28 November 2013, Volume 20 Issue 6 Previous Issue    Next Issue

    Review or Special Topic
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    Review or Special Topic
    Detection, Occurrence, and Survey of Rice Stripe and Black-Streaked Dwarf Diseases in Zhejiang Province, China
    ZHANG Heng-mu, WANG Hua-di, YANG Jian, Michael J ADAMS, CHEN Jian-ping
    2013, 20(6): 383-390.  DOI: 10.1016/S1672-6308(13)60158-4
    Abstract ( )   PDF (276KB) ( )  
    The major viral diseases that occur on rice plants in Zhejiang Province, eastern China, are stripe and rice black-streaked dwarf diseases. Rice stripe disease is only caused by rice stripe tenuivirus (RSV), while rice black-streaked dwarf disease can be caused by rice black-streaked dwarf fijivirus (RBSDV) and/or southern rice black-streaked dwarf fijivirus (SRBSDV). Here we review the characterization of these viruses, methods for their detection, and extensive surveys showing their occurrence and spread in the province.
    Research Paper
    Mapping of QTLs for Germination Characteristics under Non-stress and Drought Stress in Rice
    Zahra MARDANI, Babak RABIEI, Hossein SABOURI, Atefeh SABOURI
    2013, 20(6): 391-399.  DOI: 10.1016/S1672-6308(13)60150-X
    Abstract ( )   PDF (748KB) ( )  
    Identification of genetic factors controlling traits associated with seed germination under drought stress conditions, leads to identification and development of drought tolerant varieties. Present study by using a population of F2:4 derived from a cross between a drought tolerant variety, Gharib (indica) and a drought sensitive variety, Sepidroud (indica), is to identify and compare QTLs associated with germination traits under drought stress and non-stress conditions. Through QTL analysis, using composite interval mapping, regarding traits such as germination rate (GR), germination percentage (GP), radicle length (RL), plumule length (PL), coleorhiza length (COL) and coleoptile length (CL), totally 13 QTLs were detected under pole drought stress (-8 MPa poly ethylene glycol 6000) and 9 QTLs under non-stress conditions. Of the QTLs identified under non-stress conditions, QTLs associated with COL (qCOL-5) and GR (qGR-1) explained 21.28% and 19.73% of the total phenotypic variations, respectively. Under drought stress conditions, QTLs associated with COL (qCOL-3) and PL (qPL-5) explained 18.34% and 18.22% of the total phenotypic variations, respectively. A few drought-tolerance-related QTLs identified in previous studies are near the QTLs detected in this study, and several QTLs in this study are novel alleles. The major QTLs like qGR-1, qGP-4, qRL-12 and qCL-4 identified in both conditions for traits GR, GP, RL and CL, respectively, should be considered as the important and stable trait-controlling QTLs in rice seed germination. Those major or minor QTLs could be used to significantly improve drought tolerance by marker-assisted selection in rice.
    QTL Mapping for Grain Size Traits Based on Extra-Large Grain Rice Line TD70
    ZHANG Ya-dong, ZHANG Ying-hui, DONG Shao-ling, CHEN Tao, ZHAO Qing-yong, ZHU Zhen, ZHOU Li-hui, YAO Shu, ZHAO Ling, YU Xing, WANG Cai-lin
    2013, 20(6): 400-406.  DOI: 10.1016/S1672-6308(13)60159-6
    Abstract ( )   PDF (364KB) ( )  

    Grain size traits, including grain length, grain width and grain thickness, are controlled by quantitative trait loci (QTLs). Many QTLs relating to rice grain size traits had been reported, but their control mechanisms have not yet been elucidated. A recombinant inbred line (RIL) population of 240 lines, deriving from a cross between TD70, an extra-large grain size japonica line with 80 g of 1000-grain weight, and Kasalath, a small grain size indica variety, were constructed and used to map grain size QTLs to a linkage map by using 141 SSR markers in 2010 and 2011. Five QTLs for grain length, six for grain width and seven for grain thickness were detected distributing over chromosomes 2, 3, 5, 7, 9 and 12. Seven QTLs, namely qGL3.1, qGW2, qGW2.2, qGW5.1, qGW5.2, qGT2.3 and qGT3.1, were detected in either of the two years and explained for 56.19%, 4.42%, 29.41%, 10.37%, 7.61%, 21.19% and 17.06% of the observed phenotypic variances on average, respectively. The marker interval RM1347–RM5699 on chromosome 2 was found common for grain length, grain width and grain thickness; qGL3.1 and qGT3.1 were mapped to the same interval RM6080–RM6832 on chromosome 3. All 18 QTL alleles were derived from the large grain parent TD70. Most of the QTLs mapped in the present study were found the same as the genes previously cloned (GW2, GS3 or qGL3, GW5 and GS5), and several were the same as the QTLs (GS7 and qGL-7) previously mapped. Three QTLs, qGL2.2 on chromosome 2, qGW9 and qGT9 on chromosome 9, were first detected. These results laid a foundation for further fine mapping or cloning of these QTLs.

