Table of Content

12 September 2013, Volume 39 Issue 09

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

QTL Mapping for Plant Height and Ear Height by Using Multiple Related RIL Populations in Maize

LI Qing-Chao,LI Yong-Xiang1,YANG Zhao-Zhao1,LIU Cheng3,LIU Zhi-Zhai4,LI Chun-Hui1,PENG Bo,ZHANG Yan,WANG Di,TAN Wei-Wei,SUN Bao-Cheng, SHI Yun-Su, SONG Yan-Chun, ZHANG Zhi-Ming, et al.

Acta Agron Sin. 2013, 39(09):  1521-1529.  doi:10.3724/SP.J.1006.2013.01521

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Plant height and ear height are two important agronomic traits in maize. In this study, 11 RIL populations developed by crossing a common parent (Huangzaosi, a foundation inbred line of maize breeding in China) with other 11 elite inbred lines were applied to QTL mapping for plant height and ear height based on phenotype data of three locations in two years. A total of 269 QTL detected by single- environment analysis and 176 QTL by joint analysis were identified across all of six environments, respectively. Collectively, 21 major-effect QTL for plant height and 15 major effect QTL for ear height were detected, which were located on chromosome. 1, 2, 3, 6, 7, 8, 9, and 10. It was found that the common parent (Huangzaosi) contributed the positive alleles for some QTL across different RIL populations. Five and four environment-insensitive QTL for plant height and ear height were also identified, respectively. Five QTL clustering regions related to plant and ear height, such as bin 1.01–1.03, 1.08–1.11, 3.05–3.06, 8.03–8.05, and 9.07, were dissected, of which each region were covered under more than three environments. These genomic regions would be valuable for fine mapping and cloning of height related QTL in maize.

Construction of Maize opaque-2 Near-isogenic Lines and Rapid Detection of Lysine Content

CHEN Yan,SONG Li-Ya,ZHOU Zhi-Qiang,ZHANG De-Gui,YAN Na,ZHANG Shi-Huang,LI Xin-Hai,HAO Zhuan-Fang,WENG Jian-Feng,BAI Li,I Ming-Shun

Acta Agron Sin. 2013, 39(09):  1530-1537.  doi:10.3724/SP.J.1006.2013.01530

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The germplasm of high lysine maize in China is narrow, while the opaque-2 (o2) mutant gene can largely increase the lysine level in maize, so it is important to create opaque-2 near-isogenic lines (o2-NILs) by molecular marker assisted selection (MAS). There are two key problems in creating such lines, one is how to introgress the o2 gene into normal receptor lines correctly, and the other is the fast and convenient way to monitor the lysine content. In our study, the closely linked co-dominant SSR marker phi057 was used to detect the polymorphism between the maize donor and receptor lines, and the specific and co-dominant marker was used to construct o2-NILs. Meanwhile, we tested the lysine content of 18s group of o2-NILs by our own improved dye binding lysine (DBL) method. The results demonstrated that the normal maize inbred lines existed polymorphism, moreover, polymorphism also existed among QPM donors CA339 and Shandong2548, the marker phi057 was effective to construct o2-NILs, using different QPM donors. The lysine content varied in different genetic backgrounds, which was from 0.223% to 0.368% among normal maize inbred lines, and from 0.373% to 0.527% among o2-NILs. The increment of lysine content in o2-NILs ranged from 13% to 74%. We included that the SSR marker phi057 can select the mutant genotype of o2 gene correctly, and the improved DBL method is effective to be used in high lysine maize breeding.

A Unique orf160 Cloning and Genetic Transformation of Gossypium harknessii Cytoplasmic Male Sterile Line in Upland Cotton

LI Shuang-Shuang,LIU Guo-Zheng,CHEN Zhi-Wen,WANG Yu-Mei,HUA Jin-Ping

Acta Agron Sin. 2013, 39(09):  1538-1547.  doi:10.3724/SP.J.1006.2013.01538

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) of480 bp, orf160gene was cloned in CMS line, which located in the downstream of atp4, its N-terminal was homologous with atp6, and the C-terminal was homologous with nuclear sequence, and encoded 159 amino acids that were homologous with membrane proteins and cell cycle protein. The subcellular localization of onion epidermal cells showed the green fluorescence on cell membranes, so the mitochondria-targeting carrier can be normally expressed. The expression vectors were constructed and transformed into yeast, arabidopsis and tobacco, respectively. Compared with control, the modified yeast was abnormal and grew slowly; transformed arabidopsis and tobacco showed that the most seeds were abnormal, small and shriveled; lower seed setting rate, germinate activety and pollen grain vitality showed in individuals in T₁ and T₂ generations. All these showed that orf160 affects on the development of transformants, and further research should verify if the function of orf160 relates to the cytoplasmic male sterility of cotton.

