Acta Agronomica Sinica

Table of Content

12 February 2014, Volume 40 Issue 02

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Next-generation Sequencing for Molecular Marker Development in Maize Inbred H99

Lü Yuan-Da,LI Tan,SHI Li,ZHANG Xiao-Lin,ZHAO Han

Acta Agron Sin. 2014, 40(02): 191-197. doi:10.3724/SP.J.1006.2014.00191

Abstract ( 1203 )

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Next Generation Sequencing (NGS) has provided an effective approach to reveal the large scale of DNA polymorphic loci used as molecular markers to distinguish the genetic variations among different genotypes. Maize inbred line H99 is a common transgenic genotype with its desirable regeneration capacity. However, the genome sequence of H99 is unsequenced, which lags the molecular marker development for further maker assisted selection. Here, we used next generation sequencing to resequence H99 whole genome. The contigs assembled with SOAPdenovo2 were further scanned for potential SSR loci by MISA software. Out of 8 268 SSR loci, 4 043 site-specific primers flanking SSR loci were designed and surveyed in silico for locus polymorphism among H99, B73, and Mo17. Around 2 699 SSR loci showed the polymorphism among above three genotypes. Twenty primer pairs from 20 arms of maize chromosomes were selected and validated, and 19 primers amplified the predicted fragments. In addition, we physically mapped and annotated the polymorphic SSR loci, and elucidated the loci distribution in genome. Taken all together, the new developed SSR primers and their information, as a complement to previous ones, were expected to be beneficial to map based cloning and marker-assisted selection.

Relationship between a Water Stress Responsive Protein and Drought Resistance and Molecular Mapping of the Target Gene in Common Wheat

JIN Xiu-Feng,WANG Xian-Guo,REN Wan-Jie,ZHANG Xiao-Ke,XIE Hui-Min,FAN Feng-Gui

Acta Agron Sin. 2014, 40(02): 198-204. doi:10.3724/SP.J.1006.2014.00198

Abstract ( 789 )

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Proteins in response to water stress may closely relate to drought resistance in plants. Genes encoding such proteins are potentially used in wheat breeding aiming to improve drought resistance. The drought resistance of 128 wheat varieties (lines) was identified in two locations in the 2010–2011 growing season. These varieties were then subjected to SDS-PAGE analysis for a ~66.2 kD water stress responsive protein after seedling treatment with -0.5 MPa PEG-6000 for 48 h. Sixty-seven varieties showed expression of the target protein, whereas the remaining 61 varieties absented from the protein expression. Drought resistance index (DI) revealed significant difference between the two groups of varieties (1.00 for protein-positive varieties and 0.80 for protein-negative varieties, P < 0.01), and the ratio of protein-positive varieties in each DI level decreased with the decrease of DI value. A dominate gene was found to encode the ~66.2 kD protein using the F₃ population derived from Jinmai 47 ´ Xinong 2208, which was composed of 230 lines. The target gene was located on chromosome 5AS of wheat, linking to SSR markers Xgwm129, Xgwm304, Xbarc56, Xbarc117,and Xbarc197. The closest flanking markers were Xbarc56 and Xbarc117 with genetic distances of 2.2 cM and 2.9 cM, respectively. To validate the effectiveness of SSR markers, we conducted PCR amplification in the 128 varieties using Xbarc56 and Xbarc117 primers. Sixty-seven varieties amplified the same band as that in Jinmai 47 (high drought resistance), in which 86.6% (58/67) expressed the ~66.2 kD protein after PEG-6000 treatment. Apparently, this ~66.2 kD water stress responsive protein has a close relationship with drought resistance in common wheat, and the SSRs flanking to its coding gene are useful in marker-assisted selection.

Association of Genetic Diversity for Amy6-4 Gene with α-Amylase Activity in Germplasm of Barley

JIANG Xiao-Dong,GUO Gang-Gang,ZHANG Jing

Acta Agron Sin. 2014, 40(02): 205-213.

Abstract ( 854 )

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Amy6-4 is one of the genes codingα-amylase with high isoelectric point, which plays an important role in germination and malting process in barley (Hordeum vulgare L.). To detect the intervarietal polymorphism on Amy6-4 locus, we resequenced the Amy6-4 alleles in 58 barley varieties that are deposited in the germplasm bank of China, and analyzed the association of single nucleotide polymorphisms (SNPs) and haplotypes with α-amylase activity based on the population structure. A total of seven SNPs in five haplotypes were detected among the 58 barley entries. Haplotype H_3 was most popular with frequence of 51.7% (30/58) in the entries tested, and haplotype H_1 ranked the second with frequnce about 39.7% (23/58). However, the remaining three haplotypes only shared about 10% of the frequency. No SNP or haplotype was associated with α-amylase activity.

