Table of Content

12 November 2022, Volume 48 Issue 11

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Application of dwarf-male-sterile wheat in breeding program for Fusarium head blight resistance in Southern Yellow-Huai Rivers Valley Winter Wheat Region

ZHOU Yang, ZHANG Hong-Jun, WANG Chen-Yang, LI Hong-Jie, MAI Chun-Yan, YANG Li, LIU Hong-Wei, YU Li-Qiang, YU Guang-Jun, LIU Bing-Hua

Acta Agronomica Sinica. 2022, 48(11):  2683-2690.  doi:10.3724/SP.J.1006.2022.21017

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The dwarf-male-sterile (DMS) wheat has been used as a convenient cross breeding tool. We have upgraded DMS wheat breeding system, which included as follows: (1) development of a series of DMS wheat parental near-isogenic lines by backcrossing the DMS wheat with elite wheat parental varieties; (2) establishment of a large-scale backcrossing population by crossing the DMS wheat parental near-isogenic lines to the cultivars (lines) with the traits of interests in the breeding program; (3) application of marker-assisted selection for the major target genes; (4) induction of DMS double-haploid (DH) lines using maize pollen pollination; and (5) approach of shuttle breeding for off-season traits evaluation. By applying this system, we successfully introduced the Fusarium head blight (FHB) resistance gene Fhb1 into the genetic background of elite wheat varieties in Yellow-Huai River Valley Winter Wheat Region of China. A number of high-yielding and FHB resistance wheat lines were developed with 2-3 years in advance comparing with conventional breeding method. This method significantly increased the breeding efficiency and has a great potential for wheat breeding program.

Genome-wide association study of leaf angle traits and mining of elite alleles from the major loci in maize

QIN Wen-Xuan, BAO Jian-Xi, WANG Yan-Bo, MA Ya-Jie, LONG Yan, LI Jin-Ping, DONG Zhen-Ying, WAN Xiang-Yuan

Acta Agronomica Sinica. 2022, 48(11):  2691-2705.  doi:10.3724/SP.J.1006.2022.23019

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Leaf angle (LA) is one of the important components of the canopy structure in maize, which can directly affect the distribution of light and CO₂ in the canopy and the light capture efficiency of the population, thus affecting the yield of maize. In order to analysis the genetic basis of maize LA traits, an association panel including 854 maize inbred lines was used to analyze the first (ULA1), second (ULA2), and third (ULA3) upper leaf angle of ears in five environments, and then 2795 single nucleotide polymorphic (SNP) markers distributed on 10 chromosomes of maize genome were used for genome-wide association analysis (GWAS) of LA traits based on FarmCPU (fixed and random model circulating probability unification) model. Eighty-one significant SNP associations were identified, among which 26, 27, and 28 significant SNPs associated with ULA1, ULA2, and ULA3, and phenotypic variation explained (PVE) for each SNP was 0.03%-9.68%, 0.06%-9.30%, and 0.01%-8.23%, respectively. We further identified 17 heigh-confidence SNPs repeatedly detected for specific trait, among which three loci were firstly reported in this study, 14 loci located within the intervals that had been previously mapped, and nine SNPs were associated with more than one LA trait. Seven SNPs with PVE > 5% were classified as major SNPs, and thus nine germplasms combining the seven elite alleles with small LAs were isolated. Through searching the candidate regions of the 17 high-confidence SNPs, a total of 131 candidate genes were predicated, and a key gene DRL1 known to regulate LA of maize that located 70 kb downstream of PZE-101039301 on chromosome 1 was also identified as one of candidate genes. In summary, the genetic loci and candidate genes identified by this study will be useful for revealing the genetic mechanism of maize LA traits, and provide clues for cloning LA correlated genes. The identified elite alleles and germplasm resources can be used to increase maize yield by molecular marker-assisted selection of LA traits.

Construction and application of soybean CRISPR/Cas9 multiplex editing vector

CHEN Xiang-Qian, JIANG Qi-Yan, SUN Xian-Jun, NIU Feng-Juan, ZHANG Hui-Yuan, HU Zheng, ZHANG Hui

Acta Agronomica Sinica. 2022, 48(11):  2706-2714.  doi:10.3724/SP.J.1006.2022.14220

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Most members of one gene family have similar function in soybean. Construction of soybean multiplex editing vector to edit multiple genes or gene families have important application value in soybean gene editing and gene functions, especially for the soybean with low transformation efficiency. Here, we reported a CRISPR/Cas9 multiplex editing vector, pCambia3301- Cas9-GmU6n-gDNAn, that enabled the editing of multiple genes in soybean. In this vector, different sgRNAs were driven by different soybean U6 promoters, and multiple sgRNA expression cassettes were assembled into pCambia3301-Cas9 vector by isocaudamers. The result showed that this system could simultaneously produce multiple mutations in soybean hairy roots by targeting multiple GRF genes via single transformation events. This vector can improve the efficiency of gene editing in soybean, and provide a simple toolbox for studying functions of multiple genes and gene families in soybean for basic research and genetic improvement.

Mapping of QTLs for resistance to white-backed planthopper in Guangxi wild rice Y11

YANG Ming, LI Dan-Ting, FAN De-Jia, TAN Song-Juan, CHENG Xia-Nian, LIU Yu-Qiang, WAN Jian-Min

Acta Agronomica Sinica. 2022, 48(11):  2715-2723.  doi:10.3724/SP.J.1006.2022.12040

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White-backed planthopper (WBPH) is one of the most serious pests in rice production. Breeding resistant varieties is the most economical and effective strategy to control the white-backed planthopper. In this study, we found that Guangxi wild rice variety ‘Y11’ had high resistance to white-backed planthopper. The number and survival rate of WBPH were significantly less than the susceptible variety ‘Guanghui 998’. These results showed that ‘Y11’ displayed higher antixenosis and antibiosis against WBPH. Subsequently, ‘Y11’ was as the donor parent and an indica cultivar ‘Guanghui 998’ was as the recurrent parent by continuous backcrossing and selfing to obtain the BC₃F₉ population. Furthermore, to identify the quantitative trait locus (QTL) for white-backed planthopper resistance, we completed the evaluation of this population for WBPH resistance at seedling stage and constructed the genome-wide linkage map. Three QTLs were detected on the three different rice chromosomes, and designed as qWBPH2^Y11, qWBPH6^Y11, and qWBPH11^Y11, respectively. The LOD values were 4.8, 2.5, and 3.7, which accounted for 9.3%, 2.3%, and 5.6% of the phenotypic variation, respectively. All of the resistance alleles were from resistant parent ‘Y11’. Plant harboring qWBPH2 ^Y11 was selected from BC₃F₉ population to continuously backcross with ‘Guanghui 998’. The near isogenic line of qWBPH2 ^Y11 was developed by molecular marker assisted selection, which displayed higher resistance to WBPH than the background parent ‘Guanghui 998’. The mapping of WBPH resistance QTLs and the development of the near isogenic line in this study will be helpful for cloning resistance genes and breeding resistant in rice cultivars.

