Table of Content

12 December 2011, Volume 37 Issue 12

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Mining and Analyzing Genetic Diversity for Maize Rough Dwarf Disease Resistant Gerplasms and Its Application in Maize Breeding

XUE Lin, ZHANG Dan, XU Liang, JIN Meng-Meng, PENG Chang-Dun, XU Chen-Wu

Acta Agron Sin. 2011, 37(12):  2123-2129.  doi:10.3724/SP.J.1006.2011.02123

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Maize rough dwarf disease generally caused by rice black-streaked dwarf virus (RBSDV)has been one of the main diseases in parts of maize production area in recent 10 years. Mining maize rough dwarf virus (MRDV) resistant germplasm and then breeding resistant variety is an economical and effective approach to control the disease. One hundred and eighty-four inbred lines including 111 common maize and 73 waxy maize were screened for reaction to MRDV under field conditions during 2009 and 2010 at Nantong, Jiangsu province, China. The genetic diversity of the tested materials was investigated based on 117 polymorphic SSR markers. Cluster analysis of 184 inbred lines was conducted based on genetic similarities from SSR data by using Powermarker 3.0 software with UPGMA method. The disease evaluation resulted in identification of two and eight inbred lines with high resistance and resistance to MRDV,respectively, among them two waxy inbred lines were identified. UPGMA analysis indicated that 184 inbred lines could be classified into nine sub-groups, which were generally consistent with their known pedigree information and breeder’s experiences. Two sub-groups that separately derived from 4S and US hybrid 78599 had better resistance to MRDV than other seven sub-groups and could be used as core germplasm in genetic improvement of maize for rough dwarf disease resistance in Jiangsu province.

Mapping of Gene Conferring Resistance to Anthracnose in Common Bean (Phaseolus vulgaris L.) by Molecular Makers

CHEN Meng-Li, WANG Lan-Fen, WANG Xiao-Ming, ZHANG Xiao-Yan, WANG Shu-Min

Acta Agron Sin. 2011, 37(12):  2130-2135.  doi:10.3724/SP.J.1006.2011.02130

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Tolocate gene conferring resistance to anthracnose caused by pathogenic fugus (Colletotrichum lindemuthianum) from Chinese common bean, we established F₂ plants and F₃ families derived from a cross between red common bean cultivar F2322 (resistant to race 81) and Jing common bean cultivar F0777 (susceptible to race 81), identified resistance, and did genetic analysis. The results showed that red bean carried a single dominant gene for resistance to anthracnose, designated as Co-F2322 tentatively. Molecular genetic linkage map was constructed withMapmaker 3.0 and Mapchart 3.0. Three SSR markers (BMc32, C871, Pvm98) and two CAPs makers (g1224 and g683) that linked to the resistance gene were mapped on B1 linkage group of common bean with the distance of 26.06, 3.58, 13.56, 3.81 and 12.75 cM, respectively.

Interaction between Two Self-incompatible Signal Elements, EXO70A1 and ARC1

YANG Hun, ZHANG He-Cui, Richard CONVERSE, SHU Li-Quan, YANG Yong-Jun, XUE Li-Yan, LUO Bing, CHANG De-Long, GAO Qi-Guo, WANG Xiao-Jia

Acta Agron Sin. 2011, 37(12):  2136-2144.  doi:10.3724/SP.J.1006.2011.02136

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ARC1 and EXO70A1 are important signal elements of self-incompatibility in Brassica. To identify the interaction of ARC1-EXO70A1 during the course of SI, we cloned the coding sequences of ARC1 and EXO70A1 from Brassica napus L.and Brassica oleracea L. var. acephala. Sequence analysis showed that ARC1 consisted of 663 amino acids in Brassica oleracea and 661amino acids in Brassica napus, and there existed 45 amino acids difference between them. Sequence alignment showed that similarity positions and identity positions reached 95.9% and 93.9% between BoARC1 and BnARC1, whereas there existed only six-amino-acid difference between BoEXO70A1 and BnEXO70A1. The Similarity positions and identity positions reached 99.4% and 98.9% between BoEXO70A1 and BnEXO70A1 respectively. The homology of EXO70A1 was higher than that of ARC1. Yeast two-hybrid results indicated that the strong interaction existed between ARC1 and EXO70A1, and it could activate the expression of four reporter genes (ADE2, HIS3, AUR1-C,and MEL1) in diploid yeasts. However, low interaction existed between EXO70A1 and ARC1_N with 316 amino acids deleted from C-terminal, and it only activated the expression of three reporter genes (ADE2, AUR1-C, and MEL1). This provides an insight that the interface of interaction between ARC1 and EXO70A1 may not consist of the domains of arm repeats in ARC1. N-terminal domains of ARC1 play an essential role in the interaction of ARC1-EXO70A1. The influences of the differences in amino-acid composition between BoARC1 and BnARC1 on the interaction of ARC1-EXO70A1 couldn’t be detected by means of yeast two-hybrid system, which probably resulted from that the binding interface between ARC1 and EXO70A1 was not altered by sequence difference of two proteins in two Brassica species.