Dissection of QTLs for Panicle Traits in Rice (Oryza sativa)

WU Ya-Hui,TAO Xing-Xing,XIAO Wu-Ming,GUO Tao,LIU Yong-Zhu,WANG Hui,CHEN Zhi-Qiang

Acta Agron Sin. 2014, 40(02): 214-221. doi:10.3724/SP.J.1006.2014.00214

Abstract ( 1026 )

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Rice yield potential is closely related to panicle traits. QTLs for five panicle traits including panicle length, number of primary branches, number of secondary branches, spikelets per panicle and seed setting density were identified by using 172 plants and 138 plants from a F₂ population derived from a cross between Nipponbare and H71D in 2011 and 2012 respectively. A total of 38 QTLs were detected in the two trials, including 21 QTLs in 2011 and 17 QTLs in 2012, of them four QTLs (only 10.5%) were repeatedly detected in both years. Some QTLs controlling different traits shared the same maker interval on the chromosome with each other, which was consistent with their significant phenotypic correlations. QTLs with large effects are easily to be detected in kinds of populations and different environments. These QTLs provide useful information for meta-analysis and fine mapping, as well as MAS for high-yield rice breeding.

Construction of Molecular Genetic Linkage Map of Sugarbeet

WANG Mao-Qian,LI Bo,WANG Hua-Zhong

Acta Agron Sin. 2014, 40(02): 222-230. doi:10.3724/SP.J.1006.2014.00222

Abstract ( 1041 )

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Molecular genetic map is a fundamental tool for genomic research. In this study, a molecular genetic map was constructed using an F₂ population consisting of 200 individuals from a cross between sugarbeet JV34-2 (the high beet yield and low sugar content line) and sugarbeet 2B023 (the low beet yield and high sugar content line) and a total of 561 SRAP primers and 114 SSR primers. Approximately 56 out of 561 and 20 out of 114 primers, respectively, showed polymorphisms. Each of these polymorphic primers produced at least one scorable polymorphic DNA band which was visible enough for detection and scoring. The map consisted of nine linkage groups which included 141 (123 SRAP and 18 SSR) markers, and covered 1399.88 cM with an average distance of 9.92 cM. Three markers were still unlinked. All nine linkage groups consisting of 3–26 markers were 15.69–237.21 cM in length. Twenty point five six percent partially segregated markers distributed in the map, were mainly located on Ch3 linkage groups, and the others were mapped on Ch1, Ch2, Ch8, and Ch9. This is the first gene map of sugarbeet, constructed by SRAP and SSR markers in China. It will provide the basis for gene mapping of important characters and cloning of excellent gene in sugarbeet.

Isolation of Mesophyll Protoplast and Establishment of Gene Transient Expression System in Cotton

LI Ni-Na,DING Lin-Yun,ZHANG Zhi-Yuan,GUO Wang-Zhen

Acta Agron Sin. 2014, 40(02): 231-239. doi:10.3724/SP.J.1006.2014.00231

Abstract ( 1050 )

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In this paper, taking healthy cotyledon leaves as explants material, combining with the screening of key factors related to isolation and transformation of cotton mesophyll protoplasts, a stable and efficient transient expression and identification system for the target genes was established via transfoming the cotton mesophyll protoplast cells. The major technical system includes: the enzymatic method is used to isolate mesophyll protoplasts. In detail, healthy 12-day-old young cotton cotyledons in natural growth condition were selected as the explant, and were digested with enzyme solution including 1.5% cellulose, 0.4% macerozyme, 0.5 mol L^–1 mannitol, 20 mmol L^–1KCl, 20 mmol L^–1MES, 0.1 mol L^–1CaCl₂, and 1.0 g L^–1BSA for eight hours with gentle shaking at 28℃ and under dark conditions. The concentration of the pure cotton mesophyll protoplasts was more than 1.0×10⁶ mL^–1. Using the system, we integrated a cotton zinc finger protein gene GhZFP2 into pJIT166-GFP plasmid vector, constructed the GhZFP2:GFP fusion vectors, and transformed it into purified cotton mesophyll protoplast mediated with 40% PEG4000. As a result, cotton mesophyll protoplast with high transformation frequency was obtained. Transient expression detection for GhZFP2 protein showed that it was clearly located in the cell nucleus.