Genetic analysis of embryo, cytoplasm, and maternal effects for fat and sucrose contents in peanut seed

HU Mei-Ling, XUE Xiao-Meng, WU Jie, ZHI Chen-Yang, LIU Nian, CHEN Xiao-Ping, WANG Jin, YAN Li-Ying, WANG Xin, CHEN Yu-Ning, KANG Yan-Ping, WANG Zhi-Hui, HUAI Dong-Xin, JIANG Hui-Fang, LEI Yong, LIAO Bo-Shou

Acta Agronomica Sinica. 2022, 48(11):  2724-2732.  doi:10.3724/SP.J.1006.2022.14201

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The contents of fat and sucrose are important factors to peanut quality, and revealing their hereditary properties is critical to improve the quality in peanut. In this study, the analysis of embryo, cytoplasm, and maternal effects for fat and sucrose contents in peanut seed were conducted by using general genetic model. Five peanut lines with significantly different fat and sucrose contents were selected as parents for incomplete diallel crosses. The results indicated that the fat content was mainly controlled by embryo additive effect, followed by maternal additive effect. The sucrose content was primarily governed by maternal additive effect. Correlation analysis showed that there was a significantly negative correlation between fat and sucrose contents in peanut seed (r = -0.886^**), which was mostly managed by embryo additive and cytoplasmic effects. Predicted genetic effects suggested that 18-1951 with high fat content and JHT1 with high sucrose content were superior donor parents for improving the contents of fat and sucrose in peanut, respectively.

Differential expressed analysis by transcriptome sequencing in leaves of different ploidy Gossypium herbaceum

YANG Ya-Jie, LI Yu-Ying, SHEN Zhuang-Zhuang, CHEN Tian, RONG Er-Hua, WU Yu-Xiang

Acta Agronomica Sinica. 2022, 48(11):  2733-2748.  doi:10.3724/SP.J.1006.2022.14168

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To investigate the basis for the relative expression level of genes between the phenotypic changes of autopolyploid and the changes of genetic material during chromosome doubling, the differentially expressed genes between autopolyploids and diploids were screened by transcriptome sequencing of G. herbaceum. In this study, the diploid G. herbaceum (CK) and autopolyploid progenies were used as materials, autotriploid (T) and autotetraploid (M) plants were identified by flow cytometry. After the physiological indexes of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), proline, and soluble protein contents of autotetraploids and diploids were compared, and transcriptome sequencing were analyzed. The contents of SOD, POD, CAT, proline, and soluble protein in the leaves of autotetraploids were significantly higher than those of diploids. DESeq difference analysis showed that there were 4166 (2832 up-regulated and 1334 down-regulated), 4037 (1766 up-regulated and 2271 down-regulated), and 4184 (2679 up-regulated and 1505 down-regulated) DEGs, in CK vs T, T vs M, and CK vs M, respectively, and 205 DEGs were common expressed among three groups of pairwise comparison of different ploidy plants. GO function revealed that DEGs had significant differences in intrinsic component of membrane, integral component of membrane, catalytic activity. KEGG enrichment indicated that DEGs was more active than other pathways in flavonoid biosynthesis, phenylpropane biosynthesis, and photosynthesis-antenna protein. Through enrichment analysis, the DEGs related to ploidy in CK vs T and CK vs M were screened, and the results demonstrated that polyploidy were detected mostly up-regulated, in response to stimulus (62.46% and 54.84%), stress (57.42% and 53.85%), cell (70.16% and 66.22%), metabolism (72.73% and 66.14%), biologically active substances and resistance (60.33% and 63.37%), photosynthesis (58.06% and 63.16%), which may be the key factor leading to polyploid advantage. A total of 27 resistance-related genes (19 up-regulated and 8 down-regulated) and 11 photosynthetic-related genes (9 up-regulated and 2 down-regulated) were obtained by Nr annotation CK vs M. Cluster analysis of 27 DEGs related to photosynthesis in different ploidy of G. herbaceum showed that the relative expression of 18 genes (66.67%) had the highest expression abundance in autotetraploids. We performed Nr annotation and expression analysis on 205 DEGs common expressed among three groups, indicating that 30 genes were up-regulated, and the relative expression was the highest in autotetraploids. While 7 genes were down-regulated, and the expression was the lowest in autotetraploids. The 37 genes may be influenced by DNA gene-dose or related to plant ploidy level. The results showed that polyploid plants are superior to diploid plants in terms of resistance, growth vigor, metabolism, and photosynthesis rate.

QTL mapping and candidate genes screening of photosynthesis-related traits in Brassica napus L. during seedling stage under aluminum stress

WU Jia-Yi, YUAN Fang, MENG Li-Jiao, LI Chen-Yang, SHI Hong-Song, BAI Yan-Song, WU Xiao-Ru, LI Jia-Na, ZHOU Qing-Yuan, CUI Cui

Acta Agronomica Sinica. 2022, 48(11):  2749-2764.  doi:10.3724/SP.J.1006.2022.14225

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Due to excessive soil acidification, aluminum in soil has become one of the main factors limiting crop growth and yield. In this study, a high generation of recombinant inbred line (RIL) population constructed from Brassica napus L. varieties Zhongshuang 11 (ZS11) and 10D130 treated with 2400 µmol L^-1 aluminum solution was used as experimental materials. To explore the photosynthetic capacity and chlorophyll fluorescence related traits of rapeseed seedling stage under aluminum toxicity stress, we calculated their relative values (treatment/control) and mapped their QTLs, and screened suitable candidate genes according to the confidence interval of QTLs. The results showed that there was significantly correlation between photosynthetic capacity and chlorophyll fluorescence parameters, but there was no significant correlation between photosynthetic capacity and the chlorophyll fluorescence parameters. Relative P_n, relative G_s, relative C_i, relative Φ_PSII, relative F_v/F_o, relative F_v′/F_m′, relative q_P, relative ETR, relative NPQ, and relative dry weight were investigated and QTLs mapping were analyzed. A total of 16 QTLs related to aluminum stress and photosynthesis were detected. The locus was located on chromosomes A03, A05, A06, A08, A09, A10, C02, and C09, respectively. LOD value was 2.05-3.18, and the phenotypic variation explained was 8.1%-12.3%. The confidence intervals of QTLs for relative G_s and relative F_v'/F_m', relative Φ_PSII and relative ETR were found completely overlap at 106.038-109.129 cM of chromosome A03, 145.355-167.417 cM of chromosome A06, respectively. 47 candidate genes that may be related to aluminum stress and photosynthesis were screened, involving organic acid secretion, metal ion transport, hormone regulation, initiation of antioxidant protection, chloroplast self-regulation, and phosphorus uptake regulation. This study lays the foundation for the function research of aluminum resistance and related photosynthetic genes and the breeding of aluminum tolerant and high photosynthetic efficiency rapeseed.