Genetic Analysis and Molecular Mapping of Stripe Rust Resistance Gene in Wheat Cultivar Zhongliang 21

MA Dong-Fang, WANG Hai-Ge, TANG Meng-Shuang, YUAN Chi-Li, BAI Yao-Bo, ZHOU Xin-Li, SONG Jian-Rong, JING Jin-Hua

Acta Agron Sin. 2011, 37(12):  2145-2151.  doi:10.3724/SP.J.1006.2011.02145

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Wheat cultivar Zhongliang 21 displayed resistance to epidemic yellow rust races in China when tested with seven races of Puccinia striiformis f. sp. tritici (Pst). To use the elite resistance to Pst in wheat breeding, we identified the resistance gene (s) in Zhongliang 21 by means of phenotypic evaluation and molecular marker technique. Seedlings of the F₁, F₂, and BC₁ generations from the cross between Zhongliang 21 (resistant) and Mingxian 169 (susceptible), as well as the parents, were tested with Pst race CYR30. The results showed that the stripe rust resistance in Zhongliang 21 was conferred by a single dominant gene, which was designated Yrzhong21, temporarily. Ten simple sequence repeat (SSR) markers located on chromosome arm 5AL, Xgwm186, Xbarc165, Xwmc795, Xbarc40, Xgwm156, Xgwm617, Xwmc415, Xbarc151, Xwmc338, and Xgwm666, were linked to Yrzhong21 with the nearest flanking markers of Xgwm186 and Xbarc165. The genetic distances were 7.5 cM to Xgwm186 and 2.7 cM to Xbarc165. Based on chromosomal location, reactions to various pathotypes andpedigree analysis, we deduced Yrzhong21 is a novel resistance gene to stripe rust. Eighteen cultivars (lines) of Zhongliang series were tested with the flanking markers Xgwm186 and Xbarc165, and only 17% showed the same banding pattern as that in Zhongliang 21. This result suggested that 17% of Zhongliang cultivars (lines) might carry Yrzhong21, indicating that this resistance gene has a potential application in wheat breeding program for strip rust resistance.

Cloning and Expression of a Stress-induced GmPRP Gene in Soybean (Glycine max)

DI Ying, LEI Ting-Ting, YAN Fan, HUANG Kai-Meng, LI Xiao-Wei, ZHANG Qiang-Lin, ZHANG Hai-Jun, SU Lian-Tai, SUN Cuan, WANG Yang, LI Jing-Wen, WANG Qiang-Yu

Acta Agron Sin. 2011, 37(12):  2152-2157.  doi:10.3724/SP.J.1006.2011.02152

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Plant proline-rich proteins (PRPs) are putative cell wall proteins, which are usually associated with different abiotic and biotic stress conditions. A soybean mRNA sequence encoding a proline-rich protein (PRP) was cloned and designated as GmPRP from Jilin 32 immature embryo gene expression profiles using RT-PCR. The GmPRP consisted of an ORF with a length of 396 bp, and encoded 131 amino acids (13.79 kD) with an isoelectric point of 8.96. There was no intron in the DNA sequence of GmPRP. Except a repetitive proline-rich domain, GmPRP also contained a signal peptide in the N-terminal domain and a conserved eight cysteine motif in the C-terminal domain. The amino acid sequences of GmPRP, PvPRP and CcHyPRP shared high homology through phylogenetic analysis. The length of the promoter was 683 bp, containing several stress-induced elements: ABRE-like,G-box,W-box,GT-1,MYB,MYC,BIHD10s,DPBF,SEBF, and WRKY. Real-time quantitative PCR (qPCR) analysis revealed that GmPRP expressed highly in root and leaf and low in flower. qPCR was also performed to investigate the expression profiles of the GmPRP under different stresses such as drought, high salt, low temperature, wound, SA (salicylic acid), ETH (ethane), ABA (abscisic acid) and MeJA (methyl jasmonate). Under these stresses GmPRP showed up-regulated expression patterns. These results revealed that GmPRP might be involved in multiple pathways of plants responding to the different environmental conditions.

Analysis of Wheat Leaf Rust Resistance Genes in 14 Wheat Cultivars or Lines

HU E-E, ZHANG Na, LI Lin-Mao, YANG Wen-Xiang, LIU Da-Qun

Acta Agron Sin. 2011, 37(12):  2158-2166.  doi:10.3724/SP.J.1006.2011.02158

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The objective of this study was to detect resistance genes to leaf rust in 14 wheat cultivars or lines. The resistance of the 14 wheat cultivars or lines was investigated at seedling and adult stages, and the resistance genes at seedling stage were postulated by inoculating 16 races of Puccinia triticina. Further validation was conducted by using 21 molecular markers cosegregated with or closely linked to the known Lr genes. According to the results of both phenotypic identification and molecular marker data, the information of the resistance genes in the 14 cultivars or lines was obtained. Genes Lr3a, Lr28 and Lr50 were postulated in s98351-2-2-2-1. Gene Lr37 was possibly carried by 9629-03A-4-1-1. Lr26 was present in 97167-1-2-1-1-2-1, 919-20-2c2, 9589, Mianzhong 438, 9916-8-6, and 9916-8-18. Lr28 was possibly present in 96104-1-5-1c2. Lr1 was contained in 00-55-3-1-1. Lr24, Lr37, and Lr38 were possibly in 1R13. Lr24 and Lr38 were possibly carried by 1R17. Gene Lr10 and Lr34 were detected in 1R35, and Lr3a and Lr50 were also postulated in 1R35. Besides, 9524-1-2-2-1 might contain unknown or untested resistance genes against P. triticina pathotypes. Genes Lr9, Lr19, Lr20, Lr21, Lr29, Lr35, and Lr42 were not present in all cultivars or lines. The results indicate that these cultivars and lines carry diverse resistance genes to wheat leaf rust, and can be used as resistance resource for resistance breeding.

