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Table of Content

    12 October 2006, Volume 32 Issue 10
    • ORIGINAL PAPERS
      Enhancing Bacterial Blight Resistance of Hybrid Rice Restorer Lines through Marker-Assisted Selection of the Xa23 Gene
      LI Jin-Bo;WANG Chun-Lian;XIA Ming-Yuan;ZHAO Kai-Jun ;QI Hua-Xiong ;WAN Bing-Liang;ZHA Zhong-Ping;LU Xing-Gui
      Acta Agron Sin. 2006, 32(10):  1423-1429. 
      Abstract ( 2494 )   PDF (805KB) ( 1479 )   Save
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      The bacterial blight (BB) of rice is caused by the pathogen Xanthomonas oryzae pv. oryzae (Xoo). BB is one of the most important rice diseases all over the world. The most effective and economical approach for BB control in rice production is using BB-resistant cultivars. The broad-spectrum BB resistance gene Xa23 was originally identified from wild rice species Oryzae rufipogon. Xa23 was introduced into cultivated rice variety JG30 by cross and continuous back-crosses, which resulted in the near-isogenic line CBB23. In our previous studies, Xa23 was mapped on the long arm of rice chromosome 11. In this study, we used CBB23 as Xa23 donor and the elite but BB susceptible restorer lines 9311 and 1826 as recipients to develop BB-resistant restorer lines of hybrid rice. The Xa23-linked EST marker C189 was used to select Xa23 in the segregating populations. Marker-assisted selection (MAS) for Xa23 was performed at the seedling stage of plants and followed by conventional selection for agronomic traits at the adult stage. More than 160 introgression lines that harbored homozygous Xa23 and showed stable agronomic traits were obtained. Twenty-one of the introgression lines were subject to BB disease inoculation at the seedling and booting stages in green house, and results showed that all the tested lines were resistant to the most destructive Xoo strain PXO99(P6) while the recipient parents 9311 and 1826 were highly susceptible at both stages. In addition, we used 5 of the introgression lines as restorer lines to make hybrids by crossing them with 3 sterile lines Pei’ai 64S, Guangzhan 63S and Yuetai A. BB-inoculation tests showed the 15 hybrids were resistant or moderately resistant to PXO99 at the seedling stage and highly resistant at the booting stage. Field trials of 6 selected hybrids showed that yields of the hybrids were equal to or even higher than that of the control super hybrid rice Liangyou Peijiu. The lines C6201, C6271 and C6351 obtained in this study are hopeful of being restorer lines of hybrid rice with great potential for commercialization in the near future. These results clearly suggested that the Xa23-linked marker C189 could be effectively utilized in the BB-resistance breeding programs.

      Effect of Osmotic Stress on the Contents of Different form Polyamines in Leaves of Maize Seedlings
      LIU Huai-Pan ;JI Xiu-E;SHI Liu-Gong;LI Chao-Hai
      Acta Agron Sin. 2006, 32(10):  1430-1436. 
      Abstract ( 2499 )   PDF (485KB) ( 1061 )   Save
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      The changes in contents and forms of polyamines (PAs) in seedling leaves of two maize (Zea mays L.) cultivars, Nongda 108 (drought-tolerant) and Yedan 13 (drought-sensitive), were investigated under osmotic stress. On the 8th day after polyethylene glycol (PEG) -6 000 treatment, free spermidine (fSpd) and free spermine (fSpm) content in leaves increased significantly(P<0.05)in Nongda 108, while Yedan 13 showed a significant increase of free putrescine (fPut) content. Thus Nongda 108 gave a higher ratio of (fSpd + fSpm)/fPut than Yedan 13 in leaves under osmotic stress. Exogenous methylglyoxal-bis (guanylhydrazone) (MGBG), which is a S-adenosylmethionine decarboxylase (SAMDC) inhibitor, resulted in reduction of fSpd and fSpm contents and aggravation of PEG-induced injury to Nongda 108 leaves, while exogenous Spd treatment resulted in an increase of fSpd + fSpm in leaves, in concert with an alleviation of PEG-induced injury to seedlings of Yedan 13. Osmotic stress induced significant increases of acid soluble conjugated PA (AS-conjugated PA) and acid insoluble bound PA (AIS-bound PA) contents in leaves of Nongda 108, and osmotic stress affected slightly in Yedan 13 leaves. Exogenous phenanthrolin (o-Phen), an inhibitor of transglutaminase (TGase), aggravated PEG-induced injury to Nongda 108, coupled with decreases of AIS-bound PA content. The results suggest that fSpd, fSpm, AS-conjugated-PA and AIS-bound PA facilitate the osmotic stress tolerance of maize seedlings.

      Parental Cluster Analysis in Indica Hybrid Rice (Oryza sativa L.) by SSR Analysis
      WANG Sheng-Jun;WAN Jian-Min ;LU Zuo-Mei
      Acta Agron Sin. 2006, 32(10):  1437-1443. 
      Abstract ( 1933 )   PDF (462KB) ( 1184 )   Save
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      Heterotic groups and patterns among breeding materials provide fundamental information while utilizing heterosis in plant breeding. However, research on heterotic groups in indica rice is scarce compared with that in maize. Simple sequence repeat (SSR) analysis of the 72 loci covering the entire rice genome was carried out for 47 parental lines normally utilized in making hybrid rice in China in order to study the classification of parental lines. 72 SSR primers having stable amplified profiles detected 328 alleles among the lines tested, and the number of alleles per SSR locus ranged from 2 to 13, with the mean 4.56. The polymorphism information content (PIC) per SSR locus ranged from 0.120 to 0.878 with the mean 0.567. The genetic similarities among 47 parental lines ranged from 0.633 to 0.928 with the mean 0.741. The 47 parental lines were classified into three main groups (i.e. maintainer line group, TGMS line group and restorer line group) by un-weighted pair-group method using an arithmetic average (UPGMA) clustering method, which was approximately in agreement with pedigree information. Furthermore, seven patterns of heterotic combinations were recommended according to the grouping and hybrid rice production. SSR analysis is an effective way for heterotic grouping of hybrid parental lines in rice. The results of grouping can be used to choose parents in making hybrid rice.

      Screening Resistant-Related Genes to Powdery Mildew in Haynaldia villosa Using Barley Genechip and Studying Its Mechanism of Resistance
      CAO Ai-Zhong;WANG Xiu-E ;CHEN Ya-Ping;LI Qiao;CHEN Pei-Du ;ZOU Xiao-Wen
      Acta Agron Sin. 2006, 32(10):  1444-1452. 
      Abstract ( 2061 )   PDF (1394KB) ( 1086 )   Save
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      The technologies of genechip microarray combined with RT-PCR were used to investigate the resistance mechanism of Haynaldia villosa to the powdery mildew. The transcriptome of uninoculated resistant H. villosa,wildtype resistant H. villosa and susceptible mutant inoculated with Blumeria graminis f. sp. tritici were obtained using barley genechip microarray. RT-PCR and comparison of the transcriptome in inoculated and uninoculated resistant H. villosa indicated that the genes involved in the salicylic acid and ethylene signal transduction pathways were upregulated by B. graminis inoculation in the resistant H. villosa. RT-PCR and transcriptome comparison in the inoculated wildtype resistant and susceptible mutant showed that the genes involved in the ethylene and jasmonic acid signal transduction pathways were upregulated by B. graminis inoculation in the susceptible mutant H. villosa, while the salicylic acid signal transduction pathway was not participated in the process. The endogenous SA concentration of wildtype and susceptible mutant H. villosa inoculated for different hours were measured. SA concentration in the resistant H. villosa increased dramatically after inoculated with B. graminis, while that in the susceptible mutant remained at very low level. Since genes in the ethylene signal pathway were induced in the resistant and mutant H. villosa and genes in the salicylic acid signal transduction pathway were induced only in the resistant H. villosa, the salicylic acid signal transduction pathway might be the major pathway involved in H. villosa resistance to the powdery mildew. Genes involved in the resistance to powdery mildew in the H. villosa were also identified, including pathogenesis related protein genes, defense genes, transcription factors, signal transduction components and resistance gene analogs.

