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    12 April 2020, Volume 46 Issue 4
    • CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
      Development of genetically modified maize MIR604 matrix reference materials
      LI Jun,LI Liang,LI Xia-Ying,SONG Gui-Wen,SHEN Ping,ZHANG Li,ZHAI Shan-Shan,LIU Fang-Fang,WU Gang,ZHANG Xiu-Jie,WU Yu-Hua
      Acta Agronomica Sinica. 2020, 46(4):  473-483.  doi:10.3724/SP.J.1006.2020.93047
      Abstract ( 498 )   HTML ( 26 )   PDF (741KB) ( 222 )   Save
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      The safety supervision of genetically modified organisms (GMO) is the guarantee for the healthy development of the biotechnology, and the reference materials (RM) are the material basis for GMOs detection. The lack of RMs makes it difficult to ensure the accuracy, reliability and comparability of the test data. GM maize MIR604 is approved for import as a raw material in China. The safety supervision of GM maize MIR604 urgently requires to prepare RMs. The pure GM maize MIR604 matrix RMs were prepared through the steps of raw material identification, grinding, sieving and water content determination. The results of homogeneity test and stability test showed that the RMs in this batch had good homogeneity within the bottle and between the bottles, the property value of the RMs was stable, allowing them to be transported at room temperature for one month, as even for six months verified by the long-term stability test. The copy number ratio of the transgenic DNA to the total DNA was collaboratively characterized by nine laboratories using the duplex digital PCR of MIR604/Adh1. The certified value was 0.50. The various uncertainty components of the RM characterization results were fully evaluated, and the expanded uncertainty was combined to be 0.06 (copy/copy). The specification of RMs of this batch is 1 g bottle -1 and the minimum sample size is 100 mg. This batch of RMs can be used in the fields of safety supervision and labelling of MIR604, and laboratory quality control.

      Development of novel peanut genotypes with resistance to bacterial wilt disease, large pod, and high shelling percentage
      LI Wei-Tao,XU Zhi-Jun,CAI Yan,GUO Jian-Bin,YU Bo-Lun,HUANG Li,CHEN Yu-Ning,ZHOU Xiao-Jing,LUO Huai-Yong,LIU Nian,CHEN Wei-Gang,REN Xiao-Ping,JIANG Hui-Fang
      Acta Agronomica Sinica. 2020, 46(4):  484-490.  doi:10.3724/SP.J.1006.2020.94112
      Abstract ( 374 )   HTML ( 9 )   PDF (305KB) ( 130 )   Save
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      Bacterial wilt is an important soil-borne bacterial disease effecting yield and quality of peanut. Hundred pod weight and shelling percentage are also related to peanut yield. In this study, the major QTL qBWRB02 related to bacterial wilt resistance was identified by using the RIL population derived from the cross between Yuanza 9102 and Xuzhou 68-4. Combining with the QTL mapping results for shelling percentage and hundred pod weight in previous research, it was found that the major QTL for these three traits were distributed on different chromosomes. Based on genotype data of RIL population and phenotypic data of bacterial wilt resistance, hundred pod weight and shelling percentage in multi-environment, We screened out six novel accessions with resistance to bacterial wilt disease, large pod, and high shelling percentage from RIL population by molecular markers closely linked with major QTL, which can be used as breeding intermediates or parents in peanut breeding for high yield and high disease resistance. The results of effectively screening disease-resistant and high-yield germplasm through the combination of molecular marker-assisted selection and phenotypic identification provide a new idea for peanut breeding in the future.