Identification of Expressed Resistance Gene Analogues (RGAs) and Development of RGA-SSR Markers in Nicotiana

YUAN Qing-Hua,XIE Rui-Hong,ZHANG Zhen-Chen,MA Zhu-Wen,LI Ji-Qin,LI Shu-Ling,CHEN Jun-Biao

Acta Agron Sin. 2014, 40(02): 240-252. doi:10.3724/SP.J.1006.2014.00240

Abstract ( 1139 )

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Tobacco is an important cash crop and an ideal experimental system for studies on plant-pathogen interaction. Identification of tobacco R gene and resistance gene analogs is propitious to elucidating the underlying resistant mechanisms. In recent years, the growing public tobacco EST data provide rich source for identifying expressed RGA. In this study, 149 606 Uni-EST were assembled from 412 325 ESTs of tobacco in GenBank. By scanning the Uni-EST with 112 plant R gene protein sequences 1113 NtRGAs were identified. These expressed RGAs comprised 273, 546, 53, 102, and 30 of NBS-LRR, LRR-PK, LRR, PK, and Mlo domains encoding R genes, respectively. No domain was detected in the rest of 109 RGAs. By aligning sequence 1079 NtRGAs were allocated on 712 loci in N. benthamiana A total of 78 simple sequence repeats (SSRs) were identified from 72NtRGAs. Sixty-four primer pairs were designed base on the flanking sequence of SSR. Among them, 54 primer pairs were amplified with clear bands from tobacco genomic DNA. Nine primer pairs were detected to have polymorphism among 24 varieties of Nicotiana tabacum with two to four alleles (on average 2.56 alleles). Forty-one primer pairs were detected to have polymorphism among six species in Nicotiana with two to four alleles (on average 2.61 alleles).genome.

Cloning and Expression Analysis of Sugarcane Alkaline/Neutral Invertase (SoNIN1) Gene

NIU Jun-Qi,HUANG Jing-Li,WANG Ai-Qing,YANG Li-Tao,LI Yang-Rui

Acta Agron Sin. 2014, 40(02): 253-263. doi:10.3724/SP.J.1006.2014.00253

Abstract ( 823 )

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Neutral/alkaline invertase irreversibly catalyzes sucrose into glucose and fructose, and plays an important regulating role in plant growth and development. In the present study, the whole length of neutral/alkaline invertase gene cDNA was cloned and sequenced from leaf of sugarcane variety GT28 with RT-PCR (reverse transcription-polymerase chain reaction) and RACE (rapid amplification of cDNA ends), and named as SoNIN1. The gene consists of 2289 bp with an ORF (open reading frame) of 1812 bp encoding a polypeptide of 603 amino acids with calculated protein molecular weight of 67.79 kD, and an isoelectric point of pH 6.41. SoNIN1 gene encodes a protein that is close to that of Zea mays, Oryza sativa, andLolium perenne, belonging to the same evolutionary branch. The putative protein contains the conserved domain of alkaline/neutral invertase, and no membrane-spanning domain and signal peptide at N-end. The gene promoter sequence was cloned by using genome walking, which contains the basic components of CAAT-boxes and TATA-boxes, as well as specific acting elements such as cis-regulatory element involved in meristem activation, methyl jasmonate response and circadian rhythm, plus drought-induced MYB binding sites, abscisic acid response element, gibberellin response element, etc. Real-time PCR results showed that expression of SoNIN1 could be detected in the roots, stalks, leaves, flowers and buds, among which the highest was found in leaves, the medium in buds, and the lowestin internode +1 (enrolled by the top visible dewlap leaf). The expression of SoNIN1 gene in roots and leaves of sugarcane seedling was induced by PEG and NaCl.

Evaluation of Male-Sterility Induction Effect of Various Amino Acid Biosynthesis Inhibiting-Herbicides on Rapeseed (Brassica napus)

YU Cheng-Yu,HE Bei-Ru

Acta Agron Sin. 2014, 40(02): 264-272. doi:10.3724/SP.J.1006.2014.00264

Abstract ( 758 )