    QTL Mapping for Rice RVA Properties Using High-Throughput Re-sequenced Chromosome Segment Substitution Lines
    ZHANG Chang-quan, HU Bing, ZHU Kong-zhi, ZHANG Hua, LENG Ya-lin, TANG Shu-zhu, GU Ming-hong, LIU Qiao-quan
    2013, 20(6): 407-414.  DOI: 10.1016/S1672-6308(13)60131-6
    Abstract ( )   PDF (447KB) ( )  
    The rapid visco analyser (RVA) profile is an important factor for evaluation of the cooking and eating quality of rice. To improve rice quality, the identification of new quantitative trait loci (QTLs) for RVA profiling is of great significance. We used a japonica rice cultivar Nipponbare as the recipient and indica rice 9311 as the donor to develop a population containing 38 chromosome segment substitution lines (CSSLs) genotyped by a high-throughput re-sequencing strategy. In this study, the population and the parent lines, which contained similar apparent amylose contents, were used to map the QTLs of RVA properties including peak paste viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV), breakdown viscosity (BKV), setback viscosity (SBV), consistency viscosity (CSV), peak time (PeT) and pasting temperature (PaT). QTL analysis was carried out using one-way analysis of variance and Dunnett’s test, and stable QTLs were identified over two years and under two environments. We identified 10 stable QTLs: qPKV2-1, qSBV2-1; qPKV5-1, qHPV5-1, qCPV5-1; qPKV7-1, qHPV7-1, qCPV7-1, qSBV7-1; and qPKV8-1 on chromosomes 2, 5, 7 and 8, respectively, with contributions ranging from -95.6% to 47.1%. Besides, there was pleiotropy in the QTLs on chromosomes 2, 5 and 7.
    Infection of Early and Young Callus Tissues of Indica Rice BPT 5204 Enhances Regeneration and Transformation Efficiency
    2013, 20(6): 415-426.  DOI: 10.1016/S1672-6308(13)60153-5
    Abstract ( )   PDF (495KB) ( )  

    A rapid and reproducible method to develop transgenic plants with enhanced transformation efficiency using Agrobacterium has been developed for the elite indica rice variety BPT 5204. Different rice calli aged from 3 to 30 d were co-cultivated with pre-incubated Agrobacterium suspension culture (LBA4404: pSB1, pCAMBIA1301) and incubated in dark for 3 d. Based on the transient GUS gene expression analysis, 6-day-old young calli showed high transformation frequency followed by 21-day-old ones. Thus, both 6- and 21-day-old calli were used for assessing the stable transformation efficiency. It was observed that the 6-day-old young transformed calli showed about 2-fold higher regeneration frequency when compared with 21-day-old calli. The transformation efficiency was enhanced for young calli to 5.9% compared with 0.8% of the 21-day-old calli. Molecular and genetic analysis of transgenic plants (T0) revealed the presence of 1–2 copies of T-DNA integration in transformants and it follows Mendalian ratio in T1 transgenic plants. From the present study, it was concluded that the development of transgenic rice plants in less duration with high regeneration and transformation efficiency was achieved in BPT 5204 by using 6-day-old young calli as explants.