Analysis of Early Maturity Gene Sources in Upland Cotton Using Molecular Markers

AI Ni-Jiang,LIU Ren-Zhong,ZHAO Tu-Qiang,QIN Jiang-Hong,ZHANG Tian-Zhen

Acta Agron Sin. 2013, 39(09):  1548-1561.  doi:10.3724/SP.J.1006.2013.01548

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The traits related to early maturity in upland cotton are quantitative traits usually affected by multiple genes and environments, it is difficult to dissect their genetic basis. However, both linkage mapping and association analysis provide new tools toward interpreting the gene sources of complex traits. In this study, two F₂ mapping populations were constructed by using upland genetic standard line TM-1 as male to cross with female parents Xinluzao 8 and 10, respectively. Thirty-seven QTLs for traits related to early maturity were identified by the composite interval mapping (CIM) method of Win QTLCart 2.5 in the F₂–F_2:3 of the two mapping populations_. Positive alleles at these loci were mostly from early maturity ancestor 611-B and King cotton, respectively. In addition, most of the traits were controlled by different genes in the two sets of gene pools, showing primarily additive effects. Furthermore, in a natural population consisting of 43 different Upland cotton cultivars, 54 genetic loci significantly associated with early maturity related traits were detected through genome-wide association analysis, showing great comparability with the linkage mapping results. Our study provided insights into the genetic bases of early maturity and laid a foundation for early maturity gene pyramiding and marker-assisted selection of upland cotton.

QTL Analysis of 100-Kernel Weight Based on Chromosome Single Segment Substitution Lines in Maize

CHEN Chun-Xia**,LU Ming-Yang**,SHANG Ai-Lan,WANG Yu-Min,XI Zhang-Ying*

Acta Agron Sin. 2013, 39(09):  1562-1568.  doi:10.3724/SP.J.1006.2013.01562

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Kernel size is a key component of maize yield.Fifty-nine homozygous chromosome single segment substitution lines (SSSL) were employed to identify the QTL of 100-kernel weight of maize under six environments using t-test and overlap mapping method. Twenty QTLs of 100-kernel weight were identified on eight chromosomes of maize, of which fourteen QTLs (70.0%) were foundrepeatedly in more than two environments, four QTLs (20.0%) were found repeatedly in more than four environments, the major QTL q100kw-5-3, which was detected repeatedly under six environments, was located near the SSR markers bnlg278 and umc1680 at Bin 5.05. These results provide a good foundation for further fine mapping and cloning of major genes related to the maize kernel size.

How to Tackle Insecurity Problems in Seed Production of Two-line Hybrid Rice

LEI Dong-Yang,TANG Wen-Bang,XIE Zhi-Jian,LIU Hai,CHEN Li-Yun*

Acta Agron Sin. 2013, 39(09):  1569-1575.  doi:10.3724/SP.J.1006.2013.01569

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The security problem of seed production has seriously hampered the healthy and sustainable development of two-line hybrid rice. The safty issues on seed production of two-line hybrid rice and current research situation were pointed out in this paper. The three main reasons for unsafty in seed production of two-line hybrid rice were indicated to be unsuitable site selection, high critical sterility-inducing temperature and the drift of critical temperature. In this paper, strategies and measures were put forward based on many years of practice. Selecting dual-purpose genic male sterile line with lower critical sterility-inducing temperature could minimize the risk in seed pruduction of two-line hybrid rice and scientifically selecting a suitable site and safe duration could ensure the seed production safety of two-line hybrid rice. A new idea for determining appropriate regions and periods for seed production according to the climate data together with climatic demands of the “three safe-periods” in seed production was proposed. Besides, a system of single plant selection and identification and original seed propagation with cyclic cold water was established.

foundation seed production of dual-purpose genic male sterile lines should be adopted to avoid the drift of critical sterility-inducing temperature.

Generation and Characterization of PgPGIP1 Transgenic Wheat Plants with Enhanced Resistance to Take-All and Common Root Rot

YANG Li-Hua,WANG Jin-Feng,DU Li-Pu,XU Hui-Jun,WEI Xue-Ning,LI Zhao,MA Ling-Jian,ZHANG Zeng-Yan