      Soft wheat quality traits in Jiangsu province and their relationship with cookie making quality
      ZHANG Ping-Ping,YAO Jin-Bao,WANG Hua-Dun,SONG Gui-Cheng,JIANG Peng,ZHANG Peng,MA Hong-Xiang
      Acta Agronomica Sinica. 2020, 46(4):  491-502.  doi:10.3724/SP.J.1006.2020.91050
      Abstract ( 527 )   HTML ( 13 )   PDF (645KB) ( 176 )   Save
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      The objectives of this study were to investigate soft wheat quality traits with fertilizer management practice in southern region of the Huaihe river in Jiangsu province, and to suggest quality selection parameters in soft wheat breeding. Fifteen high quality soft wheat varieties or advanced lines were grown at three environments with the combination of location and year. High-molecular-weight glutenin subunits (HWM-GS) of tested genotypes were identified. Kernel hardness, grain and flour protein content, wet gluten content, ash content, Zeleny sedimentation value, parameters of farinograph, mixograph, and rapid viscocity analysis (RVA), solvent retention capacity (SRC), gluten protein quantification, and cookie quality were investigated. No sample met the national soft wheat quality standard (GB/T 17320-2013, GB/T 17893-1999) for protein content, wet gluten content, and farinograph stability, few samples met the standard for sedimentation value, and all samples exceeded the standard for kernel hardness and farinograph absorption. Kernel hardness, ash content, and RVA parameters were not significantly associated with cookie quality parameters. Zeleny sedimentation value, absorption and stability of farinograph, peak time and right of peak slope of mixograph, water SRC, sodium carbonate SRC, lactic acid SRC, glutenin/gliadin ratio, unextractable polymeric protein (UPP), and %UPP were significantly correlated with cookie diameter, with r = -0.657, -0.601, -0.617, -0.659, -0.676, -0.857, -0.726, -0.616, -0.546, -0.541, and -0.637, respectively (r ≤ -0.520, P < 0.05; r ≤ -0.652, P < 0.01). One multiple regression model only with water SRC as a variable could explain 73.76% of the total variation of cookie diameter, and the other regression model with both water SRC and kernel protein content as variables could explain 83.90% of the total variation. Based on the selection of grain hardness and protein content, reducing gluten strength and general water holding capacity is the main targets in soft wheat breeding program, and water SRC, lactic acid SRC and mixograph parameters are the most important selection parameters.

      Pathogenesis-related protein gene SfPR1a from Salsola ferganica enhances the resistances to drought, salt and leaf spot disease in transgenic tobacco
      HENG You-Qiang,YOU Xi-Long,WANG Yan
      Acta Agronomica Sinica. 2020, 46(4):  503-512.  doi:10.3724/SP.J.1006.2020.94082
      Abstract ( 299 )   HTML ( 8 )   PDF (3929KB) ( 142 )   Save
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      In order to investigate whether SfPR1a, a pathogenesis-related protein gene from an annual halophytic species Salsola ferganica Drob., was involved in the response to plant defense, qRT-PCR was employed to detect its expression patterns under abscisic acid (ABA), jasmonic acid (JAs), ethylene synthesis direct precursor (ACC), and NaCl treatments. We also identified resistances to salt, drought and Pseudomonas syringae tomato (PstDC3000) of transgenic tobacco were identified. The expression of SfPR1a gene in roots was significantly higher than that in shoots, and positively induced by ABA, JAs, ACC, and NaCl treatments. The malondialdehyde (MDA) content of transgenic tobacco was significantly lower than that of wild-type tobacco, showing a strong resistance to drought. The ectopic expression of SfPR1a gene improved plant growth under salt stress. After infection of P. syringae, transgenic tobacco leaves showed serious necrosis reaction, but the overall resistance phenotype of the plants was significantly better than that of WT. Subcellular localization analysis showed SfPR1a was localized in the plant cell apoplastic space. The above results indicated that the SfPR1a gene is involved in plant resistance to abiotic and biotic stresses.

      Genetic stability of wheat-rye 6RS/6AL translocation chromosome and its transmission through gametes
      LI Qing-Cheng,HUANG Lei,LI Ya-Zhou,FAN Chao-Lan,XIE Die,ZHAO Lai-Bin,ZHANG Shu-Jie,CHEN Xue-Jiao,NING Shun-Zong,YUAN Zhong-Wei,ZHAN Lian-Quan,LIU Deng-Cai,HAO Ming
      Acta Agronomica Sinica. 2020, 46(4):  513-519.  doi:10.3724/SP.J.1006.2020.91051
      Abstract ( 746 )   HTML ( 19 )   PDF (1915KB) ( 179 )   Save
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      The wheat-rye 6RS/6AL translocation line HM812-41 harbors the powdery mildew resistance gene Pm56. In order to evaluate the potential utilization in breeding, the translocation line was crossed to common wheat varieties Shumai 580, Shumai 830, and Shumai 969. The F1 hybrids were then reciprocally crossed with Chinese spring to estimate the genetic stability of 6RS/6AL and its transmission rate through male and female gametes in different genetic backgrounds. Double-top crossing (DTC) strategy was used to improve the agronomic traits of the translocation line. Genome in situ hybridization analysis indicated that the 6RS/6AL translocation was very stable during transmission. The 6RS/6AL translocation was transmitted to offsprings with a high frequency, which was 45.05%-53.33% for female gametes and 43.94%-53.04% for male gametes. Based on the agronomical performances of DTC F2 populations, we found that the 6RS/6AL translocation was not linked to obvious defects for major agronomic traits, such as plant height, spike length, spikelet number and seed-setting ratio in selfing. The agronomic traits of the translocation line can be obviously improved through DTC strategy.