      Gene Effects of Resistance to Head Smut in Maize
      GAO Shu-Ren ;LI Xin-Hai;WANG Zhen-Hua;LI Ming-Shun;ZHANG Shi-Huang
      Acta Agron Sin. 2006, 32(10):  1453-1457. 
      Abstract ( 2079 )   PDF (473KB) ( 1134 )   Save
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      Head smut of maize is a kind of worldwide disease. Development of resistant varieties is an effective choice to control the disease, which depends on the knowledge of the resistance resources and genetic mechanism. In order to select and breed resistant varieties, some resistant resources of head smut have been selected. The resistance to head smut of maize is quantitative character controlled by numerous genes, and additive effect of resistant gene plays the leading role, while the dominant effect and the epitasis effect are much weaken. In this study, two resistant inbred lines (Qi 319 and Mo17) and two susceptible lines (Huangzao 4 and E28) were used to produce four cross populations. The parental lines, F1, F2, BCR (F1 backcrossed to the resistant parents) and BCS (F1 backcrossed to the susceptible parents) were evaluated by artificial inoculation in Beijing and Heilongjiang province in 2004. The randomized complete block design in the filed was used with 2 repetitions. The parental lines and F1 were grown in 1-row lots, BCR and BCS backcross generations in 4-row pots, F2 in 8-row plots, and the rows were 5 m long each and spaced 0.7 m apart with 17 holes per row and 2 seedlings per hole. In soft ripe stage, the total number of the seedlings and the number of the diseased seedlings and the diseased seedling rate of various generations by taking the plot as a unit was calculated. The gene effects of resistance to head smut in maize was evaluated through generation means for the four cross combinations. The additive-dominant genetic model used was Y=m+αa+βd; the additive-dominance-epistasis genetic model used was Y=m+αa+βd+α2aa+αβad+β2dd. The variances among means of generations in the four cross combinations were analyzed to find the models for a, d, aa, ad and dd gene effects using least squares regression analysis. Point estimated of m, a, d, aa, ad and dd were obtained by solving the system of equations. For the former model, the genetic effects were evaluated by the least squares regression analysis, and the latter that was analyzed by the same method, but the effects with no-significant should be omitted firstly, after that the χ2 test was involved to judge the significance of the models. The results showed that the additive effects were significant in 4 cross combinations, and dominant effects were significant in 3 cross combinations. The inheritance of resistance in Qi 319×E28 and Mo17×E28 fitted additive-dominant model, whereas the inheritance of Qi 319×Huangzao4 and Mo17×Huangzaov4 was in accordance with additive-dominant-epistasis model. The results indicated that the mode of resistance to head smut varied under different genetic background of maize. Therefore, not only the level of resistance to head smut is important, but also that of parental combination and F1 should be emphasized.

      An Early Warning System to Predict Waterlogging Injuries for Winter Wheat in the Yangtze- Huai Plain (WWWS)
      JIN Zhi-Qing;SHI Chun-Lin
      Acta Agron Sin. 2006, 32(10):  1458-1465. 
      Abstract ( 1942 )   PDF (825KB) ( 1103 )   Save
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      Waterlogging is one of the most common meteorological injuries for winter wheat in the Yangtze-Huai Plain, China. Waterlogging not only reduces wheat root activity, photosynthesis and nutrient metabolism when it occurs during the critical growth stages, but also makes it easy for wheat to be damaged by weed, insects and diseases.
      In recent 20 years, with global climate warming, the temperature during wheat growing season has significantly increased in the studied region, in company with reduction of sunshine duration. The combined effect has enhanced waterlogging and often results in reduction of wheat yield.
      An early warning system to predict waterlogging injuries for winter wheat (WWWS) was established in this study, aiming at improving meteorological service for local wheat production.
      The WWWS consists of two wheat models, i.e., models with and without waterlogging consideration. The latter was rebuilt based on the Wheat Cultivational Simulation, Optimization and Decision- Making System (WCSODS) developed by the authors, i.e., cutting off some optimization models and adding to the submodels of dry matter partitioning, root dry matter increase and leaf senescence in late period, as well as linking directly the LAI dynamics with dry matter production. The former was constructed by increasing several submodels to the wheat model without considering waterlogging, which described the effects of waterlogging on wheat photosynthesis, dry matter partitioning and leaf senescence, respectively. After running these two models under same meteorological condition, the yield difference (ΔY) simulated would give the degree of waterlogging for wheat, i.e., the lager the ΔY, the severer the waterlogging for wheat, and vice versa. In other words, ΔY serves as a criterion of the WWWS to predict if wheat waterlogging occurs or not.
      The results of sensitivity analyses for the model considering waterlogging showed that wheat responded more slightly to waterlogging in early stage (tillering and elongation) than in late stage (booting and filling) and the yield loss percentage increased with increasing of waterlogging duration in days. These results are coincident with the knowledge of local wheat experts, indicting that the model with waterlogging consideration is rather reasonable.
      The methodologies in development of the WWWS for early warning purpose were also discussed, including building soil moisture submodel to estimate the waterlogging coefficient (fSW), constructing the future weather database files during wheat growing period, regulating and determining the regional parameters of wheat model using the long-term yield data after deducting the part of yield increase due to scientific and technological progress, establishing the indices for warning waterlogging injuries and connection of the WWWS with the Regional Global Climate Change Model (RGCM) etc. Finally, the WWWS was validated using the historical data (1991–2000) both of climates and wheat yields in Nanjing and Nantong areas. The results showed a good prediction for water- logging injuries with 90% correctness. Testing forecasts were also made to predict wheat waterlogging injuries in recent 3 years (2002–2005) using the WWWS and RGCM output in Nanjing, Hefei and Nantong areas and the results showed that predictions in two years were correct and a supplement forecast also gave a correct prediction in another year.
      In summary, the WWWS can be used as a useful tool to predict waterlogging injuries for winter wheat in the Yangtze-Huai Plain.