Acta Agron Sin. 2013, 39(09):  1576-1581.  doi:10.3724/SP.J.1006.2013.01576

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Take-all disease is primarily caused by a soil-borne fungus Gaeumannomyces graminis var. tritici (Ggt). The disease common root rot is mainly caused by fungal pathogen Bipolaris sorokiniana (teleomorph Cochliobolus sativus). Both of them are important diseases of wheat (Triticum aestivum L.)worldwide. PgPGIP1, a polygalacturonase-inhibiting protein from Panax ginseng, can reduce the infection of some fungal phytopathogens through inhibiting the polygalacturonase activity of the pathogens. In this study, the full-length coding sequence of PgPGIP1 gene was synthesized, and the gene transformation vector pA25-PgPGIP1 was constructed. In the expression vector pA25-PgPGIP1, the PgPGIP1 gene can be expressed highly in monocot plants driving by maize ubiquitin promoter. Embryo callus of Yangmai 18 was bombarded by the gold particle containing pA25-PgPGIP1. The transgenic wheat plants from T₀ to T₄ generations were subjected to PCR, RT-PCR, and Q-RT-PCR assays. Results showed that the PgPGIP1 gene was indeed introduced into four transgenic wheat lines, and inherited from T₀ to T₄ generations and expressed. After inoculation with Ggt and B. sorokiniana, the disease evaluations  showed that the four transgenic wheat lines expressing PgPGIP1 displayed an enhanced resistances to take-all and common root rot compared with untransformed Yangmai 18.

Developing Restorer Lines Pyramiding Different Resistant Genes to Blast and Bacterial Leaf Blight by Marker-assisted Selection in Rice

PAN Xiao-Biao,CHEN Kai,ZHANG Qiang,HUANG Shan-Jun,XIE Liu-Jie,LI Mei,Meng Li-Jun,XU Zheng-Jin,XU Jian-Long,LI Zhi-Kang

Acta Agron Sin. 2013, 39(09):  1582-1593.  doi:10.3724/SP.J.1006.2013.01582

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The novel blast resistance genes, Pi-GD-1(t), Pi-GD-2(t), and GLP8-6(t) from rice variety Sanhuangzhan2 (here abbreviated them as G1, G2 and G8, respectively) and bacterial blight (BB) resistance gene, Xa23 were introgressed into three elite restorer lines (Minghui86, Shuhui527 and Zhehui7954) by marker-assisted pyramiding breeding approaches in combination with artificial inoculation and stringent phenotypic selections. The five derived blast and bacterial blight resistance restorer lines, Minghui86-G1-G2-Xa23, Shuhui527-G2-Xa23, Mingzhe-G2-G8-Xa23-1, Mingzhe-G2-G8-Xa23-2 and Mingzhe-G1-G2-G8-Xa23, demonstrated similar or wider blast resistance spectrum as compared with the donor parent, Sanhuangzhan 2. The five derived BB resistant restorer lines and their derived hybrid combinations with II-32A demonstrated similar BB resistance spectrum to the donor parent, IRBB23. The newly developed BB resistant restorers and their derived hybrids were identical to their respective original versions for agronomic traits especially under disease free condition. However, under severe disease condition, the five BB resistant restorer lines exhibited significantly higher grain weight, spikelet fertility and grain yield as compared with the respective original restorer lines, thus further resulting in significantly higher grain yields in BB resistant hybrids than in their respective original hybrids. Improvement of resistance of blast and BB for restorer lines by molecular marker-assisted pyramiding was discussed.

Agrobacterium tumefaciens Mediated Transformation of RNAi CP Gene into Soybean (Glycine max L.)

ZHANG Jie-Qiong,LI Hong-Yan,HU Xiao-Nan,SHAN Zhi-Hui,TANG Gui-Xiang

Acta Agron Sin. 2013, 39(09):  1594-1601.  doi:10.3724/SP.J.1006.2013.01594

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 Soybean mosaic virus (SMV) causes a severe disease in soybean, which can be efficiently prevented by planting resistant cultivars. In order to improve the SMV resistance of soybean, an agrobacterium-tumefaciens mediated gene transformation was conducted in this study by using RNAi soybean mosaic virus coat protein (CP)gene as the expression vector, bar gene as the selective marker gene, and cotyledonary-node as the explant to get RNAi transformation soybean. As results, 22 putative transgenic soybean plants were obtained and 18 positive transgenic soybean plants were identified by coating with leaves herbicide, using bar protein quick dip stick and PCR analysis. The segregation ratio of T₁ transgenic progeny showed that the transformed gene could be inherited according to the Mendel's law. The T₁ southern blot analysis showed that the imported interference fragment was one copy. After SMV friction inoculation, the RNAi CP transgenic soybean plants showed good resistance to SMV. DAS-ELISA analysisat three weeks after SMV inoculation revealed that 100% of the non-transgenic lines SMV while only 7.69% of the RNAi plants were infected by SMV. The results demonstrated that the RNAi CP transgenic soybean plants obtained in the study are valuable resources for improving the SMV resistance of soybean.

