, RWC, activities of SOD and POD, and the gene expression level in leaves were analyzed, showing there were no significant differences between the two lines under normal watering conditions. After 20 d of stress treatment, the phenotype of transgenic plants T2 was significantly better than that of control L3, and RWC was significantly higher than that of L3. The MDA content, SOD and POD activities of leaves in each line increased significantly, while the MDA content of transgenic plants increased less than, and the activities of SOD and POD of transgenic plants increased more than those of the control, indicating that the cell membrane damage and membrane lipid peroxidation of the transgenic plants were lighter than those of the control, and the drought tolerance of transgenic plants was significantly improved. Transcriptome sequencing and bioinformatic analysis showed that compared with L3, there were 430 differentially expressed genes in T2, including 287 up-regulated genes and 143 down-regulated genes. Functional annotation and significance enrichment showed that all differentially expressed genes were involved in three broad categories of GO functional classification systems, that was biological processes, cell components and molecular functions. Most of these differentially expressed genes concentrated on the membrane in cells, and mainly related to signal transduction, redox, biological mediation, stress response, development process, system immune process, nucleic acid and protein binding transcription factor activity, transport activity and catalytic activity. The expression of a large number of abiotic stress-related genes was up-regulated, including PPR protein family, P450 protein family, heat shock protein family and MLO protein family, indicating that these genes play a very important role in drought-stress resistance of AtDREB1A transgenic potato. This study lays a foundation for further understanding AtDREB1A’s regulatory network to improve potato drought resistance.

Development of SSR markers and genetic diversity analysis in mung bean

YE Wei-Jun,CHEN Sheng-Nan,YANG Yong,ZHANG Li-Ya,TIAN Dong-Feng,ZHANG Lei,ZHOU Bin

Acta Agronomica Sinica. 2019, 45(8):  1176-1188.  doi:10.3724/SP.J.1006.2019.84155

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SSR markers play an important role in basic research and crop breeding due to their advantages of large number, high polymorphism and co-dominant inheritance. However, there are still few SSR markers available in mung bean. In this study, the magnetic bead enrichment method and sequencing technology were combined to identify the SSR loci of mung bean in high throughput, a total of 3,275,355 SSR loci were found, and 2742 markers were developed. A total of 157 markers were selected for validation by PCR method, 90 (57.33%) showed polymorphic among 10 mung bean accessions. Forty SSR markers with clear PCR products, high polymorphism and uniform distribution on chromosomes were selected to evaluate the genetic diversity among 90 mung bean accessions. The number of alleles per marker varied from two to eight, with an average of three. The effective number of alleles ranged from 1.31 to 4.21, with a mean value of 2.16. The Nei’s gene diversity was between 0.23 and 0.76, with an average of 0.51. Polymorphism information content was between 0.22 and 0.72, with a mean of 0.43. Cluster analysis distributed 90 materials into two clusters, including four groups. The germplasm of group II came from several areas, while those of groups I and III were mainly from North China and Shandong province, respectively. Most of the gerplasm from Hebei province were clustered in Group IV. These polymorphic SSR markers will be valuable for genetic diversity analysis, high-resolution genetic linkage maps construction, gene mapping and marker assisted selection in mung bean breeding.

Potassium uptake and genome-wide association analysis of rice under different nitrogen levels

ZOU Wei-Wei,LU Xue-Li,WANG Li,XUE Da-Wei,ZENG Da-Li,LI Zhi-Xin

Acta Agronomica Sinica. 2019, 45(8):  1189-1199.  doi:10.3724/SP.J.1006.2019.82058