A Novel Quick Method for Detecting Target DNA Binding Sites of Protein

ZHU Ming, WEI Wei, CHEN Ming, ZHANG Xian-Sheng, XU Zhao-Shi, LI Lian-Cheng, MA Wei-Zhi

Acta Agron Sin. 2011, 37(12):  2167-2172.  doi:10.3724/SP.J.1006.2011.02167

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DREB (dehydration-responsive element-binding protein) transcription factors play important roles in the stress response and regulation of plants growth and development. In traditional DNase I Foot printing, DNA probes is labeled with isotope and then performed polyacrylamide gel electrophoresis to separate digested labeled-DNA fragments, which takes various steps, with low differentiation rate and to detect fewer samples. To explore the mechanism oftranscriptional regulation of DREB3 in soybean, we used an improved DNase I Foot-printing method combining with EMSA (electrophoretic mobility shift assay) to identify binding region of proteins and to find out the core element in binding site. In this research, DNA was labeled using fluorescence instead of isotope and automated capillary electrophoresis polyacrylamide gel electrophoresis was replaced to detect digested DNA fragments. Finally, DNA binding site of GmMYB1 with GmDREB3 promoter was identified rapidly via the modified DNase I Foot printing. On the other hand, restriction enzyme was used to validate this result. To further confirm binding element in GmDREB3 promoter, we used a putative DNA binding element of GmMYB1 to complete EMSA, indicating that GmMYB1 can bind target DNA element in vitro. In short, compared with classic DNase I Foot printing, the modified method is more rapid, accurate and reliable, which will be advantageous as a high throughout method to largely identification of interaction between protein and target DNA sites in the future.

Analysis of Genetic Structure for Indica Rice Landraces from Different Provinces in China

ZHANG Yuan-Yuan, SHU Ai-Ping, ZHANG Li-Na, CAO Gui-Lan, HAN Long-Zhi

Acta Agron Sin. 2011, 37(12):  2173-2178.  doi:10.3724/SP.J.1006.2011.02173

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Two hundred and eighty accessions of indica rice landraces from 14 provinces in China were analyzed using 78 microsatellite markers distributed across the whole rice genome. The genetic structure of indica rice landraces was studied by Powermarker, Structure 2.2 and Popgen 32 softwares. The 280 indica rice landraces were classified into six groups based on Nei′s genetic distance, the indica rice landraces of adjacent provinces were massed in same larger groups and those of each province were clustered together in same small groups. The genetic basis of indica rice landraces in same province was similar. But the indica rice landraces of Shaanxi were clustered in two groups and those of Taiwan in three groups, indicating their genetic bases were complicated. The 280 indica rice landraces were classified into four groups by Structure 2.2, and those of the provinces with near geographical position were clustered in the same groups. But the indica rice landraces of Shaanxi and Taiwan were dispersedly clustered in to different groups, which was similar with the result analyzed by Powermarker. The result analyzed by Popgen32 showed that 280 indica rice landraces were classified in to four groups at the level of 0.27, the landraces of adjacent provinces were clustered into same small groups or big groups except these from individual province. The results analyzed by three softwares were mainly accordant except partial difference, which can complement each other. The indica rice within a province was clustered together into small same groups, the genetic structure was correlated with geographical place. The genetic bases of indica rice landraces from Shaanxi and Taiwan was complicated.

Application of Artificial Neural Network in Genomic Selection for Crop Improvement

SHU Yong-Dun, TUN Lei, WANG Dan, GUO Chang-Gong

Acta Agron Sin. 2011, 37(12):  2179-2186.  doi:10.3724/SP.J.1006.2011.02179

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With important progress in marker technologies, marker-assisted selection (MAS) has been used broadly for the crop improvement. Biparental populations are designed for the detection of quantitative trait loci (QTLs), but their application is retarded. The association mapping (AM) is applied directly to natural populations, which has been proposed to mitigate the lack of relevance of biparental populations in QTL identification. Many QTLs are identified by the two methods, which have encouraged genetic improvement of crop. However, they are using significant thresholds to identify QTL from estimated means that estimated effects are biased. Therefore, small-effect QTLs can’t be identified and missed entirely, while lots of traits of crop are controlled by those small-effect QTLs. Genomic selection (GS) has been proposed to make good for these deficiencies. Genomic selection predicts the breeding values of lines in a population by analyzing their phenotypes and high-density marker scores, and by including all markers in the model, and benefits from unbiased estimation of all chromosome segment effects, even when they are small. The GS incorporates all marker information in the prediction model, which avoids biased marker effect estimates and captures more of the variation from small-effect QTLs. Furthermore, markers carry information on the relatedness among lines, which contributes to prediction accuracy. Such accuracies are sufficient to select parents strictly on the basis of marker scores even for traits such as yield, tolerance to abiotic stress. From the view of perspective of the products from plant breeding, the genomic selection would greatly accelerate the breeding cycle, and enhance annual gains. GS would develop a prediction model from training population, genotyped and phenotyped, by estimated the markers effects. Then GS model would take genotypic data from candidate population to predict genomic estimated breeding values (GEBV), and there are some methods used for GS model, such as best linear unbiased prediction (BLUP), ridge regression BLUP (RR-BLUP),and Bayesian linear regression (BLR). These models are well used for crop genomic selection breeding. However, all the models are developed based on line or regression, while the relationships of genetic sites in life are not non-line or regression. The neural network was introduced to genomic selection in crop improvement in this study. The crop genomic selection model was optimized by non-linear model system. Therefore, the high efficient genomic selection system was established, and the prediction results were compared with these of other linear models, such as RR-BLUP, BLR.In wheat genetic data simulation, the correlation coefficient between the true breeding value of unphenotyped experimental lines and that predicted by genomic selection based on the neural network reached 0.6636, while that of RR-BLUP, BLR and BLR with pedigree information was 0.6422, 0.6294, and 0.6573, respectively. Meanwhile, the best prediction was 0.8379, which indicated the genomic selection based on the neural network is superior to these of other linear regression models. This level of accuracy was sufficient for selecting for agronomic performance using marker information alone. Such selection would substantially accelerate the breeding cycle, and enhance gains per unit time. Therefore, this research showed that GS has more potential for incorporating it into breeding schemes.

