Table of Content

12 August 2016, Volume 42 Issue 08

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Genetic Effects of Branch Angle Using Mixture Model of Major Gene Plus Polygene in Brassica napus L.

WANG Wen-Xiang,HU Qiong,MEI De-Sheng,LI Yun-Chang,ZHOU Ri-Jin,WANG Hui,CHENG Hong-Tao,FU Li,LIU Jia*

Acta Agron Sin. 2016, 42(08):  1103-1111.  doi:10.3724/SP.J.1006.2016.01103

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Branch angle is one of important plant architectural traits in rapeseed (Brassica napus), which is the basic requirement for high-density cultivation and mechanical harvesting. To reveal the genetic mechanism of branch angle in rapeseed, we produced six generations (P₁, P₂, F₁, F₂, BCP₁, and BCP₂) from a cross between loose-type 6098B and compact-type Purler to analyze genetic effects of branch angle in rapeseed by the mixed major gene plus polygene inheritance model. The branch angle showed a continuous normal distribution, where both the basal branch angle and the top branch angle were dominated by a pair of major gene with additive-dominant effects plus polygenes with additive-dominance-epistasis effects (D-0 model). The additive effect and dominant effect of major gene of the top branch angle were 4.939 and –4.156, the heritability in BCP₁, BCP₂ and F₂ was 34.08%, 1.40%, and 14.99%, respectively for the major gene, and 24.43%, 61.72%, and 63.98%, respectively for the polygenes. The additive effect and dominant effect of major gene of the basal branch angle were 2.217 and –1.941, the heritability in BCP₁, BCP₂ and F₂ was 7.86%, 1.24%, and 4.84%, respectively for the major gene, and 66.46%, 58.49%, and 73.96%, respectively for the polygenes. Results of this study found that the branch angle traits of 6098B×Purler is controlled by polygenes, but there is a major gene among them. The research may be useful for further understanding and genetic improvement of plant architecture in rapeseed.

Cloning and Functional Identification of the ATHB12 Gene of HD-Zip IFamily in Potato(Solanum tuberosum L.)

WU Liang-Liang,YAO Lei,MA Rui,ZHU Xi,YANG Jiang-Wei,ZHANG Ning*,SI Huai-Jun

Acta Agron Sin. 2016, 42(08):  1112-1121.  doi:10.3724/SP.J.1006.2016.01112

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HD-Zip I is a class of plant-specific transcription factors, which has an important role in response to adversity stress in plant. A ATHB12 gene of HD-Zip I transcription factors was cloned from potato cultivar Gannongshu2, which contains a 759 bp open reading frame (ORF) encoding a protein of 252 amino acid residues. ATHB12 gene is located on potato chromosome 1, and its promoter region sequence contains cis-acting elements including ABRE, LTRECOREATCOR15, WBOXATNPR1 responsive to abiotic stresses (ABA, temperature, dehydration and salt stress). ATHB12 gene expressed in root, stem and leaf of potato, with the highest expression in the root. qRT-PCR analysis confirmed that the gene was induced by PEG, NaCl and ABA, but repressed by cold treatment. The overexpressed-vector of ATHB12 gene driven by the constitutive promoter CaMV 35S was constructed, and the transgenic plants were obtained using Agrobacterium-mediated transformation system. The malondialdehyde (MDA) content in the transgenic plant leaves was significantly lower (P<0.05), whereas the proline content was significantly higher (P<0.05) than those of non-transgenic control under drought stress. The fresh and dry weight of the transgenic plant root was higher than that of non-transgenic plants. These results showed that ATHB12 gene may be involved in response to stress.