      Sequence Analysis of Δ12-Fatty Acid Desaturase in Different Arachis Genotypes
      YIN Dong-Mei;CUI Dang-Qun
      Acta Agron Sin. 2006, 32(10):  1466-1471. 
      Abstract ( 1989 )   PDF (614KB) ( 1055 )   Save
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      The quality of peanut oil largely depends on the quantity of oleic (18:1) and linoleic acid (18:2), which comprise more than 80% of the total fatty acids in peanut. Oleic acid is a monounsaturated fatty acid and has the function of reducing the content of low-density lipoprotein (LDL) in human bodies. Therefore, the increase of the content of oleic acid in peanut will not only improve oil stability and favor but also be good for the health of consumers. And Δ12-fatty acid desaturase (FAD) gene is an important gene to maintain a high content of oleic acid.
      The objectives of the present research were to further study the roles of the FAD gene in the growth and development of peanut cells and to reveal the regulation mechanisms in fatty acid metabolism,using different types of peanut genotypes. On the basis of the conservative sequence of Δ12-fatty acid desaturase, a cDNA was isolated, which consisted of 1 140 bp and encoded a polypeptide of 379 amino acid resides with a calculated molecular weight of 42 kDa. The putative amino acid sequence had three histidine conservative regions sharing integral-protease specificity and the hydrophobicity analysis showed that the sequence of the encoded amino acids had two hydrophobic structures sharing the characteristics of membrane-anchored protein,which totally crossed the membrane four times. These analyses revealed the obtained sequence was Δ12-fatty acid desaturase. The phylogenetic-tree analysis demonstrated that in Arachis the FDA sequence was conservative and highly homogenous to those in other species. Amino acid sequence comparison of peanut with other lipid-modifying enzymes provides insight to the evolution of enzyme structure/function relationships. The results of this study will provide molecular evidence for probing the phylogenetic relationships among the plants of Arachis. The significance of these findings and the evolution of plant fatty acid diversity were discussed.

      Chromosome Pairing Behavior and Reproduction in the Hybrid Developed by the Interaction of Different Pollen Sterile Genes in Autotetraploid Rice
      ZHAO Ming-Hui;LIU Xiang-Dong;LU Yong-Gen;LI Jin-Quan;GUO Hai-Bin
      Acta Agron Sin. 2006, 32(10):  1472-1478. 
      Abstract ( 1964 )   PDF (915KB) ( 1155 )   Save
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      Autotetraploid rice is a special germplasm with four sets of genome that is derived from diploid rice treated by colchicine. Compared with its diploid progenitor, the chromosomes and genome of the autotetraploids are doubled, thus the phenotype or morphology of the autotetraploids, especially the re
      Cooked Rice Texture and Starch RVA Properties for Indica Rice under Different Ecological Conditions
      XIE Li-Hong;YANG Shi-Hua;CHEN Neng;DUAN Bin-Wu;ZHU Zhi-Wei;LIAO Xi-Yuan
      Acta Agron Sin. 2006, 32(10):  1479-1484. 
      Abstract ( 1953 )   PDF (1006KB) ( 1165 )   Save
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      It is well known that environments had significant effects on the yield and quality of rice. Environment factors, such as cropping season (primarily temperature at filling stage) and management and cultural practices (plant density and time of nigtrogen fertilization, water management) may change the rice quality traits (chalkiness, Gel consistence, apparent amylose content and protein content etc.) and RVA viscosity. However, little information has been known about the effect of cropping location with different ecological conditions on the cooked rice texture and starch RVA property, and now the starch RVA viscosity and cooked rice texture are need to evaluate the eating quality of cooked rice. RVA breakdown viscosity was negatively correlated to the hardness of cooked rice. Stickiness was one of the main factors to determine the eating quality of cooked rice. In this paper, six indica rice cultivars with different levels of apparent amylose content (AAC) were selected to study their variation in the cooked rice texture and starch RVA properties among six cropping locations widely distributed in China (Gaozhou, Guangdong; Zunyi, Guizhou; Jiujiang, Jiangxi; Shi’en, Hubei; Yangzhou, Jiangsu; Hanzhong, Shaanxi). The results indicated that all six indica rice cultivars exhibited highly significant difference in stickiness and hardness as determined by Instron 4301 analyzer among 6 experimental locations. In Gaozhou, the 3 cultivars (Zheyou 1500, Qingliu’ai 1, and Liangyoupeijiu) exhibited the highest adhesiveness and stickiness values, while Zhongjian 2 had the lowest hardness, adhesiveness and stickiness values across all the locations. The significant difference was also detected for the parameters of RVA properties (hot, final, peak, breakdown, consistence and setback viscosity values), although the extent of difference was cultivar-dependent. The cultivars with middle, high AAC had similar RVA viscosity curves in Yangzhou, Zunyi and Hanzhong, and exhibited higher peak and breakdown viscosities in Gaozhou than in other locations, but low AAC cultivar Zhongjian 2 showed the lowest peak and breakdown viscosity in Gaozhou. The variances of 9 parameters (adhesiveness, stickiness, hardness, hot viscosity, final viscosity, peak viscosity, breakdown viscosity, consistence viscosity, setback viscosity) in genotype × environment interactions were significant at the 1% probability level. Based on the above coefficients of variation the parameters can be divided into three groups: adhesiveness was low; hot viscosity, final viscosity, peak viscosity, breakdown viscosity, consistence viscosity, stickiness and hardness were high; and setback viscosity was the highest. The high coefficients of variation of breakdown viscosity and stickiness, which proved to be closely related with the eating quality of cooked rice, indicated that there was a potential to improve the quality of rice cultivars. Taken together, the above results suggested that cropping location affected the eating quality of cooked indica rice. In order to bring all potentialities into full play to improve rice-eating quality, in addition to choosing high quality rice cultivars, suitable growing location must be considered.

      Effects of Chemical Regulation on Grain Relative Plumpness and Its Relationship with Yield and Grain Quality of Large Panicle Japonica Rice
      ZHAO Quan-Zhi;LÜ; Qiang;YIN Chun-Yuan;GAO Tong-Mei;NING Hui-Feng;QIAO Jiang-Fang;LIU Hui;CHEN Jing-Rui
      Acta Agron Sin. 2006, 32(10):  1485-1490. 
      Abstract ( 1978 )   PDF (544KB) ( 1029 )   Save
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      The poor grain plumpness is the general question in modern large panicle rice cultivars. The relationship of grain plumpness with grain yield and grain quality has not been reported. The field experiment was conducted in 2003–2004 to research the dynamic changes of grain filling rate, grain plumpness, relative plumpness and their relationship with grain yield and grain quality using the rice cultivar of Yujing 6 with chemical regulation treatments of T27, T23, PR1 and T30 (the check is water) at 5 days before heading. The grain relative plumpness is expressed by the percentage of 1000-grain weight of inferior grains to superior grains in one panicle of rice. The result indicated that the super-grain filling rate was 256% more than that of inferior-grain at early grain-filling stage (5–12 days after heading), and the filling rate of inferior-grain was 16.67% and 154.55% more than that of super-grain at mid-filling stage and later-filling stage respectively. The dynamic changes of grain plumpness and 1000-grain weight in superior grain were also different from those in inferior grain. The grain relative plumpness reduced rapidly at 5–12 day, rose rapidly at 12–19 days and rose slowly at 19–32 days after heading. The grain relative plumpness of PR1 treatment was higher than that of CK and other treatments obviously. There were significant positive correlation at P=0.05 or P=0.01 between grain relative plumpness and mean 1000-grain weight, economic coefficient, theoretical yield and true yield, brown rice percentage of inferior-grain, significant negative correlation at P=0.05 or P=0.01 between grain relative plumpness at 19–32 days after heading and chalky percentage, chalky area, chalkiness, and significant positive correlation between the grain relative plumpness at 19 days after heading and milled rice percentage, head rice percentage of inferior-grain. The results suggest that the Grain relative plumpness is a suitable index to express the relationship between super grain and inferior grain in one panicle.

