Table of Content

12 July 2006, Volume 32 Issue 07

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ORIGINAL PAPERS

Evolution Characteristics of Grain Yield and Plant Type for Mid-season Indica Rice Cultivars

YANG Jian-Chang;WANG Peng;LIU Li-Jun;WANG Zhi-Qin;ZHU Qing-Sen

Acta Agron Sin. 2006, 32(07):  949-955. 

Abstract ( 2148 )   PDF (706KB) ( 1648 )   Save

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Rice is a most important food crop in China and its grain yield per hectare has been over 6 ton in recent years, which is 65% higher than that of the world, on average. Improvement in rice cultivars plays an important role in the increase of the grain yield. However, little is known about physiological and agronomical features responsible for the improvement. In this study, 16 typical mid-season indica rice cultivars (including hybrid combinations) applied in the production in Jiangsu Province during the last 60 years were used, and classified into six types of early tall (ET), improved tall (IT), dwarf cultivars (DC), semi-dwarf cultivars (SDC), semi-dwarf hybrid (SDH), and super rice (SR), according to their application times, plant types and genotypes. All the tested cultivars were grown in the field and the evolution characteristics of grain yield and its components, source-sink relationships and plant types were investigated. Results showed that grain yield was progressively increased with the evolution of the cultivars. Increase in grain yield was attributed mainly to the increase in total number of spikelets, which resulted mainly from large panicles. DC had the greatest, whereas SR had the least, percentage of filled grains. There was no significant difference in 1000-grain weight among the six types of cultivars. From ET to DC, plant height was reduced and biomass and harvest index were simultaneously increased, especially the harvest index increased more. From DC to SR, plant height was a little increased, and biomass dramatically increased, especially after heading, and harvest index a little changed. Improvement of rice cultivars significantly reduced the leaf angle of the top three leaves on stems and increased leaf area at heading. Increase in spikelets, however, was more than that in leaf area, which resulted in the increase of grain-leaf ratio (the ratio of total spikelet number to leaf area at heading). With the improvement of rice cultivars, root dry weight and the ratio of root to shoot were increased, but the amount of root bleeding sap was reduced. The speed of reduction in the concentration of zeatin and zeatin riboside in root bleeding sap and leaves from heading to maturity was SR>SDH>SDC. The results suggest that enlargement of sink resulted from large panicles, increase in biomass especially from heading to maturity and improvement of plant type contribute to the increase of grain yield for modern rice cultivars. Low root activity may account for the low percentage of filled grains for SR. Approaches to further increase in grain yield of rice were discussed based on the evolution characteristics of the cultivars.

Evaluation of the Plant Growth Model GREENLAB-Maize

MA Yun-Tao;GUO Yan ; ZHAN Zhi-Gang;LI Bao-Guo;Philippe de Reffye

Acta Agron Sin. 2006, 32(07):  956-963. 

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Plant architecture and topology are important determinants of crop performance and agro-ecological adaptation, and should thus be taken into account in crop modelling approaches. This has not been done in most crop models designed to answer agronomic questions.
GREENLAB-Maize model combines the dynamic simulation of the complete plant architecture with simple algorithms of biomass formation, for which the growing organs are competing. Plant is considered at organ level (roots, leaves, internodes, cobs, etc.) and thus as a set of sinks competing for assimilates. Morphogenetic processes are governed by generic organ expansion laws associated with organ-specific parameters supposed to be independent from environmental conditions. Environment will then define the carbon supply available to the plant at any given time step. An advantage of the model is that it can be used to get the values of parameters for a given species (target file) to retrieve morphogenetic and organogenetic history of the plant.
Based on the above reasoning, multi-fitting technique was introduced in GREENLAB-Maize model to compute the values of endogenous parameters, which can trace back the dynamical process between source and sink as plant growth. The aim of this study was to make a first evaluation of the ability of GREENLAB-Maize to get the values of endogenous parameters taking both field heterogeneity and inter-annual trials according to the variability in environmental condition. This study focused on the case of one maize genotype cropped in three years in non-limiting conditions but with natural seasonal variation.
Four field experiments were conducted at the China Agricultural University (latitude N，longitude E). ND108 cultivar seeds were sown in rows in north-south direction with a row spacing 0.6 m and plant spacing 0.6 m within the row (27 778 plants·ha^-1). Water and nutrients were supplied to maintain non-limiting conditions. Meteorological data were acquired from a field station located on the site. Tillers were pruned systematically when they appeared to maintain ‘mono-culm’ architecture. The average number of leaves in a plant of this genotype at maturity was 21. Four plants were taken to measure the fresh weights and dimension of individual organs (i.e. internodes, leaf sheaths, leaf blades, cobs and tassels). Leaf blade area was characterized using a LI-COR Model 3100 Area Meter (Lincoln, NB, USA).
Statistical analysis of the results showed that (1) multi-fitting clearly improves the stability of parameters more among experiments and growths than single fitting; (2) the biomass of the plant and its parts were significantly different between years and seasons (except leaf sheath biomass), but not among plants sampled at the same time; (3) the differences of endogenous parameters were little between different years, growth stages and individual maize plant.
The parameters optimized with multi-fitting of year 2000 experiment were then considered as the reference set of parameters and used to simulate plant growth for other experiments. There was a good agreement between simulated and measured data for organ biomass and geometry. Then three-dimensional visualization of maize plant among different growth stages were brought about based on these processes to study the growth of individual maize plant.

Researching the Mechanism in Plant in vitro Culture via “Communication” Experiment and to Establish the Methods Widely Used for Tissue Culture of Wheat

WANG Hai-Bo;FAN Yun-Liu

Acta Agron Sin. 2006, 32(07):  964-971. 