Molecular Cloning and Expression Analysis of Potassium Channel Gene NKT6 in Nicotiana sylvestris

JIN Yi-Rong, BAI Yan, SONG Yu-Feng, ZHANG Liang, DONG Lian-Hong, LIU Chao-Ke, FENG Xiang-Guo, HU Xiao-Ming, WANG Qian, LIU Hao-Bao

Acta Agronomica Sinica. 2013, 39(09):  1602-1611.  doi:10.3724/SP.J.1006.2013.01602

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Shaker family potassium channels play a crucial role in absorption and transportation of potassium in plants. A new potassium channel gene, designated as NKT6 (GenBank accession number KC310448), was isolated from N. sylvestris using homologous cloning strategy. The full length sequence of NKT6 cDNA was 2137 bp. The deduced protein sequence contained 618 amid acids and exhibited high homology with Shaker family potassium channels. The genomic sequence of NKT6 contained 11 exons and 10 introns. The phylogenetic tree showed that NKT6 belonged to Group II of Shaker family. Real-time quantitative PCR assay indicated that the expression level of NKT6 in stem was the highest at full-bloom stage of Nicotiana sylvestris. Subcellular localization assay showed NKT6 was localized on plasma membrane and endoplasmic reticulum of tobacco epidermal cells. The expression level of NKT6 declined under drought and ABA treatment. These results demonstrated that NKT6 might play a role in stomatal movement.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effect of Tillage Practices on Growth and Development and Yield of Winter Wheat in Double Cropping Area in North China

KONG Fan-Lei,YUAN Ji-Chao,ZHANG Hai-Lin,CHEN Fu

Acta Agron Sin. 2013, 39(09):  1612-1618.  doi:10.3724/SP.J.1006.2013.01612

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The objective of this study was to understand the effect of different tillage practices on growth durations of critical stages, population size, and final yield of winter wheat in the double-cropping area in North China. In a two-year field experiment from september 2009 to summer 2011, we compared the effects of no tillage with straw mulch (NTS), conventional tillage with straw (CTS), rotary tillage with straw (RTS), and conventional tillage without straw (CT), under the conditions of same sowing date and similar seedling densities within a year. The growing process, population size, grain filling, and final yield of winter wheat received no significant influence of the three tillage practices (RTS, CTS, and CT). The growing process of wheat was delayed significantly in NTS treatment, which resulted in late maturity. The lower yield in NTS than in other treatments was related with the significantly smaller number of tillers per plant, population size, amount of dry matter accumulation in NTS. Compared with CT, NTS showed a decreased fertile spike number by 14.4%–16.9% and a lower grain yield by 16.4%–18.3%. Although the growing process of NTS was delayed, and the yield was decreased because of the small population size, the grain filling period of NTS was longer and the grain weight was higher in NTS than in other treatments. Therefore, to ensure the population number of NTS by increasing seeding rate and selecting strong tillering varieties is the problem in urgent need to be solved in NTS technology research and application.

Effects of Different Cultivation Patterns on Photosynthetic Characteristics and Water Use Efficiency in Dryland Spring Maize

ZHANG Ren-He,HU Fu-Liang,YANG Xiao-Qin,GAO Jie,HAO Yin-Chuang,ZHANG Xing-Hua,XUE Ji-Quan

Acta Agron Sin. 2013, 39(09):  1619-1627.  doi:10.3724/SP.J.1006.2013.01619

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Under water-limited conditions, increasing water use efficiency (WUE) is essential for successful maize production. This study aimed at increasing grain yield and WUE through improving crop management. A maize cultivar Zhengdan 958 was planted at Changwu of Shaanxi Province in 2010 and 2011 with four treatments including local farmers’ practice (CK), high-yielding and high efficiency cultivation (HHC), super high yielding cultivation (SHC), and super high yielding and high efficiency cultivation (SHEC). The photosynthetic characteristics and WUE under the different cultivation patterns were analyzed. The results showed that the average yield for CK, HHC, SHC and SHEC was 7.7, 9.2, 11.7, and 10.6 t ha^-1, respectively, and 20.1%, 52.9%, and 37.7% higher than that of control. WUE was increased by 27.8%, 60.9%, and 45.1%under HHC, SHC, and SHEC, when compared with local farmers’ practice. Compared with the control, HHC, SHC and SHEC also significantly increased net photosynthetic rate (P_n), transpiration rate (T_r), leaf water use efficiency (WUE_L), electron transport rate (ETR), quantum yield (Φ_PSII), photochemical quenching (q_P) of photo-system II in leaf, delayed the mean decreasing rate of leaf senescence and leaf senescence duration. In addition, the post-anthesis dry matter accumulations were 29.0%, 82.3%, and 56.1% higher in HHC, SHC, and SHEC than in the control. The results indicated that grain yield and WUE could be increased through integrating and optimizing cultivation techniques in maize production, which attributed to the higher photosynthetic rate, delayed leaf senescence at latter growth stages and higher post-anthesis dry matter accumulation and transportation to grains.