Transcriptional Analysis of Maize Resistance against Fusarium graminearum

LIU Yong-Jie,MA Chuan-Yu,MA Xue-Na,XU Ming-Liang*

Acta Agron Sin. 2016, 42(08):  1122-1133.  doi:10.3724/SP.J.1006.2016.01122

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Gibberella stalk rot, caused by Fusarium graminearum (teleomorph, Gibberella zeae), is one of the most devastating soil-borne diseases in maize. It seriously decreases maize yield and quality. Molecular mapping  led to the identification of twoQTLs, qRfg1 and qRfg2, on chromosomes 10 and 1 respectively, conferring resistance to Gibberella stalk rot. In order to characterize the defense mechanism of maize against F. graminearum, NIL-R with resistant alleles at both QTLs and NIL-S with the susceptible alleles at both QTLs were generated and used in transcriptome analysis. After inoculation of young seedling roots of both NILs with the F. graminearum spores, the inoculated roots were sampled at 0, 6, and 18 hours after inoculation (hai) for transcriptome analysis using RNAseq. The basal difference was achieved by the comparison between control samples. In total, 2958 genes were differentially expressed between control samples of NIL-R and NIL-S, among which 1170 genes were more abundant in NIL-R. GO analysis revealed that genes involved in biological processes related to JA/ET and SA biosynthesis, JA/ET mediated signaling pathway and SA mediated signaling pathway were significantly enriched. Phenylpropanoid biosynthesis process was enriched in the genes more abundant in NIL-R and genes encoding enzymes involved in phenylpropanoid biosynthesis like PAL, 4CL2, CAD, and HCTwere more abundant in NIL-R. There were 431 genes differentially expressed between NIL-R and NIL-S at 6 hai, among which 83 genes were more abundant in NIL-R. Genes encoding pathogenesis-related (PR) proteins like lipid-transfer protein and germin-like proteinwere more abundant in NIL-R. Among the 1292 genes differentially expressed between NIL-R and NIL-S. At 18 hai, 291 genes were more abundant in NIL-R. Genes involved in ET biosynthesis like ACO and JA biosynthesis like LOX were more abundant in NIL-R. Genes involved in DON detoxification like PDR1 and MDR2 were more abundant in NIL-R. After inoculation with F. graminearum, 428 genes were exclusively up-regulated in NIL-R at 6 hai compared with control. Genes involved in ET biosynthesis and ET-mediated signaling pathway like ACO, ERF, EBF1, and EIL1 and pathogenesis-related genes like PR1, OSM34, and germin-like protein were exclusively up-regulated in NIL-R. At 18 hai, 359 genes were exclusively up-regulated in NIL-R compared with control. Pathogenesis-related genes like PR1, PR4, and genes encoding the transporters of DON out of cytoplasm likeABC transport family protein, heavy metal transport protein and MATE efflux family protein were exclusively up-regulated in NIL-R. All these results indicate that NIL-R can increase the resistance of maize to F. graminearum by the constitutive resistance characterized by the higher expression of genes related to defense responses. Genes involved in defense responses exclusively up-regulated in NIL-R and higher expression level of disease resistance genes in NIL-R at 6 and 18 hai may restrict the pathogen invasion after infection. The phenylpropanoid biosynthesis pathway and DON-detoxification proteins identified in this study are important for the resistance against F. graminearum infection.




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 本研究由引进国际先进农业科学技术计划(948计划)项目(2003-Q04)资助。

This study was supported by the Program of Introducing International Super Agricultural Science and Technology(948 Program) (2011-G15).

^* 通讯作者(Corresponding author): 徐明良, E-mail: mxu@cau.edu.cn, Tel: 010-62733166

第一作者联系方式: E-mail: liu_yongj@126.com

Received(收稿日期): 2016-01-11; Accepted(接受日期): 2016-05-09; Published online(网络出版日期):2016-05-30.

URL: http://www.cnki.net/kcms/detail/11.1809.S.20160530.0905.008.html

Identification of Dwarfing Wheat Germplasm SN224 and Analysis of QTLs for Its Agronomic Characters