Insect Pollinators in CGMS Hybrid Seed Production of Cajanus cajan

LI Zheng-Hong, LIANG Ning, MA Hong, Kul Bhushan SAXENA, LIU Xiu-Xian, ZONG Xu-Xiao

Acta Agron Sin. 2011, 37(12):  2187-2193.  doi:10.3724/SP.J.1006.2011.02187

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Pigeonpea [Cajanus cajan (L.) Millspaugh] is the only shrubby food legume crop in the world, with drought tolerance. Insect pollinators are essential on flower pollination in CGMS pigeonpea lines, and their species, abundance, visiting frequency are the key factors for pigeonpea hybrid production. More than forty-six species of insects were reported as flower visitors in the open field for pigeonpea production outside China, and Megachile spp. were the major pollinators. Reports on relations between insect pollinators and pigeonpea hybrid production were seldom in the world. In China, there is not any research report on relation between CGMS hybrid production of pigeonpea and its insect pollinators. Therefore, species, abundance, visiting frequency of flower-visiting insects at flowering stage and hybrid yield of pigeonpea were investigated recently, in pigeonpea hybrid production field in Yuanmou County in Yunnan province of China, using CGMS based ICPH2671 hybrid. The results indicated 25 species of flower-visiting insects were observed, among them the main species including Megachile velutina Sm., Megachile sp5, Xylocopa tenuiscapa Westw., Apidae sp and Megachile sp2 were confirmed. At blooming stage, the visiting frequency of flower-visiting insects on each observed primary branch of the CGMS male sterile line was 2.8 times per 10 minutes, while on CGMS restorer line was 5.2 times per 10 minutes. This indicated the preference of flower-visiting insects to the flowers of restorer line. The significantly different visiting frequency of flower-visiting insects between male sterile and restorer lines resulted in very similar dry seed yields of male sterile line (383.7 g plant^–1) and restorer line (357.0 g plant^–1). This indicated enough pollen transportation from restorer line to male sterile line by pollinators, even much less visiting frequency appeared on the flowers of male sterile line compared to that of restorer line.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of “Sanding” Cultivation Method on Nutrient Uptake and Nitrogen Use Efficiency in Double Cropping Super Rice

JIANG Peng, HUANG Min, Md. Ibrahim, CENG Yan, JIA Bing, SHI Wan-Ju, XIE Xiao-Bing, JU Ying-Bin

Acta Agron Sin. 2011, 37(12):  2194-2207.  doi:10.3724/SP.J.1006.2011.02194

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To determine the uptake and utilization pattern of nitrogen (N), phosphorus (P), and potassium (K) in double cropping super rice, we conducted a field experiment in Changsha and Liuyang city, Hunan province, China during 2008–2010. N, P, and K uptake and utilization of super early rice Luliangyou 996 and Lingliangyou 268 and super late rice Tianyouhuazhan and Fengyuanyou 299 were compared among “Sanding” cultivation method (quantify the target yield, quantify the population indexes and quantify the cultivation techniques), no-tillage and seedling broadcasting, and traditional cultivation method. Compared with traditional cultivation method, N, P and K accumulations by “Sanding” cultivation method were less at mid-tillering, almost the same at panicle initiation, and more at full heading (average amount of N, P and K uptake was 10.71, 2.23, and 11.82 g m^-2 in early rice, and 12.25, 2.69, and 16.37 g m^-2 in late rice, respectively) and maturity (average amount of N, P and K uptake was 13.61, 3.01, and 13.71 g m^-2 in early rice, and 17.16, 3.31, and 18.31 g m^-2 in late rice, respectively). Average nitrogen use efficiency with “Sanding” cultivation method [53.40 kg kg^-1, 55.98%, and 22.27 kg kg^-1 of partial factor productivity, nitrogen recovery efficiency (RE_N) and nitrogen agronomic efficiency (AE_N), respectively] was higher than that with traditional cultivation method by 29.00%, 88.20%, and 46.67%, respectively. N, P and K accumulation by “Sanding” cultivation method was similar to that by no-tillage and seedling broadcasting. However, average partial factor productivity, RE_N and AE_N with “Sanding” cultivation method were 6.29%, 6.12%, and 15.19% higher than those with no-tillage and seedling broadcasting, respectively. Thus, nitrogen use efficiency could be improved by adoption of “Sanding” cultivation method in double rice production in South China.

Influence of Planting Methods on Root System Morphological and Physiological Characteristics of Super Rice under High-yielding Cultivation Condition

LI Jie, ZHANG Hong-Cheng, CHANG Yong, GONG Jin-Long, HU Ya-Jie, LONG Hou-Yuan, DAI Ji-Gen, HE Zhong-Xiang, HU Ke, WEI Hai-Yan, GAO Hui