Abstract ( 1881 )   PDF (832KB) ( 1055 )   Save

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Plant in vitro culture has a history of more than one hundred years, but it is still unable to be predicted and inferred. There are 4 kinds of elements for plant in vitro culture: genotype (genetic elements), explant-type (physiological elements), medium (chemical elements), culture-conditions (physical elements). In order to find out the effects of these elements and the mechanisms in plant in vitro culture, a series of “communication” experiments aimed at revealing the relationship between culture- elements and culture-results were conducted. Wheat was used as the main materials (Table 1). Callus induction, subculture and callus quality improvement and evaluation were carried out with mature and immature embryos of different varieties on different media (MS, LS, N6, C17 etc.) under different conditions (Table 2, 3). The effects of genotype, explant-type, medium, culture-conditions to plant tissue culture were studied systematically. The results showed that: Genotype only determined the quality but did not limit the induction of callus. Explants affected both the formation of callus and its quality at early stage. The difference of callus quality originated from explants was no less than that from genotypes. Despite of providing nutrients, medium also played a very important role in regulating the quality of callus. Generally, 2,4-D, NH₄⁺ usually accelerated cell division and the growth of callus but cytokinin, NO₃^- showed opposite effects. Light had the similar effects to cytokinins. Temperature variation played an influential role to callus too. These results were also improved with corn, rice, millet, cotton and so on. All the functions from these elements in in vitro culture can be considered or imagined as the effects at physiological and biochemical levels and they can be managed as coadjutant factors according to the needs of callus quality improvement. With this idea, plant in vitro culture comes to be more controllable. Through this study, a series of methods wildly used for wheat tissue culture was established.

Effect of Controlled Soil Drying on Grain Filling and Activities of Key Enzymes for Starch Synthesis in Rice (Oryza sativa L.)

WANG Wei ;CAI Yi-Xia;CAI Kun-Zheng;ZHANG Jian-Hua ;YANG Jian-Chang;ZHU Qing-Sen

Acta Agron Sin. 2006, 32(07):  972-979. 

Abstract ( 1913 )   PDF (656KB) ( 1233 )   Save

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Heavy application of nitrogen fertilizer, especially in highly productive areas, is well known to lead a delayed senescence. Unfavorably-delayed senescence retards the active and ordered process that partitions the photosynthetic assimilates into grains, and results in a decrease in grain-filling rate and grain weight. A moderate soil drying applied at grain filling period can enhance the plant senescence and may improve grain filling. In present study, the concrete container experiments were conducted at Yangzhou University. Two rice combinations were grown at the rate of 5 g N·m^-2 (NN) and 20 g·m^-2(HN) at initial heading in order to have variable development of senescence. A moderate soil drying was imposed from 9 d after anthesis in consideration that the division of endosperm cell is sensitive to water deficit. The study was designed to test the hypothesis: if a soil drying is controlled properly at mid-late stage of grain filling, an early senescence induced by drought stress would accelerate the rate of grain filling and increase grain weight and yield where the senescence is unfavorably delayed. If so, it would be further evaluated whether the enzymes regulating grain starch synthesis were changed by water stress.
In present study, we found that, plant senescence was unfavorably delayed by heavy application of nitrogen, which resulted in a slow grain filling and low grain yield (Table 1). Water deficit treatment significantly reduced mid-day leaf water potential and enhanced plant senescence at mid-later stage of grain filling (Fig.1, Fig.2). Such drought stress significantly increased grain-filling rate by 8.5%–13.6% at NN and 25.3%–28.0% at HN, and shortened grain-filling period by 2.8–3.9 d at NN and 4.2–4.9 d at HN, respectively, when compared to well-watered treatments(Table 1). The grain weight and grain yield in water stress treatments were significantly decreased at NN, but significantly increased at HN. A slow rate of starch accumulation caused by HN application was attributed to enzyme activity decreases in the metabolism of sucrose to starch (Fig.3, Fig.5 and Fig.6). The treatment of water stress increased sink activity by increasing enzyme activities, including sucrose synthase (SuSy), ADP-glucose pyrophosphorylase (ADP-Gppase), soluble starch synthase(SSS) and starch branching enzyme (SBE), and resulted in enhanced starch accumulation in grains (Fig.5, Fig.6). In NN treatments, the shortage of assimilation supply and the enzyme activity decreases in the metabolism of sucrose to starch were responsible for the decreases in grain weight and yield under water stress conditions(Fig.4, Fig.5 and Fig.6). It is concluded that a soil drying is properly applied in conditions where plant senescence was unfavorably delayed caused by heavy application of nitrogen fertilizer, can improve grain filling through increasing starch accumulation rate, as the result of inducing and enhancing activities of SuSy, ADP-Gppase, SSS and SBE.

Influence of Puroindoline Gene on Milling Performance, Steamed Bread and Noodle Qualities in Spring Wheat

CHEN Feng;CHEN Dong-Sheng ;QIAN Sen-He;ZHANG Yan;XIA Xian-Chun;HE Zhong-Hu

Acta Agron Sin. 2006, 32(07):  980-986. 

Abstract ( 1969 )   PDF (573KB) ( 1234 )   Save

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Grain hardness, controlled by hardness gene (Ha) on the short arm of chromosome 5D, is one of the most important quality characteristics and serves as a basis for classification and marketing of bread wheat (Triticum aestivum L.) quality. A total of 41 wheat cultivars (lines) from Chinese spring wheat region and CIMMYT were used to investigate variation of SKCS hardness index, puroindoline alleles, milling yield, flour ash content, water absorption, flour color (L*, a* and b*), total pentosans and water-soluble pentosans contents, steamed bread and noodle processing qualities. Five Pina-D1a/Pinb-D1a (wild type), 28 Pina-D1b/Pinb-D1a, seven Pina-D1a/Pinb-D1b and one (Qingchun 533) Pina-D1a/Pinb-D1c genotypes were observed in surveyed wheats. Grain hardness showed significantly positive correlation with water absorption (r=0.80), while significantly negative correlation with flour brightness L* (r= －0.77). Means of SKCS hardness index, milling yield, water absorption, and steamed bread weight, volume, width and total score in genotypes with mutational puroindoline allele were significantly higher than those in wild type. Means of SKCS hardness index, flour ash content, flour a* absolution value and water-soluble pentosans content in genotypes with PINA null (Pina-D1b/Pinb-D1a) were significantly higher than those of Pina-D1a/Pinb-D1b, while surface score of steamed bread and firmness of noodle is significantly lower than those of Pina-D1a/Pinb-D1b. In addition, means of noodle brightness L*, L*－b* value and firmness in wild genotype (Pina-D1a/Pinb-D1a) were significantly higher than those in PINA null (Pina-D1b/Pinb-D1a) type, while surface color of steamed bread and yellowness of noodle was significantly lower than those in PINA null type. This indicated that the performance of steamed bread and noodle from Pina-D1a/Pinb-D1b type is slightly superior to that from wild type and PINA null. This study provides useful information for improving Chinese wheat quality.