      Developing the key germplasm of Chinese peanut landraces based on phenotypic traits
      YAN Cai-Xia,WANG Juan,ZHANG Hao,LI Chun-Juan,SONG Xiu-Xia,SUN Quan-Xi,YUAN Cui-Ling,ZHAO Xiao-Bo,SHAN Shi-Hua
      Acta Agronomica Sinica. 2020, 46(4):  520-531.  doi:10.3724/SP.J.1006.2020.94101
      Abstract ( 464 )   HTML ( 3 )   PDF (2315KB) ( 171 )   Save
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      Chinese peanut landraces are important parent resources in peanut breeding due to their abundant genetic diversity. In this study, a total of 2741 original accessions from peanut seed bank were divided into 26 groups based on their botanical variety and ecological distribution. The key accessions were established based on the analysis of 13 phenotypic traits by the square root strategy, UPGMA clustering within groups and random sampling in individual clusters, and evaluated by t-test, F-test, Chi-squared test, ranging, the ratio of phenotypic retention, and phenotypic correlation analyses. Finally, the principal components analysis (PCA) and the histogram analysis were used to re-confirm the key germplasm. The total of 259 as a key germplasm was selected, accounting for 9.4% of total accessions, which included 14 of var. fastigiata, 85 of var. vulgaris, 42 of var. hirsuta, 103 of var. hypogaea and 15 of irregular type. There were no significant differences (P < 0.05) in means, variance, coefficient of variation, and Shannon-weaver diversity index for 13 phenotypic traits between key germplasm and entire collection. The key germplasm preserved the distribution range, the ratio of phenotypic retention and the phenotypic correlation of primary collection, with similar composition of botanical variety and ecological distribution. PCA and the histogram confirmed the homogeneity of genetic structure and distribution frequency between two collections. Thus, this key germplasm can represent the genetic variability and population structure of entire collection, and enhance innovation of peanut genetic resources and exploitation of elite alleles.

      Genome-wide identification and expression analysis of HD-ZIP I subfamily genes in maize
      LIANG Si-Wei,JIANG Hao-Liang,ZHAI Li-Hong,WAN Xiao-Rong,LI Xiao-Qin,JIANG Feng,SUN Wei
      Acta Agronomica Sinica. 2020, 46(4):  532-543.  doi:10.3724/SP.J.1006.2020.93040
      Abstract ( 637 )   HTML ( 20 )   PDF (2133KB) ( 303 )   Save
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      Transcription factors (TFs) are indispensable regulators of plant response to abiotic stress and play an important role in the whole growth and development process. HD-ZIP proteins constitute a large family of transcription factors that are found only in plants and are divided into four subfamilies (HD-ZIP I-IV). HD-ZIP I subfamily genes mainly participate in response to extreme environments such as drought and osmotic stress and treatments of ABA and ethylene. Here, we identified 17 HD-ZIP I subfamily genes in the maize genome using the hidden Markov model (HMM), which distributed non-uniformly on six chromosomes of maize and were more closely related to rice than to Arabidopsis. Furthermore, these HD-ZIP I subfamily genes exhibited multiple expression patterns in seven tissues, showing strong tissues-specific expression. Moreover, maize HD-ZIP I subfamily genes showed different response patterns and degrees to different stresses, such as high salinity, waterlogging and cold stress. In addition, maize HD-ZIP I subfamily genes also showed a complex response pattern under treatment of five different hormones. These results provide valuable reference information for dissecting function and molecular mechanism of HD-ZIP I subfamily genes in maize.