WANG Xin,MA Ying-Xue,YANG Yang,WANG Dan-Feng,YIN Hui-Juan,WANG Hong-Gang

Acta Agron Sin. 2016, 42(08):  1134-1142.  doi:10.3724/SP.J.1006.2016.01134

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SN224 is a dwarfing wheat line derived from a cross between hexaploid triticale (AABBRR, 2n = 6x) and common wheat (AABBDD, 2n = 6x). We evaluated its cytologic characteristic and main agronomic characters, and analyzed the genetic basis of dwarfing trait in order to use the germplasm in wheat breeding program.This white grain wheat had compact plant type, spindle-shaped panicle and moderate resistance to powdery mildew (Blumeria graminis f. sp. tritici, Bgt) and stripe rust (Puccinia striiformis f. sp. tritici, Pst). There were 42 chromosomes in root tip cells, showing 21 bivalents in pollen mother cells. FISH confirmed that SN224 was a 1BL·1RS translocation line. The plant height was between two parents of F₁ from a cross between SN224 and Huixianhong and distributed continuously and normally in F₂ population. The detection of specific molecular marker for genes Rht-B1b, Rht-D1b, and Rht8 indicated that this line had none of the three dwarfing genes. In the meantime, the introduction of 1RS had no obvious effect on plant height. The F₂ population was used to construct a genetic linkage map containing 134 SSR markers which covered a total length of 1332.1 cM. Two major dwarfing QTLs on chromosomes 1B and 4B were detected by additive-inclusive composite interval mapping (ICIM-ADD). QPh1B and QPh4B, located in Xwmc719–Xgwm18 and Xgwm368–Xmag4284 intervals, explained 20.0% and 10.2% of phenotypic variation, respectively. Seven QTLs controlling ear length, panicle number per plant, and kernel number per spike were detected. The QTL in KSUM062–Xmag4284 interval contributed to decrease plant height, increase ear length and panicle number per plant.

Noodle Quality Evaluation of New Wheat Cultivars from Northern China Winter Wheat Regions

KONG Xin-Xin,ZHANG Yan,ZHAO De-Hui,XIA Xian-Chun,WANG Chun-Ping,HE Zhong-Hu

Acta Agron Sin. 2016, 42(08):  1143-1159.  doi:10.3724/SP.J.1006.2016.01143

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Fifty-two cultivars and lines from Northern China Winter Wheat Regions, and six cultivars from Australia and America were planted in two locations in two years to evaluate their milling quality, Mixograph and Mixolab parameters, pasting properties and noodle quality. Five gene-specific markers were used to test their effectson quality traits. The results indicated that most of the tested cultivars were featured with hard grain and strong gluten. Large variations of flour yield, flour a* value, b* value, yellow pigment content, PPO activity, Mixograph parameters, Mixolab parameters such as development time and stability were observed. The Mixograph parameter width at 8 min and Mixolab parameter stability were important for predicting noodle quality, accounting for 36.9% and 28.0% of the variation for noodle total score, respectively. Ppo-A1a and Ppo-A1b genotypes had the frequency of 41.4% and 58.6%, respectively, with significant difference in (P<0.05) PPO activity. The frequency of Ppo-D1a and Ppo-D1b was 51.7% and 48.3%, respectively, and there was no significant difference in PPO activity between two genotypes. The frequency ofPsy-A1a and Psy-A1b was 81.0% and 19.0%, respectively, and the yellow pigment contents of two genotypes were significantly different (P<0.05). The 1BL/1RSand non-1BL/1RScultivars had the frequency of 13.8% and 86.2%, respectively, with significant difference (P<0.05) in flour L* value, yellow pigment content, Mixgraph parameters such as right of peak slope and width at 8 min, and Mixolab parameter stability. Four cultivars including Zhoumai 26, Zhongmai 895, Sunzell, and CA1004 showed excellent noodle quality. This study provides important informations for wheat breeding and cultivar extension.

Construction of tgw6 Mutants in Rice Based on CRISPR/Cas9 Technology

WANG Jia-Feng,ZHENG Cai-Min,LIU Wei,LUO Wen-Long,WANG Hui,CHEN Zhi-Qiang*,GUO Tao*

Acta Agron Sin. 2016, 42(08):  1160-1167.  doi:10.3724/SP.J.1006.2016.01160

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A set of tgw6 (Thousand grain weight 6) mutants were constructed using CRISPR/Cas9 technology in this study. Three sites of 20 nt guide RNA (gRNA) targeted to the exon of TGW6 were designed and transcribed from the U3, U6a and U6b promoters, respectively. The three target sites of gRNA were then ligated to the vector pYLCRISPR/Cas9-MT(I) based on golden gate cloning strategy. The recombinant plasmid was transferred to a rice cultivar, H447 (R819/Yuzhenxiang//R819 BC₃F₆) by Agrobacterium-mediated transformation. Sequencing for the genomic DNA of TGW6 locusinT₀ rice showed the mutagenesis frequency for TGW6 was more than 90%, including 51% of the homozygous deletion mutations. Further analysis for the T₁ mutants showed almost all the homozygous deletion mutants improved the thousand grain weight significantly (more than 5%). The successful tgw6 editing not only provided a series of tgw6 mutants for high and stable yield of rice but also proved that CRISPR/Cas9 is a facile and powerful means of rice genetic engineering for scientific and agricultural applications, which has important theoretical and practical significance for rice breeding.