Site-specific Nitrogen Management Increases Fertilizer-nitrogen Use Efficiency in Rice

LIU Li-Jun;XU Wei;SANG Da-Zhi;LIU Cui-Lian;ZHOU Jia-Lin;YANG Jian-Chang

Acta Agron Sin. 2006, 32(07):  987-994. 

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Low fertilizer-nitrogen (N) use efficiency (FNUE) is a serious problem in rice production in China. The objective of this study was to explore the possibility to improve FNUE by adopting real-time N management (RTNM) and site-specific N management (SSNM). With an indica hybrid rice Shanyou 63 and a japonica cultivar Wuyujing 3 as materials, a plot experiment in field conditions was carried out during 2001–2003 to evaluate agronomic performance and FNUE under RTNM and SSNM. The results showed that grain yield in the plot without N application ranged from 5.5 to 7.4 t/ha (Table 4), indicating rather high indigenous N content in soil. Compared with farmers’ fertilizer practice (FFP), RTNM and SSNM increased grain yield by －4.4% to 7.0% and 0.2%–9.3%, agronomic efficiency (AE) of fertilizer-N by 195.7%–297.0% and 169.6%–276.4%, respectively (Table 5). SSNM was demonstrated in 20 farmers’ fields in two villages of Wuxi, Jiangsu Province in 2003 and 2004. AE, recovery efficiency (RE) and physiological efficiency (PE) of fertilizer-N in FFP in two years were only 2.8–6.7 kg grain/kg N, 33.7%–34.7% and 8.4–18.6 kg grain/kg N, respectively. SSNM reduced N rate by 38.7%–41.3%, increased grain yield by 2.5%–3.5%, and enhanced AE, RE and PE by 88.3%–117.7%, 34.0%–39.5% and 46.1%–61.6%, respectively (Table 6 and Table 7), when compared with FFP. Similar results were obtained on large-scale extension of SSNM in Jiangsu Province (Table 8). These results suggested that SSNM has great potential for improving FNUE without any sacrifice in the yield. AE and PE in SSNM in farmers’ fields were still very low in this study. Reasons for low FNUE and approaches to improving it were discussed.

QTL Mapping for Developmental Behavior of GMP Content in Wheat

LI Wei-Hua ;YOU Ming-Shan;LIU Wei;XU Jie;LIU Chun-Lei;LI Bao-Yun ;LIU Guang-Tian

Acta Agron Sin. 2006, 32(07):  995-1000. 

Abstract ( 1868 )   PDF (490KB) ( 1189 )   Save

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Glutenin macropolymer (GMP) content is a key factor influencing wheat processing quality, which is determined by quantitative trait locus (QTL). To date many QTLs related to quality characteristics, including the GMP content, have been mapped on wheat chromosomes. However, these researches were all focused on gene expression at a certain developmental stage, and could gave little information to understand the dynamic effects of corresponding QTLs at different developmental stages as well as the directions of gene action. In the present paper, QTL mapping for developmental behavior of wheat GMP content was studied, using recombinant inbred lines (RIL) population derived from Jing 771×Pm97034. The results showed that eight conditional QTLs and ten unconditional QTLs were detected in different seed filling periods totally, but no one was detected in all periods. Each of these genes expressed in a special period. The additive effects of a conditional QTL located on chromosome 1A could be detected 12 days after anthesis, which could account for 6.21% of phenotypic variation in GMP content. A new conditional QTL was detected 17 days after anthesis, accounting for 14.14% of phenotypic variation. At the period of 17–22 days after anthesis the gene expression was active, and three unconditional QTLs and the two conditional QTLs were detected to be located on chromosome 1B, 5B, 6B and 7B with smaller additive effects, and the general contribution rate of the two conditional QTLs was 12.67%. Four QTLs located on chromosome 2D and 3B were detected 27 days after anthesis with larger additive effects, in which the two conditional QTLs accounted for 16.37% of phenotypic variation, while the other two unconditional QTLs accounted for 23.94%. Up to 32 days after anthesis, there still two new expressed genes were detected, but the net genetic variation declined, and conditional QTL just explained 11.43% of phenotypic variation.

The Expression Difference of OsEXP3 and OsEXP5 mRNA in Dryland Rice

GAO Ying;CHEN Nai-Zhi;WANG Xue-Chen

Acta Agron Sin. 2006, 32(07):  1001-1005. 

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The OsEXP3 and OsEXP5 genes are α-expansin genes of rice reported in GenBank. In this research, according to mRNA sequence of OsEXP3 and OsEXP5 in GenBank, we designed a pair of primers each and cloned two fragments of the genes from the roots of four dryland rice cultivars using RT-PCR. It proved that expansin gene also expressed in the roots of dryland rice. The expression character of OsEXP3 and OsEXP5 genes in the roots was studied through the method of Northern-blot. The results showed the OsEXP3 gene was high expressed in 3-d-old roots and 20-d-old roots, but low expressed in 8-d-old roots and 15-d-old roots (Fig.6-a); the OsEXP5 gene was high expressed in 3-d-old roots and not expressed in 8-d-old roots of IRAT109 (Fig.6-b). And the expressions of OsEXP3 and OsEXP5 genes were enhanced in 8-d-old roots treated with 50 µmol/L ABA for three hours ( Fig.6-a and Fig.6-b). The expression of OsEXP3 was enhanced in 3-d-old seedlings with drying for 3 hours and then reduced to control level after rewatering (Fig.6-a), while that of OsEXP5 enhanced in 8-d-old seedlings with drying for 5 days (Fig.6-b). The results show the expressions of OsEXP3 and OsEXP5 genes are regulated by development stages and regulated positively by ABA and drought stress. And the expression stage of the OsEXP3 gene is different from that of OsEXP5, indicating OsEXP3 and OsEXP5 function in different stages of development under drought-stress condition.

Mutagenic Differences of Space Environment and Ground γ-irradiation in Rice

WANG Jun-Min;XU Jian-Long ;WEI Li-Jun;SUN Ye-Qing;LUO Rong-Ting;ZHANG Ming-Xian;BAO Gen-Liang


Acta Agron Sin. 2006, 32(07):  1006-1010. 