Downstream target gene network regulated by AhGLK1 and AhHDA1 using ChIP-seq in peanut

LIU Xing, SU Liang-Chen, LI Li-Mei, LI Ling

Acta Agronomica Sinica. 2022, 48(11):  2765-2773.  doi:10.3724/SP.J.1006.2022.14143

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Peanut (Arachis hypogaea L.) is an important economic and edible oil crop whose growth, yield and quality are seriously affected by drought stress. In order to further investigate the mechanism of drought tolerance in peanut, chromatin immunoprecipitation sequence (ChIP-seq) was conducted to analyze immunoaffinity separation of specific binding DNA fragments with AhHDA1 (Arachis hypogaea L. histone deacetylase 1) and transcription factor AhGLK1 (Arachis hypogaea L. Golden2-like 1) for sequence identification, revealing the downstream target gene networks regulated by AhHDA1 and AhGLK1. Through alignment and analysis, 65.71, 63.90, and 70.06 million clean beads were obtained for GLKHDA and input IP from the sequencing run, respectively. The unique alignment of reads to the reference genome sequence were 74.97%, 76.81%, and 76.75%, respectively. GLK-IP obtained 714 peaks and HDA-IP obtained 543 peaks. Peaks were distributed into exons, introns, upstream, downstream, intergenic and other functional elements. GO enrichment revealed that 35.1% and 32.8% of the peak-related genes of AhGLK1-IP and AhHDA1-IP were enriched in “molecular function”. 39.3% and 44.2% were enriched in “biological process” and 25.5% and 22.8% were enriched in “cellular components”, respectively. KEGG pathway enrichment showed that AhGLK1-IP related genes were significantly enriched in metabolic, biosynthesis of antibiotics, glyoxylate and dicarboxylate metabolism, microbial metabolism in diverse environments, carbon metabolism, biosynthesis of secondary metabolites and biosynthesis of amino acids pathways. Whereas, AhHDA1-IP related genes were significantly enriched in N-glycan biosynthesis, arginine, proline and phenylalanine metabolism pathways. Moreover, there were four common peaks enriched both in AhGLK1-IP and AhHDA1-IP. A common conserved motif sequences (AGAA/T) was presented in the motif sequences specifically enriched by AhGLK1-IP and AhHDA1-IP. These results of the study have some reference value for further understanding the functions of AhGLK1 and AhHDA1 genes and the regulatory mechanism of peanuts in response to drought stress and post-drought recovery growth.

Dirigent gene family identification and expression profiling of Vigna angularis responsive to Uromyces vignae infection

KE Xi-Wang, YUAN Meng-Qi, XU Xiao-Dan, YIN Li-Hua, GUO Yong-Xia, ZUO Yu-Hu

Acta Agronomica Sinica. 2022, 48(11):  2774-2785.  doi:10.3724/SP.J.1006.2022.14189

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To clarify the role of Dirigent (DIR) gene family of adzuki bean (Vigna angularis) in response to Uromyces vignae infection, genome-wide identification of the DIR family genes of V. angularis (VaDIRs) was conducted. A total of 33 VaDIRs in the V. angularis genome were identified, among which 29 members were located on 8 chromosomes, respectively. Phylogenetic analysis showed that VaDIRs consisted of 4 subfamilies (DIR-a, DIR-b/d, DIR-e, and DIR-f). Cis-acting elements analysis of the promoter of VaDIRs indicated that all members of VaDIRs contained hormones and pathogen responsive elements. Transcriptomic data of the rust resistant cultivar at different times after inoculation revealed that 17 VaDIRs members were differentially expressed, among which 6 VaDIRs were significantly upregulated at 24 hours post inoculation (hpi), and 2 members were highly expressed both at 24 and 48 hpi. The relative expression of the genes mentioned above were further confirmed in different resistant cultivars responsive to U. vignae infection by qRT-PCR. Results demonstrated that VaDIR14, VaDIR16, and VaDIR33 in resistant cultivar were significantly induced than those in the susceptible cultivar during the fungal infection. In short, our results indicated that members of VaDIRs could be used as positive regulators in resistant cultivar to prevent U. vignae infection.

Genetic diversity and its association analysis of SSR markers with starch content in faba bean (Vicia faba L.)

LIU Yu-Ling, ZHANG Hong-Yan, TENG Chang-Cai, ZHOU Xian-Li, HOU Wan-Wei

Acta Agronomica Sinica. 2022, 48(11):  2786-2796.  doi:10.3724/SP.J.1006.2022.14190

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Starch is the most abundant type of carbohydrate in faba bean grain. In general, starch content affects its physical and chemical properties, thereby affecting the quality and the use of faba bean. Understanding the genetic diversity of faba bean varieties and finding molecular markers closely linked to faba bean starch content are of great significance to the molecular marker-assisted (MAS) breeding of faba bean. In this study, 260 accessions of faba bean germplasm were used as test materials to determine the total starch content, amylose content and amylopectin content in 2019 and 2020. To analyze the genetic diversity and population genetic structure of 260 accessions of faba bean materials, the GLM and MLM models of Tassel 2.1 software were used to analyze the association between markers and starch content using 132 pairs of SSR markers with significant polymorphism. The results showed that the coefficient of phenotypic variation ranged from 13.21% to 20.52% with an average value of 14.85%, indicating that the test population had a certain phenotypic diversity. A total of 629 polymorphic locus were detected by 132 markers in 260 accessions of faba bean materials. The average number of alleles at each site was 4.77, and the range of variation was 2-11. The value of polymorphism information (PIC) was between 0.0385 and 0.7772, with an average of 0.4935. About 50% of the PIC values were greater than the average, indicating that the diversity of markers used in this study was relatively high. Cluster analysis divided 260 materials into three groups. Group I included 42 materials, Group II included 59 materials, and Group III included 159 materials. The classification results reflected the genetic relationship between faba bean varieties. The population genetic structure analysis divided 260 materials into two subgroups, indicating that the test population structure was relatively simple, which was conducive to association analysis. Based on the GLM model and the MLM model, eight markers significantly (P < 0.01) associated with the content of total starch, amylose and amylopectin were detected in two years respectively. The explanation rates of single markers for phenotypic variation were 4.54%-9.04% and 2.69%-10.39%, respectively. The SSR-10927 marker was significantly (P < 0.05) associated with amylopectin content in two years and in both models, and was significantly (P < 0.05) associated with the total starch content in the two models in 2019 and the MLM model in 2020 with the highest detection rate. The results of this study laid a theoretical foundation for faba bean MAS breeding and the selection of parental materials.