      Effect of Nitrogen Application on Main Quality and RVA Profile Characters of Hybrid Rice
      WAN Liang-Jun;GONG Zhen-Kai;ZHANG Hong-Cheng ;LIN Zhong-Cheng;HUO Zhong-Yang ;DAI Qi-Gen ;XU Ke
      Acta Agron Sin. 2006, 32(10):  1491-1497. 
      Abstract ( 1998 )   PDF (545KB) ( 1087 )   Save
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      Rice quality can be improved through nitrogen fertilizer strategy, such as the rate and the timing of application. The establishment of “the leaf age model of development process of rice” makes rice cultivation move accurate in growth and development process modeling, cultivation diagnosis standardization and regularization of technical measures. The objective of this study was to find the suitable way of nitrogen application for improving the rice quality under the condition of the high yield. Using hybrids Kyou818 and Changyou1 planted with a total applied nitrogen amount of 225 kg/ha in the all growth stage. The different proportion of N-fertilizer at earlier and middle stages (the ratio of basic-tilling and stem- panicle fertilizer was 3:7, 5:5 and 7:3, respectively) and N-applying leaf age of stem- panicle N-fertilizers (Stage of remaining leaf primordium number 5, 3; 5, 4, 3, 2, 1; 4, 2; 3, 1, respectively) were imposed on the experiment. The results showed that with the increasing of N-application rate at earlier stages, head milled rice, protein content, setback, chalkiness and pasting temperature were decreased; gel consistency, peak viscosity and breakdown increased gradually; effect of N-fertilizer on trough viscosity and final viscosity varied with different cultivars. It suggested that the decrease of the nitrogen application proportion at middle stage improved facial features、cooking quality and viscosity of amylum, but adverse effect on milling quality and nutrient quality were found. Effect of N-applying leaf age on quality varied in different application proportions and cultivars. With decreasing proportion of N-application at middle stages, good facial features, cooking quality and viscosity of amylum were obtained by postponing the time of N-applying leaf age. Some quality indexes of Changyou 1 reached maximum (such as gel consistency, peak viscosity, trough viscosity, final viscosity and breakdown etc.) or minimum (such as chalkiness percentage, chalkiness degree and setback etc.) when the time of panicle fertilizer application was at a leafage later than that of K-you 818. This maybe attributes to Changyou 1 with long days-to-maturity. As a whole, the N-application proportion of 7:3 at earlier and middle stages could result in a good performance for quality of the two cultivars, while under this proportion, a much more good performance for quality of K-you 818 and Changyou 1 could be observed when applied stem- panicle N-fertilizers with equal amount in 4th and 2nd, and 3rd and 1st leaf age from top, respectively.

      Effects of Nitrogen Levels and Experimental Sites on Processing Quality Characteristics and Stability in Strong Gluten Wheat
      ZHAO Guang-Cai;WAN Fu-Shi;CHANG Xu-Hong;LIU Li-Hua;YANG Yu-Shuang;CHI Zhong-Zhi;YANG Li-Zhen
      Acta Agron Sin. 2006, 32(10):  1498-1502. 
      Abstract ( 1919 )   PDF (441KB) ( 1082 )   Save
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      The wheat (Triticum aestivum L.) grain quality was affected by genetic factors, ecological and cultivated conditions. The quality characteristics of the same variety would be convertible under different environment conditions. Seven cultivars of strong gluten wheat from main productive area were planted in six provinces to study N-fertilizer and environment effects on processing quality characteristics with the treatments of different N-fertilizer applications. The date was analyzed by AMMI model. The results indicated that within the range of 0–300 kg/ha fertilizer levels, wet gluten content, sedimentation, water absorption, development time, stable time, extensibility and bread volume all increased with the amount of N-fertilizer added. The CV of wet gluten content, sedimentation, development time and stable time were bigger, which indicate that these characters are sensitivity to N-fertilizer. While water absorption was not sensitive to nitrogen application, showing a better stability. In different sites, the CV of stable time was the highest and the CV of water absorption was the lowest. Among different cultivars, the CV of development time, stable time and extension area were bigger, but the CV of other quality characters was lower. Analysis of main processing quality characters by AMMI, when regard the N-fertilizer treatment and experimental site as environment factors and cultivars as genotype factor, it showed that effect of environment on wet gluten content, development time, extensibility, bread volume and bread score was more than genotype, while the effect of genotype on sedimentation, water absorption, stable time and extension area was more than environment. The interaction (G×E) of all quality indexes was extremely significant. In this trial, the amount of N-fertilizer application affected mostly the paste development time, next to which were the stable time, the wet gluten content, sedimentation and extension area in sequence. The water absorption was very stable. Some of the processing quality characteristics were sensitive to the environmental effect, while others were dependent on the genotype.

      QTL Analysis of Agronomic Traits with Sequenced Rice Varieties
      ZHANG Qi-Jun ;LIANG Yong-Shu;YE Shao-Ping;DENG Qi-Ming ;WANG Ling-Xia ;LI Ping ;YU De-Rong;ZOU Jiang-Shi;LÜ;; Chuan-Gen
      Acta Agron Sin. 2006, 32(10):  1503-1510. 
      Abstract ( 1976 )   PDF (701KB) ( 1023 )   Save
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      Rice (Oryza sativa L.) is an important food crop, which provides more than 50 percent of foods in China. Most of crop traits are quantitative in nature, which are controlled by polygene, so it’s very important for crop improvement to map quantitative trait loci (QTLs). In this research, rice varieties which whole genome have been sequenced, Nippinbare and 93-11, and their F2 lines were planted at Lingshui County, Hainan Province in 2004. The phenotypic values of 8 agronomic traits including number of tillers (TN), number of effective tillers (ETN), number of panicle (PN), panicle length (PL), main panicle length (MPL), days to heading (DH), plant height (PH), and flag length (FL) were surveyed with three replication. Correlation coefficients between these traits calculated by means of the software of Excel 2000 were found to be similar to other research conclusions. A F2 linkage map (152 simple sequence repeats (SSRs) markers and covering 2 455.7 cM of the genome length) was applied to detect QTLs with Mapmaker/QTL 1.1b. Under the condition that LOD>2.0 and P<0.005, 41 QTLs were detected, which distributed on all rice chromosomes. The phenotypic variations (VE) explained by individual QTL were ranged from 11.0% to 46.4%, among which 22 QTLs explained VE by more than 20%. The molecular basis of inheritance and the applications of QTL for rice agronomic traits with sequenced rice materials as mapping parents were discussed.