Abstract ( 1966 )   PDF (414KB) ( 985 )   Save

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Radiosensitivity，which is defined as visible damage or stimulus to seedling growth by physical or chemical mutation treatments, is a very important characteristic in the field of induced mutation breeding. In the present study, the radiosensitivity and mutagenic effects were studied using 24 different rice cultivars by treatments of space carrying of spacecraft “Shen-Zhou 4” which was launched in 2002 in China and ⁶⁰Co γ-irradiation on the ground. Radiosensitivity was expressed based on the total physiological damage or stimulus of seedling height and seed setting rate in M₁ generation, and mutations of plant height and heading date in M₂ were observed. The results indicated that japonica rice had stronger radiosensitivity of space environment mutation and γ-irradiation than indica rice, bred cultivars stronger than landraces, medium-late indica and late indica stronger than early indica whereas no significant differences among different japonica climate ecotypes. Most cultivars non-sensitive to γ-irradiation were also non-sensitive to space mutation and only one-fourth of cultivars sensitive to γ-irradiation showed radiosensitivity to space mutation (Table 1). Space flight had obvious stimulus effects on seedling growth for 54.2% cultivars. In M₂ generation, mutations of plant height and heading date could be induced by both space environment and γ-irradiation but the mutation frequencies were quite different (Table 2). There were significant correlations between the total physiological damage in M₁ and the mutation frequencies of dwarfing, high plant and early maturity in M₂ after space flight. A conclusion is that space environment shares incomplete same mutagenic mechanisms with γ-irradiation. The results in the present study provide some useful information for rice space mutation breeding in the future.

Genetic Mechanism of High Yield in G. hirsutum cv. Simian 3Ⅰ. Inheritance Analysis Using Major Gene Plus Polygene Mixed Inheritance Model

ZHANG Pei-Tong;ZHU Xie-Fei;GUO Wang-Zhen;YU Jing-Zhong;ZHANG Tian-Zhen

Acta Agron Sin. 2006, 32(07):  1011-1017. 

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Simian 3, with high yield and high lint percentage, have been one of the most excellent cotton cultivars in China and most extensively grown in Yangtze River cotton-growing valley. The genetics mechanism of high yield in Simian 3 is the key of great significance to high yield breeding. Both RIL population and B₁, B₂ and F₂ generations derived from the cross Simian 3×Carmen, together with two parents and F₁ generation, were grown in 3 environments at Nanjing city and Guanyun county, Jiangsu Province, to make a genetics analysis of high yield and its components for G. hirsutum cv. Simian 3. Jointly segregating analysis were used to analyze the genetics of lint yield and its components in the combination of Simian 3×Carmen by using the method of major gene plus polygene mixed inheritance model. The optimum models of all traits were major gene plus polygene mixed inheritance models. The result indicated that there might be all major genes for yield and its components, and their expression could be greatly influenced by various environments. The genetics parameters of major genes were varied more greatly than those of the polygene, which indicated that the effect of environmental condition on the performance of the major gene was larger than that of the polygene. More environments should be used in genetic studies or breeding to improve the selection efficiency for the yield, which can be influenced sharp by environmental condition.

Assessment of Genetic Relationship among Tropical and Temperate Maize Populations by Mixed (AD) Model

LIANG Wen-Ke ;ZHANG Shi-Huang;QI Ting-Xiang;TUO Hong-Zhang;QIU Fa-Zhan;LIU Yong-Zhong;ZHENG Yong-Lian; XU Shang-Zhong

Acta Agron Sin. 2006, 32(07):  1018-1023. 

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Nowadays the most common methods for evaluating heterosis population and its genetic pattern in maize are based on analyses of parentage, SCA and molecular markers, but each method has its limitation. In the present study, a mixed linear (AD) model and the Minimum Norm Quadratic Unbiased Estimation (MINQUE) (1) method were introduced to estimate the variance components of yield and the values of F1 heterosis, using 2 tropical and 7 temperate maize (Zea mays L.) populations. The 9 populations were crossed by Griffing Ⅳ design, and 36 combinations were made. All hybrids were planted by random block with 4 replications in Anyang of Henan Province and Shiyan of Hubei Province in 2002 and 2003, respectively. The number of rows per ear (RPE), number of kernels per row (KPR), hundred-kernel weight (HKW) and plot-kernel weight (PKW) were measured with 24 plants in the middle of each plot. A parameter for genetic differences measurement between parent populations, i.e. ω/(2μ) = heterosis over mid-parent value—heterosis over better-parent value, was introduced. The analysis of AD model showed that additive (VA) and dominative (VD) effects of yield and its components as well as their interactions with environment (VAE and VDE) reached highly significant level (P<0.01) (Table 2). For PKW, the ratios of variance components to total variances were sequenced as dominance > dominance ´ environment > additive ´ environment > additive, while the ratios of additive effect to total variances were ranked as RPE > KPR > HKW > PKW (Table 2). The estimation of genetic differences (GD) among the 9 populations was ranged from 0.02% to 21.61% (Table 4), and there was no linear relationship between the GD and heterosis. Three crosses, 3´6 (BSSS C9´Stay Green C4), 2´3 (BS16´BSSS C9) and 1´3 (Suwan1´ BSSS C9), with parents of medium GD in this study showed strong heterosis and great potential in maize breeding in temperate zones. This study provided valuable information for developing new heterosis pattern between tropical and temperate maize germplasm.

Identification of QTLs for Seed Setting Rate in Rice under Different Growing Environments

HAN Long-Zhi ;ZHANG San-Yuan;QIAO Yong-Li ;KIM Jong-Hwan;XU Fu-Rong;CAO Gui-Lan;NAN Zhong-Hao;DAI Lu-Yuan;YEA Jong-Doo;OH Hee-Jong

Acta Agron Sin. 2006, 32(07):  1024-1030. 