Genome-wide identification and expression analysis of BBX gene family in potato (Solanum tuberosum L.)

MA Wen-Jing, LIU Zhen, LI Zhi-Tao, ZHU Jin-Yong, LI Hong-Yang, CHEN Li-Min, SHI Tian-Bin, ZHANG Jun-Lian, LIU Yu-Hui

Acta Agronomica Sinica. 2022, 48(11):  2797-2812.  doi:10.3724/SP.J.1006.2022.14199

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The B-box (BBX) gene family is a type of zinc finger protein transcription factor that plays an important role in the growth and development of plants. In this study, 30 potato BBXs family members (StBBXs) were identified, and their physical and chemical properties, chromosomal location, gene structure, protein conserved domains, gene repetition events, expression patterns, and protein interaction network were analyzed. The results showed that 30 StBBXs were unevenly distributed on 11 chromosomes. According to their gene structures and phylogenetic characteristics, 30 StBBXs were divided into 5 subclasses. Collinearity analysis indicated that there were 15 pairs BBX genes which were orthologous to potato (Solanum tuberosum) and Arabidopsis. We analyzed the relative expression profiles of StBBX genes in different tissues of double haploid (DM) potato, as well as under abiotic stresses and hormone treatments by RNA-seq downloaded from the PGSC (Potato Genome Sequencing Consortium) database. In addition, to explore the relative expression patterns of the StBBX genes in these tissues, we performed RNA-seq on the tuber skin and flesh of three potato varieties with different colors and analyzed their correlations with the expression of key genes for anthocyanin synthesis. Furthermore, the protein interaction network of StBBXs which differentially expressed in color tuber tissues was constructed using String database. These results provide a theoretical basis for further understanding the StBBX gene family, further function of StBBX genes in abiotic stress tolerance and anthocyanin biosynthesis in potato, and StBBX genes in potato might be related to abiotic stress responses and anthocyanin biosynthesis.

Mapping and analysis of QTLs for grain size in rice based on high density genetic map

SONG Bo-Wen, WANG Chao-Huan, ZHAO Zhe, CHEN Chun, HUANG Ming, CHEN Wei-Xiong, LIANG Ke-Qin, XIAO Wu-Ming

Acta Agronomica Sinica. 2022, 48(11):  2813-2825.  doi:10.3724/SP.J.1006.2022.12069

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In this study, QTL mapping of grain size related traits and pyramided effect analysis of different sites were carried out to lay a foundation for marker-assisted breeding and fine mapping of grain size related genes. A total of 192 recombinant inbred lines derived from indica rice cultivars Modasui and Hanghui 315 were planted in three different seasons. A high-density genetic map was constructed based on whole-genome resequencing technology, and the QTLs for grain shape traits were mapped by complete interval mapping (ICIM) and verified by composite interval mapping (CIM). QTL mapping was carried out for grain length, grain width, length-width ratio, 1000-grain weight, cross-sectional area, and grain circumference. 50 and 81 QTLs were detected by ICIM and CIM, respectively, and 43 QTLs could be detected simultaneously. They were clustered on chromosome 2, 3, 5, 7, 8, and 9. Their highest phenotypic contribution rates were 15.74%, 54.07%, and 15.89%, respectively. These loci could be the candidate loci for subsequent gene function studies. According to the genotyping of bin markers, different progenies were divided into Hanghui 315 type and Modasui type in each QTL interval. Further data processing and analysis were performed to analyze the pyramided effect of QTLs. It was found that individuals with more pyramided synergistic alleles showed higher phenotypic values in different environments. The identified lines with multiple synergistic alleles can be used as donor parents in breeding practices.

Effects of shading at grain filling stages on anthocyanin accumulation and related gene expression characteristics in seed coat of black mung bean

MA Chao, FENG Ya-Lan, WU Shan-Wei, ZHANG Jun, GUO Bin-Bin, XIONG Ying, LI Chun-Xia, LI You-Jun

Acta Agronomica Sinica. 2022, 48(11):  2826-2839.  doi:10.3724/SP.J.1006.2022.14172

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To investigate the accumulation of anthocyanin in the seed coat of mung bean and the effects of shading on it, two cultivars with different seed colors (green and black) were both shaded after flowering 5 days under the conditions of field cultivation. The accumulation of various anthocyanin components in seed coat were assessed using spectrophotometry combined with liquid chromatography tandem mass spectrometer. The relative expressions of structural genes and the activity of three anthocyanin synthase enzymes were both analyzed. The results showed that the seed coat of black mung bean began to accumulate anthocyanins at 16 days after flowering (S3 period), and the detectable anthocyanins at the near-mature period (S4 period) were delphinidin (88.67%, main pigment), cyanidin (8.68%), procyanidin (1.05%), petunidin (0.94%), pelargonidin (0.34%), and peonidin (0.32%) according to the proportion of each component. In the black mung bean seed coat at S4 period, the main pigment components of the three anthocyanins were delphinidin-3-O-glucoside (76.61%), cyanidin-3-O-glucoside (89.17%), and procyanidin B3 (28.64%). In general, the relative expression levels of the anthocyanin synthesis structural genes (PAL, C4H, 4CL, CHS, CHI, F3’H, F3’5’H, DFR, LDOX, and UFGT) in the seed coat of black mung bean were significantly higher than green mung bean, among which DFR (37185%), LDOX (4409%), and F3’5’H (3299%) had the largest differential expression multiples. The activities of PAL, CHI, and UFGT in black mung bean seed coat were also greater than those of green mung bean. The relative expression levels of nine anthocyanin synthesis structural genes and the activity of two anthocyanin synthesis-related enzymes were dramatically positively correlated with the contents and the total contents of most anthocyanin components. The relative expression levels of eleven anthocyanin synthesis structural genes and the activities of three anthocyanin synthesis-related enzymes were remarkably reduced under shading conditions, which ultimately led to a noticeable decrease in the content and total amount of anthocyanin components. The results provide a theoretical foundation for the regulation mechanism of black mung bean seed coat coloration, and also contribute to the auxiliary selection of black mung bean breeding.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of polyaspartic acid-chitosan on photosynthesis characteristics and yield in spring foxtail millet