Association Analysis for MixographProperties in Ningmai 9 and Its Derivatives

JIANG Peng,ZHANG Ping-Ping,ZHANG Xu,CHEN Xiao-Lin,MA Hong-Xiang*

Acta Agron Sin. 2016, 42(08):  1168-1175.  doi:10.3724/SP.J.1006.2016.01168

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The mixograph property is one of the rheological properties affecting the quality of end-use products in wheat. Ningmai 9 isa soft wheat cultivar planted largely in the middle and lower reaches of Yangtze River and served as a main parent of 17released wheat cultivars. For the purpose of utilizing Ningmai 9 in molecular marker-assisted selection, 185 polymorphic SSRmarkers associated with mixograph properties were tested in Ningmai 9 and its 117 derivatives. The mixed-linear model (MLM) was used in combination of phenotypic data collected in the 2009–2010 and 2010–2011 growing seasons. A total of 13 SSRs were identified to be significantly associated with mixograph properties (P<0.01), explaining 5.71–12.33% of phenotypic variations.Among the 13 markers, three, three, two, and seven were associated with mix time (MT),peak height (PH), peak width (PW), eight-minute width (8MW),respectively. MarkersXwmc11, Xbarc320, Xbarc110,and Xgwm577 for 8MW,Xwmc594 for MT,and Xgwm299 for PWwere identified over two years. Besides, Xwmc594 and Xgwm577 were associated with both (MT) and 8MW. The six markers identified over two years all negativelyaffectedmixograph parametersat Ningmai 9 background and might be used in softwheat breeding.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effect of Low Nitrogen Rate Combined with High Plant Density on Yield and Nitrogen Use Efficiency of Machine-transplanted Early-late Season Double Cropping Rice

CHEN Jia-Na,CAO Fang-Bo,XIE Xiao-Bing,SHAN Shuang-Lü,GAO Wei,LI Zhi-Bin,HUANG Min,ZOU Ying-Bin*

Acta Agron Sin. 2016, 42(08):  1176-1187.  doi:10.3724/SP.J.1006.2016.01176

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In order to alleviate the contradictions of growth period mating problem of machine-transplanted double cropping rice in Changjiang Rive regions, a field experiment with three nitrogen rates (0, 110–140, and 176–189 kg N ha^–1) and three plant densities (36.4, 28.6, and 19.0 hill m^–2) was conducted using conventional early variety “Zhongjiazao 17” in both early and late seasons to explore the effects of machine transplanting densities and N application on yield and N recovery efficiency (RE_N) in 2014–2015. Adopting the same conventional early variety was able to reach the high yield in machine-transplanted early-late season double cropping rice. The treatment of high density (36.4 hills m^-2) with high nitrogen rate (176 kg ha^–1 in early season, 189 kg ha^–1 in late season) had the highest yield of 16.94 t ha^-1 in 2014 and 16.99 t ha^-1 in 2015, but not significantly higher than the treatment of high density with low nitrogen rate (110 kg ha^–1 in early season, 140 kg ha^–1 in late season). RE_N declined with increasing N application and improved with increasing density. The treatment of high density with low nitrogen rate showed the highest RE_N of 62.77%, 55.75%, 65.82%, 64.37% in early and later season 2014 and 2015, respectively 12.11%, 9.01%, 8.49%, and 2.14% higher than the treatment of high density with high nitrogen rate. The treatment of high density with low nitrogen rate displayed certain advantages of dry matter accumulation and radiation use efficiency compared with the treatment of low density (19.0 hills m^-2) with high nitrogen rate. As a result, adopting high planting density and low nitrogen fertilizer could not only achieve high yield, but also significantly improve RE_N in early-late season double cropping rice. The key technology provided in the study would be available for machine-transplanted double cropping rice cultivation in the Yangtze River regions.