      Characteristics of Yield and Yield Components in Conventional Indica Rice Cultivars with Different Nitrogen Use Efficiencies for Grain Output
      DONG Gui-Chun;WANG Yu-Long;ZHANG Yue-Fang;CHEN Pei-Feng;YANG Lian-Xin;HUANG Jian-Yie
      Acta Agron Sin. 2006, 32(10):  1511-1518. 
      Abstract ( 1942 )   PDF (855KB) ( 1072 )   Save
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      Improving nitrogen use efficiency in crops is of great importance both in crop production and environmental protection. Genetically improving crop varieties so as to make full use of the potentials in nitrogen uptake and utilization has been considered as one of the most economical and effective ways to enhance nitrogen use efficiency in crops. Nitrogen use efficiency depends on the ability of nitrogen uptake and utilization in rice plant. Many studies have shown that there exist genotypic differences in nitrogen use efficiency for biomass and grain production in rice. Yet, little information in the characteristics of yield components, biomass production and allocation, nitrogen uptake and allocation and structure of root system in rice varieties with higher nitrogen use efficiency has been reported. In this study,eighty eight and one hundred and twenty two conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Leaf area index, dry matter weight (including root system), nitrogen content of rice plant, yield and its components were measured. The tested rice cultivars were clustered into 6 types (i.e. A, B, C, D, E and F,A was lowest, F was highest) based on their nitrogen use efficiency for grain output (NUEg) level by the MinSSw method, to study their characteristics of yield and yield components. Results were as follows: (1) Difference of NUEg in the cultivars used in this study were very large, the ratio of the maximal NUEg to the minimum NUEg in 2001 and 2002 were 344% and 425%, respectively. The average NUEg of A, B, C, D, E and F were 20.51, 31.04, 35.64, 39.46, 43.55 and 50.92 g grain·g-1N in 2001, and were 24.33, 31.61, 35.83, 39.06, 43.51, 50.00 g grain·g-1 N in 2002, respectively. The result of experiments in two years showed the same tendency. (2) As NUEg increased, yield level of conventional indica rice cultivars significantly increased. Polynomial regression analysis showed that yield level was significantly influenced by total nitrogen uptake (including root system) and NUEg which indicated that higher yield level can be reached by improving nitrogen uptake and NUEg of conventional indica rice cultivars. (3) The cultivars with high NUEg were higher in panicle number, sink potential, grain setting percentage, grain yield per unit leaf area and harvest index, but lower in leaf area index. The relationships between spikelet number per panicle, 1000-grain-weight, biomass and NUEg were not significant.

      Changes of Photosynthesis in Panax ginseng Leaves at Different Growth Stages
      XU Ke-Zhang;ZHANG Mei-Shan;WU Zhi-Hai;ZHANG Zhi-An;CHEN Zhan-Yu;LI Da-Yong
      Acta Agron Sin. 2006, 32(10):  1519-1524. 
      Abstract ( 2105 )   PDF (1102KB) ( 1102 )   Save
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      Panax ginseng is a famous special herb medicine. As a perennial shade-loving medicine crop, it will be harvested after growing at least 5–6 years. The net photosynthetic rate(Pn) is very low (2–4 µmol CO2·m-2·s-1) in leaves of Panax ginseng , which is an important limitation factor for production. In order to investigate the changes of the characteristics and the limitation factors of photosynthesis in Panax ginseng leaves at different growth stages, net photosynthetic rate (Pn) and related parameters in leaves of 1–6 years old Panax ginseng grown in the field and in phytotron were measured by infrared gas analyzer. The net photosynthetic rate reached the maximum , then decreased with leaf age in fully expanded leaves of one-year old Panax ginseng without forming reproductive organ. In leaves of 2–6 years old plant, the first peak of net photosynthetic rate appeared in the fully expanded leaves, then Pn had little decrease at flowering stages and reached the second peak at green fruit stage (fruit growing stage), at last persistently decreased at red fruit(ripe fruit) and yellowing leaf stages. For the experiment with removing flower bud, the second Pn peak did not appeared at green fruits, and Pn was higher in red fruits and yellowing leaf stages, as compared with control plants. The results showed that the changes of Pn are regulated by reproductive growth at different growth stages. Apparent quantum yield (AQY) did not show obvious changes from leaf fully expanded to green fruit stages, which the maximum AQY was observed in fully expanded leaves. AQY was decreased with the decrease of Pn after green fruit stage. The leaves grown under low light (10% of full light) and optimum light (30% of full light) were showed more slowly decrease of Pn than these under high light (50% of full light) after green fruit stage. The leaf senescence and the decrease of Pn were accelerated in each growth stage under high light and high temperature; conversely the senescence and the decrease of Pn were delayed in each growth stage under low light and low temperature. Stomatal conductance(Gs) and transpiration rate(Tr) had similar change trends to Pn at different growth stages. Intercellular CO2 concentration(Ci) was kept stable from leaf fully expanded to green fruit, and increased persistently after green fruit. The changes of Ci indicated that the decrease of photosynthesis was not caused by stomatal limitation at red fruit and yellowing leaf stages. There was negative correlation between Pn and specific leaf weight (SLW) from leaf fully expanded to red fruit. So, it can be deduced that changes of photosynthesis are related with accumulation and demand of photosynthate. There were higher WUE and lower Ci at green fruit then at other stages. The results indicate that water supply at green fruit stage is very important to improve the photosynthetic productivity.

      The Screening of Mutants and Construction of Mutant Population for Cultivar “9311” in Rice (Oryza sativa L.)
      YE Jun;WU Jian-Guo;DU Jing;ZHENG Xi;SHI Chun-Hai
      Acta Agron Sin. 2006, 32(10):  1525-1529. 
      Abstract ( 2296 )   PDF (2861KB) ( 1376 )   Save
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      Rice has become an established model system in the last decade and the organism chosen in the study of the cereal genomes. In order to find more mutants in the same genetic background, the seeds of indica rice cultivar 9311 were treated with γ-rays or EMS (ethyl methan sulfonate). Some mutants with the variations of leaf, stalk, panicle or root traits were found in the progenies, which the mutation frequency was 5.62%. Four hundred and sixty-five out of the 675 mutants were induced by γ-rays, and the other 210 mutants by EMS. Comparing with the EMS mutagenesis population, more mutants were produced in γ-rays mutagenesis population. But some mutants, such as the purple leaf sheath mutant and lesion resembling disease mutant, were only found in EMS mutagenesis population. The mutant library created will be helpful for gene identification and gene functional analysis.