WANG Qi, XU Yan-Li, YAN Peng, DONG Hao-Sheng, ZHANG Wei, LU Lin, DONG Zhi-Qiang

Acta Agronomica Sinica. 2022, 48(11):  2840-2852.  doi:10.3724/SP.J.1006.2022.14224

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To investigate the regulation effect of polyaspartic acid-chitosan (PAC) on photosynthetic characteristics and yield of spring foxtail millet, this experiment was conducted using foxtail millet varieties of Zhangzagu 13 (Z13) and Huayougu 9 (H9) in Gongzhuling Experimental Station of Chinese Academy of Agricultural Sciences (43º29'55"N, 124º48'43"E) in 2020 and 2021. Conventional fertilization (CN) and PAC with fertilization (PN) treatments were set under six nitrogen fertilizer application levels of 0, 75, 112.5, 150, 225, and 337.5 kg hm^-2. The results showed that the photosynthetic rate, SPAD value and soluble protein content of flag leaf, net assimilation rate, leaf area duration, and crop growth rate of foxtail millet of two varieties increased first and then decreased with the increase of nitrogen application. PN could increase SPAD value and soluble protein content of flag leaf at post anthesis stage and photosynthetic rate of flag leaf at anthesis and mid-filling stage under the same nitrogen application level. Meanwhile, the net assimilation rate, leaf area duration, and crop growth rate of foxtail millet were also increased, which promoting the accumulation of population photosynthate. The increase effect of the items above was more significant under the low-middle nitrogen application levels of 75, 112.5, and 150 kg hm^-2. Compared with CN, the yield of Z13 increased by 11.24%-21.55% and 8.65%-14.22% in 2020 and 2021, respectively. The yield of H9 increased by 5.53%-15.75% and 10.43%-16.17% in 2020 and 2021, respectively, compared with CN. Correlation analysis indicated that the yield was significantly positively correlated with net assimilation rate, leaf area duration, crop growth rate, and photosynthetic rate. In conclusion, PAC combined with nitrogen fertilizer could increase the ability to photosynthesize and grain yield under the background of one-time basic fertilizer application, which could be an important technique for achieving high grain yield and efficiency in foxtail millet production in China.

Evaluation on concentration and nutrition of micro-elements in wheat grains in major wheat production regions of China

CHU Hong-Xin, MU Wen-Yan, DANG Hai-Yan, WANG Tao, SUN Rui-Qing, HOU Sai-Bin, HUANG Ting-Miao, HUANG Qian-Nan, SHI Mei, WANG Zhao-Hui

Acta Agronomica Sinica. 2022, 48(11):  2853-2865.  doi:10.3724/SP.J.1006.2022.11099

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Wheat is a kind of staple food crop, and an important source for carbohydrates and microelement for human health. Therefore, it is of great significance to clarify the micronutrient concentration and nutritional status of wheat grain in the major wheat production regions in China, for the purpose of optimizing wheat micronutrient management and maintaining human health. Totally, 1112 wheat and soil samples were collected from 17 major wheat production provinces in China during 2016 to 2020. Microelement concentrations of the samples were determined and nutritional status was evaluated by comparison with the acceptable daily intake value (ADI) according to the human micronutrient intake standard of Chinese Nutrition Society and health risk assessment method of United States Environmental Protection Agency, as well as the dietary habit of Chinese residents. Results showed that the average grain iron (Fe) concentration of wheat in China was 43.8 mg kg^-1 when 72.9% of the samples of Fe concentration was under the lower Fe limit of 50 mg kg^-1, and all the samples were under the upper limit of 140 mg kg^-1. The average grain manganese (Mn) concentration was 43.0 mg kg^-1 when only 4.1% of samples were under the lower limit of 22 mg kg^-1 and 23.7% of samples were above the upper limit of 50 mg kg^-1. The average grain copper (Cu) concentration was 4.6 mg kg^-1 when 7.6% of samples were under the lower limit of 3 mg kg^-1 and no sample was above the upper limit of 10 mg kg^-1. The average grain zinc (Zn) concentration was 31.4 mg kg^-1 when 85.8% of samples were under the lower limit of 40 mg kg^-1 and only 4.1% was above the upper limit of 50 mg kg^-1. The average grain boron (B) concentration was 1.2 mg kg^-1 when 29.2% of samples was under the lower limit of 0.8 mg kg^-1 and no sample was above the upper limit of 10 mg kg^-1. The average grain molybdenum (Mo) concentration was 0.5 mg kg^-1 when 18.8% of samples were under the lower limit of 0.2 mg kg^-1 and only 0.4% of samples was above the upper limit of 2 mg kg^-1. There were regional variations in the contents of wheat grain micronutrient in major wheat production regions in China, among which the contents of Fe and Zn were generally low in most regions, and the contents of B and Mo were insufficient in some areas, while the content of Mn was high, and the content of Cu was basically in the recommended concentration ranges.

Effects of single seed precision sowing on population quality, nutrient utilization of peanut in medium and high yield drylands

WANG Jian-Guo, GENG Yun, YANG Dian-Qing, GUO Feng, YANG Sha, LI Xin-Guo, TANG Zhao-Hui, ZHANG Jia-Lei, WAN Shu-Bo

Acta Agronomica Sinica. 2022, 48(11):  2866-2878.  doi:10.3724/SP.J.1006.2022.14212