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A total of 134 resequenced rice landraces were used for assessing the potassium content, plant dry weight and potassium accumulation at three different nitrogen levels including no nitrogen fertilizer (N0), 96 kg ha ^-1 (N1), and 192 kg ha ^-1 (N2) under normal field cultivation, respectively. All the three traits displayed normal distribution with abundant variations under N0, N1, and N2 nitrogen levels, respectively. K accumulation and plant dry weight showed positive correlation with nitrogen levels. Meanwhile, the negative correlation was detected between K content and dry weight, and there was positive correlation between dry weight and K accumulation. In addition, the K content showed significantly lower in indica than in japonica, while the dry weight and K accumulation in indica were significantly higher than those in japonica. A total of 12 SNPs presented significant association with the potassium content, plant dry weight and potassium accumulation under three diferent nitrogen levels, including two SNPs for K accumulation, five SNPs for K content and five SNPs for dry weight. A SNP (Chr6_1,524,776) associated with potassium content on chromosome 6 was detected at N1 level. Its flank contained a receptor-like kinase, RUPO, which interacts with potassium transporters in rice. According to the difference of potassium content, one SNP and three SNPs were identified with high nitrogen and low nitrogen response, respectively. While four candidate genes closed to the SNP (Chr10_2,822,026) were associated to K content relatively changed under both high nitrogen and low nitrogen levels, showing different expression levels under different nitrogen levels.

Identification of QTL related to seed size in peanut (Arachis hypogaea L.)

ZENG Xin-Ying,GUO Jian-Bin,ZHAO Jiao-Jiao,CHEN Wei-Gang,QIU Xi-Ke,HUANG Li,LUO Huai-Yong,ZHOU Xiao-Jing,JIANG Hui-Fang,HUANG Jia-Quan

Acta Agronomica Sinica. 2019, 45(8):  1200-1207.  doi:10.3724/SP.J.1006.2019.84173

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Seed size-related traits are the direct factors determining the yield of peanut. To identify the QTL related to seed size-related traits, a recombinant inbred lines (RIL) population (188 progenies) derived from Zhonghua 16 × J11 was used in this study. A genetic linkage map of 947.3 cM in length was constructed, containing 21 linkage groups and 289 SSR markers. Seed size-related traits showed extensive variations in two years’ phenotyping. Between most of the traits with significant correlation. Based on the genetic map, we detected 66 QTL with the explained phenotypic variance (PVE) of 3.23%-33.01% were detected using the WinCart 2.5 software. The number of QTL for seed length (SL), seed width (SW), ratio of seed length to width (LWR) and hundred seed weight (HSW) were 18, 16, 18, and 14, respectively. Notably, the A05A1500-A05A1530 interval on Chromosome A05 harbored three QTL, i.e. qSLA05.1 and qSLA05.2 for SL and qHSWA05.1 for HSW, and the A06B135-A06B113 interval on B06 harbored three QTL as well, i.e. qSWB06.2 and qSWB06.4 for SW and qHSWB06.4 for HSW. These stable and major QTL pave a way for fine mapping of peanut yield-related traits and molecular breeding.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Combined effects of low temperature and weak light at grain-filling stage on rice grain quality

ZHANG Cheng-Xin,GUO Bao-Wei,TANG Jian,XU Fang-Fu,XU Ke,HU Ya-Jie,XING Zhi-Peng,ZHANG Hong-Cheng,DAI Qi-Gen,HUO Zhong-Yang,WEI Hai-Yan,HUANG Li-Fen,LU Yang,TANG Chuang,DAI Qi-Xing,ZHOU Miao,SUN Jun-Yi

Acta Agronomica Sinica. 2019, 45(8):  1208-1220.  doi:10.3724/SP.J.1006.2019.82067