      Researches of Simulation Models of Rape(Brassica napus L.) Growth and Development
      CAO Hong-Xin;ZHANG Chun-Lei;LI Guang-Ming;ZHANG Bao-Jun;ZHAO Suo-Lao;WANG Bao-Qing;JIN Zhi-Qing;GAO Liang-Zhi
      Acta Agron Sin. 2006, 32(10):  1530-1536. 
      Abstract ( 1953 )   PDF (590KB) ( 1365 )   Save
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      Agricultural model is one of core technology for digital agriculture, and crop simulation model is an important content in agriculture model. The aim of simulation model of rape growth and development (SMRGD) was to develop Rape Cultivation Simulation-Optimization-Decision Making System(Rape-CSODS) , to design its planting , to regulate and control its growth and development, and to fulfill its high yield, good quality, high benefits and standard production eventually. The SMRGD were developed based on field experiments with 2 cultivars, 6 sowing dates and 3 sites from 2002 to 2005 in middle valley of Yangtze river in China and relative data from references of rape researches, employed ideas of R/WCSODS (Rice/Wheat Cultivation Simulation-Optimization-Decision Making System), which included phenology, leaf age, biomass, leaf area index (LAI), and shoot and ramification number dynamics models, in the same time, the SMRGD and its parameters were also assessed, calibrated and tested. The average absolute deviation(de), correlation coefficients(r) and the standard errors of their absolute deviation(Sde) of the observed and simulated values for growth period duration of two cultivars in Wuhan and Wuhu were -0.9 to -0.3 d, with the correlation coefficient from 0.9996 to 0.9997 and 2.2 to 2.3 d, respectively, the most absolute deviation was 4 d. The de, Sde, r and the most absolute deviation of dry matter weight and LAI for “Zhongshuang 9” in Wuhan between the observed and simulated values were 7.3 g·m-2 and -0.1043, 59.13 g·m-2 and 0.1506, with the correlation coefficients 0.9916 and 0.9863, and 98.8 g·m-2 and -0.27, respectively, 1:1 line of them was in Fig.2 to 4. Temperature and light were main driving factors in the models of phenology and leaf age for rape, a life cycle of rape was divided into 4 development phases including from sowing to emergence, from emergence to enlongation, from enlongation to early anthesis, and from early anthesis to maturity, which made the model higher precision, good adaptability, wide usability, easy to master and suitable to use in management of rape production. The vernalization models for rape could be use in winter, semi-winter and spring rape varieties. The photosynthesis of green stem and pods were taken account simply in the population dynamic models for rape. The structure and functions of Rape-CSODS also were discussed in this study.

      Preliminary Studies on Heredity of Fertility for Low Temperature Induced Genic Male Sterile Line and Photoperiod (thermo)-Sensitive Genic Male Sterile Line in Rice (Oryza sativa L.)
      LIANG Man-Zhong;WANG Xiao-Hui; WU Hou-Xiong;CHEN Liang-Bi
      Acta Agron Sin. 2006, 32(10):  1537-1541. 
      Abstract ( 1880 )   PDF (509KB) ( 1063 )   Save
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      Since the discovery of the mutant (Nongken 58S) in Nongken 58 (Oryza sativa ssp. japonica) field by SHI Ming-Song in Hubei Province in 1973, many P(T)GMS (photoperiod (thermo)-sensitive genic male sterile) lines derived from Nongken 58S have been developed. Nongken 58S is PGMS (photoperiod-sensitive genic male sterile) rice which fertilize in short day-length and low temperature condition and sterilize in long day-length and high temperature condition. Genetic studies have shown that PGMS gene of Nongken 58S is governed by one or two recessive genes. Allelism of sterile genes of Nongken 58S and its derivative lines was founded that sterile gene of Nongken 58S is allelic to that of P(T)GMS line derived from Nongken 58S, but not allelic to non-Nongken 58S derivative P(T)GMS lines. go543S is low temperature induced recessive genic male sterile rice which fertilize in high temperature condition and sterilize in low temperature condition. In order to study the interaction of those recessive sterile genes whose effects of photoperiod and temperature on the fertility are reverse, 7 hybrids between go543S and Nongken 58S and its derivatives 7001S, Pei’ai 64S, Changxuan 3S and 8 backcrosses were made. Hybrids F1 was sterile during whole growth season under natural condition(2004,Changsha, Hunan, China; Table 1), which indicated that sterile genes of go543S was phenotypically allelic to gene of P(T)GMS lines derived from Nongken 58S. However the hybrids F1 did not fertilized in high temperature condition as go543S did, and did not fertilized in low temperature and short day-length condition either as Nongken 58S and its’ derivatives. It is evident that the genes of P(T)GMS rice are epistasis to the genes of go543S under high temperature with long day-length, while under low temperature with short day-length the genes of go543S are epistasis to the genes of P(T)GMS rice. Similar results were obtained from greenhouse treatment under long day-length and high temperature condition and short day-length and low temperature condition (Table 2). Frequency distribution of fertile segregation in the backcross of the hybrids of go543S and P(T)GMS rice was founded that the backcrosses with female parent go543S were recorded half low temperature induced recessive genic male sterile plants whose fertility was similar to that of go543S (Fig.1, Fig.2), while those with male parents were recorded half P(T)GMS plants which were fertile under low temperature with short day-length, indicating goodness-of- fit to Medelian ratio for recessive sterile genes.

      Photosynthetic Characteristics of Pinellia ternata (Thunb.) Breit.
      JIN Zhong-Ying;PENG Zheng-Song;LI Yu-Ming;WANG Mei
      Acta Agron Sin. 2006, 32(10):  1542-1548. 
      Abstract ( 1940 )   PDF (559KB) ( 997 )   Save
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      Pinellia ternata (Thunb.) Breit. is a wild medical plant. Their tubers were a crude drug of traditional Chinese medicine. For satisfying the demand of the drug market, some farmers began to cultivate this species in the field. The knowledge concerning physiological characteristics of P. ternata was an important guidance to its domestication, cultivation and cultivar breeding. This study focused on the photosynthetic characteristics of P. ternata, and expected to provide a scientific basis for choosing reasonable cultivation habitat and sieving preferential germplasm resource for field production of this crude drug.
      The photosynthetic characteristics of live mature leaves in P. ternata plants were determined with the LI-6400 portable photosynthesis system. The net photosynthetic rate (Pn) was measured under different light intensities condition, and then drawing the curve of Pn respond to light intensities according to the results. The diurnal variation of Pn was measured at sunny day from 7:00–7:00 pm. From 9:00–11:00 am was the time for measuring the Pn of P. ternata populations. Ten plants were chosen at choice from a population, and each plant was measured 3 times. The mean values were used to describe the Pn of the given populations. In all the measuring course, the photosynthetically active radiation was controlled stably at 1 000 μmol photons·m-2·s-1 with the red-blue light source provided by the LI-6400 portable photosynthesis system. Original data were dealt with by MS Excel 2000 and analyzed by SPSS 11.0.
      The results showed that the light compensation point of P. ternata was 19.19 μmol photons·m-2·s-1(Fig.1), indicating that P. ternata is a shade-loving plant. The initial apparent quantum efficiency of P. ternata was high up to 0.0604, indicating its high use efficiency of the light. Leaf photosynthesis was regulated by stoma and affected by relative humidity and light intensity .The curve of diurnal variation of net photosynthetic rate from leaves of P. ternata had two peaks (Fig.2). Fig.3 showed the effect of light intensity (Fig.3-a), temperature (Fig.3-b), relative humidity (Fig.3-c), stomatal conductance (Fig.3-d), intercelluar CO2 concentration (Fig.3-e), transpiration rate (Fig.3-f) on Pn of P. ternata. And it was correlated significantly with light intensity and transpiration rate, with the correlation coefficient of 0.820 and 0.713 respectively (Table 1). It was suggested that intercropping of P. ternata with tall crops would get shadowy environment, decrease midday depression of photosynthesis, and increase photosynthetic daily assimilation amount. The light intensity is one of the main factors of influencing Pn of P. ternata, and the midday depression of this species was observed in this investigation. But what causes midday depression of P. ternata couldn’t be light intensity (Fig.3-a). Although the light intensity was high up to 1055.7 μmol photons·m-2·s-1 at midday, it was not too high to result in decrease Pn of P. ternata (Fig1 & Fig3-a). Pn of 16 populations of P. ternata was measured and analyzed by SPSS 11.0, showing the very significant difference among them (Table 3). The Pn of the population PT3 that derived from Chongzhou Country, Sichuan Province, was 22.4 μmol CO2·m-2·s-1, which was the maximum among all the investigated populations (Table 2). Besides, there were other two populations, PT4 and PT6 which respectively derived from Zhongjiang and Shehong, also expressed very high Pn value. Theses three populations were considered adaptive to cultivation in the field. There were 14 of 16 populations in which individual plants showed the same Pn in statistics in the same population, which indicating to some extent that genotypes of individual plants are homozygous in these populations. And the other two populations PT7 and PT15, which respectively derived from Luxian and Guangan, were statistically different in Pn of individual plant, which means that the genetic diversity exist in these two populations. Therefore, in order to get the consistent cultivation type of photosynthetic characteristic, artificial choice is necessary.