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To investigate the suitable single seed precision sowing density in medium and high-yield drylands and provide a theoretical basis for high-yield and high-efficiency cultivation in peanut, the overyielding mechanism of single seed precision sowing was studied by analyzing the differences of individual and population quality and nutrient absorption under different single seed precision sowing planting densities of peanut in medium and high-yield drylands. High-yield drylands were selected in Pingdu (PD) of Shandong province and middle drylands were selected in Jiyang (JY) of Shandong province for field experiments in 2018 and 2019. Three single seed precision sowing density treatments were established. Compared with the double-seed sowing (278,000 plants hm^-2, DS_18.0, CK), three single seed precision sowing treatments were 278,000 plants hm^-2 (SS_9.0), 238,000 plants hm^-2 (SS_10.5), and 208,000 plants hm^-2 (SS_12.0), respectively. Plant spacing of single seed sowing of SS_9.0, SS_10.5, and SS_12.0 treatments in peanut was 9.0, 10.5, and 12.0 cm, and plant spacing of double-seed sowing of DS_18.0 treatment in peanut was 18.0 cm. The results showed that compared with double seed sowing treatment (DS_18.0), single seed precision sowing cultivation improved leaf SPAD, net photosynthetic rate, leaf area index (LAI), the peak value, and duration of leaf area index were higher. Single seed precision sowing exerted the potential of single plant dry matter production, increased the maximum accumulation rate of population dry matter by 6.1% to 20.7%, and realized the rapid accumulation of dry matter. For high-yield drylands in Pingdu, the population dry matter accumulation was SS_12.0>SS_9.0>SS_10.5>DS_18.0 at mature stage, and that was SS_9.0>SS_12.0>SS_10.5>DS_18.0 under middle-yield dryland in Jiyang. Compared with DS_18.0, the population dry matter accumulation of single seed sowing cultivation increased by 5.4%-14.9%. Single seed precision sowing cultivation promoted the absorption and the accumulation of N, P, K, and Ca of individual plants and population plants, and increased the distribution ratio of N and P nutrients to pods, and improved fertilizer utilization efficiency. For high-yield drylands, by increasing individual productivity and increasing the number of full fruits and 100-fruit weight per plant, single seed precision sowing had achieved population yield increase of 13.6%-19.1% (2018) and 15.5%-23.8% (2019), and the suitable single seed precision sowing density was 208,000 plants hm^-2. In the middle yield dryland, single seed precision sowing promoted individual fitness and formed the population advantage of high density, which was the key effect to increase production with an increase of 8.4%-19.4% (2018) and 13.9%-27.8% (2019), and the suitable density was 278,000 plants hm^-2. In conclusion, the population quality and nutrient absorption of high-yield drylands were better than that of middle-yield drylands. The single-seed precision seeding cultivation model can make full use of the production potential of a single plant for medium and high-yield drylands in peanut, promote the accumulation of photosynthetic product and the absorption and utilization of nutrients, and consequently improve the quality of peanuts in both medium and high-yield drylands. This mechanism was characterized by “strong source”, “smooth flow”, and “large sink”. Therefore, this method could help to increase the pod yield and harvest index, and realize the high yield and high efficiency of peanut.

Photosynthetic physiological characteristics of high yield super rice variety Nanjing 5718

WEI Xiao-Dong, ZHANG Ya-Dong, SONG Xue-Mei, CHEN Tao, ZHU Zhen, ZHAO Qin-Yong, ZHAO Ling, LU Kai, LIANG Wen-Hua, HE Lei, HUANG Sheng-Dong, XIE Yin-Feng, WANG Cai-Lin

Acta Agronomica Sinica. 2022, 48(11):  2879-2890.  doi:10.3724/SP.J.1006.2022.12078

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Nanjing 5718 is a rice variety with good eating quality approved by Jiangsu province in 2019 and was confirmed as super rice by the Ministry of Agriculture and Rural affairs in 2021. Studying its yield composition characteristics, photosynthetic characteristics, and physiological basis can be helpful to investigate photosynthetic traits of super rice variety, improve its photosynthetic performance through genetic improvement, and provide the theoretical basis for high-yield breeding and cultivation of japonica rice. In this study, the parents of Nanjing 5718 and Huaidao 5, a widely popularized rice variety with the same growth period type, as the control, dry weight of aboveground of plant, chlorophyll contents, photosynthetic rates, and photochemical characteristics of photosystem II (PSII), core antenna protein expression, photosynthetic enzyme activities, and chloroplast ultrastructure were investigated in Nanjing 5718 from full expansion of flag leaves at the beginning of booting to 35 days after flowering. The results showed the pigment contents of the leaves in Nanjing 5718 were higher, which were close to male parent Yanjing 608. The net photosynthetic rates, dry weight, and PSII electron transfer activities of flag leaves at the late growth stage were significantly higher in Nanjing 5718 than those in parents and Huaidao 5. The light energy conversion performance of PSII was superior. The core antenna protein CP43 and CP47 were more stable under strong light and high temperature, and their adjustment ability of Nanjing 5718 was better than that of parents and Huaidao 5. In addition, the activities of RuBP carboxylase in flag leaves were higher, the contents of photosynthetic products were higher, the chloroplast structure was more stable, the senescence characteristics appeared later, and the chloroplast decay rates were slower in Nanjing 5718, compared with parents and Huaidao 5. The results indicated that high photosynthetic performance of flag leaves was the basis for the formation of high yield characteristics of super rice Nanjing 5718 with large panicles. The great activity and function of photosystem proteins were main factors of improving leaf photosynthesis, and the stability of chloroplast structure could provide powerful support for high photosynthetic efficiency of leaves.

Characteristics of water supply-demand equilibrium and water production benefits of the dryland multiple cropping patterns in the Yangtze River basin

ZHANG Jia-Yun, MA Shu-Mei, YU Chang-Bing, WANG Shu-Bin, WEI Ya-Feng, YANG Wen-Yu, WANG Xiao-Chun

Acta Agronomica Sinica. 2022, 48(11):  2891-2907.  doi:10.3724/SP.J.1006.2022.14206

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The seasonal drought is a serious problem because of the unevenly distributed rainfall during the years in the Yangtze River basin. To construct multi-cropping patterns of intercropping with drought avoidance and disaster reduction as the main body is the fundamental way to realize the efficient utilization of water resources. Therefore, we carried out dryland multiple cropping patterns evaluation in test in the Yangtze River (Sichuan, Hubei, Hunan, Jiangxi, and Jiangsu) from 2016 to 2020, the cropping patterns was set as wheat-summer maize (C1), wheat-summer maize ‖ summer soybean (C2), forage rape-spring maize/summer soybean (C3), and potato-spring maize/summer soybean (C4) in Sichuan. Rape-maize‖summer soybean (B1), forage rape-spring maize ‖ spring soybean (B2), and potato / spring maize / summer soybean (B3) in Hubei; rape-maize ‖ summer soybean (N1), forage rape-spring maize/summer soybean (N2), and forage rape-spring maize ‖ spring soybean-autumn soybean (N3) in Hunan; potato/spring maize/summer soybean (X1), rape-maize ‖ summer soybean (X2), ryegrass-spring maize/summer soybean (X3), and ryegrass-spring maize ‖ spring soybean (X4). Wheat-fresh maize/fresh maize (S1), wheat-fresh maize/fresh soybean (S2), fresh broad bean/fresh maize-fresh maize (S3), and fresh broad bean/fresh maize-fresh soybean (S4) in Jiangsu. We compared the characteristics of supply-demand equilibrium, the paddy of the overall productions and the water benefits of different cropping patterns with the AquaCrop model. These results showed that the water satisfy rate of C4 was 5.28%, 2.91%, and 6.00% higher than C1, C2, and C4, and the paddy of the overall production was 71.2%, 49.3%, and 25.6% higher, respectively, and the water benefit was 329.29%, 123.42%, and 45.52% higher in Sichuan. The water satisfy rate of B3 was 3.99% and 3.51% higher than B1 and B2, and the paddy of the overall production was 36.8% and 25.8% higher, and the water benefit was 295.60% and 69.01% higher in Hubei, respectively. The water satisfy rate of N2 was 9.08% and 2.93% higher than N1 and N3, and the water benefit was 58.47% and 183.33% higher in Hunan, respectively. The water satisfy rate of X1 was 7.94%, 6.70%, and 4.05% higher than X2, X3, and X4, and paddy of the overall production was 112.4%, 152.5%, and 116.8% higher, respectively, and the water benefit was 97.03%, 126.14%, and 77.68% higher in Jiangxi, respectively. The water satisfy rate of S4 was 7.94%, 6.70%, and 4.05% higher than X2, X3, and X4, and paddy of the overall production was respectively 35.4%, 17.5%, and 12.6% higher, and the water benefit was 60.25%, 14.93%, and 45.56% higher in Jiangsu, respectively. Potato-spring maize/summer soybean in Sichuan, potato/spring maize/summer soybean in Hubei, forage rape-spring maize/summer soybean in Hunan, potato/spring maize/summer soybean in Jiangxi and fresh broad bean/fresh maize-fresh soybean in Jiangsu were the appropriate cropping patterns that can improve the water supply-demand equilibrium, paddy of the overall production, and water benefit. To avoid seasonal drought and achieve annual high yield, the appropriate multiple cropping patterns of intercropping should be selected depending on the rainfall conditions in the dryland of the Yangtze River basin.