Path Analysis between Yield of Spring Maize and Meteorological Factors at Different Sowing Times in North China Low Plain

TAO Zhi-Qiang,CHEN Yuan-Quan,LI Chao,YUAN Shu-Fen,SHI Jiang-Tao,GAO Wang-Sheng,SUI Peng

Acta Agron Sin. 2013, 39(09):  1628-1634.  doi:10.3724/SP.J.1006.2013.01628

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In order to study high temperature stress problem of spring maize at grain filling stage in North China Plain, an experiment was conducted using two varieties (Zhengdan 958 and Jinhai 5) sown in six sowing times in Wuqiao County, Hebei Province. We investigated the relationship between meteorological factors and maize yield, hoping to find the evitable sowing time to avoid high temperature stress at grain filling stage . Preliminary results showed that meteorological factors during grain filling stage were different when the sowing time was different. Compared with other sowing time, the treatment with sowing time of early April had more than 5.0–47.4 mm of rainfall, more than 41.0–70.0 h of sunshine, and 0.2–0.6°C of diurnal temperature , but the most serious high temperature stress ( ≥33°C days and mean daily temperature up to 15 d and 28.4°C respectively). Compared with other sowing time, the treatment with sowing time of mid May had weak high temperature stress (≥33°C days and mean daily temperature up to 8 d and 26.0°C respectively), but more rainfall, sunshine hours and diurnal temperature range, that of Mid April, late April and early May had more serious high temperature stress. The sowing treatment of late May had weaker high temperature stress, but more rainfall, less sunshine hours and diurnal temperature range. The order of grain yield for different sowing times from high to low was early April, mid May, early May, late April, mid April, late May. Yield of Zhengdan 958 and Jinhai 5 was up to 9912.0 kg ha^-1 and
11 046.0 kg ha^-1 in early April respectively, 9906.0 kg ha^-1 and 10 852.5 kg ha^-1 in mid May respectively. Yield of the other four sowing times was 6.0%–28.2% lower than that of early April and mid May. The result of path analysis showed that the yield of spring maize sown in early April was the highest, due to its higher diurnal temperature range and sunshine hours, resulting in the greater direct positive effects on 1000-grain weight and grain number per ear than those of other sowing treatments from flowering to maturity, and relieving the negative effect of high temperature stress. The yield of spring maize sown in mid May was higher than that of other sowing treatments (except sown in early April), because of avoiding high temperature stress, increasing 1000-grain weight and grain number per ear, while its lower diurnal temperature range and sunshine hours led to lower yield compared with that sown in early April. High temperature stress or cloud and drizzle had higher negative effect on 1000-grain weight and grain number per ear, and diurnal temperature range and sunshine hours had lower positive effect on yield in other sowing date (mid April, late April, early May, and late May).

Canopy Structure and Matter Production Characteristics of F₁, F₂, and Their Parents in Two Cotton Hybrids

FENG Guo-Yi,GAN Xiu-Xia,YANG Mei-Sen,YAO Yan-Di,LUO Hong-Hai,ZHANG Ya-Li,ZHANG Wang-Feng

Acta Agron Sin. 2013, 39(09):  1635-1643.  doi:10.3724/SP.J.1006.2013.01635

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A field experiment was conducted using the F₁, F₂ of two cotton hybrids of Shiza 2 and Xinluzao 43 and their parents NT2, H2, and 4-14. After measuring the leaf area index (LAI), leaf inclination angle (MTA) and light interception rate (LIR) at different growing periods, it is clear that the matter production of hybrid cotton was affected directly by the parameter changes of the canopy structure and photosynthetic characteristics of two cotton hybrids parents. The results revealed that the over-parent hereosis of F₁ in two cotton hybrids was observed on LAI and mid-parent heterosis of them was provided with LIR. Both LAI and LIR were observed obviously with matrilineal genetic characteristics, while MTA was influenced by paternal inhentance. The canopy structure of F₂ in two cotton hybrids was mainly influenced by the related parameters of F₁ in hybrid cotton indexes and their decreasing rate. The decreasing rate was deduced by the over-parent hereosis on LAI. The photosynthate accumulation of F₁ in two cotton hybrids was mainly influenced by the numerical value of their parents and over-parent hereosis, and the photosynthate accumulation of F₂ in two cotton hybrids was mainly influenced by the related parameters of F₁. The initial time of the highest increasing velocity of photosynthate accumulation and the linear increasing period was later, the linear increasing period and the active increasing period of photosynthate accumulation were longer, the total photosynthate accumulation and the highest increasing velocity were larger in two cotton hybrids. The photosynthate and yield were very high in F₁ of hybrid cotton, and there was a high yield only in F₂ of hybrid cotton. Based on choosing the parents with the optimizated canopy structure, we should be make a well combination between father plant with larger MTA and mother plant with larger LAI, which will be provides used for improving hybrid cotton photosynthetic performance, increasing light use efficiency for enhancing yield potential further. The study provided come theoretical parameters for breeding high photosynthetic efficiency hybrid line andimproving utilization of F₂ in hybrid cotton.