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Oilseed rape is very sensitive to most sulfonylurea herbicides. The active constituent of sulfonylurea herbicides is acetolactate synthase (ALS), which catalyzes the common reaction to synthesize three branched-chain amino acids including leucine, valine, and isoleucine in plants. Some sulfonylurea herbicides have strong gametocidal effect on rapeseed. In the present paper, we evaluated the gametocidal effect of 26 herbicides inhibiting the biosynthesis of amino acids after leaf-spraying them at bolting stage of rapeseed (Brassica napus). Application of 6000 mg ha^–1 glufosinate ammonium and 22 500 mg ha^–1 glyphosate, inhibiting the biosynthesis of glutamine and phenylalanine respectively, caused partially male sterile. Except Bispyribac-sodium, Florasulam + flumetsulam, and Ethametsulfuron, the twenty-three ALS-inhibiting herbicides, including eighteen sulfonylureas, two imidazolinones, one sulfonylamino-carbonyltriazolinone, one triazolopyrimidines, and one pyrimidinylthio (or oxy)-benzoate, could induce male sterility in Brassica napus. Among them, Imazethapyr (600 mg ha^–1), Pyrazosulfuron-ethyl (150 mg ha^–1), Nicosulfuron (240 mg ha^–1), Monosulfuron (200 mg ha^–1), and Chlorsulfuron (120 mg ha^–1) had high gametocidal efficiency which was not stable when the dosage changed slightly, indicating that they would be potential CHAs for Brassica napus by fine adjustment of dosage. Foliar application of Tribenuron-methyl or Amidosulfuron at the doses from 60 to 90 mg ha^–1 on 20 Brassica napus varieties (lines) showed 95% male sterility as well as lower phytotoxicity on pistil fertility. In conclusion, Tribenuron-methyl and Amidosulfuron are the best gametocides for Brassica napus among those herbicides. Our findings of gametocidal effect of those chemicals extend the function of ALS-inhibiting herbicides.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of High Temperature Stress at Heading Stage on Pollination and Fertilization of Different Types of Rice Variety

ZHANG Zu-Jian,WANG Qing-Qing,LANG You-Zhong,WANG Chun-Ge,ZHU Qing-Sen,YANG Jian-Chang

Acta Agron Sin. 2014, 40(02): 273-282. doi:10.3724/SP.J.1006.2014.00273

Abstract ( 908 )

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High temperature stress at heading stage is one of the important natural disasters causing the reduction of the seed setting rate of rice in the middle-lower reaches of Yangtze River. This study investigated the effects of high temperature stress at heading stage on fertilization rate of modern rice varieties and combinations, including modern inbred japonica, three-line hybrid indica rice and two-line hybrid indica rice cultivars under the field condition. The modern inbred japonica cultivar showed better high temperature tolerance at heading stage, while the hybrid rice, especially the two-line hybrid indica rice cultivar, was susceptible to high temperature at heading stage, and their fertilization rate was close to zero under 39℃ at heading stage. Shanyou 63 showed well tolerance to moderate high temperature stress, which was decreased rapidly under the severely high temperature. The high temperature tolerance showed the great differences among cultivars under the same treatment. The pollen number per anther in the two tested super two-line hybrid rice was the highest, which was more than 1750. Ningjing 1 had the lowest pollen number, which was only 979.8 per anther. In general, the pollen number per anther in hybrid rice was higher than that in inbred rice, and that in indica higher than that in japonica. The correlation of pollen number per anther was not significant with high temperature tolerance. High temperature stress decreased the anther dehiscence coefficient significantly. Ningjing 1 could maintain certain extent of longitudinal fracture rate under the severely high temperature stress, and more pollen quantity on stigma after anthesis. The results indicated that high temperature tolerance at heading stage is not related with pollen production, but has close relationship with anther dehiscence and pollen quantity on stigma.

Productivity and Eco-physiological Characteristics of Late Japonica Rice in Double-Cropping Rice System

ZHANG Hong-Cheng,XU Ke,ZHANG Jun,LI Guo-Ye,DONG Xiao-Bo,HUA Jin,ZHOU Pei-Jian,CHENG Fei-Hu,HUANG Da-Shan,CHEN Zhong-Ping,CHEN Guo-Liang,FANG Ming-Zhen,DAI Qi-Gen,HUO Zhong-Yang,WEI Hai-Yan,GAO Hui

Acta Agron Sin. 2014, 40(02): 283-300. doi:10.3724/SP.J.1006.2014.00283

Abstract ( 780 )