Acta Agron Sin. 2011, 37(12):  2208-2220.  doi:10.3724/SP.J.1006.2011.02208

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A field experiment was conducted to compare the root system morphological and physiological characteristics of two super rice cultivars (Huaidao9 and Xudao3) using three planting methods, i.e., precisionartificial transplanting with dry nursery middle and strong seedlings (AT), mechanical transplanting with small seedlings (MT) and direct seeding (DS). Results were as follows. (1) Yields of super rice under different planting methods were very significantly different. Compared with AT, yields of MT and DS reduced by 5.05% and 13.68%, respectively. (2) The population root number was DS>MT>AT, while the difference was decreasing with the growing process. Total population root length was shown to be DS>MT>AT at jointing and MT>AT>DS at heading and maturity. Root number per stem showed no significant difference among different planting methods, and total root length per stem was AT>MT>DS with generally significant difference. Length of single root was of no significant difference between AT and MT, though both were significantly higher than DS. As for root diameter, the result was AT>MT>DS and the difference among different planting methods was significant. (3) Population root dry weight showed no significant difference between MT and DS at jointing, that both had the extremely significantly higher value than AT. There was no significant difference among different planting methods at heading, but when at maturity it was AT>MT>DS and the difference was very significant. As for decreasing rate of population root dry weight after heading, it was DS>MT>AT with significant difference. Root dry weight per stem was AT>MT>DS through jointing, heading and maturity, and the difference among different planting methods was mostly very significant. Decreasing rate of root dry weight per stem after heading displayed no significant difference between DS and MT, but both of them had the significantly higher value than AT. Shoot dry weight reduced in order for AT, MT and DS, but root-shoot ratio increased in the same order. (4) Compared with AT, roots of MT and DS were mainly distributed within the soil layer of 0–10 cm underground, especially for DS, the root proportion in 0–5 cm soil layer could sum up to 65%. Ratio of root dry weight in 0–5 cm soil layer to total root weight increased in order for AT, MT and DS, while the ratios in the soil layers of 5–10 cm, 10–15 cm and >15 cm reduced in that order. (5) Population root absorption area showed no significant difference among different planting methods at jointing, performed as AT>MT>DS at heading with very significant difference, and, at maturity, showed no significant difference between MT and AT, both of which had the very significantly higher value than DS. Root absorption area per stem was of no significant difference between AT and MT at jointing and maturity while both had the very significantly higher value than DS, and was AT>MT>DS at heading with very significant difference. (6) Population root bleeding intensity after heading increased in order for AT, MT and DS, but root bleeding intensity per stem reduced in the same order. The results suggested that planting methods have significant influence on root morphological and physiological characteristics of super rice. The different single root length and diameter and the difference in root distribution pattern in soil layer are two most significant characteristics of rice roots under different planting methods. Compared with AT and MT, the DS method develops roots of shallower distribution, smaller single root length and diameter and higher population root number, though with shorter total root length per stem, lower root dry weight, and less absorption area and bleeding intensity after heading. Compared with AT, root diameter of MT was smaller, distribution shallower, after heading root dry weight of plant population and of single stem both lower and declining faster, and total root length and bleeding intensity per stem inferior.

Effects of Water Management and Nitrogen Application Strategies on Nutrient Absorption, Transfer, and Distribution in Rice

SUN Yong-Jian, SUN Wan-Wan, LIU Shu-Jin, YANG Zhi-Yuan, CHENG Hong-Biao, GU Xian-Wen, MA Jun

Acta Agron Sin. 2011, 37(12):  2221-2232.  doi:10.3724/SP.J.1006.2011.02221

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Hybrid rice Gangyou 527 was used to investigate the effects of three irrigation regimes (submerged irrigation, W₁; dry cultivation, W₃; and the treatment W₂ that was damp irrigation before booting stage, shallow irrigation at booting stage, wetting-drying alternation irrigation from heading stage to mature stage) and different nitrogen (N) application ratios on absorption, transport action and distribution of N, phosphorus (P), potassium (K), and yield in rice under the high yield condition of 180 kg N ha^-1. The results showed that there was an obvious interaction between water management and N application strategies on grain yield and N, P and K absorption and transfer at the mainly growth stages. Under water-nitrogen interaction condition, there existed significantly positive correlations between the amounts of N, P and K absorption at various growth stages, and there existed highly significantly positive correlations between the accumulations of N, P, and K at heading stage and their transfer amounts during filling stage, but excess the ratio of postponed N application to the total N rate or W₃ treatment resulted in the transport amounts of N, P, and K significantly decreased during grain filling e.g. 2.73–18.00%, 8.03–19.70%, 6.52–17.02%, respectively. Furthermore, there were positive correlations between yield and the accumulations of N, P, and K with the max correlation coefficients at heading stage, mature stage, and heading stage. The accumulations of N, K before heading stage could promote nutrient transfer and yield. According to yield performance and its relationship with N, P, and K absorption characteristics, the optimum ratio of postponed N application to the total N rate was 40–60% underW₁. The N application of base (30%), tillering (30%), and panicle (40%) fertilizers equally applied at stages of 4th and 2nd leaves emerged from the top under W₂, was the best model in this paper referred to as the water-nitrogen application coupling management model. However, W₃ treatment was suitable for using 20–40% of the ratio of postponed N application to the total N application rate.

Effects of Controlled-Release Urea on Yield and Photosynthesis Characteristics of Maize (Zea mays L.) under Different Soil Fertility Conditions

WANG Yong-Jun, SUN Ji-Zhuan, YANG Jin-Qing, WANG Kong-Jun, DONG Shu-Ting, YUAN Cui-Beng, WANG Li-Chun