      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Characteristics of yield components and population quality in high-nitrogen- utilization wheat cultivars
      DING Yong-Gang,LI Fu-Jian,WANG Ya-Hua,TANG Xiao-Qing,DU Tong-Qing,ZHU Min,LI Chun-Yan,ZHU Xin-Kai,DING Jin-Feng,GUO Wen-Shan
      Acta Agronomica Sinica. 2020, 46(4):  544-556.  doi:10.3724/SP.J.1006.2020.91041
      Abstract ( 383 )   HTML ( 26 )   PDF (721KB) ( 417 )   Save
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      In the rice-wheat rotation system, 24 and 23 wheat cultivars were separately planted in Yangzhou and Suining of Jiangsu province in 2016-2017 and 2017-2018. According to nitrogen utilization rate (NUR), these cultivars were clustered into three groups, i.e., NUR-H (NUR ≥ 50%), NUR-M (NUR 40%-50%), and NUR-L (NUR ≤ 40%), to identify the differences in grain yield, yield components, and population quality, which would provide a reference for cultivar selection for high-yield and high-efficiency in wheat production. Yangmai 25 and Ningmai 21 in Yangzhou and Huaimai 35 in Suining showed NUR-H phenotypes in consecutive two years. Grain yield of the NUR-H cultivars was more than 6500 kg hm -2 in Yangzhou and 7000 kg hm -2 in Suining, which were significantly higher than those of NUR-M and NUR-L groups. NUR-H group had more spikes, and it grains per spike and 1000-grain weight were not significantly different from those of the other groups. Grain yield and spikes number were significantly positively correlated with NUR among different cultivars. More stem and tiller number, higher percentage of fertile tillers and higher leaf area index (LAI) at the milk-ripening stage were shown in the NUR-H group. A higher dry matter accumulation at stages of booting, anthesis, and maturity, after anthesis, and in the vegetative organs at maturity were found in the NUR-H group. However, there were no differences in dry matter remobilization and harvest index among different cultivars. Number of stems and tillers at booting and anthesis, LAI at the milk-ripe stage, and dry matter accumulation at each stage after anthesis, and in the vegetative organs at maturity were significantly positively correlated with NUR in the all cultivar in two sites. A vigorous tillering capacity at the early growing phase and a higher LAI and photosynthetic production at the late growth stages could be observed in NUR-H cultivars, resulting in more photosynthate for grain-filling. Furthermore, the critical parameters of cultivar screening for high-yield and high-efficiency in wheat following rice were proposed, that is 16,000-20,000 kg hm -2 dry matter accumulation at maturity and 4100-6700 kg hm -2 dry matter accumulation after anthesis.

      Estimation of total nitrogen content in sugarbeet leaves under drip irrigation based on hyperspectral characteristic parameters and vegetation index
      LI Zong-Fei,SU Ji-Xia,FEI Cong,LI Yang-Yang,LIU Ning-Ning,DAI Yu-Xiang,ZHANG Kai-Xiang,WANG Kai-Yong,FAN Hua,CHEN Bing
      Acta Agronomica Sinica. 2020, 46(4):  557-570.  doi:10.3724/SP.J.1006.2020.94045
      Abstract ( 384 )   HTML ( 5 )   PDF (653KB) ( 150 )   Save
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      The purpose of this paper is to clarify the quantitative relationship between total nitrogen content of sugar beet and high-resolution vegetation remote sensing, to explore the establishment of an optimal estimation model for total nitrogen content of sugar beet, and to monitor the growth of sugar beet. Xinjiang drip-irrigated sugar beet (Beta356) was selected to collect the reflectance spectra of leaf cluster during the leaves rapid growth period, root expansion period and sugar accumulation period by the ASD field hyperspectral apparatus. The total nitrogen content was also measured and the relationship between original spectral reflectance and total nitrogen content was analyzed. According to the correlation between the first-order differential spectral reflectance and total nitrogen content, a total nitrogen content estimation model was established. The model with spectral characteristic parameter Dr762 power function had a good ability to estimate total nitrogen content in leaves of beet, with the determination coefficient, relative error, and root mean square error of 0.747, 21.635, and 4.914, respectively. Various function estimation models were established based on vegetation index and leaf total nitrogen content. The linear function under vegetation index Dr762-Dr496 had better ability to estimate leaf total nitrogen content. Its determinant coefficient, relative error, and root mean square error were 0.794, 23.008, and 5.372, respectively.