Effects of Heat Stress During Grain Filling on Sugar Accumulation and Enzyme Activity Associated with Sucrose Metabolism in Sweet Corn

ZHAO Fu-Cheng,JING Li-Quan,YAN Fa-Bao,LU Da-Lei,WANG Gui-Yue,LU Wei-Ping

Acta Agron Sin. 2013, 39(09):  1644-1651.  doi:10.3724/SP.J.1006.2013.01644

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With the trends of global warming, the extreme high temperature stress often happens during crop grain filling in the world. Heat stress has been an important factor limiting grain yield and quality. To determine the effects of heat stress on fresh kernel yield, quality and enzyme activities of sucrose metabolism, we carried out an experiment was carried out in artificial phytotron using two sweet corn cultivars (Xiatian 1 and Yuetian 16) with two typical temperature treatments (high temperature, HT and control, CK) during grain filling. The results indicated that the growth process of sweet corn was accelerated, but the weight and quality of kernel was decreased seriously under high temperature. The weight of 100-fresh-kernel and kernel water content were markedly reduced, but content of pericarp was increased. At the optimum harvest stage of fresh ear (with kernel water content 68%–74%), the fresh kernel weight of the two cultivars was reduced significantly by 20.8% (Xiatian 1) and 16.4% (Yuetian 16) under higher temperature respectively. The contents of soluble sugar and sucrose first increased and then decreased during the grain filling stage. High temperature was not favorable to sugar accumulation, resulting in sucrose content decrease and starch content increase. Sucrose phosphate synthetase (SPS) and sucrose synthetase (SS) play an important role in sucrose synthesis and degradation. SS catalyzes the interconversion of sucrose. Heat stress decreased the activities of SPS and SS (synthetic) and increased the activity of SS (cleavage), which inevitably leads to a depression in sucrose content and a reduction in kernel quality. The maximum SS (synthetic) activity in process of grain filling of two sweet corns appeared earlier under high temperature, while that of SPS activity appeared earlier in Xiatian 1 and did not in Yuetian 16.

Effect of Ordered Transplanting and Optimized Broadcasting on Super High Yield and Photosynthetic Productivity and Exploration of Rice Super High Yield Model

XU Ke,GUO Bao-Wei,ZHANG Hong-Cheng,ZHOU Xing-Tao,CHEN Hou-Cun,ZHANG Jun,CHEN Jing-Du,ZHU Cong-Cong,LI Gui-Yun,WU Zhong-Hua,DAI Qi-Gen,HUO Zhong-Yang,WEI Hai-Yan,GAO Hui,CAO Li-Qiang,et al.

Acta Agron Sin. 2013, 39(09):  1652-1667.  doi:10.3724/SP.J.1006.2013.01652

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Rice seedling broadcasting is a technique of light and simple cultivation method in China and the stable super high yield from using the method relies on the ordered plantation of rice. Three planting methods including ordered transplanting (OT), optimized broadcasting (OB) and cast transplanting (CT) using dry-raising seedlings in plastic plates were compared with mechanical transplanting (MT) to investigate the photosynthetic productivity and matter accumulation characteristics during the formation of super high yield in respect of seedling establishment, tillering, LAI, grain-leaf ratio, photosynthetic potential, matter production, accumulation and translocation in late stages. Using methods of ordered transplanting and optimized broadcasting rice seedlings had the better population quality with earlier seedling establishment at the beginning, and their LAI, leaf area duration, grain-leaf ratio, matter production, accumulation in each growing stage, and net photosynthetic rate and matter translocation in later growing stages were all significantly or very significantly superior to those of cast transplanting. Moreover, in late growing stages, they showed comparatively better population light transmittance and ventilation, slower senescence, and higher matter production and lodging resistance as well. The transplanting hill number for of 3- and 2-hole closely gathered plates were 30–60 percent less than that for single-hole ones, which improved transplanting speed. Although 3-hole seedlings had earlier seedling establishment in early growing stage, 2-hole seedlings kept higher matter production and lodging resistance in middle and late growing stages. Eventually, two hole seedings had higher yield than 3-hole seedlings and 1-hole seedlings. With their higher population starting point, earlier seedling establishment, proper matter accumulation in early growing stage as well as higher matter production, accumulation and translocation ability in later growing stages, ordered transplanting and optimized broadcasting methods were capable of leading to the stable super high yielding cultivation of super rice. Two-hole plate transplanting seedlings showed better matter production and obvious growth superiority during the whole growth stage, and 3-hole one also showed growth superiority in some aspects, which could lead us to the conclusion that 2- and 3-hole plate seedlings ordered transplanting are new-typed cultivation patterns of super high yielding in super rice.