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In the condition of high yield cultivation,a field experiment was conducted with representative japonica rice cultivars (Wuyunjing 24, Nanjing 44, Zhendao 11, Changyou 1, Changyou 5, Yongyou 8) and the typical local late indica rice cultivars in double-cropping areas (Poyang and Shanggao in Jiangxi Province). Differences of grain yield, quality and net income between japonica and indica were studied systematically. The productivity advantages and its mechanism of late japonica rice were explained from the effects of temperature and light, plant type, and photosynthesis. Results showed that the average yield of late japonica rice in three years was 9.6, 8.3, and 9.9 t ha^-1 respectively, which was higher than that of indica rice significantly. The highest yield of Yongyou 8 in 2011 was 10.6 t ha^-1. The grain number per panicle, seed-setting rate of japonica rice were higher than those of indica rice, which was the reason of higher yield of japonica rice. Milling quality, cooking and eating quality of japonica rice were also better than those of indica rice significantly, while appearance quality showed an opposite tendency. The brown rice rate, milled rice rate, and head rice rate of japonica rice were significantly higher than thoseof indica rice while the amylose content, protein content of japonica rice were significantly lower than thaose of indica rice. And the gel consistency of japonica rice was also longer. The appearance quality including chalky grain rate, chalkiness area and degree of japonicawere significantly higher than those of indica rice. The benefits of late japonica rice were significantly higher than those of indica rice, with the net income of 11890.6, 10252.1, 16565.9 Yuan ha^-1 in these years, respectively, which were higher than those of indica rice by 23.8%, 23.6%, and 26.7% respectively. The physiological and ecological characteristics of productive advantages of late japonica rice in double-cropping rice area were as follows. Firstly, growth duration of japonica rice was longer than that of indica rice significantly and japonica rice was more adapted to grow in cool weather at the later period of grain filling, increasing utilization of temperature and solar radiation and ensuring maturity safely. Secondly, strong photosynthetic capacity of japonica rice at the later period increased dry matter accumulation and total grain filling. Thirdly, japonica rice improved resistances to cold, premature senescence, and lodging due to strong root, stem and sheath.

Effects of Exogenous ABA and 6-BA on Protein Content and Grain Filling Process in Different Types of Stay-Green Wheat

YANG Dong-Qing,LI Yu-Ling,NI Ying-Li,YIN Yan-Ping,YANG Wei-Bing,CUI Zheng-Yong,ZHANG Yong-Tai,MA Ren-Yuan,WANG Zhen-Lin

Acta Agron Sin. 2014, 40(02): 301-312. doi:10.3724/SP.J.1006.2014.00301

Abstract ( 1082 )

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This study aimed to understand the grain filling process and protein biosynthesis in grain of stay-green wheat in response to exogenous hormones. At blooming stage, plants of Wennong 6 (stay-green cultivar) and Jimai 20 (control) were sprayed with 10 mg L^-1 abscisic acid (ABA) and 6-benzyladenine (6-BA) for four days.Compared with Jimai 20, Wennong 6 had longer grain-filling duration (t₃) and the active growth phase (D), higher mean grain-filling rate (G_mean) and maximum grain-filling rate (G_max), larger thousand-grain weight (TGW), and greater grain yield (GY). All parameters for grain filling were higher in superior grain than in inferior grain. G_mean, G_max, TGW, and GY were promoted by ABA or 6-BA treatment in both cultivars. However, the effects of exogenous hormones on t₃ and D were interacted with grain position in a panicle and genotype. Exogenous ABA and 6-BA treatment obviously increased protein content at 35 days after anthesis (DAA). The glutenin contents in ABA-treated and 6-BA-treated Wennong 6 significantly increased at 35 DAA; however, those in Jimai 20 decreased at 35 DAA. Exogenous ABA increased endogenous zeatin (ZR) content from 7 DAA to 21 DAA. In Wennong 6, GA₃ content in superior grain was significantly decreased from 7 DAA to 21 DAA by 6-BA treatment, however, its content in inferior grain was enhanced. In both cultivars, application of ABA and 6-BA resulted in significant increases of endogenous auxin (IAA) and ABA contents from 7 DAA to 21 DAA, along with significant enhancement of glutaminesynthetase (GS) activity.

Regeneration Capacity and Some Affecting Factors of Different Parts of Young Seedlings of Maize (Zea mays L.)

MA Hai-Zhen,ZHU Wei-Wei,WANG Qi-Bai,WANG Guo-Liang,LI Xin-Zhen,QI Bao-Xiu

Acta Agron Sin. 2014, 40(02): 313-319. doi:10.3724/SP.J.1006.2014.00313

Abstract ( 925 )

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Currently, immature embryo is the most widely used explant for maize regeneration and transformation. However, this material source is restricted by geographical condition, developmental stages and the growing season. Here, we isolated different parts the of three-day-old seedlings to study their regeneration capacity, aiming to establish an alternative efficient regeneration system for maize. Using the shoot tips and primary root of three-day-old seedlings of maize germinated in dark and light as explants, the effects of illumination, genotype, and different concentration of Ca²⁺ in the induction medium on the primary callus induction rate and seedling differentiation rate were analysed. The result showed that shoot tips and the root tips derived from seedlings germinated in the dark were better source materials. Root materials isolated from the mature zone of the primary root could not be weed to induce primary callus. The primary callus induction rate was the highest when 5 mmol L^-1 of Ca²⁺ was added in the induction medium. The callus induction and differentiation rates of both explants from the six different genotypes were very different. However, the effect of the genotype on primary callus induction and differentiation rates from the two explants was consistent. The differentiation rate and the morphology of the callus from the two explants of the same genotype were also similar. From above, we propose that the 3-day-old seedlings of Qi319 and Luyuan 92 germinated in the dark have the potential to replace the immature embryos for maize tissue culture in the future.