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The quantitative trait loci (QTLs) for seed setting rate were identified using F_2:3 population including 200 lines derived from a cross of indica and japonica “Milyang 23/Jileng 1” with microsatellite markers. The evaluation of seed setting rate was conducted in Beijing, Kunming, Sanya, Gongzhuling of China and Chuncheon of Korea, respectively. The value of seed setting rate and its distribution in F₃ lines and the number of detected QTL were significantly different due to different growing environments, indicating the interaction between QTL and environment significantly. The seed setting rate showed near normal or partional continuous distributions, suggesting that it was quantitative trait controlled by many genes. Fourteen QTLs were detected on chromosome 1, 2, 3, 4, 6, 7, 8, 10 and 12, which explained the observed phenotypic variance from 4.9% to 15.3%. qSSR1, qSSR2, qSSR6 and qSSR12 which were found in more than two growing environments were detected in RM1–RM259 on chromosome 1, RM263–RM6 on chromosome 2, RM340–RM30 on chromosome 6 and RM270–RM17 on chromosome 12, respectively, and explained 4.9%–8.4%，4.8%–7.2%，7.6%–10.7% and 7.4%–10.4% of observed phynotypic variation, respectively. The allelic genes of QTLs mostly coming from Jileng 1 were partial dominance or dominance or over dominance to these of Milyang 23.

Genotype Differences of Fertilizer-Nitrogen Use Efficiency in Waxy Corn

LU Yan-Li;LU Wei-Ping;LIU Xiao-Bing;WANG Ji-Feng;LIU Ping; LU Da-Lei; SU Hui

Acta Agron Sin. 2006, 32(07):  1031-1037. 

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Many researches have shown that the absorption, translocation and utilization of nitrogen varied markedly in different genotypes of common corn. However, there are few reports on waxy corn is this field. In this study, 31 cultivars of waxy corn (Zea mays L. ceratina Kulesh) released recently within China were employed to evaluate their nitrogen use efficiencies (NUE) by indices of agronomic efficiency (AE), recovery efficiency (RE), physiological efficiency (PE), and partial factor productivity (PFP). The field experiment was split plot design with nitrogen treatment (225 kg N/ha) or control (0 kg N/ha) as main factor, and the 31 cultivars were planted randomly in each plot. Five plants of each cultivar were sampled at anthesis, fresh ear harvest (21 days after anthesis) and physiological maturity stages, respectively for measuring nitrogen contents in different organs of leaf, leaf sheath, culm, tassel, bracteal leaf, ear axis and kernel. Results showed that there were significant genotype differences of N use efficiencies among the 31 cultivars in terms of AE, RE, PE, and PFP (Table 2–4). Cluster analysis revealed that the cultivars with high yield potential and NUE for whatever product of fresh ear, fresh kernel or maturity kernel were FN 2146, JKN 267, JKN 218, YBN 1, SW42 and SAUWX02 (Fig.1). Compared with other cultivars, their average yields of the fresh ear, fresh kernel and maturity kernel were higher by 17.9%, 18.1% and 28.6%, the average AEs of the fresh ear, fresh kernel and maturity kernel were higher by 45.2%, 50.2% and 64.7%, the average REs of the fresh ear, fresh kernel and maturity kernel were higher by 35.1%, 35.1% and 36.7%, the average PEs of the fresh ear, fresh kernel and maturity kernel were higher by 4.5%, 9.7% and 20.3%, and the average PFPs of the fresh ear, fresh kernel and maturity kernel were higher by 17.9%, 18.1% and 28.6%, respectively. It is confirmed by correlation analysis that increasing the N harvest index and N translocation rate may promote NUE in waxy corn.

Distribution of Vernalization Gene Vrn-A1 in Chinese Wheat Cultivars Detected by STS Marker

ZHANG Xiao-Ke ;XIA Xian-Chun;HE Zhong-Hu ;ZHOU Yang

Acta Agron Sin. 2006, 32(07):  1038-1043. 

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Growth and development habit (spring vs. winter) of wheat (Triticum aestivum L.) is determined by Vrn genes, which affect its adaptability. The two-step procedure required for the CAPS marker and the additional cost of restriction enzyme were the limitation in high throughput screenings in breeding programs, so it was hoped that the CAPS marker could be replaced by the STS marker. The STS marker and CAPS marker of Vrn-A1 gene were compared by testing 22 Chinese wheat cultivars, and then 250 Chinese wheat cultivars were used to detect the Vrn-A1 gene distribution. The testing results of STS marker for Vrn-A1 gene in the 22 Chinese wheat cultivars were completely consistent with those of CAPS marker, suggesting that the STS marker is efficient and reliable for identifying Vrn-A1 gene in wheat breeding program. The average frequency of Vrn-A1 gene was 36.8% in the 250 tested Chinese wheat cultivars. Frequencies of Vrn-A1 gene in Northern Winter Wheat Region, Yellow & Huai River Facultative Winter Wheat Region, Middle & Low Yangtze Valley Winter Wheat Region, Southwestern Winter Wheat Region, Northeastern Spring Wheat Region, Northern Spring Wheat Region, Northwestern Spring Wheat Region and Xinjiang Winter-Spring Wheat Region were 3.0%, 19.8%, 17.4%, 35.3%, 100%, 100%, 100% and 42.9%, respectively. The differences of Vrn-A1 gene frequency were highly related to the growth habit of wheat. Middle & Low Yangtze Valley Winter Wheat Region and Southwestern Winter Wheat Region had a decreased frequency of Vrn-A1 gene, which increased from 1950s to 1970s, and then decreased since 1980 in Yellow & Huai River Facultative Winter Wheat Region. Frequency of Vrn-A1 gene was 27.6% in 58 cultivars whose planted area was more than 670,000 ha annually, and 70% in 10 cultivars with largest grown area in China from 1949 to 2000. The information could be useful for improving adaptability and yield potential of Chinese wheat cultivars.

Effects of High Temperature Stress on ATPase Activity of Plasma Membrane and NH₄⁺ Absorption Rate in Roots of Early Rice

SHI Qing-Hua;LI Mu-Ying;XU Jing-Biao;TAN Xue-Ming

Acta Agron Sin. 2006, 32(07):  1044-1048. 