      Screening for Good Quality Rice Germplasm Resources Resistant to Rice Blast

      HUANG Fu;YE Hua-Zhi ;XIE Rong;LIU Cheng-Yuan

      Acta Agron Sin. 2006, 32(10):  1549-1553. 
      Abstract ( 1997 )   PDF (393KB) ( 1021 )   Save
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      The blast resistance and milling and appearance grain quality of 40 rice germplasm resources were evaluated. The 40 rice germplasm resources had high or moderate resistance to rice blast with leaf blast severity of 1–6 scales, panicle neck blast of 1–5 scales and resistance frequency of 40.0%–100.0%, among them 20 germplasm rice resources had over 80% of resistance frequency. The average resistance frequency of the 40 resources to dominant ZB race group, important ZA race group and ZC race group were 80.0%, 70.2% and 80.5% respectively. While, the susceptible check variety Shanyou 63 had high susceptibility with leaf blast of 9 scales, panicle neck blast of 9 scales and resistance frequency of 6.7%. 24 good quality rice germplasm resources were selected from 40 resources with brown rice rate of 76.1%–80.9%, milled rice rate of 68.7%–72.6%, head rice rate of 35.7%–64.3%, chalkiness rate of 5%–30%, chalkiness degree of 1.2%–12.7%, grain length/width of 2.7–3.6. The milling and appearance quality of 6 rice germplasm resources reached the third grade of the national high quality rice standards and that of 4 rice germplasm resources reached the second grade. The resources are important for breeding new high-yield and good quality varieties or hybrid rice combinations resistant to rice blast.

      Effects of Proportional Application of Sesame Seed Cake Fertilizers and Chemical Fertilizer on the Aroma Quality of Flue-cured Tobacco Leaves
      WU Xue-Ping;ZHONG Xiu-Ming;QIN Yan-Qing;LIU Shuang
      Acta Agron Sin. 2006, 32(10):  1554-1559. 
      Abstract ( 2535 )   PDF (692KB) ( 1093 )   Save
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      It is still unclear how seed cake fertilizer affects the aroma compounds of flue-cured tobacco leaves. The results for the optimum application rate of sesame seed cake fertilizer and chemical fertilizer for a good quality of flue-cured tobacco leaves were inconsistent in previous reports , and most of them were gained based on the research using middle leaves of tobacco. In this study, the responses of chemical properties and aroma compounds of flue-cured tobacco leaves in different positions of plant to the proportional application of see cake fertilizer and chemical fertilizer were tested and the underlying mechanism of flue-cured tobacco flavor quality was explored using upper, middle and lower tobacco leaves. The results showed that application of 50% sesame cake and 50% chemical fertilizer could result in a suitable ratio of nicotine to sugar and higher neophytadiene, ketons and aldehyde contents for all leaves in different positions of tobacco plant grown in the mid-fertilize brown soil of Henan Province, therefore, the comprehensive quality of tobacco was improved , having small odor, suitable irritation, comfortable lingering smell, mild smoke and good combustibility. The quality discrepancy between the leaves in different positions was also diminished. Based on results obtained in our research, we recommend the optimal fertilizer blends for the tobacco grown in Henan Province as 50% sesame cake nitrogen with 50% chemical fertilizer nitrogen.

      Effect of Different Cultivated Practices on Pentosan Content in Wheat Grains
      WANG Li-Fang;JIANG Dong;DAI Ting-Bo;JING Qi;CAO Wei-Xing
      Acta Agron Sin. 2006, 32(10):  1560-1565. 
      Abstract ( 1952 )   PDF (433KB) ( 1030 )   Save
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      Pentosan plays important role in determining quality for baking, forage, beer-making and health food in wheat. However, knowledge of cultivation practices impacts on pentosan content in wheat grain were investigated based on a serial of field and pool experiment. Cultivars of Xuzhou 26, Yangmai 10, Yangmai 9 and Ningmai 9 were selected with five treatments including sowing date, spikelet and leaf removal, interaction of water stresses and nitrogen, nitrogen rate and nitrogen topdressing were conducted in 2001–2004. The results indicated that early and late sowing treatments significantly increased pentosan content in wheat grains by 2.13% and 8.07% respectively compared with that of period sowing date treatment (Fig.1). As compared with the control, pentosan content with spikelet-removal (sink reduction) treatment was decreased by 9.38% and 6.97% while that in flag leaf-removal (source reduction) treatment was increased by 1.81% and 14.83% in Xuzhou 26 and Yangmai 9, respectively (Fig.2). The main effects of water stress and nitrogen and the interaction effect between water and nitrogen were significant on grain pentosan content. Grain pentosan content in wheat under post anthesis waterloging was 2.87% lower than that of control. Impacts of nitrogen and water interaction on pentosan content differed with cultivars (Table 2). Grain pentosan content decreased with increasing nitrogen, however the decreasing tendency slowed down with increasing nitrogen. Pentosan content in wheat grains was significantly decreased by topdressing nitrogen (Fig.3–4). Pentosan content showed linearly correlated to grain weight when single grain weight exceeds 40 mg. In conclusion, these cultivation practices significantly regulated thousand-grain weight and subsequently determined grain pentosan content in wheat.