Response of Soluble Substances Content in Flag Leaves during Late Growth Stage and Plant Productivity of Rice to Elevated CO₂ in North China

WANG Hui-Zhen,ZHAO Hong-Liang,FENG Yong-Xiang,JIANG Le,NING Da-Ke,XIE Li-Yong,LIN Er-Da

Acta Agron Sin. 2014, 40(02): 320-328. doi:10.3724/SP.J.1006.2014.00320

Abstract ( 893 )

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The responses of high yield and good quality japonica varieties Songjing 9 and Daohuaxiang 2 to elevated CO₂ concentration in North China were studied by using FACE experimental system. The soluble sugar content, soluble protein content and total chlorophyll content in flag leaves of rice were measured at late growth stage, rice yield per plot and yield components were measured at harvest stage. The results showed that elevated CO₂ concentration increased soluble sugar content in flag leaf for Songjing 9 and Daohuaxiang 2 obviously during heading stage, milky stage and ripening stage, with the peak value of 11.7% and 47.5%, respectively. Elevated CO₂ concentration obviously reduced soluble protein content in flag leaf during heading stage and ripening stage for Songjing 9 and Daohuaxiang 2, which was 16.2% and 10.5% in the largest reduction, respectively. Elevated CO₂ concentration obviously increased total chlorophyll content in flag leaf for Songjing 9 and Daohuaxiang 2 from heading stage to milky stage, with the largest increase of 18.9% and 22.5%, and then decreased after milk stage. Elevated CO₂ concentration increased seed yield of individual plant, total biomass and economic coefficient with an average of 6.82%, 1.50%, 12.64% for Songjing 9, and 2.56%, 2.13%, 26.05% for Daohuaxiang 2. The results indicated that elevated atmospheric CO₂ concentration increases rice plant productivity, but with diffrence effects on soluble sugar, soluble protein and chlorophyll in flag leaf of different rice varieties at different growth stages. The reason is likely that is elevated atmospheric CO₂ concentration promotes rice growth and development, leading to a early maturity, then senescent leaf promotes soluble sugar’s decomposition, and speeds up transportation of soluble protein from function leaf to seeds.

Variability of Phytate Content and Phytase Activity among Wheat Cultivars from Yellow and Huai River Valleys

LI Ying-Rui,CHEN Ru-Mei,YAN Jun,HE Zhong-Hu,ZHANG Yong

Acta Agron Sin. 2014, 40(02): 329-336. doi:10.3724/SP.J.1006.2014.00329

Abstract ( 918 )

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Phytate content and phytase activity are key factors influencing bioavailability of iron and zinc. To understand the status of phytate content and phytase activity in wheats from the Yellow and Huai River Valleys Winter Wheat Region, 212 representative cultivars and advanced lines were sown in Anyang, Henan province, China in 2009–2010 and 2010–2011 cropping seasons. Phytate content and phytase activity varied greatly among these cultivars, ranging from 2.18 to 13.37 g kg^-1 of phytate content and from 10 to 1759 U kg^-1 of phytase activity, with the mean values of 5.72 g kg^-1 and 657 U kg^-1, respectively. Both indices were significantly affected by genotype and genotype ´ season interaction, with genotype effect being predominant. All cultivars were classified into five groups based on the seasonal standardized values of phytate content and phytase activity, with significant difference among groups. Four cultivars, i.e., Shimai 12, Heng 4568, Luomai 21, and Jimai 096141 exhibited low phytate content and high phytase activity, and can be used in wheat breeding program aiming at improving iron and zinc nutritional quality.

Characteristics of Grain Filling in Wheat Growing in Sichuan Basin

WU Xiao-Li,TANG Yong-Lu,LI Chao-Su,WU Chun,HUANG Gang,MA Rong

Acta Agron Sin. 2014, 40(02): 337-345. doi:10.3724/SP.J.1006.2014.00337

Abstract ( 1067 )