Acta Agron Sin. 2011, 37(12):  2233-2240.  doi:10.3724/SP.J.1006.2011.02233

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Conventional fertilizers have played an important role to increase the yield during the production of maize in China. However, a great deal of conventional fertilizers utilization with low nutrient use efficiency not only leads to enormous waste of resource, but also causes the related environmental risk. Fortunately, controlled-release fertilizers with high nutrient use efficiency and low nutrient loss ratio are essential for increasing crop yield, nitrogen (N) utilization efficiency, and reduction of potential environmental risk. Additionally, soil fertility affects grain yield and fertilization utilization efficiency remarkably in practice. Obviously, it is essential to identify the optimum controlled-release urea (CRU) rate in different fields. Therefore, a pot experiment was conducted to explore the effects of controlled-release urea on yield and photosynthesis characteristics of maize under different soil fertility conditions from 2006 to 2007. In the trial, two types of controlled-release urea, CRU₃₀ and CRU₆₀ with 30 d and 60 d release durations, were used compared with the conventional urea (U) under two soil fertility conditions. All six treatments were supplied with N 5.43g pot^-1, P₂O₅ 2.10 g pot^-1 and K₂O 5.24 g pot^-1 as base fertilizer. Biomass above ground, harvest index (HI), leaf area (LA), net photosynthetic rate (P_n), chlorophyll content and nitrogen content were investigated. Biomass above ground was increased significantly by CRU, but the increasing effects were different to CRU₃₀ and CRU₆₀. Under low soil fertility conditions, the yield increase effect was CRU₃₀>CRU₆₀>U (P<0.05), and the dry matter weight in CRU₃₀ treatment was 18.9% higher than that in U treatment. Correspondingly, under high soil fertility conditions, that was CRU₆₀>CRU₃₀>U (P<0.05), and the dry matter weight in CRU₆₀ treatment was 18.29% higher than that in U treatment. In addition, CRU enhanced the dry matter distribution to grain and partial factor productivity from applied nitrogen (PFPN) significantly under two soil fertility conditions. Among all treatments for dry matter distribution after anthesis and PFPN, the effect of CRU₃₀ was the highest under low soil fertility condition, however, the effect of CRU₆₀ was the highest under high soil fertility condition. CRU improved the dry matter accumulation and partitioning to grain after anthesis, especially enhanced the biomass above ground per plant, grain number per ear and 1000-kernel weight remarkably because the treatments of CRU₃₀ and CRU₆₀ kept the LA, P_n, chlorophyll content and nitrogen content at a higher level after anthesis. Accordingly, the controlled-release urea with short release duration is suggested to be utilized as the base fertilizer under low soil fertility conditions, however, that with long release duration under high soil fertility conditions in practice.

Effect of Nitrogen Fertilization Timing on HMW-GS Accumulation and GMP Size Distribution in Wheat Grains

CAO Li, WANG Zhen-Lin, DAI Zhong-Min, YIN Yan-Ping, DI Hua-Xu, NI Yang-Li, CA Tie, LI Yong, WANG Beng, CHEN Er-Ying, GUO Dun-Xiang, CHEN Xiao-Guang

Acta Agron Sin. 2011, 37(12):  2241-2250.  doi:10.3724/SP.J.1006.2011.02241

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Wheat processing quality has close relationships with high molecular weight glutenin subunits (HMW-GS) and glutenin macropolyer (GMP) in grains. Nitrogen fertilization scheme could affect the accumulation of HMW-GS and the size distribution of GMP. In this study, we used a strong gluten winter wheat cultivar, Jinan 17, and a weak gluten winter wheat cultivar, Lumai 21, to investigate the effects of nitrogen topdressing stage on the accumulation of HMW-GS and the size distribution of GMP in grains. The nitrogen fertilizer rate during the whole growth period was 225 kg ha^-1, of which a half was applied as base fertilizer and the other half was topdressed at pseudo stem erection (SE, GS 30), jointing (JT, GS 32), or booting (BT, GS 41) stage. The spike samples were collected from 7 d after anthesis (DAA) to maturity with a 7-day interval. The HMW-GS in grains formed before 14 DAA, and Jinan 17 had higher contents of HMW-GS and GMP than Lumai 21, which indicated that more glutenin is accumulated in the strong gluten cultivar than in the weak gluten cultivar. At maturity, the contents of HMW-GS and GMP in Jinan 17 showed decreasing trends with the delay of topdressing practice, and the highest values were observed in the SE treatment. In Lumai 21, compared to the SE and BT treatments, the JT treatment significantly accelerated the HMW-GS accumulation at middle-late stage of grain filling, and the rapid accumulation period was prolonged. At middle-late stage of grain filling, the accumulation rates of x-type subunits (1, 4, 5, and 7) were increased significantly in the SE treatment of Jinan 17 and the JT treatment of Lumai 21, whereas the y-type subunits were seldom affected by nitrogen application timging. For both cultivars, delay of nitrogen topdressing enhanced the percentages of volume and surface of GMP particle with diameter less than 12 μm, but reduced those of GMP particle with diameter larger than 100 µm. The percentage of GMP particle number with diameter larger than 12 μm was increased in Jinan 17 with the delay of nitrogen topdressing but decreased in Lumai 21.The percentage of large GMP particle volume was higher in Jinan 17 (containing subunit pair 4+12) than in Lumai 21 (containing subunit pair 5+10). This result suggested that polymerization of subunits and GMP particles are related to not only the subunit type but also the subunit content per unit of flour.

Differentiation of Multiple Shoot Apical Meristems in Mutant Rice with One Embryo Causing Multiple Plumuples

GUO Jing-Yu, CHEN Zhi-Xiong, YANG Bing-Yao, CHEN Xin-Fen, LIU Xiang-Dong, LEI Yong-Gen

Acta Agron Sin. 2011, 37(12):  2251-2260.  doi:10.3724/SP.J.1006.2011.02251

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The proper formation and development of shoot apical meristem during plant embryonic development is prerequisite to generate leaves, buds and stems. Rice (Oryza sativa L.) mutant line 4001 produces multiple plumules in one seed and is considered as an important mutant with abnormal differentiation of shoot apical meristem. While the embryonic basis of the mutant with multiple plumules is yet unknown. To elucidate the cytological basis, mature embryo sac structure and process of double fertilization were observed with whole-mount eosin B-staining confocal laser scanning microscopy (WE-CLSM), semi-thin plastic sections and scanning electron microscopy (SEM). The observation by WE-CLSM showed that both embryo sac structure and double fertilization process were normal in the mutant line, suggesting that the abnormal traits were related to the later embryonic development. By semi-thin plastic sections and SEM, the retardation of embryonic development and the formation of multiple shoot apical meristems (SAM) under abnormal orientation were observed in one embryo of the mutant line, compared with those of wild-type rice. At three days after pollination, the process of embryonic development was slower in the mutant line than in the wild type rice. The abnormality included the diverse number of SAMs under irregular orientation and the changes of dorsal-ventral axis. Two separate plumules, two plumules in one coleoptile and two connected plumules with one separate plumule were also observed in the mutant line 4001. It was concluded that differentiation of multiple SAMs and the the changes of dorsal-ventral axis in one embryo contribute to the multiple plumuples in the mutant line. It was inferred that mutant trait-related genes might play important roles in the regulations of the timing of shoot apical meristem differentiation, the number of undifferentiated cells and the establishment of dorsal-ventral axis.