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In recent years, the low temperature and less sunshine occurred frequently during the heading and filling stages of rice in southern China, which affected rice quality. An experiment was conducted with four treatments including low temperature and weak light combined stress (LW), low temperature under normal light (LN), weak light under normal temperature (WN) and normal temperature under normal light (NN) in five periods of grain filling stage (1-7 d, 8-14 d, 15-21 d, 22-28 d, 29-35 d) to research the influences of low temperature and weak light combined stress on rice quality. The chalkiness rate (CR), chalkiness size (CS) and chalkiness degree (CD) among different stress treatments in each period all showed a trend of LW > LN > WN > NN, in which LW in each setting period of grain filling stage was significantly or very significantly different from NN, in each period within 21 days of grain filling stage, LW was also significantly or very significantly different from WN and LN, and single stress was also significantly or very significantly different from NN, except the whiteness in the period of 1-7 d of grain filling stage in 2016. And in each period within 21 days of grain filling stage, there were no significant difference between WN and LN, of which each was significantly different from LW in some periods. The brown rice rate, milled rice rate and head milled rice rate of different stress treatments in each period reflected NN > WN > LN > LW, in which LW, LN, and WN were all significantly or very significantly different from NN in each period within 21 days of grain filling stage and in some periods after 21 days of grain filling stage. Head milled rice rate was affected more deeply than brown rice rate and milled rice rate by the combined stress or single stress, especially at the periods within 21 days of grain filling stage. LW reduced the amylose, gel consistency, appearance, viscosity and taste value of rice significantly or very significantly and increased protein content and hardness significantly or very significantly; WN and LN showed the same influence trend as LW. LW reduced the peak viscosity, trough viscosity and break down of rice significantly except the breakdown of 29-35 d of grain filling stage, and increased final viscosity, set back and peak time significantly too. In general, low temperature and weak light combined stress and single stress deteriorate the rice quality in various degrees during different periods, especially the combined stress within 21 days of grain filling stage.

Establishment and application of spring maize leaf longevity model based on Gaussian function

LI Yao-Yao,FAN Pan-Pan,MING Bo,WANG Chun-Xia,WANG Ke-Ru,HOU Peng,XIE Rui-Zhi,LI Shao-Kun

Acta Agronomica Sinica. 2019, 45(8):  1221-1229.  doi:10.3724/SP.J.1006.2019.83082

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Leaf longevity is a key factor affecting photosynthetic productivity. The quantitative evaluation of canopy leaf longevity is of significance for maize plant growth and yield formation. The experiments were conducted in the experiment station of Institute of Crop Sciences, the Chinese Academy of Agricultural Sciences, Gongzhuling, Jilin province in 2015-2017. The dates of leaf expanded and senesced at each leaf position were recorded from fixed plants of Xianyu 335 and Zhengdan 958. The maize leaf longevity model was established based on Gaussian function ($y=a+b\times {{\text{e}}^{\frac{-{{\left( x-c \right)}^{2}}}{2{{d}^{2}}}}}$) with 2015 and 2016 test data, and validated with 2017 data. The physiological significance of model parameters was specified and the method developing leaf longevity model was simplified. The maize leaf longevity model constructed under the research conditions had good inter-annual stability and large differentiation ability across cultivars. By further analyzing, five turning points were definitely well fitted to establish this model, which greatly simplified the data requirements for developing this model and the possibility of using this model to group the maize leaves was discussed. The five turning points were these calculated by the first derivative (the point for maximum longevity), the second derivative (the point for the highest rate of longevity), and the third derivative (the point for longevity beginning to increase rapidly) equal to zero, also the topmost leaf position (n) and the bottom leaf position. This study provides ideas and methods for analyzing the maize leaf productive ability quantitatively, and the reference for improving various maize growth models and other related researches.

Effects of organic manure combined with nitrogen fertilizer on spring maize yield and soil fertility under drip irrigation

WANG Yan-Li,WU Peng-Nian,LI Pei-Fu,WANG Xi-Na,ZHU Xu

Acta Agronomica Sinica. 2019, 45(8):  1230-1237.  doi:10.3724/SP.J.1006.2019.83080

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The study focused on the problems of poor fertility, low nutrient utilization and weak productivity in sandy soil of Ningxia provinces. A two-year of continuous field positioning experiment designed by split block, the main treatment for non-organic fertilizer (-M) and organic fertilizer 3000 kg hm ^-2(+M) treatment, and the secondary treatment for pure nitrogen of 0 (N0), 75 (N75), 125 (N125), 225 (N225), and 300 (N300) kg hm ^-2, total 5 different nitrogen fertilizer dosages. The aim for this study was to screen the best fertilizer combination for improving soil fertility and achieving high yield, high quality of corn. The application of organic fertilizer combined with nitrogen fertilizer could effectively increase the contents of soil organic matter, total N, total P, available K, and available P, the dry matter accumulation and grain yield of maize, and two treatments of applying organic fertilizer 3000 kg hm ^-2combined with pure nitrogen of 300 kg hm ^-2 and 225 kg hm ^-2 performed the best. There was no significant difference in yield among the treatments of organic fertilizer combined with pure nitrogen of 150, 225, and 300 kg hm ^-2, these three treatments increased maize yield by 74.21%, 91.33%, and 81.23% respectively compared with that of the treatment without organic fertilizer, and the average yield of organic fertilizer treatments was 24.28% higher than that of non-organic fertilizer treatments. Organic fertilizer combined with pure nitrogen of 225 kg hm ^-2 to 300 kg hm ^-2 is recommended in the test area.