      Screening and characterization of high-quality and high-yield japonica rice varieties in Yanhuai region of Anhui province
      WEI Ping-Yang,QIU Shi,TANG Jian,XIAO Dan-Dan,ZHU Ying,LIU Guo-Dong,XING Zhi-Peng,HU Ya-Jie,GUO Bao-Wei,GAO Shang-Qin,WEI Hai-Yan,ZHANG Hong-Cheng
      Acta Agronomica Sinica. 2020, 46(4):  571-585.  doi:10.3724/SP.J.1006.2020.92044
      Abstract ( 615 )   HTML ( 2 )   PDF (317KB) ( 254 )   Save
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      A field experiment was conducted with 74 conventional japonica rice varieties (lines), which were divided into four types according to the yield and taste value, i.e. high yield with good quality (HG), high yield with bad quality (HB), medium yield with good quality (MG), and medium yield with bad quality (MB). Among them, HG, HB, MG were weed to analyze their yield, quality differences and characteristics in HG formation, providing a scientific basis and theoretical support for screening, planting and extending the suitable varieties in Yanhuai area of Anhui province. The yield of MG was 16.95%, 16.76%, and 16.52%, 16.33% lower than that of HG type and HB type, respectively in 2017 and 2018. In 2017, compared with HB type, HG and MG types decreased by 39.31% and 42.63% in amylose content, increased by 22.06% and 19.12% in length of gel consistency, and decreased by 11.60% and 17.78% in protein content. The characteristics of these HG japonica rice varieties were mainly as follows: the yield was 8.35-9.16 t hm -2, the number of panicles per unit area was 310×10 4-320×10 4 hm -2, the grain number per panicle was around 140, the 1000-grain weight was over 25 g; the taste value was 60-74, the length of gel consistency was 80-90 mm, and the protein content was between 6% and 8%.

      Effects of planting density on lodging resistance and straw forage characteristics in two hulless barley varieties
      ZHAO Xiao-Hong,BAI Yi-Xiong,WANG Kai,YAO You-Hua,YAO Xiao-Hua,WU Kun-Lun
      Acta Agronomica Sinica. 2020, 46(4):  586-595.  doi:10.3724/SP.J.1006.2020.91038
      Abstract ( 410 )   HTML ( 11 )   PDF (776KB) ( 188 )   Save
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      Planting density is an important factor affecting the lodging resistance and straw feeding characteristics of hulless barley. Two varieties the lodging-resistant variety Kunlun 14 and the lodging variety Menyuanlianglan, were used to study the effects of planting density on the growth and development, lodging characteristics and straw feeding characteristics. The effects of planting density on two varieties were not entirely consistent. With the increase of planting density, the traits of root and stem increased firstly and decreased then in Kunlun 14, whereas gradually decreased in Menyuanlianglan; and the relative lodging-resistance indexes of Kunlun 14 were increased firstly and decreased then, without lodging occurred, while these in Menyuanlianglan were significantly declined, resulted in lodging in early stage, lodging rate and degree increased; the chemical constituents neutral detergent fiber, acid detergent fiber, cellulose, hemicellulose and lignin in the stem of Kunlun 14 increased firstly and decreased then with the increase of planting density, whereas these of Menyuanlianglan showed a downward trend, with the increased relative feeding value. Based on lodging resistance and straw forage characteristics of two varieties, we concluded that the suitable density of Kunlun 14 should be 3.75×10 6 plants hm -2, and that of Menyuanlianglan for grain and forage should be 3.00×10 6 to 3.75×10 6 plants hm -2.