Yield, Nitrogen Absorption and Utilization of Rice Varieties with the Highest Population Productivity of Nitrogen Fertilization in Huaibei Area

LIANG Jian,Li Jun,LI Xiao-Feng,SHU Peng,ZHANG Hong-Cheng,HUO Zhong-Yang*,DAI Qi-Gen,XU Ke,WEI Hai-Yan,GUO Bao-Wei

Acta Agron Sin. 2016, 42(08):  1188-1200.  doi:10.3724/SP.J.1006.2016.01188

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The field experiment was carried out using 34 medium-maturing medium japonica rice varieties grown in Huaibei area with seven nitrogen application levels (0, 150.0, 187.5, 225.0, 262.5, 300.0, and 337.5 kg ha^-1) to investigate their yield and nitrogen absorption and utilization. We defined the highest rice yields under different nitrogen levels as the highest population productivity of N fertilization. According to the highest population productivity of N fertilization, rice varieties were classified into four types including top type (TT), high type (HT), middle type (MT), and low type (LT). Yield components, population photosynthate production and N absorption and utilization of the four types rice varieties were compared. The main results indicated that optimum N levels of tested varieties corresponding to their highest population productivity of N fertilization converged in the range of 225.0-300.0 kg ha^-1, while the highest grain yields were significantly different among tested varieties. With increasing productivity level, panicles per unit area increased firstly and decreased then, spikelets per panicle and total spikelet number increased and seed-setting rate declined percentage of productive tillers, leaf area index, photosynthetic potential, ratio of leaf area of productive tillers, ratio of leaf area from flag leaf to 3rd leaf, grain-leaf ratio and total dry matter accumulation increased. The ratio of nitrogen accumulation shown trend of LT > MT > HT > TT from transplanting to jointing stage and TT > HT > MT > LT from jointing to heading stage and from heading to maturity stage. N uptake rate was the fastest in the top type, and the slowest in low type and 36.59%, 34.36%, 51.85% higher in top type than in low type at translating to jointing, jointing to heading and heading to maturity growing stages. N use efficiency and N requirement for 100 kg kernel increased with increasing productivity level. According to the N use efficiency, 34 varieties were divided into low ANRE (apparent nitrogen recovery efficiency), middle ANRE, higher ANRE and high ANRE. Wuyunjing 27, Zhongdao 1, Ningjing 4, and Lianjing 7 belonged to high yield and high ANRE varieties.

Effects of Potassium Fertilizer Rate on Biomass accumulation and Grain Yield of Yongyou Japonica/indica Hybrids Series

WEI Huan-He,MENG Tian-Yao,LI Chao,SHI Tian-Yu,MA Rong-Rong,WANG Xiao-Yan, YANG Jun-Wen, ZHANG Hong-Cheng,DAI Qi-Gen,HUO Zhong-Yang,XU Ke,WEI Hai-Yan,GUO Bao-Wei

Acta Agron Sin. 2016, 42(08):  1201-1214.  doi:10.3724/SP.J.1006.2016.01201

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In order to investigate proper potassium application rate and its effects on growth and grain yield for Yongyou japonica/indica hybrids series, a field experiment was conducted using Yongyou 12 and Yongyou 538 with five treatments of 0, 75,150,225, and 300 kg ha^-1potassium application. Results indicated that compared with check treatment (0 kg ha^-1), potassium application increased yield by 9.2−14.0% for Yongyou 12, and 9.8−15.0% for Yongyou 538. In both years, the highest yield of Yongyou 12 and Yongyou 538 was both achieved at potassium application rate of 225 kg ha^-1. Potassium application significantly increased number of panicles and spikelets per panicle. With the increase of potassium application rate, leaf area index and plant dry matter weight at jointing, heading, and maturity stages, as well as leaf area duration and dry matter accumulation from jointing to heading, and leaf area duration from heading to maturity were increased synchronously. Dry matter accumulation of plant from heading to maturity increased firstly and decreased then with the increase of potassium application rate, and the highest dry matter accumulation was achieved at potassium application rate of 225 kg ha^-1. Compared with check treatment (0 kg ha^-1), potassium application increased SPAD value, photosynthetic rate, and root blending rate from heading to maturity. Compared with check treatment (0 kg ha^-1), potassium application increased significantly nitrogen and potassium absorption at jointing, heading, and maturity stage. Nitrogen and potassium accumulation from heading to maturity was increased firstly and decreased then with the increase of potassium application rate, and the highest nitrogen and potassium accumulation was achieved at potassium application rate of 225 kg ha^-1. K partial productivity, internal nutrient efficiency in K, and K agronomy efficiency all decreased with the increase of potassium application rate.