Dynamic model of vegetation indices for biomass and nitrogen accumulation in winter wheat

WU Ya-Peng,HE Li,WANG Yang-Yang,LIU Bei-Cheng,WANG Yong-Hua,GUO Tian-Cai,FENG Wei

Acta Agronomica Sinica. 2019, 45(8):  1238-1249.  doi:10.3724/SP.J.1006.2019.81084

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Using remote sensing technology to monitor and timely promote and control wheat growth in real time may improve the yield. In this study, the water-nitrogen coupling test was set up at different locations using a high yield cultivar Zhoumai 27. The suitable vegetation indices for monitoring above ground nitrogen uptake and biomass of winter wheat were selected and the dynamic models with preferred vegetation indices at different yield levels were established. The results showed that (1) different water-nitrogen coupling patterns significantly affected the canopy spectral changes of wheat, with the opposite characteristics at 350-700 nm and 750-900 nm; (2) The modified red-edge ratio (mRER), soil-adjusted vegetation index [SAVI (825, 735)], red edge chlorophyll index (CI_red-edge) and normalized difference spectral index (NDSI) were the main vegetation indices sensitive to the two agronomic growth indices and with a good compatibility, and the stages well correlated with yield were from jointing to mid-filling; (3) the double Logistic model could fit the dynamic changes of vegetation index very well, and the fitting accuracy was higher at high and super high yield levels (R ² > 0.825), but lower at low yield level (R ² = 0.608-0.736). In comparison, CI_red-edge and SAVI (825, 735) were more suitable for evaluating wheat growth. The results of this study are of great significance for evaluating crop yield faced on growing situation in the field, seedling management, and promoting or controlling plant growth according to classification in wheat production.

Effects of tillage and straw returning methods on N₂O emission from paddy fields, nitrogen uptake of rice plant and grain yield

FENG Jun-Heng,HUANG Jin-Feng,LIU Tian-Qi,CAO Cou-Gui,LI Cheng-Fang

Acta Agronomica Sinica. 2019, 45(8):  1250-1259.  doi:10.3724/SP.J.1006.2019.82051

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Conservation tillage is an important practice to improve agricultural soil fertility. However, the effects of this practice on crop nitrogen uptake and grain yield remain unknown. Here, a 2-year field experiment was conducted to investigate the effects of different tillage (conventional intensive tillage [CT] and no-tillage [NT]) and straw returning methods (preceding crop straw returning [S] and removal [NS]) on soil N₂O emission, root nitrate reductase and glutamine synthetase activities, nitrogen uptake of rice plants and grain yield in the 2016 and 2017 rice growing seasons at Huaqiao town, Wuxue county, Hubei province. The tillage practices and straw returning methods had significant effects on the N₂O emission from paddy soil. Compared with CT treatment, NT treatment enhanced the N₂O emission by 12.5%-18.2% in 2016 and 21.1%-38.6% in 2017. S treatments increased the soil N₂O emission by 38.5%-45.5% in 2016 and 13.1%-29.5% in 2017 as compared with NS treatments. Straw returning methods had significant effects on root nitrate reductase and glutamine synthetase activities, as well as on nitrogen uptake of rice plants and grain yield. Compared with NS treatments, S treatments had 6.7%-45.9% higher root nitrate reductase activity and 9.0%-46.7% higher root glutamine synthetase activity, resulting in 12.5%-26.0% higher nitrogen uptake of rice plants and 9.4%- 12.6% greater grain yield. Our results indicate that straw returning significantly increases nitrogen uptake and grain yield, and also promotes soil N₂O emissions, suggesting that the effects of long-term NT and straw returning on global warming potential and soil carbon sequestration should be taken into account when assessing the global warming potential of these practices.