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The growing condition for winter wheat is relatively unfavourable in Sichuan Basin due to less radiation in wheat growing season, drought stress at mid growing stage, and high temperature at late growing stage. Wheat cultivars in this area are commonly characterized with large grain weight and long filling period. Therefore, quality of grain filling is critical to final yield. The objective of this study was to understand the effects of genotype and environment on characteristics of grain filling of wheat in Sichuan Basin. Ten representative cultivars were grown in three locations in 2010–2011 and 2011–2012 wheat growing seasons, and the dynamics of grain filling were observed. The average grain weight was 48.25 g over two years. There were three phases during grain filling, namely grain-filling pyramid period (T₁), grain-filling fast increase period (T₂), and grain-filling slowly increase period (T₃). The durations were sequenced as T₃ (16.30 d) > T₁ (13.41 d) > T₂ (12.98 d), and the grain-filling rates were 0.618, 0.772, and 2.205 mg grain^-1 d^-1, respectively. The contributions of biomass to grain were 21.21% in T₁, 58.27% in T₂, and 20.53% in T₃. Clearly, about 80% of dry matter has been accumulated before T₃ phase. In the same growing season, grain weight and grain-filling rates including maximum, (R_max),mean (R_mean), and phase (R₁, R₂, and R₃) rates of grain filling were mainly influenced by genotype, whereas other parameters for grain filling were mainly influenced by location. Grain weight was significantly correlated with R_mean, R_max, R₂, and R₃. Chuanmai 42, Chuanyu 23, and Chuanmai 56 were characterized with early anthesis, high grain filling speed, long time of grain filling, and large grain weight.

RESEARCH NOTES

Comparison of Winter Rapeseed Varieties (Lines) Different with Cold-Resistance Planted in the Northern-Extending Regions in China under Low Temperature before Winter

LIU Zi-Gang,ZHANG Chang-Sheng,SUN Wan-Cang,YANG Ning-Ning,WANG Yue,HE Li,ZHAO Cai-Xia,WU Jun-Yan,FANG Yan,ZENG Xiu-Cun

Acta Agron Sin. 2014, 40(02): 346-354. doi:10.3724/SP.J.1006.2014.00346

Abstract ( 864 )

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We arranged filed experiments in Tianshui (original planting area), Lintao, Lanzhou, and Yongdeng (extending northern areas), Gansu province, Brassica campestris varieties (lines) to investigate the seedling morphology, photosynthetic parameters, and stomatal morphological characteristics. The results showed that growth habit of winter rapeseed seedlings was changed from suboptimal-erection into prostrate in the northern regions as compared with that grew in the original region. G_s and C_i of leaf were decreased, while T_r was increased in low temperature treatment. When moved to the northern-extended regions, P_n of the cold-sensitive varieties (lines) was decreased, while P_n of strong cold-resistant varieties (lines) was increased. The number of daily emergency of leaf in northern-extended winter rapeseeds was reduced. The root length and root diameter were increased. Stomata of strong cold-resistant varieties (lines) maintained open, while the majority of stomata of weak cold-tolerant varieties (lines) were closed or semi-closed. When moved to northern-extended regions, seedlings of winter rapeseed were prostrate; the photosynthesis of strong cold-resistant cultivars was enhanced, while those of weak cold-tolerant varieties (lines) was reduced. The photosynthates products were preferentially transported into the underground parts and stored in roots.

Comparison and Analysis of Effects of Antisense Oligodeoxynucleotide Inhibition of NtGNL1 in Three Culture Systems of Tobacco

LIAO Fang-Lei,WANG Lu,XIN Ke-Xing,CHEN Wen-Rong,GUO Wei-Dong

Acta Agron Sin. 2014, 40(02): 355-361. doi:10.3724/SP.J.1006.2014.00355

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To develop the antisense oligonucleotide inhibition technology in plant materials, we used the known-function-gene NtGNL1 as the target to establish the optimum application system and further analyze the specific role of NtGNL1. Based on the mRNA of target gene, we designed, commercially synthesized and then applied the antisense oligonucleotide sequences into the in vitro cultured ovules, seeds and pollen tubes to inhibit the expression of NtGNL1. The results revealed that the co-culture of antisense oligodeoxynucleotides hardly affected the pattern formation of the embryos, as well as the seeds germination, despite the expression of NtGNL1 decreasing during short periods. Significantly, the antisense oligodeoxynucleotides down-regulated the expression of target gene in the in vitro cultured pollen tubes. Microscopic time laps observation of pollen tubes by FM4-64 staining indicated that the inhibition also changed the vesicles distribution model and the direction of vesicle trafficking. Furthermore, the mRNA expression of five genes related to membrane trafficking was also analyzed by semi-quantitative PCR, showing that three genes were down-regulated after the antisense oligodeoxynucleotides entered into the pollen tubes. All these results implied that the inhibition of NtGNL1 expression will affect several key points of vesicle trafficking in pollen tubes.