Abstract ( 1835 )   PDF (374KB) ( 1051 )   Save

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Cultivars of early rice with heat resistance: Nongda 228 and 082, and those with heat sensitivity: Molizhan and Xeiqingzao B were used to study the ATPase activity of plasma membrane and NH₄⁺ absorption rate in roots under high temperature stress. The results indicated that under high temperature stress, H⁺-ATPase and Ca²⁺-ATPase activities of plasma membrane were increased in roots of Nongda 228 and 082 while declined in roots of Molizhan and Xeiqingzao B, with significant differences between them by Duncan’s method test. The protein content in all cultivars declined under high temperature stress. The NH₄⁺ absorption rate had no change in the cultivars with heat resistance but declined in the cultivars with heat sensitivity under high temperature.

Physiological Responses to Low Temperature Stress in Hybrid Rice at Seedling Stage

WANG Jing ;ZHANG Cheng-Jun;CHEN Guo-Xiang ;WANG Ping;SHI Da-Wei; LÜ; Chuan-Gen;SUN Lei;XU Suo-Kou


Acta Agron Sin. 2006, 32(07):  1049-1056. 

Abstract ( 1894 )   PDF (1034KB) ( 1043 )   Save

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To clarify the resistance of high-yield hybrid rice (Oryza sativa L.) at seedling stage to chilly temperature, the photosynthetic characters and protein component of two cultivars, a newly-developed cultivars super-hybrid rice Liangyoupeijiu and a traditional chill-sensitive hybrid rice Shanyou63, were investigated by setting 25℃ as control and 10℃ as low temperature treatment. The results showed that the chlorophyll contents, the consuming oxygen activity of photosystemⅠ (PSⅠ) and oxygen evolution activity of photosystemⅡ (PSⅡ) of thylakoid membrane were decreased obviously in low temperature treatments, so were the absorption spectrum and the emission spectrum of thylakoid membrane at room temperature. The contents of O₂^．- and MDA of Liangyoupeijiu were decreased slightly, but these of Shanyou 63 were increased. Chilly temperature caused an increase of the activity of SOD compared with the control in two cultivars. As compared with the control, CAT activity was higher in Liangyoupeijiu and lower in Shanyou63. All the indexes for Shanyou 63 showed a more distinctive dropping trend. After chilly treatment, the soluble protein content in two cultivars especially in Liangyoupeijiu was significantly higher than those of control. The SDS-PAGE of soluble protein revealed that the protein bands were increased during chilly treatment, but this change did not occur in thylakoid membrane proteins. In the control, almost all parameters investigated except the activities of PSⅠ and PSⅡ were higher in Shanyou 63 than in Liangyoupeijiu, which means that at the seedling stage，Liangyoupeijiu may have stronger resistance to chill-stress than Shanyou63 although the latter has higher photosynthetic function.

The Effects of Spermidine Pretreatment on Antioxidative Capacity in Wheat Seedlings under Osmotic Stress

DUAN Hui-Guo ;YUAN Shu;HUANG Zuo-Xi;SUN Xin;QING Dong-Hong;DONG Ling;LIN Hong-Hui

Acta Agron Sin. 2006, 32(07):  1057-1062. 

Abstract ( 1886 )   PDF (473KB) ( 977 )   Save

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The effects of spermidine (Spd) pretreatment on relative water content (RWC), H₂O₂ content, malonyldialdehyde (MDA) level, electrolyte leakage and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidese (APX) in wheat seedlings (Triticum aestivum L. cv. Miannong 4) were investigated under osmotic dehydration by －0.6 MPa polyethylene glycol 6000 (PEG-6000). Half of eight-day-old seedlings (control) were daily sprayed with distilled water + 0.02% (V/V) Tween-80 and irrigated with half-strength Hoagland’s nutrient solution, and the other half seedlings (Spd pretreatment) were daily sprayed with 0.2 mmol/L Spd + 0.02 % (V/V) Tween-80 and irrigated with 0.2 mmol/L Spd + half-strength Hoagland’s nutrient solution for 2 days before osmotic stress. The results showed that the RWC decreased, lipid peroxidated, as well as H₂O₂ content and electrolyte leakage increased in seedling leaves of control under osmotic stress, while these changes deferred in Spd pretreatment. Under osmotic stress, the activities of SOD, POD and APX increased, but CAT activity decreased in control. Spd pretreatment increased the activities of SOD and POD. Moreover, the activities of POD, CAT and APX, especially SOD in seedling leaves of Spd pretreated were higher than those of control during the throughout osmotic stress period. It suggested that Spd could induce and maintain the higher level of antioxidant enzyme activities, and decrease the concentration of H2O2, therefore alleviate oxidative damages by osmotic stress, and promote antioxidant capacity of wheat seedlings under osmotic stress.

Effects of Sowing Date on Activities of Enzymes Involved in Grain Starch Synthesis and Starch Component Accumulation in Wheat Cultivar Gaocheng 8901

LIU Xia ;YIN Yan-Ping;HE Ming-Rong;WANG Zhen-Lin

Acta Agron Sin. 2006, 32(07):  1063-1070. 

Abstract ( 2052 )   PDF (631KB) ( 1154 )   Save

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Grain starch is synthesized from sucrose of leaves, and regulated by a series of enzymes in wheat (Triticum aestivum L.). Previous researches have revealed that sowing date affects wheat quality by changing protein content, wet gluten content, sedimentation value, dough development time and stability time. Grain quality also relates to starch content, especially the component of starch. In order to understand the regulation mechanism of sowing date to the accumulation and component of grain starch, a wheat coultivar, Gaocheng 8901, was employed with different sowing dates. The starch (amylose and amylopectin) content in grain, and the activities of sucrose-phosphate synthase (SPS), sucrose synthase (SS), adenosine diphosphorate glucose pyrophrylase (AGPase), uridine diphosphorate glucose pyrophrylase (UGPase), soluble starch synthase (SSS) and granule-bound starch synthase (GBSS), as well as sucrose content in flag leaf and grain were determined during grain filling. The results showed that the accumulation of amylose was decreased under both early and late sowing treatments, but that of amylopectin increased significantly (P<0.01) (Fig.1). The optimum daily sunlight hour (ASH) for amylose and amylopectin accumulation were 9.06 and 11.07 hours, respectively (Table 1). The amylopectin content was maximal when the average daily air temperature (ATD) was 22.75℃, while amylose content showed a positive correlation with ATD from 17℃ to 25℃. Under late sowing treatment, the activities of SS and SPS increased in flag leaf, but decreased in grain significantly (P<0.05) 14 days after anthesis, while the sucrose accumulation in flag leaf and grain both reduced (Fig.3–6). Late sowing also resulted in the increase of AGPase activity, SSS activity and amylopectin accumulation, but the decrease of UGPase and GBSS activities in grain at mid to late period of grain filling (Fig.7, 8). The above results suggest a feedback system of sucrose metabolism by starch accumulation in wheat, which takes function through reducing the activity of SPS instead of SS in grain. The approach of sucrose decomposition catalyzed by SS is not the unique one for starch synthesis in grain. AGPase, SSS, UGPase and GBSS all play important roles in starch synthesis, of which UGPase and GBSS activities are restrained at certain stages to regulate the transformation of sucrose to starch and the accumulation of starch component, so that a reasonable ratio of amylose to amylopectin can be kept.