Response of yield and associated physiological characteristics for different wheat cultivars to nitrogen stress at mid-late growth stage

LI Chao-Su,WU Xiao-Li,TANG Yong-Lu,LI Jun,MA Xiao-Ling,LI Shi-Zhao,HUANG Ming-Bo,LIU Miao

Acta Agronomica Sinica. 2019, 45(8):  1260-1269.  doi:10.3724/SP.J.1006.2019.81083

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Soil nitrogen (N) deficiency at mid-late growth stage is one of the serious factors leading to lowered grain yield of wheat. The high yield potential of synthetic hexaploid wheat-derived cultivar (SDC) has been well documented, however, its responses to N deficiency at mid-late growth stage need further study. Six cultivars were grown under two fertilizer-N applied conditions over two consecutive growing seasons (2015-2017). The cultivars consisted of three typical SDC (Chuanmai 42, Chuanmai 104 and Mianmai 367) and three non-synthetic hexaploid wheat-derived cultivar (NSC; Mianmai 37, Chuannong 16, and Chuanmai 30). Two N treatments consisted of normal N application (Nn, 150 kg hm ^-2, basal fertilizer 40%, top dressing 60%) and N stress (Ns, 60 kg hm ^-2, basal fertilizer only), and grain yield and associated physiological traits of these wheat cultivars in response to N deficiency at mid-late growth stage were studied. It turned out that the mean yield reduction of SDC (19.6%) and NSC (20.4%) was close under N stress, while SDC showed 14.4% (Nn) and 15.9% (Ns) advantages on yield than NSC at both N treatments. Besides, the biomass and grain number per unit area of SDC were higher than those of NSC. At anthesis, SDC and NSC had roughly the same leaf area index (LAI) values, whereas the LAI decline in SDC was less than that in NSC at mid-late grain-filling stage. Compared with NSC, the LAI of SDC was 25.1% (Nn) and 16.0% (Ns) higher at 22 days after anthesis, respectively. The SPAD values of flag and penultimate leaves in SDC were always higher than those in NSC at both N treatments during grain filling period, and the gap between them was increased under N stress. The differences in net photosynthetic rate (NPR) and canopy photosynthetic rate (CAP) between the two types of wheat also mainly appeared at mid-late grain-filling stage, and SDC still had advantages compared with NSC under Ns. In addition, the nitrate N, ammonium N and soluble sugar content in flag and penultimate leaves in SDC were higher than those in NSC under N stress condition. At last, SDC had higher N utilization efficiency (NUtE) than NSC, which difference between SDC and NSC was further increased by N stress. Overall, the above results indicate that the productivity of SDC is stronger than that of NSC at low N condition, which might be related to the higher sink capacity and longer leaf function period in SDC.

RESEARCH NOTES

Characteristics and expression analysis of BoPINs family genes in Brassica oleracea

WANG Yu-Kui,ZHANG He-Cui,BAI Xiao-Jing,LIAN Xiao-Ping,SHI Song-Mei,LIU Qian-Ying,ZUO Tong-Hong,ZHU Li-Quan

Acta Agronomica Sinica. 2019, 45(8):  1270-1278.  doi:10.3724/SP.J.1006.2019.84129

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In order to explore the number and expression of the BoPINs gene family participating in self-incompatibilty of Brassica, their expression after self-pollination and cross-pollination were detected by transcriptome analysis, and the corresponding gene structure, phylogenetic tree and expression patterns of the family were further analyzed by bioinformatics. This gene family contained 5-9 exons and 4-8 introns. The amino acid of the encoding protein residues were between 350 and 650 and had molecular weights ranging from 38 kD to 70 kD. Except that BoPIN5 and BoPIN8 did not contain internal hydrophilic cytoplasmic regions, the remaining six BoPINs proteins contained a hydrophobic region at both ends and an internal hydrophilic ring, showing they located on membrane. The evolutionary analysis indicated that BoPINs were closely related to the BrPINs and the AtPINs gene family. Chromosome localization analysis indicated that BoPIN1-1, BoPIN3-1, BoPIN3-2, and BoPIN6 members of the family were linked to S-loucs to different degrees. Tissue-specific expression analysis indicated that BoPIN1-1, BoPIN1-2, BoPIN2, BoPIN3-1, BoPIN3-2, BoPIN4, BoPIN6, BoPIN7-1, and BoPIN7-2 had higher expression levels in the stigma. Data expression profiling and fluorescence quantitative analysis indicated that six of the eight BoPINs genes were down-regulated after self-pollination. All these results indicate that six members of the eight BoPIN gene family members on the membrane may participate in the self-incompatibility response of Brassica oleracea in a negative regulatory manner.