Effect of potassium application on vascular tissue structure and material transport properties in summer maize (Zea mays L.)

SONG Jie, REN Hao, ZHAO Bin, ZHANG Ji-Wang, REN Bai-Zhao, LI Liang, WANG Shao-Xiang, HUANG Jin-Ling, LIU Peng

Acta Agronomica Sinica. 2022, 48(11):  2908-2919.  doi:10.3724/SP.J.1006.2022.23005

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Field experiments were conducted at the Dongping Agricultural Science Institute, Tai’an city, Shandong province from 2020 to 2021, using Denghai 605 (DH605) as the experimental material. The objective of the study is to explore the effects of K application on vascular system structure and material transport properties in summer maize, five K₂O application rates of 0 kg hm^-2 (K₀), 150 kg hm^-2 (K₁), 225 kg hm^-2 (K₂), 300 kg hm^-2 (K₃), and 375 kg hm^-2 (K₄) were set under uniform N and P fertilizer rates (N 225 kg hm^-2 and P₂O₅ 110 kg hm^-2). The results showed that maize leaf thickness, leaf vein cross-sectional area, and xylem area increased and then decreased with the increase of K application rates, and reached the maximum at K₃ treatment. K application significantly increased the cross-sectional area, the number and area of small and big vascular bundles at the basal stalk and ear-pedicel in maize. The ratio of stalk vascular area to cross-sectional area reached the highest value at K₂ treatment, while the ratio of ear-pedicel vascular was significantly higher in K₂ and K₄ treatments than in other treatments. The number and area of vascular bundles of ear-axis revealed a trend of increasing first and then decreasing with K fertilization, and the total area of vascular bundles was significantly higher in K₂ and K₃ treatments than in other treatments. K application significantly increased the bleeding intensity of stem and ear-pedicel, both of which were the highest under K₂ treatment at filling stage. Correlation analysis revealed that the total area and number of vascular bundles of the stem, the total area and total number of vascular bundles of the ear-pedicel were significantly and positively correlated with grain yield. The total area of vascular bundles of ear-axis were significantly and positively correlated with 1000-grain weight. In conclusion, K₂ conditions promoted the development of the vascular systems in the leaves, stems, and ears of maize, increased the bleeding sap, and enhanced the fluidity of the “flow” system, thus improving grain yield in summer maize.

Effects of soil water deficit and elevated atmospheric CO₂ concentration on leaf photosynthesis of winter wheat

ZHENG Yun-Pu, CHANG Zhi-Jie, HAN Yi, LU Yun-Ze, CHEN Wen-Na, TIAN Yin-Shuai, YIN Jia-Wei, HAO Li-Hua

Acta Agronomica Sinica. 2022, 48(11):  2920-2933.  doi:10.3724/SP.J.1006.2022.11109

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To understand the mechanisms of agricultural ecosystem structure and function in response to soil water deficit under future elevated atmospheric CO₂ concentration, we examined the effects of soil water deficit and elevated CO₂ concentration ([CO₂]) on the stomatal traits, leaf photosynthesis, water use efficiency as well as Rubisco activity and gene expression of winter wheat with environmental growth chambers, whereby the [CO₂] was controlled accurately with CO₂ sensors. Our results showed that water deficit significantly decreased the plant biomass and net photosynthesis rates (P_n) of winter wheat by 33% and 29%, whereas elevated [CO₂] partially mitigated the negative effects of water deficit on plant growth and physiological processes of winter wheat. Meanwhile, water deficit also reduced the stomatal width and regularity of stomatal distribution pattern on winter wheat leaves, but higher [CO₂] could optimize the leaf gas exchange efficiency with more regular distribution pattern of stomata. Moreover, elevated [CO₂] not only enhanced the P_n of winter wheat plants under water deficit, but also substantially reduced the transpiration rates (T_r) by 25%, and thus elevated [CO₂] increased the water use efficiency by 61% when winter wheat plants subjected to water deficit. In addition, elevated [CO₂] boosted the initial activity and activation state of Rubisco as well as soluble protein content by 66%, 38%, and 15%, and meanwhile significantly enhanced the gene expression levels of RbcL3 and RbcS2 by 453% and 417%, respectively. These results suggested that elevated [CO₂] may optimize leaf gas exchange through modifying stomatal traits as well as the activity and gene express of Rubisco, and thus increased plant biomass, P_n, and water use efficiency to efficiently alleviate the physiological stress of water deficit on growth and development processes of winter wheat. Our findings may not only provide data for further understanding the impacts of water deficit on grain yield and water use efficiency of winter wheat under elevated [CO₂], but also have important significance for adaptation management of agricultural ecosystems under global change.