Cation-Responsive Mechanisms of Oats to Alkali Stress

SA Ru-La,LIU Jing-Hui,LIU Wei,BAI Jian-Hui,WANG Zhan-Hai

Acta Agron Sin. 2014, 40(02): 362-368. doi:10.3724/SP.J.1006.2014.00362

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In a pot experiment, an alkali-tolerant oat variety, Vao-9, and an alkali-sensitive variety, Baiyan 5, were exposed to 25, 50, 75, and 100 mmol L^-1 of alkali stress (molar ratio of Na₂CO₃-to=NaHCO₃ = 1:1). The contents of Na⁺, K⁺, Ca²⁺, and Mg²⁺ absorbed by oat seedling and their distribution characteristics in root, stem, and leaf were measured after a short-term (14 d) or a long-term (28 d) stress treatment. The objective was to understand the physiological adaptation to alkali stress in oat in the view of ion balance absorption and distribution. After short-term stress, the cation contents in oat plants showed the variations of increased Na⁺, decreased K⁺, and minor changes in Ca²⁺ and Mg²⁺. Besides, the distribution proportions of the four ions in various organs were not significantly different between the two varieties. Compared to short-term stress, long-term stress resulted in larger increase of Na⁺ content and larger decreases of K⁺, Ca²⁺, and Mg²⁺ contents in all organs of both varieties. Vao-9 absorbed more Na⁺and Ca²⁺ than Baiyan 5, and the absorptions of K⁺ and Mg²⁺ were not significantly different between varieties, but the distribution characteristics of the four ions in various organs were different between the two varieties.Under 100 mmol L^-1 alkali stress, 5.9 percent Na⁺ in leaf were lower distributed and 13.5 percent K⁺, 28.9 Ca²⁺, 10.9 Mg²⁺ more distributed in Vao-9 than in Baiyan 5, 5.4 percent Na⁺ in stem higher and 9.8 K⁺lower in Vao-9 than in Baiyan 5 , 28.9 Ca²⁺, 10.9 Mg²⁺ in root were lower in Vao-9 than in Baiyan 5, As a result, the Na⁺ content and the ratios of Na⁺/K⁺, Na⁺/Ca²⁺, and Na⁺/Mg²⁺ in leaf were lower in Vao-9 than in Baiyan 5. Clearly, oat plant has the mechanism of selective absorption and distribution of various cations in different organs in response to alkali stress.

Genetic Diversity Analysis on Local Upland Cotton Cultivars in Xinjiang Based on SSR Markers

AI Xian-Tao,LIANG Ya-Jun,SHA Hong,WANG Jun-Duo,ZHENG Ju-Yun,Tu-Er-Xun-Jiang,DUO Li-Kun,LI Xue-Yuan,HUA Jin-Ping

Acta Agron Sin. 2014, 40(02): 369-379. doi:10.3724/SP.J.1006.2014.00369

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Xinjiang, the largest prior cotton production region in China, has made remarkable genetic improvement in upland cotton (Gossypium hirsutum L.). There has been a substantial raise in yield potential, cotton-planting area and total production in Xinjiang since 1970s. The new upland cotton cultivars have contributed a lot to yield increase, in which Xinjiang-bred upland cotton varieties play an important role in cotton production in both Northern and Southern Xinjiang. However, seldom research on genetic basis of genetic diversity and pedigree relationship has been evaluated in upland cotton varieties in Xinjiang so far. This study aimed to reveal the genetic diversity of 94 upland cotton varieties in Xinjiang by genome analysis using SSR markers. The results indicated that SSR molecular markers could be employed in revealing the genetic diversity. One hundred and fifty-three polymorphic lociwere detected by amplified with 54 pairs of primers with allelic variation of 2-6 per primer pair and the average of 2.93. The genotypic diversity (H’) spanned from 0.0439 to 0.7149, with the average of 0.4491. The PIC value ranged from 0.0430 to 0.6640, and the average was 0.3831. The coefficients of genetic similarity among 94 tested cultivars varied from 0.3846 to 0.9835. And more than 71.9% of similarity coefficients fell into the interval of 0.601–0.800, indicating that the genetic similarity among the cultivars was high, whereas the genetic diversity might not be abundant. According to UPGMA cluster analysis, 94 tested cultivars were divided into two clusters when the threshold valve was given as 0.63, showing the relatively simple genetic relationship among the upland cotton varieties in Xinjiang, and relatively low genetic diversity and narrow genetic basis. The results of molecular clustering on genetic diversity of upland cotton coincided in large degree with the pedigree relationship. In conclusion, there is no much difference on molecular level among Xinjiang-bred upland cotton varieties. Materials with much wider genetic backgrounds are suggested to be used to diversify the genetic basis of cotton varieties in Xinjiang.