      Effects of different soil improvement measures on soil physicochemical properties and microbial community structures in mechanically compacted acidified sugarcane field
      LUO Jun,LIN Zhao-Li,LI Shi-Yan,QUE You-Xiong,ZHANG Cai-Fang,YANG Zai-Qi,YAO Kun-Cun,FENG Jing-Fang,CHEN Jian-Feng,ZHANG Hua
      Acta Agronomica Sinica. 2020, 46(4):  596-613.  doi:10.3724/SP.J.1006.2020.94102
      Abstract ( 554 )   HTML ( 11 )   PDF (637KB) ( 263 )   Save
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      Exploring the effects of different soil improvement measures on soil physical properties, soil nutrients, soil microorganisms and sugarcane yield is of great significance to make the improvement strategy for mechanically compacted acidic soil. In the present study, four soil improvement treatments including applications of loosening soil essence (B2), bacterial manure (B3), organic fertilizer (B4), and quicklime (B5) were set up, with no soil amendment as control (B1) to explore the physical properties, nutrients and microorganisms of soil and sugarcane yield components in two successive crop seasons. The application of organic fertilizer (B4) significantly reduced soil bulk density, soil compactness, soil penetration resistance and shear strength resistance and significantly improved total porosity, aeration porosity and pore porosity of soil. The solid-phase volume ratio of soil was significantly lower than that of control, while the liquid-phase volume ratio of soil was significantly higher than that of control, and the organic matter content and total nitrogen of soil were also significantly improved in B2 treatment. The soil compactness and total porosity of B2 and B3 treatments were reduced, improving the soil physical properties to some extent. The soil pH of B5 treatment was significantly improved. The soil available phosphorus content of B3 and B5 treatments was significantly increased. The Shannon index, Chao1 index, and ACE index of soil bacteria and fungi treated with B2, B3, B4, and B5 were higher than those of the control. The four soil improvement measures improved the species diversity and richness of bacteria and fungi in tilled soil layer, reduced the relative abundance of Proteus, Acidobacteria, and basidiomycetes increased the relative abundance of Actinomycetes, Curvularia and ascomycetes, and changed the composition of other fungal communities. These four soil improvement measures improved the number of effective stems and single stem quality of sugarcane at maturity stage to varying degrees, resulting in increased yield of sugarcane. Among them, the effect of organic fertilizer was the best, and followed by that of bacterial manure. This study provides a scientific basis for screening suitable measures to improve the fertility of the mechanically compacted acidic soil, and increase sugarcane yield.

      Effects of density and row spacing on population light distribution and male and female spike differentiation of summer maize in hilly area of central Sichuan
      JIN Rong,LI Zhong,YANG Yun,ZHOU Fang,DU Lun-Jing,LI Xiao-Long,KONG Fan-Lei,YUAN Ji-Chao
      Acta Agronomica Sinica. 2020, 46(4):  614-630.  doi:10.3724/SP.J.1006.2020.93034
      Abstract ( 546 )   HTML ( 8 )   PDF (4468KB) ( 317 )   Save
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      In order to facilitate mechanical production, the corn production in parts of central Sichuan has gradually changed from the intercropping spring planting to the net summer planting. In order to clarify the population structure of the net summer maize for high yield and suitable for mechanization in the region, the effects of density and row spacing on population light distribution and male and female spike differentiation of summer maize were studied with two-factor splitting test design. With the increase of planting density, the maize effective panicle increased, with a gradually decreased increase range, and finally decreased due to the increase of empty stalk and lodging. With the density increased, the angle between stem and leaf and the opening angle decreased, the leaf orientation value increased, the group transmittance decreased significantly, the extinction coefficient increased, and the spike length and middle diameter of the male and female spikes at the panicle differentiation and floret differentiation stages, the tassel spindle length and pairs spikelet number at the silking stage, as well as the total small flower number, the silking floret number, the fertilized floret number and the fertilization rate per plant decreased, while the degraded floret number, the abortive flower number and the abortion rate increased, which eventually led maize bald ear tip become longer, the grain number per panicle and 100-grain weight decreased significantly. With the increase of planting density, the yield increased first and then decreased, with the highest yield under 67,500 plants hm -2. For the average yield of two years, the treatment of 67,500 plants hm -2 had a significant increase of 17.00% and 14.03% compared with the treatments of 45,000 and 90,000 plants hm -2, respectively. In addition, under the density of 45,000 and 67,500 plants hm -2 for two years, the equal row spacing was better than the corresponding wide and narrow rows, and the maize plant type was compact in 60 cm row spacing treatment, which improved group light conditions and fertilization rate per plant, reduced small flower abortion rate, and increased maize yield. Under the density of 90,000 plants hm -2 in 2018, (110+50) cm wide and narrow treatment improved the ventilation and light transmission conditions in the field, promoted the differentiation of female and male ears, and increased the maize yield. Therefore, the high-yield cultivation of summer maize in the central Sichuan area should be performed by properly reducing row spacing and increasing plant density, which are suggested as (60+60) cm and 67,500 plants hm -2 respectively.