Effects of Nitrogen Application on Agronomic Traits and Yield of Rapeseed in No-tillage Rice Stubble Field

HAN Zi-Hang, ZHANG Chang-Sheng, WANG Ji-Jun, ZHANG Dong-Xiao, SHANG Song, CHEN Ai-Wu, ZHOU An-Sheng, HU Li-Yong, TUN Jiang-Sheng, FU Ting-Dong

Acta Agron Sin. 2011, 37(12):  2261-2268.  doi:10.3724/SP.J.1006.2011.02261

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To investigate the effects of various nitrogen applications adapted to direct-seeding rapeseed on agronomic performances and grain yields in no-tillage rice stubble field, we used the rapeseed cultivar Huaza 9 in plot experiments under the no-tillage direct-seeding and transplanting cultivations during 2006–2010. It was observed that a top-dressing applied during the duration of stem extension increased grain yield under various base manure application rates. When two top-dressing were used during the growth of the rapeseed plants, effects of fertilizer applications on yield formation depended on application date and amount of base manure. When base manure application rate was 112.5 kg N ha^–1, the high grain yields were obtained with the top-dressing applied for the stem extension and flowering, respectively. However, in the condition that the base manure application rate was 202.5 kg N ha^–1, the high grain yields were gained when the mid-December fertilizer and stem-extension fertilizer were applied. On the other hand, when the base manure and top-dressing fertilizers were setting at the ratio of 5:5, the high grain yields were observed for both direct-seeding and transplanting rapeseeds, independent of the amount of nitrogen application. The results also showed that the mentioned four modes for nitrogen application significantly decreased the amount of N-fertilizer and increased the grain yields under both no-tillage direct-seeding and transplanting cultivations.

Effects of Cadmium Stresses on Physiological Characteristics, Pod Yield, and Seed Quality of Peanut

GAO Fang, LIN Yang-Jie, ZHANG Jia-Lei, YANG Chuan-Ting, ZHANG Feng, YANG Xiao-Kang, DIAO Hua-Jian, LI Xiang-Dong

Acta Agron Sin. 2011, 37(12):  2269-2276.  doi:10.3724/SP.J.1006.2011.02269

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A pot experiment was carried out to study the effects of different cadmium concentrations on peanut physiological characteristics, yield and quality using peanut cultivars of Yuhua 15 and XB 023. Five Cd concentrations [0 mg kg^–1 (CK),1.0 mg kg^–1 (light Cd stress),2.5 mg kg^–1 (medium Cd stress),7.5 mg kg^–1 (heavy Cd stress) and 15.0 mg kg^–1 (high Cd stress)] were treated by basal dressing in 2009 and 2010. The results showed that light and medium Cd stresses could promote peanut vegetative growth, but heavy and high Cd stresses inhibit its growth. Heavy and high Cd stresses decreased the chlorophyll content and photosynthetic rate of the two peanut cultivars while light and medium Cd stresses increased the chlorophyll content of XB023 leaves. Cd stresses decreased the yield of pod and kernel. The yield of Yuhua 15 decreased obviously when the Cd concentration reached 2.5 mg kg^–1 (medium Cd stresses), however, for XB023, reached 7.5 mg kg^–1 (heavy Cd stresses). Cadmium stress had different influence on peanut quality in different cultivars. It could increase the content of soluble sugar, decrease the content of protein and oil, and reduce the ratio of oleic acid to linoleic acid (O/L) in Yuhua 15 kernels; But decrease the content of soluble sugar and oil, reduce the ratio of oleic acid to linoleic acid (O/L) in XB023 kernels. Light and medium Cd stresses could increase the content of protein and its components of Lys and Thr in peanut kernels. Cd stresses could increase the cadmium content in peanut. The cadmium content was higher in Yuhua 15 plants than in XB 023 plants, but was less in seed kernel than in XB 023 kernel.

RESEARCH NOTES

Method Comparison of Using SRAP and ISSR and Combination of Both in Origin and Evolution of Jute

DAO Ai-Fen, QI Jian-Min, SU Jian-Guang, LI Ai-Jing, LI Mu-Lan, FANG Beng-Beng, LIN Li-Hui, XU Jian-Tang, TUN Jian-Mei, LIN Pei-Qing

Acta Agron Sin. 2011, 37(12):  2277-2284.  doi:10.3724/SP.J.1006.2011.02277

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The objective of this study was to compare the feasibility of using SRAP, ISSR and combination of the both in origin and evolution of jute (Corchorus L.). Ninety-six jute genotypes were tested by these three methods. The results were as follows: (1) The percentage of polymorphic bands of SRAP was 100%, which was higher than that of 98.1% of ISSR, and the polymorphic bands amplified per primer by SRAP were also higher than these of ISSR. (2) On the dendrogram based on SRAP data, jute genotypes were close to be classified. The trend of origin and evolution of jute could be clarified. However, a few genotypes were misled to other taxonomic groups, which affected the accuracy of analysis on origin and evolution of jute. On the dendrogram based on ISSR data, many capsularis cultivars were found to be clustered together and couldn’t be identified clearly, and also the time of origin was difficult to confirm. (3) Based on the dendrogram derived from SRAP and ISSR data, different taxonomic groups of jute were found to be clustered orderly, and the relationship of origin and the trend of evolution within jute genus manifested clearly. (4) The strategy of SRAP and ISSR combination was better than that of SRAP alone, and then followed by ISSR. Hence, the strategy of SRAP and ISSR combination should have priority in studies on the origin and evolution of jute.