Effect of Plant Growth Regulators on Key Enzymes in Sucrose Metabolism of Ear Leaf and Grain at Filling Stage of Spring Maize

LI Guang-Yan,WANG Qing-Yan,XU Yan-Li,LU Lin,Jiao Liu,DONG Xue-Rui,DONG Zhi-Qiang

Acta Agron Sin. 2016, 42(08):  1215-1223.  doi:10.3724/SP.J.1006.2016.01215

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In order to explore the new cultivation techniques, chemical control was established inthis study.We conducted a field experiment using two varieties of Zhongdan 909 and Jidan 35with treatments of leaf-sprayingethylene-chlormequat-potassium (ECK) in V6, andPASP-KT-NAA (PKN) in V9. The results showed that ECK & PKN increased the activities of sucrose synthetase(SS)and sucrose phosphate synthetase (SPS) and sucrose content during early grain filling stage (10-20 d after anthesis)in ear leaf, and decreased sucrose content in ear leaf during late grain filling stages (30-50 d after anthesis),especiallyit improved the ability of sucrose synthesis at the late filling stage (50 d after anthesis). ECK & PKN also decreased SS (synthesis) activity in grain during middle and late grain filling stages and increased SS (resolving) activity, promoting sucrose decomposition ability, withless effect on SS(synthesis) and SPS activitiesin grain. The yields of Zhongdan 909 and Jidan 35 compared with their own control were respectively increased by 4.61% and 7.78%.The studyindicated that ECK & PKN enhance sucrose synthesis in leaf and decompositionability in grain, andpromote the translocation of carbon assimilation to grain, resulting in highgrain-filling rate,high grain weight, and high yield.

Dynamics in Contents of Different Types of Polyamine in Wheat Embryos and Its Relationship with Resistance to Drought Stress

DU Hong-Yang, LIU Gu-Ting, YANG Qing-Hua,LIU Huai-Pan

Acta Agron Sin. 2016, 42(08):  1224-1232.  doi:10.3724/SP.J.1006.2016.01224

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This study aimed at understanding the functions of different kinds of polyamine in developing embryos of wheat under drought stress. The drought resistant variety “Luomai 22” and the drought-sensitive variety “Yumai 48” were treated for 10 days with drought stress (DS) and DS plus exogenous polyamines (Spd and Spm) and inhibitors (MGBG and O-Phen) on the 10th day after anthesis. In both varieties, the levels of free Put, Spd and Spm and the content of acid soluble covalently conjugated polyamines (ASCC-PA) increased under DS treatment, particularly, the free Put content in Yumai 48 increased rapidly and continuously during 10 days after treatment. The increased magnitude of free Spd and Spm contents in Luomai 22 embryos was similar to that in Yumai 48 embryos at the early stage of DS, but significantly larger than that in Yumai 48 embryos at later stage of DS. The content of acid insoluble covalently conjugated Put (AISCC-Put) was low in both varieties at early stage of DS, however, increased obviously in Luomai 22 at later stage of DS, with a significantly higher level in Luomai 22 than in Yumai 48. Application of exogenous Spd or Spm resulted in significantly increased free Spd and Spm contents in Yumai 48 at later DS stage; simultaneously, the relative water content of flag leaf and the relative dry matter increase rate of grain increased and the relative plasma membrane permeability of flag leaf decreased, indicating improved drought resistance in Yumai 48. Polyamine inhibitors showed negative effects on drought resistance, in which MGBG had a strong inhibition on the conversion from free Put to free Spd or Spm in embryos of Luomai 22 and O-Phen depressed AISCC-Put induction by drought stress. These results suggest that drought tolerance of wheat might be improved by the easy conversion from free Put to free Spd, Spm, or AISCC-Put after flowering.