Effect of Nitrate Reductase (NR) Inhibitor on NR Activity in Oilseed Rape (Brassica napus L.) and Its Relation to Nitrate Content

HUANG Hai-Tao,RONG Xiang-Min,SONG Hai-Xing,LIU Qiang,LIAO Qiong,LUO Ji-Peng,GU Ji-Dong,GUAN Chun-Yun,ZHANG Zhen-Hua

Acta Agron Sin. 2013, 39(09):  1668-1673.  doi:10.3724/SP.J.1006.2013.01668

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 This study aims at inspecting the regulation mechanisms of NR activity and its relation to nitrate content in oilseed rape. A sand culture experiment with N treatment at normal (15 mmol L^–1 NO₃^–) and deficiency (7.5 mmol L^–1 NO₃^–) levels and NR activity obligate inhibitor treatment using oilseed rape genotypes with high nitrogen use efficiency (NUE) (H1: 742 and H2: Xiangyou 15) and low NUE (L1: 814 and L2: H8) was conducted to study differences of NR activity and nitrate contents between genotypes and N application levels. The results indicated that, compared with control treatment, inhibitor treatment under N normal and deficiency levels decreased NR activity by 54.1% and 55.9% respectively, but could not influence the nitrate content of leaves. NR activity and nitrate content of N normal level treatment were 46.9% and 16.4% higher than those of N deficiency level. Nitrate content of high NUE genotypes was significantly lower than that of low NUE genotypes. NR activity (NRAact) of H2 was significantly higher than that of low NUE genotype, resulting from that H2 possesses higher relative expression level of major NR gene (nia2). In conclusion, there are significant differences in NR activity and nitrate content between genotypes and N application levels. However, nitrate content can not be significantly influenced by somewhat changes of NR activity.

Changes of Arabinoxylan Content in Malting Barley under Different Environments and Cultivation Conditions

ZHANG Xiao-Qin,XUE Da-Wei,ZHANG Guo-Ping

Acta Agron Sin. 2013, 39(09):  1674-1678.  doi:10.3724/SP.J.1006.2013.01674

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Arabinoxylan (AX) content in barley grains is a principal chemical component affecting malt quality. The changes of arabinoxylan content and endoxylanase activity (EA) in grains during grain filling and their responses to agronomic factors, such as nitrogen rate and application timing, plant density, and growing site, were investigated using two-rowed barley cultivars, Hua 30, Zheda 9, and Zhexiu 12. All that three barley cultivars had the same changing trend in AX content and EA during grain-filling period. Contents of total arabinoxylan (TAX) and water unextractablearabinoxylan (WUAX), and EA declined constantly during grain filling stage, and content of water extractablearabinoxylan (WEAX), a small proportion of TAX, increased at early stage and declined at late stage. When Zheda 9 was planted in Hangzhou and Tongxiang of Zhejiang Province, TAX content in grains was significantly higher in Hangzhou than in Tongxiang, and the opposite was true for WEAX content. The effects of plant density and nitrogen application rate and timing were not significant on both TAX and WEAX contents in Tongxiang, while the effect was significant of these factors on WEAX contents in Hangzhou.

RESEARCH NOTES

Responses of Plant Productivity and Nitrogen Use Efficiency to Nitrogen Fertilization Rate among Rice Varieties Released from Different Years in Liaoning Province

LI Zhi-Jie,ZHANG Zhen-Ping,ZHANG Yi,DENG Ai-Xing,SONG Zhen-Wei,ZHENG Cheng-Yan,ZHANG Wei-Jian

Acta Agron Sin. 2013, 39(09):  1679-1686.  doi:10.3724/SP.J.1006.2013.01679

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To study the changes of rice plant productivity and resource use efficiency during the variety improvement eras can benefit future genetic improvement and agronomic innovation for high-yield with high-efficiency. A field experiment was conducted at Shenyang, Liaoning Province, China, with 12 leading Japonica rice varieties released during 1950–2010 period under five nitrogen application rates. Our results showed that the highest biomass production and grain yield of the varieties released after 1990 were significantly higher than those of the ones released before 1989. The increases in grain number per panicle contributed to the main parts of historical improvement of rice yield. The amounts of N application for the highest yields of the varieties released after 1990 were significantly higher than those released before 1989, while there were no significant differences in plant productivity under the low N application rate among all the varieties. For all the N treatments, agronomic efficiency (AE) and partial factor productivity (PFP) increased with the years, however, there were no consistent trends of physiological efficiency (PE) and recovery efficiency (RE) among the years. Grain N concentrations decreased with the time, while no consistent trends were found in the changes of leaf and stem N concentrations. For all the varieties released in different years, plant N concentration increased and N use efficiencies (NUE: AE, PFP, PE and RE) decreased with increasing N application rate. The efficiencies of varieties released after 1990 were significantly greater than those released before 1989 at high N application rates, while there were no significant differences in NUE between varieties at low N application rate. These results demonstrate that genomic improvement and nitrogen application increasing have simultaneously contributed to the enhancement of rice productivity, though the progresses scales of rice productivity enhancement and NUE improvement are different. More efforts need to be paid in the new variety breeding and agronomic innovation for high-yield with high-efficiency in Liaoning Province.