      RESEARCH NOTES
      Development and application of SSR loci in monoploid reference genome of sugarcane cultivar
      WANG Heng-Bo,QI Shu-Ting,CHEN Shu-Qi,GUO Jin-Long,QUE You-Xiong
      Acta Agronomica Sinica. 2020, 46(4):  631-642.  doi:10.3724/SP.J.1006.2020.94135
      Abstract ( 425 )   HTML ( 3 )   PDF (1819KB) ( 153 )   Save
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      Sugarcane is one of the most important sugar crops in the world. However, it is difficult to develop SSR on a large scale since the genome of cultivar has not been sequenced, which limits the genetic improvement of sugarcane. In this study, a template of monoploid sugarcane genome was assembled using a set of 4660 BAC library sequences (with a cumulative length of 382 Mb, predicting 25,316 genes) from cultivar ‘R570’. SSR loci were identified by using MISA (Microsatellite identification tool) software. The distribution characteristics of the monoploid genome ‘R570’ was comprehensively analyzed by comparing with the SSR loci of four Gramineae plants (Sorghum bicolor, Zea mays, Oyrza sativa, and Brachypodium distachyon). Fifty pairs of primers with TG and AG repeat motifs were designed to verify the amplification efficiency and polymorphism by PCR amplification in four Saccharum clones (R570, ROC1, LA purple, and SES208) and twenty four core parents of sugarcane. A total of 27,241 SSR loci were identified, with an average of 6.29 SSR loci per BAC clone and an average density of 71.33 SSR Mb -1 which was much lower than that of sorghum (350.00 SSR Mb -1). The mono-nucleotide (11,079) and tri-nucleotide repeat motifs (6447) accounted for 64.33% of the total SSR loci. The number and proportion of tri-nucleotide repeat motifs were the largest in the four Gramineae plants. In addition, A/T (accounting for 84.8%) motif had the highest proportion and C/G (accounting for 15.2%) motif the lowest proportion in the mono-nucleotide repeat motifs and TGT/ACA (accounting for 16.04%) motif had the highest proportion in the trinucleotide repeat motifs. In general, the genomes in Gramineae plants are rich in A/T repeat motifs. In the polymorphism validation of 50 pairs of primers (41 pairs of TG motif and 9 pairs of AG motif), 45 pairs of primers (90%) were found to be able to amplify successfully, of which 35 (70%) were polymorphic in 4 sugarcane clones. Furthermore, 20 pairs of polymorphic SSR primers were used to detect 24 core parents of sugarcane, a total of 95 alleles were amplified with an average of 4.75 alleles per primer, verifying the application feasibility of these primers for the genetic diversity analysis in sugarcane. The development of SSR markers from the monoploid genome of cultivars ‘R570’ not only enriches the number of SSR markers available in sugarcane genetic analysis, but also facilitates the genetic diversity analysis of sugarcane population and the genetic mechanism dissection of important agronomic traits, which provides a foundation for the in-depth research of molecular breeding in sugarcane.

Co-sponsored:
the Crop Science Society of China
the Institute of Crop Science, CAAS
China Science Publishing & Media Ltd.
Published: Science Press
Editor-in-chief: Wan Jian-min
Associate Editors-in-Chief:
Chen Xiao-ya Yang Jian-chang Zhang Xian-long Wang Jian-kang Xu Ming-liang Liu Chun-ming Wang Dao-wen Sun Chuan-qing Ding Yan-feng Jin Wei-wei Chu Cheng-cai Cheng Wei-hong
Director of the editorial department:
Cheng Wei-hong
CN 11-1809/S
ISSN 0496-3490
Post subscription code: 82-336

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  • Started in 2013
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Editor in chief: Wan Jian-min
CN 10-1112/S
ISSN 2095-5421, 2214-5141(online)
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