      REVIEW
      The Compensatory Mechanism in Exploring Crop Production Potential
      ZHAO Ming ;LI Jian-Guo;ZHANG Bin;DONG ZHi-Qiang;WANG Mei-Yun
      Acta Agron Sin. 2006, 32(10):  1566-1572. 
      Abstract ( 2279 )   PDF (922KB) ( 1307 )   Save
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      High yield is an invariable theme in crop science, and the exploration of crop yield potential is a hotspot of crop science researches. While great strides have been made in exploring the breakthrough of crop yield potential, the capability of over-compensation effects was considered to be a potential untouched part for higher grain yield. In this article, the concept, types, functionary effects and mechanisms of crop compensation were commentated, and a broad sense of crop compensation concept was presented on the basis of integrated analysis. Unbalanced changes often taking place in different factors in different hierarchies or same hierarchy, by the function of systemic regulation, some factors could be improved. That is crop compensation. Compensative effects are ubiquitous in crop system, there are not only “gain and loss” compensations in adverse conditions, but also “asynchronous improved” ones in favorable conditions and even sometimes in high yield plant populations. “Gain and loss” compensation was defined as crop could improve some important elements at the cost of depressing or losing its intrinsic performances of some other elements at specific hierarchy. When the crop population and the single plant are almost in perfect harmony, no more gains could be obtained by “Gain and loss” compensation, a new way must be found to break the yield limit. And “asynchronous improved” compensation might be fall back on. In the synchronous improvements of composing elements at specific hierarchy, one lesser improvement of some element might promote a significant improve of other element. This kind of change in crop system was defined as “asynchronous improved” compensation. Once one limited factor was improved, some other factors in crop system might change and a new harmonization at the higher level will be formed, correspondingly the crop yield would increases to a new level. On the basis of crop compensation effects and the “three combination structure” yield theory, two effective approaches, “structural exploration” and “functional exploration”, were put forward and carried out in exploring crop yield potential, and the mechanisms and the application effects of the approaches were expatiated from the overcompensation profile, which would provide an instructive guidance for higher crop yield.

      Mechanism and Application of Cytoplasmic Male-sterility in Sunflower (Helianthus annuus L.)
      XU Su-Xia;LIU Gong-She
      Acta Agron Sin. 2006, 32(10):  1573-1578. 
      Abstract ( 1942 )   PDF (459KB) ( 1047 )   Save
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      Sunflower (Helianthus annuus L.) is one of four main oil crops in the world and its hybrid production depends on three lines (sterile line, maintainer line and restoring line). That is why cytoplasmic male sterility (CMS) in sunflower is the research focus through years. The sterility mechanism of PET1, the single source of hybrid breeding of sunflower, is the occurrence of chimeric genes resulting from the intramolecular recombination in mitochondrial genome. As a result, the chimeric gene encoded a new polypeptide which impair the development of male gamete. The physiological mechanisms by which the products of these genes interfere with the formation of male gametophytes are still the subject of intense research. Variable germplasm of CMS would decrease the crisis of single source for hybrid production, and make lots of sense in ornamental sunflower as well.

      RESEARCH NOTES
      Mathematical Model of Quantitative Diagnosis on Dynamic Nitrogen Demand of Cotton after Anthesis Based on Critical Nitrogen Concentration Diluation Model
      XUE Xiao-Ping ;WANG Yi-Lin;GUO Wen-Qi;CHEN Bing-Lin;ZHOU Zhi-Guo
      Acta Agron Sin. 2006, 32(10):  1579-1585. 
      Abstract ( 1829 )   PDF (821KB) ( 1036 )   Save
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      The critical nitrogen concentration of a plant can be defined as the minimum nitrogen concentration required for maximum biomass grown at any time. The critical nitrogen concentration dilution curve can be described by the power equationCNEN=a×DM-bM , FNC=aⅹDM-bM,where CNFNC(%) is the total nitrogen concentration in the aboveground dry matter,DMM is the aboveground biomass(mg·ha-1,a represents the nitrogen concentration in aboveground dry biomass when DMM =1 mg·ha-1 and b is a statistical parameter g...
      Quantitative Genetic Analysis of Seed Dormancy in Maize (Zea mays L.)
      LAN Hai;GAO Shi-Bin;FAN Qing-Qi;CAO Mo-Ju;TANG Qi-Lin;PAN Guang-Tang;RONG Ting-Zhao
      Acta Agron Sin. 2006, 32(10):  1586-1588. 
      Abstract ( 1974 )   PDF (324KB) ( 988 )   Save
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      Inheritance of seed dormancy in the cross R08×A318 in Zea mays L. was detected by applying the major gene plus poly-gene model of quantitative traits to a joint analysis of multi-generations (P1, P2, F1, B1:2, B2:2 and F2:3). The results indicated that seed dormancy in the cross R08×A318 was controlled by one major gene with entirely dominance effects plus polygene with additive-dominance effects(the D-4 model).Genetic variance values of the major gene in B1:2,B2:2 and F2:3 populations were es...
      Ear Growth and Grain Filling Characteristics of Different Cultivars in Waxy Maize
      LIU Ping;WANG Cong-Liang;WANG Feng-Ge;LU Wei-Ping ;GUO Jing-Lun;WANG Ji-Feng;LIU Xiao-Bing
      Acta Agron Sin. 2006, 32(10):  1589-1591. 
      Abstract ( 2100 )   PDF (312KB) ( 1016 )   Save
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      Fifteen waxy maize cultivars were used in this experiment.There were significantly differences in fresh ear yield and grain yield among cultivars and a positive correlation between fresh ear yield and grain yield.After silking,the dynamic changes of ear growth and grain filling were similar among cultivars.The dry weight increment of ear and grains presented an "S-shaped" curve,which could be simulated by Richards equation.The parameters of G_(max),V_2, T_2 had important effect to increase the ear weight an...

      Phylogenetic Analysis of Partial Tobacco Germplasm Resources with AFLP Markers
      DU Chuan-Yin ;LIU Hong-Xiang;TIAN Ji-Chun
      Acta Agron Sin. 2006, 32(10):  1592-1596. 
      Abstract ( 1956 )   PDF (769KB) ( 993 )   Save
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      Phylogenesis of 48 tobacco germplasms from different countries or regions was analyzed with amplified fragment length polymorphism(AFLP).Four pairs of AFLP informative primers generated 323 scorable bands in total,in which 174 bands were polymorphic and the average percentage of polymorphic bands was 55.72.Cluster analysis based on Euclidean distance by unweighted pair-group method using arithmetic average(UPGMA) clearly separated the 48 germplasms into two groups,namely N.tabacum L.group and N.rustica L.gr...

Co-sponsored:
the Crop Science Society of China
the Institute of Crop Science, CAAS
China Science Publishing & Media Ltd.
Published: Science Press
Editor-in-chief: Wan Jian-min
Associate Editors-in-Chief:
Chen Xiao-ya Yang Jian-chang Zhang Xian-long Wang Jian-kang Xu Ming-liang Liu Chun-ming Wang Dao-wen Sun Chuan-qing Ding Yan-feng Jin Wei-wei Chu Cheng-cai Cheng Wei-hong
Director of the editorial department:
Yan Chun-ling
CN 11-1809/S
ISSN 0496-3490
Post subscription code: 82-336

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  • Started in 2013
  • Covered by SCIE
  • Open access in ScienceDirect

Editor in chief: Wan Jian-min
CN 10-1112/S
ISSN 2095-5421, 2214-5141(online)
Online published:
https://www.sciencedirect.com/journal/the-crop-journal
Submission: https://www.editorialmanager.com/cj/
E-mail: cropjournal@caas.cn
Tel: 8610-82108548

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