Effects of Drip Irrigation Patterns on Wheat Yield and Water Use Efficiency in Heilonggang Region

NIE Zi-Jin,CHEN Yuan-Quan,ZHANG Jian-Sheng,SHI Jiang-Tao,LI Chao,GAO Wang-Sheng,SUI Peng

Acta Agron Sin. 2013, 39(09):  1687-1692.  doi:10.3724/SP.J.1006.2013.01687

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A field experiment with different drip irrigation patterns was conducted in Heilonggang region, Hebei Province, China in the 2010–2011 and 2011–2012 winter wheat growing seasons to develop suitable drip irrigation schedule in this region. The yields and water use efficiencies (WUE) of wheat in different drip irrigation treatments with flood irrigation as control were compared under total water supplies of 225, 180, 150, and 120 mm, respectively. Under the condition of 225 mm irrigation, drip irrigation and irrigation frequency (1–3 times) had no significant difference in effect on yield and WUE. Drip irrigation resulted in 45–105 mm reduction of irrigation amount as compared to the control, with no significant yield loss, and a significant increase of WUE. Correlation analysis indicated that the contribution of yield components showed a sequence of spike number > 1000-grain weight > grain number per spike. These results showed that drip irrigation technique should have ta potential of water saving and yield stability in wheat production of the experimental region.

Analysis of Parental Relationship for Soybean Cultivars Released from 1983 to 2010 in Beijing

LIU Zhang-Xiong1,SUN Shi1,LI Wei-Dong2,CHEN Li-Jun3,CHANG Ru-Zhen1,QIU Li-Juan1,*

Acta Agron Sin. 2013, 39(09):  1693-1700.  doi:10.3724/SP.J.1006.2013.01693

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To explore the relationship and genetic diversity of soybean cultivars in Beijing and provide theoretical guidance for soybean breeding, we traced the pedigree information of 90 soybean cultivars released from 1983 to 2010 and calculated the coefficients of parentage (COP) between the parents and between cross combinations. The results showed that 19 of 90 cultivars had relationships in their parents. A total of 4005 cross combinations were made with 90 varieties, and 63.62% of the combinations shared parental relationship, but their average COP value was only 0.031, showing that there existed abundant genetic diversity because there were not close relationship among most cultivars; COP value between cultivars reduced in the process of time, but increased from 2005 to 2010. Cluster analysis suggested that 78 cultivars could be divided into 10 groups, showing characters of cultivars of different times and evolution of cultivars. Nine varieties were found to be core parents. In general, the genetic basis of soybean cultivars in Beijing was abundant but genetic diversity became narrower in the process of time.

Molecular Cloning and Bioinformatics Analysis of K+ Transporter Gene (GmKT12) from Soybean (Glycine max [L.] Merri)

ZHU Xiao-Ling,CHEN Hai-Feng,WANG Cheng,HAO Qing-Nan,CHEN Li-Miao,GUO Dan-Dan,WU Bao-Duo,CHEN Shui-Lian,SHA Ai-Hua,ZHOU Rong,ZHOU Xin-An

Acta Agron Sin. 2013, 39(09):  1701-1709.  doi:10.3724/SP.J.1006.2013.01701

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GmKT12 predicted as a potassium transporter is of great importance in absorbing nutrients, signal transduction in plant growth. At present, there are few reports about the gene. In this paper, one low K tolerant soybean line You 06-71 and one low K intolerant line Hengchun 04-11 were weed as plant materials. In order to research the expression level of GmKT12 in low potassium stress conditions, RNA was extracted and tested by Real-time PCR in eight periods. The results showed that there were highly significant differences between two lines due to their was diversity of amino acid sequence and protein structure. Homology and Bioinformatic analysis after cloning the target sequence from the two lines showed that comparing with GmKT12,there were 56 homologous genes with more than 30 percent similarity, GmKT12 andGlyma18g18822 were nearest in the phylogenetic tree. The protein encoded by GmKT12 was soluble transmembrane protein which contained 11–12 membrane structural domains, and possessed multiple phosphorylation sites. These indicated that the protein might take part in plant signal transduction and regulate potassium ions transportation into or out of cells. In conclusion, GmKT12 might play a pivotal role in potassium absorption in soybean, on which the research is important.