Waxy Protein Identification and Starch Pasting Properties of CIMMYT Wheat Lines

MU Pei-Yuan ;HE Zhong-Hu ;XU Zhao-Hua;WANG De-Sen;ZHANG Yan;XIA Xian-Chun

Acta Agron Sin. 2006, 32(07):  1071-1075. 

Abstract ( 2308 )   PDF (453KB) ( 1042 )   Save

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Starch pasting properties, one of the major factors influencing the quality of Dry White Chinese Noodle, is great affected by Wx-A1, Wx-B1 and Wx-D1 protein subunits, among which Wx-B1 null makes the biggest contribution. In order to detect new gemplasm to improve the quality of Chinese noodles, four hundred and eighty-eight spring wheat lines from CIMMYT 35th International Bread Wheat Screening Nursery (35th IBWSN) and 20^th Semiarid Wheat Screening Nursery (20^th SAWSN) were collected and planted in Linhe, Inner Mongolia in 2003. Samples were harvested to identify their Waxy protein subunits and the relationship with RVA (rapid viscosity analyzer) parameters. 191 lines with Wx-B1 null subunit and 28 lines with Wx-D1 null subunit were identified by SDS-PAGE. The results indicated that final viscosity and set back of lines with subunits of Wx-B1 null and Wx-D1 null were significantly higher than those with normal Wx protein subunit, while peak viscosity and break down of Wx-D1 null lines were significantly lower than those of normal Wx lines, peak viscosity and break down of Wx-B1 null lines were significantly higher than those of Wx-D1 null lines. Significant variation among the lines for RVA parameters except for peak time was also observed. Compared with China’s spring wheat, the CIMMYT spring wheat lines expressed higher peak viscosity, though viscosity, final viscosity, larger break down and set back, as well as longer and stable peak time. RVA parameters for lines from 35thIBWSN were much higher than those from 20^th SAWSN.

Effect of Free-air CO2 Enrichment on Spikelet Differentiation and Degeneration of Japonica Rice (Oryza sativa L.) Cultivar Wuxiangjing 14

YANG Hong-Jian;YANG Lian-Xin;HUANG Jian-Ye;LIU Hong-Jiang;DONG Gui-Chun;YAN Shi-Ming;ZHU Jian-Guo;WANG Yu-Long

Acta Agron Sin. 2006, 32(07):  1076-1082. 

Abstract ( 2036 )   PDF (555KB) ( 963 )   Save

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The experiment was conducted at Anzhen city, Wuxi，Jiangsu, China, to study the effect of free-air CO₂ enrichment [FACE, 200 μmol·mol^-1 higher than ambient(AMB)] on spikelet differentiation and degeneration, using the japonica cultivar Wuxiangjing 14, in 2001–2003. Results of FACE treatment showed that the survived spikelets per panicle have decreased by 10.4 to 12.6, i.e. 6.88% to 8.49%. There were no significant effects on the differentiated spikelets per panicle and the degenerated spikelets of the primary branches per panicle, while an increase of the number and percentage of spikelets degenerated on the secondary branches per panicle compared with those under AMB; The plant N accumulation per differentiated spikelet at heading and N absorption per differentiated spikelet from stem elongating to heading were significantly lower, whereas the content of soluble carbohydrates in stem and sheath at heading and the ratio of that to nitrogen content in rice plant were significantly higher compared with those under AMB; the degenerated spikelets per panicle negatively and significantly correlated with the N accumulation per differentiated spikelet at heading (－0.848**) and with the N absorption per differentiated spikelet from elongating to heading (－0.961**), respectively; While the degenerated spikelets per panicle positively and significantly correlated with the content of soluble carbohydrates in stem and sheath (0.808*) and with the ratio of the soluble carbohydrates content in stem and sheath to nitrogen content in rice plant at heading stage (0.837*), respectively. It was speculated that the ability of N absorption weakened, carbon metabolism strengthened and nitrogen metabolism weakened due to FACE during the period of spikelets formation, were the primary causes of largely degenerating number of differentiated spikelets and decreasing number of spikelets per panicle under FACE condition.

Analyses of Multiple Agronomic Factors Relative to Specific Leaf Area in Winter Rape Cultivars

LIU Tie-Mei; ZOU Wei;LIU Tie-Fang;XIE Guo-Sheng;CAO Wei-Xing;LI Wei-Ping;CAO Cou-Gui;WU Jiang-Sheng;HU Li-Yong;FU Ting-Dong

Acta Agron Sin. 2006, 32(07):  1083-1089. 

Abstract ( 1964 )   PDF (600KB) ( 1093 )   Save

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Specific leaf area (SLA), the ratio of green leaf area to its dry weight, is one of most important parameters of leaf function evaluation, growth of crop and high yielding breeding. Second-order regression equation of relations between SLA and concerned agronomic factors (plant density, nitrogen, phosphorus, potassium and boron fertilizer) in rape cv. Huashuang 3 at elongation stage was firstly established according to second-order regression with orthogonal, rotatable and central composite design. In the meantime, the influences of different cultivars, development time and dry weight of shoot and root to SLA were also firstly studied systemically. Mono-factor analysis showed that absolute contribution ratio of each factor was plant density > potassium fertilizer > phosphorus fertilizer > nitrogen fertilizer > boron fertilizer. Moreover, Parabola relationship between SLA and nitrogen, potassium, phosphorus, boron fertilizers as well as plant density, respectively, showed that suitable plant density and proportional fertilizer application contributed to suitable population SLA pattern and optimum population morphogenesis. SLA of winter rape showed a trend of decline-increase-decline during its growth (Fig.1, 2). Multiple comparisons indicated that SLA remained steady during winter, but was significantly different at other developmental stages, and no significant difference between cultivars (Fig.1 and Table 3). SLA was negatively correlated with leaf weight, root weight and stem weight, respectively (Table 5, 6). Moreover, path analysis showed that SLA was influenced not only by root weight, stem weight and leaf weight but also by their interaction effects (Fig.3, Table 7). In conclusion, SLA could be another parameter evaluating colony nutrient level and critical fertilizer application. Leaf weight contribution in prophase and stem weight contribution in metaphase and anaphase could benefit to small SLA and optimum population morphogenesis.