Screening and Identification for Drought Resistance during Germination in Sorghum Cultivars

WU Qi,ZHOU Yu-Fei,GAO Yue,ZHANG Jiao,CHEN Bing-Ru,XU Wen-Juan,HUANG Rui-Dong

Acta Agron Sin. 2016, 42(08):  1233-1246.  doi:10.3724/SP.J.1006.2016.01233

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Germination is a key stage showing drought resistance in sorghum. The present study was conducted to investigate the responses of 54 different sorghum cultivars (hybrid combinations) to drought stress during germination and screen sorghum cultivars suitable for growing in arid environment. PEG-6000 (–0.4 MPa) was used to simulate the typical drought stress environment in artificial climate chamber. Eight parameters including germination potential, germination rate, germination drought resistance index were measured. The results indicated that the comprehensive factor score functions were suitable for the comprehensive assessment of drought resistance during germination of sorghum cultivars based on principal component analysis (PCA). Based on comprehensive factor scores (Y-value), 54 sorghum cultivars (hybridized combinations) were clustered into four groups, in which 13218A×20982R was the highest drought resistant hybrid, 13 cultivars (hybridized combinations) were drought resistant, e.g. Jiza 133, 23 cultivars were drought sensitive, e.g. Sumac, and 17 cultivars were highly drought sensitive, e.g. Liaoza 35. Results of PCA showed that germination drought resistance index, germination rate and root length can be used to screen a large number of sorghum cultivars with drought resistance.

RESEARCH NOTES

Rapid Development of Glu-1 Locus Near-isogenic Introgression Lines Using HMW-GS Deletion Mutant

ZHANG Xing-Xing,WANG Zhao-Jun,YANG Yu-Shuang,WANG Dao-Wen,ZHENG Wen-Ming,DONG Zhen-Ying

Acta Agron Sin. 2016, 42(08):  1247-1252.  doi:10.3724/SP.J.1006.2016.01247

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Wheat (Triticumaestivum L., AABBDD) highmolecular weight glutenin subunits (HMW-GS) were encoded by the genes located inGlu-A1, Glu-B1and Glu-D1 loci.Evaluation and optimization of the combination of HMW-GS are very importantto understand Glu-1functions. In this study, we constructed aHMW-GS deletion mutant, DLGlu1 withXiaoyan 81 background, and crossed it with Glenlea, a Canada elite wheat variety with superior end-use quality. Combining the technologies of wheat embryo culture and molecular marker-assisted selection (MAS), we obtained seven introgression lines containing GlenleaGlu-A1a, Glu-B1al, and Glu-D1d loci, which can be developed as a complete set of near-isogenic introgression lines possessingGlenleadifferentHMW-GS genes. Our study indicated that the Glu-1 deletion mutant DLGlu1is of great value in the fast development of Glu-1 near-isogenic introgression lines and the studyand utility of wheat Glu-1.

Cloning and Functional Analysis of wzy2-1Gene in Wheat

QIANG Zhi-Quan,LIANGYa-Jun,YU Zheng-Yang,DUYa,ZHANGShuai,ZHUWei-Ning,ZHANG Lin-Sheng

Acta Agron Sin. 2016, 42(08):  1253-1258.  doi:10.3724/SP.J.1006.2016.01253

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Dehydrins (DHNs) are identified as the group II of LEA proteins and involved in plant abiotic stress tolerance.In this study,we isolated a novel Kn-type dehydrin genefrom wheat cultivarZhengyin 1, which was designated wzy2-1.The full length of wzy2-1 is 1740bp,encoding 579 amino acids andcontaining nine conserved K-fragments.Sequence alignment indicated that wzy2-1hadhighhomologytoDhn5gene in Hordeumvulgare.The WZY2-1 protein waspredicted to be a highly-hydrophilic and disordered protein. The WZY2-1 protein was successfully expressed in E. coli strain BL21 (DE3). We found that WZY2-1 protein improved the tolerance to low or high temperature, salt and osmotic stressesin E. coli. The qRT-PCR assay indicated that the expression of wzy2-1gene was inducedby low temperature, PEG, and salt stresses rather than ABA. Thus, we conclude that wzy2-1 is an ABA-independent gene.