Mitochondrial Microsatellite Variability of Tobacco CMS Lines with Four Different Cytoplasms

LI Feng-Xia, YANG Ai-Guo, CUI Meng-Meng, GONG Da-Beng, WANG Wei-Feng, SUN Yu-Ge

Acta Agron Sin. 2011, 37(12):  2285-2292.  doi:10.3724/SP.J.1006.2011.02285

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Sequence variation of the mitochondrial DNA has a direct relation with cytoplasmic male sterility (CMS). In this study, we analyzed mtSSR variability offour sterile cytoplasm types, including four CMS lines, their maintainer lines and sterial cytoplasm sources, and explored the relationship between mtSSR variability and CMS. Based on the entire mitochondrial DNA sequence of Nicotiana tabacum, we identified 39 mtSSR loci having more than ten mononucleotide repeats and 24 mtSSR markers that can be used to analyze mitochondrial DNA variability of four sterile cytoplasm types. The results showed that the mtSSR polymorphism was very low in N. tabacum, which was 10.5%, and there were some different loci between the CMS lines and their maintainer lines, the wild tobaccoprovided the sterile cytoplasm. Such as, in the Nat(sua.)S, the different loci were located in coding regions of orf138a, orf138c and intergenic region orf102–orf210; in the Nat(gla.)S, the different loci were located in two coding regions of orf138a, orf138c and four intergenic regionsnad2–sdh3, rps12–orf125b, orf116–orf101b, orf102–orf210; in the Nat(rep.)S, the different loci werelocated in coding regionorf190 and intergenic region orf104c–orf202; in the Nat(rus.)S, the different loci werelocated in coding regions oforf137 and rps12–orf125b. These different loci likely related to their CMS. The results also showed that the fragments of 184, 172, 212 and 225 bp were amplified by mtSSR primer TMS20 in four types of CMS of ms G-28, 86-6, 98-43, 116, respectively, and using this primer we could distinguish the four types of CMS of Nat(sua.)S, Nat(gla.)S, Nat(rep.)S, Nat(rus.)S between each other.

Effect of Low Temperature at Seedling Stage on Antioxidation Enzymes and Cytoplasmic Osmoticum of Leaves in Wheat Cultivar Yangmai 16

LI Chun-Yan, CHEN Sai-Sai, XU Wen, LI Dong-Sheng, GU Xiao, SHU Xin-Kai, GUO Wen-Shan, BIAN Chao-Nian

Acta Agron Sin. 2011, 37(12):  2293-2298.  doi:10.3724/SP.J.1006.2011.02293

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Morphological, physiological and biochemical changes in wheat seedlings (cv. Yangmai 16) under low temperature treatments (-4°C, -6°C, and -8°C) were studied by means of artificial temperature-controlled phytotron. Severer freezing-injured plants were observed in treatments with lower temperature and longer stress. The symptoms of injury were that the top of leaves became yellow and wilting (the second and third grade of freezing injury), then the whole leaves were all wilting (the fourth grade of freezing injury), and main stems and most of tillers were finally dead (the fifth grade of freezing injury). No plants showed freezing injury greater than the third grade in treatments of -4°C and -6°C for 24 h. However, the treatments of -8°C for 24 h and 48 h resulted in 16.7% and 39.6% of plant being frozen to death, respectively. The activities of superoxide dismutase (SOD), catalase (CAT), and peroxide dismutase (POD) in the second leaf from the top increased at the beginning of low temperature treatments, and with the increasing of stressSOD activity declined. The contents of malonaldehyde (MDA), proline, soluble sugar, and soluble protein were significantly increased in treatments with lower temperature and longer stress. These physiological and biochemical changes may help to alleviate the low-temperature injury to wheat plants.

Cotton Hybrid Purity Tested by SSR Markers and Its Correlation with Phenotype Identification in Field

KUANG Meng, YANG Wei-Hua, ZHANG Yu-Cui, HU Gong-Xia, WANG Yan-Qin, ZHOU Da-Yun, FENG Xin-Ai, SU Chang, ZHOU Gong

Acta Agron Sin. 2011, 37(12):  2299-2305.  doi:10.3724/SP.J.1006.2011.02299

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Cotton is one of the most important cash corps. Hybrid cotton is extensively grown in China. Hybrid seeds are generally planted and used for purity identification. The processtakes long time and much money. Therefore, it is important to explore a new method to inspect the purity of hybrid cotton. In order to explore the validity of hybrid cotton purity identification using SSR marker technique, the purity for six hybrids was tested by SSR approach and morphological assessment, and the correlation between the two methods was researched. Primers with complementary band type screened out from 36 evenly distributed SSR pairs were applied in purity identification. Morphological traits including plant type, boll, leaf shape, flower and stem were observed. Two statistics methods were used for testingpurity based on SSR marker, and the results were compared to that of morphological identification. Among the six hybrid cottons, 34 primer pairs had 101 heterozygous loci, with an average of 16.8 heterozygous loci for on each hybrid. The purity based on morphology was higher than that on SSR markers, the results of “Single locus on average” (the average value of purity test by each SSR locus) had a higher correlation with morphology compared to “Double locus difference” (if more than two SSR loci of an individual are different from the tested cultivar’s, the individual is considered as farraginous plant), and the correlation would be better after calibration (correlation coefficient reached to 0.7841). Correlation based on EST-SSR was much better than that on Genomic-SSR. There was certain relativity at different loci of the same chromosome. The purity was relevant to different statistics method and marker type. There will be a good correlation for purity identification between methods of SSR marker and morphology if the hybrid parents are highly pure.