RESEARCH NOTES

Analysis of Growth and Development and Yield of Corn Mulched with Plastic Film and Straw

BU Yu-Shan; MIAO Guo-Yuan;SHAO Hai-Lin;WANG Jian-Cheng

Acta Agron Sin. 2006, 32(07):  1090-1093. 

Abstract ( 2041 )   PDF (273KB) ( 1276 )   Save

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The effects of straw mulching (SM) and plastic film mulching (PM) on corn growth and yield were studied by pot and field experiments in two years. The results showed that plant height, stem diameter, net photosynthetic rate, and accumulation of dry matter in root and shoot of corn were increased by SM and PM. The promotion effect of PM treatment on corn growth and development was bigger at the earlier stage of corn growth, while that of SM treatment mainly at the middle and later stages of corn growth. The reason of increasing corn yields by SM and PM was mainly due to the increases of ear length and grains per ear, indicating the effects of SM and PM on corn yields were performed at jointing to heading stages when female ear differentiated and developed, while not at seed-filling period under the experimental condition.

Changes of Phytohormone Contents in Anther Abortion of Cytoplasmic Male Sterile Cotton

XIE Hai-Yan;JIANG Pei-Dong;WANG Xiao-Ling;ZHANG Zhao-Wei;ZHU Wei;WANG Xue-De

Acta Agron Sin. 2006, 32(07):  1094-1096. 

Abstract ( 1963 )   PDF (279KB) ( 1133 )   Save

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Content of 4 Phytohormones, IAA, GA₃, ZR and ABA, were measured by enzyme-linked immunosorbent assay (ELISA) in anthers of cytoplasmic male sterile cotton and its maintainer, restorer and hybrid F₁ during five development stages to study the relationship between male sterility and phytohormone changes. The results showed that the differences of IAA, GA₃, ZR and ABA contents were not significant among the fertile anthers from maintainer, restorer and hybrid F₁, but very significant between fertile and sterile anthers. Fertile anthers were higher in IAA, GA₃ and ZR contents, but lower in ABA content than sterile anthers, especially at the abortion stage of pollen mother cells. According to abortion characteristics and hormone changes of sterile anther, it was suggested that IAA, GA₃ and ZR deficiency might be associated respectively with the inhibition of starch grain accumulation, expansion-restraint of pollen mother cells and tapetal cells and no tetrad formed, and that abortion and even death of pollen mother cells and tapetal cells in sterile anther might be accelerated by high ABA accumulation.

Effects of Improving Space Factors on Growth and Yield of Soybean

HAN Bing-Jin

Acta Agron Sin. 2006, 32(07):  1097-1100. 

Abstract ( 1879 )   PDF (353KB) ( 1017 )   Save

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To distinguish effects of soil factors and space factors, the experiment was conducted in black soil area, and soybean plants were cultivated with a model of different rages of sash. The results showed that: yield of soybean was effectively increased by enlarging space within the scope of effective nutrient area of soybean, and yield of soybean increased significantly when the soil area of single plant was smaller. Meanwhile, as the soil area enlarged, the effect of space on increase of yield was decreased. It was implied that pods per plant, 100-seed weight were obviously increased while the useless pod rate decreased, leaf area and dry weigh pea plant were increased and plant height and pod height decreased by improving (enlarging) space factors. Therefore, for black soil area with higher fertility of soil, it is very important in soybean production to utilize and breed plant-type-compact and high-photosynthesis-efficiency soybean cultivars.

Changes of RNase Vitality in the Anther Abortion Processes of Several Male Sterile Lines in Rapeseed (Brassica napus L.)

NIE Ming-Jian ;WANG Guo-Huai;CHEN Guang-Yao

Acta Agron Sin. 2006, 32(07):  1101-1103. 

Abstract ( 1828 )   PDF (242KB) ( 1191 )   Save

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The anther abortion processes of five different types of male sterile lines in Rapeseed (Brassica napus L.) are studied by contrast. The results show that the RNase vitality and the amount of free UMP of the male sterile lines increase greatly and the amount of RNA and soluble protein decrease obviously in the process of abortion. The relative coefficient between RNase vitality and the amount of RNA, which are negatively linearly related, is －0.9796**. Therefore the abnormal increase of RNase vitality is closely related with the male sterility in rapeseed (Brassica napus L.).

Relationship between Distribution of ¹⁴C-assimilates and Kernel Abortion in Maize

ZHANG Feng-Lu; JIANG Ya-Li;ZHAO Guo-Shun;ZHANG Jun-Hua

Acta Agron Sin. 2006, 32(07):  1104-1106. 

Abstract ( 1989 )   PDF (274KB) ( 1072 )   Save

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The distribution of ¹⁴C-assimilates in plant organs and different positions of ear in maize (Zea mays L.) was studied by feeding the ear leaf with ¹⁴CO₂ at early period of kernel development. The results showed that ear was the main sink organ during kernel filling period, but the distribution of ¹⁴C-assimilates was uneven in different parts of ear. The distribution of ¹⁴C-assimilates in cob ranked as basal>middle>upper part, while the amount of ¹⁴C-assimilates in kernel sequenced as middle>basal>upper part of the ear. The sugar concentration in upper cob was not less (P>0.05) than that in middle part, but the content of reducing sugar in aborted kernels was significantly higher (P<0.05) than that in kernels at middle part of ear. It suggests the main reason of kernel abortion at ear tip in maizewould be low sink strength in kernels instead of assimilate deficiency.