Activity and gene family expression of β-amylase in Brassica napus differing in harvest index

JIN Shu-Rong,WANG Yan-Mei,CHANG Yue,WANG Yue-Hua,LI Jia-Na,NI Yu

Acta Agronomica Sinica. 2019, 45(8):  1279-1285.  doi:10.3724/SP.J.1006.2019.94001

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The transferring efficiency of photosynthate from source organs to grains is the key process to increase the harvest index in Brassica napus, and amylase activity in source organs affects the transport intensity of assimilates to grains. The relationship between β-amylase (BAM) and the formation of high harvest index in rapeseed had not been clear. In this study, three different inbred lines, high-yield and high-harvest index rapeseed, high-yield and low-harvest index rapeseed, and low-yield and low-harvest index rapeseed were selected, and stem, leaf, silique pericarp and seed were sampled at 5, 10, 15, 20, and 25 d after the final flowering to analyze the activity of β-amylase and the expression level of its gene family members. The activity of β-amylase increased with the development of source organs. The activity of β-amylase in leaves and silique pericarps of high-harvest index rapeseed was significantly higher than that of low-harvest index rapeseed. In the β-amylase gene family, the expression of BAM1, BAM4, and BAM5 in the stem, leaf and silique pericarp of rapeseed increased with the development of organs. At 25 d after the final flowering, the expression of BAM1 and BAM3 in leaves and silique pericarps of high-harvest index rapeseed was significantly higher than that of low harvest index rapeseed. The expression of BAM4 and BAM5 in the silique pericarps of rapeseed with high harvest index was significantly higher than that of rapeseed with low harvest index at 15 d and 20 d after the final flowering. Taken together, BAM1 and BAM3 may enhance the transport intensity of photosynthate to grains by promoting starch degradation in leaves and silique pericarps in rapeseed with high harvest index, and BAM4 and BAM5 may regulate the transport of photosynthate to grains mainly by acting on starch degradation in silique pericarps. BAM4 and BAM5 may also be involved in the regulation of starch in rapeseed seeds.

Effects of ridge-furrow mulching on soil enzyme activity, physicochemical properties and yield in continuous cropping potato field

YAO Kai,ZHAO Zhang-Ping,KANG Yi-Chen,ZHANG Wei-Na,SHI Ming-Fu,YANG Xin-Yu,FAN Yan-Ling,QIN Shu-Hao

Acta Agronomica Sinica. 2019, 45(8):  1286-1292.  doi:10.3724/SP.J.1006.2019.94007

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A local variety “Xindaping” was planted in the yield for three-year continuous cropping under six planting patterns, including flat plot without mulching (CK), flat plot with mulching (T1), planting on-ridge with full mulching (T2), planting on-furrow with full mulching (T3), planting on-ridge with half mulching (T4) and planting on-furrow with half mulching (T5). The catalase activity, urease activity and alkaline phosphatase activity were improved under T2, and ridge-furrow plastic-mulching planting pattern reduced soil pH. Especially, T2 has the most obvious effect on the improvement of physicochemical properties of potato rhizosphere soil, and the conductivity was raised by ridge-furrow mulching cultivation pattern. Compared with CK, ridge-furrow plastic-mulching planting pattern significantly increased potato yield, which was up to 75% in T2. This study aims to provide a theoretical basis for overcoming potato continuous cropping obstacles and increasing potato yield in semi-arid areas.