RESEARCH NOTES

Interactions between CMLs and NPG1 and related proteins in pollen germination of Brassica oleracea L. var. capitata

XU Bin, CAO Shao-Yu, SU Tian, PENG Meng-Ling, LYU Xia, LI Zhen-Lin, ZHANG Guo-Ping, XU Jun-Qiang

Acta Agronomica Sinica. 2022, 48(11):  2934-2944.  doi:10.3724/SP.J.1006.2022.14243

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As one of calmodulin families, calmodulin-like (CMLs) regulate plant growth and development, hormone regulation, stresses, which have great significance to the further study of calmodulin-like protein involved in pollen germination and growth. In this study, to explore the interaction between CMLs and NPG1 related genes in pollen development of Brassica oleracea L. var. capitata, and to explore the function of CMLs in pollen development and germination, 12 CMLs genes related to pollen development and germination, and pollen germination genes NPG1, NPGR1, and NPGR2 were cloned from “ZG”. Interactions between them were detected by yeast two-hybrid test. and the relative expression levels of NPG1, NPGR1, and NPGR2 after different pollination time was detected. The results showed that the open reading frames (ORFs) of 12 CMLs genes ranged from 447 bp to 1095 bp, among which CML20, CML48, CML49, and CML50 contained 4 introns, CML21 contained 2 introns, and the others contained no introns. All of them contained no signal peptide and transmembrane domain, all of them were extracellular proteins and hydrophilic proteins which contain 2-4 EF-hands, with amino acids range of 148-364 aa. Subcellular localization was mainly located in cell membrane, vacuole, and nucleus. NPG1, NPGR1, and NPGR2 were clustered on different evolutionary branches, which were the closest to Brassica rape and Brassica napus, and closer to Arabidopsis thaliana. Yeast two-hybrid showed that CML13, CML21, CML24, CML42 could not interact with NPG1, NPGR1, and NPGR2 in vitro, CML15, CML20, CML25, CML39, CML41, CML48, and CML49 could interact with NPG1, NPGR1, and NPGR2, CML50 could interact with NPGR1 and NPGR2, but not with NPG1. The relative expression level of NPG1 increased significantly after pollination, while the relative expression levels of NPGR1 and NPGR2 didn’t change significantly. The relative expression levels of CMLs genes were varied at different pollination times, and CML15, CML20, CML39, CML41, and CML49 were a trend of first increasing and then decreasing. In conclusion, several CMLs proteins were screened which can interact with NPG1 and NPGRs, indicating that CMLs can participate in the process of pollen germination and pollen tube elongation, and it was expected to provide references for the research on the mechanism of Ca²⁺ signaling system participating in pollen germination and pollen tube elongation.

Effects of cadmium stress on root growth of maize (Zea mays L.) varieties with different cadmium-tolerant at seedling stage

QU Meng-Xue, SONG Jie, SUN Jing, HU Dan-Dan, WANG Hong-Zhang, REN Hao, ZHAO Bin, ZHANG Ji-Wang, REN Bai-Zhao, LIU Peng

Acta Agronomica Sinica. 2022, 48(11):  2945-2952.  doi:10.3724/SP.J.1006.2022.13077

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Cadmium pollution in soil is a serious threat to crop production, and it is of great significance for the breeding of new cadmium-tolerant maize varieties. To study the effects on the growth and development of maize roots at seeding stage, the maize varieties with different cadmium tolerance performance were selected as experimental materials. Using cadmium-tolerant variety Xinrui 57 (XR57) and cadmium-sensitive variety Liyuan 296 (LY296) as experimental materials, the differences of root morphology, root respiration, and physiological characteristics between two varieties were investigated by hydroponic culture with different cadmium concentrations (0 mg L^-1 and 10 mg L^-1). The results indicated that the root of the two types of maize varieties accumulated excessive cadmium, which seriously affected the root growth. The cadmium accumulation in the root of LY296 reached 1219.77 μg plant^-1, which was 16.17% higher than that of XR57, indicating the root indexes significantly lower than control. The total root length, total root surface area, total root volume, root dry weight, and lateral root density of nodal root in cadmium stress were decreased by 43.92%, 40.84%, 39.34%, 33.33%, and 62.54%, respectively. After cadmium stress, the variations of cytoprotective enzymes of the two varieties were different. The activities of SOD decreased significantly, XR57 and LY296 decreased by 43.05% and 57.54%, respectively, while the activities of POD and CAT in XR57 both increased significantly, which were 1.26 and 1.58 times higher than control, respectively. The activities of POD and CAT in LY296 had a downward trend, resulting in a significant increase in H₂O₂ content and aggravating oxidative stress. The contents of soluble protein and proline were increased significantly in XR57 roots after cadmium treatment, but LY296 had no significant change. The root respiration rate of both varieties were inhibited by cadmium stress, and the suppression was more pronounced in XR57, which was conducive to reducing the decrease of root biomass. XR57 also further enhanced the antioxidant capacity by increasing the proportion of alternative oxidase respiratory pathway. In conclusion, the cadmium accumulation of root significantly inhibited the growth of maize root at seedling stage, but low cadmium accumulation of the cadmium-tolerant maize variety can regulate the change of root physiological characteristics and the change of root respiration chain transfer pathway to alleviate cadmium poisoning, and it can also breathe through lower consumption by metabolic cost, maintain plant growth and development, while the cadmium-sensitive maize variety had no these advantages.

Relationship between yield differences of different genotypes of oats and leaf physiological characteristics

LIU Yan-Di, ZHAO Bao-Ping, ZHANG Yu, MI Jun-Zhen, WU Jun-Ying, LIU Jing-Hui

Acta Agronomica Sinica. 2022, 48(11):  2953-2964.  doi:10.3724/SP.J.1006.2022.11107

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To understand the effects of leaf physiological characteristics on yield during flowering process in oats, this experiment was conducted in 2020 and 2021, using nine varieties with different sources, maturity, ear type, plant type, and number of spikelets as experimental materials, and variance analysis, principal component analysis, cluster analysis, and other methods are used to analyze the relationship between the yield differences of different genotypes of oats and the physiological characteristics of leaves. The results showed that there were significant differences in the physiological characteristics of different varieties. The grain yield of high-yield varieties and lower-product varieties was significantly higher by 73.61% to 4.78%. The contents of GA₃, ZR, IAA, SPS, SS activities, net photosynthetic rate, the overall level of leaf sucrose content, dry matter accumulation, and ear sucrose assimilation efficiency was better than those of low-yield varieties. Among them, the lower GA₃ content, SPS activity, and net photosynthetic rate product varieties were significantly higher by 49.17% to 13.70%, 33.29% to 4.43%, and 87.88% to 5.72%. The results showed that the number of spikelets, the number of grains per spike, the content of gibberellin in leaves, the activity of sucrose phosphate synthase, and the net photosynthetic rate had the most significant effects on high-yielding varieties. These results indicated that increasing the number of bearing spikelets and the number of grains per ear can be used as a breakthrough to increase yield, appropriately opening the “source” and delaying leaf senescence to ensure the activity of enzymes and hormones, which had a positive impact on yield in oat.