    Super Rice Cropping Will Enhance Rice Yield and Reduce CH4 Emission: A Case Study in Nanjing, China
    JIANG Yu, WANG Li-li, YAN Xiao-jun, TIAN Yun-lu, DENG Ai-xing, ZHANG Wei-jian
    2013, 20(6): 427-433.  DOI: 10.1016/S1672-6308(13)60157-2
    Abstract ( )   PDF (232KB) ( )  
    A pot experiment was performed to learn the differences in plant productivity and CH4 emission between two rice cultivars, super rice variety Ningjing 1 and traditional variety Zhendao 11, which were currently commercially applied in Nanjing, China. Similar seasonal changes of CH4 emission fluxes and soil solution CH4 contents were found between the tested cultivars. Although there was no significant difference in plant biomass production between the cultivars, the grain yield of Ningjing 1 was significantly higher by 35.0% (P < 0.05) than that of Zhendao 11, whereas the total CH4 emission from Ningjing 1 was 35.2% lower (P < 0.05). The main difference in the amounts of CH4 emission between the cultivars occurred in the period from the tillering stage to the heading stage. The biomass-scaled and yield-scaled CH4 emissions were respectively 3.8 and 5.2 mg/g for Ningjing 1, significantly lower than those for Zhendao 11 (7.4 and 12.8 mg/g, respectively). According to the relationships between the plant growth characteristics and the CH4 emission, a stronger root system contributed mainly to the lower CH4 emission of Ningjing 1, as compared with Zhendao 11. Our results demonstrated that super rice has advantages not only in grain productivity but also in CH4 emission mitigation. Further expansion of super rice cropping will enhance rice yield and reduce greenhouse gas emission in China.
    Simulation of Canopy Leaf Inclination Angle in Rice
    ZHANG Xiao-cui, LU Chuan-gen, HU Ning, YAO Ke-min, ZHANG Qi-jun, DAI Qi-gen
    2013, 20(6): 434-441.  DOI: 10.1016/S1672-6308(13)60161-4
    Abstract ( )   PDF (300KB) ( )  
    A leaf inclination angle distribution model, which is applicable to simulate leaf inclination angle distribution in six heights of layered canopy at different growth stages, was established by component factors affecting plant type in rice. The accuracy of the simulation results was validated by measured values from a field experiment. The coefficient of determination (R2) and the root mean square error (RMSE) between the simulated and measured values were 0.9472 and 3.93%, respectively. The simulation results showed that the distribution of leaf inclination angles differed among the three plant types. The leaf inclination angles were larger in the compact variety Liangyoupeijiu with erect leaves than in the loose variety Shanyou 63 with droopy leaves and the intermediate variety Liangyou Y06. The leaf inclination angles were distributed in the lower range in Shanyou 63, which matched up with field measurements. The distribution of leaf inclination angles in the same variety changed throughout the seven growth stages. The leaf inclination angles enlarged gradually from transplanting to booting. During the post-booting period, the leaf inclination angle increased in Shanyou 63 and Liangyou Y06, but changed little in Liangyoupeijiu. At every growth stage of each variety, canopy leaf inclination angle distribution on the six heights of canopy layers was variable. As canopy height increased, the layered leaf area index (LAI) decreased in all the three plant types. However, while the leaf inclination angles showed little change in Liangyoupeijiu, they became larger in Shanyou 63 but smaller in Liangyou Y06. The simulation results used in the constructed model were very similar to the actual measurement values. The model provides a method for estimating canopy leaf inclination angle distribution in rice production.
    Influence of Rice Genotypes on Folding and Spinning Behaviour of Leaffolder (Cnaphalocrocis medinalis) and Its Interaction with Leaf Damage
    2013, 20(6): 442-450.  DOI: 10.1016/S1672-6308(13)60154-7
    Abstract ( )   PDF (381KB) ( )  
    Folding and spinning behavior of Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) in different categories of rice genotypes viz., resistant, susceptible, hybrid, scented, popular and wild rice genotypes were significantly different. Longer leaf selection time and folding time per primary fold; shorter primary fold and whole leaf fold; lower number of binds per primary fold and whole leaf fold were recorded in resistant and wild rice genotypes. In the correlation analysis, it was found that the leaf folding parameters were positively correlated to leaf folder damage whereas the leaf spinning parameters were negatively correlated. Similarly, the morphological characters differed significantly among the chosen genotypes and were related to leaffolder damage. The leaf width and total productive tiller number were positively correlated to leaffolder infestation. Results also indicated that the trichome density and length, leaf length and plant height might contribute to resistance whereas total number of green leaves had no effect on leaffolder infestation. In the scatter plot analysis between leaf folding and spinning characters and leaffolder damage, the genotypes were separated into four groups viz., resistant (TKM6, Ptb 33, LFR831311, Oryza rhizomatis and O. minuta), moderately resistant (ASD16 and CORH1), moderately susceptible (ADT36, Pusa Basmati and CB200290) and susceptible (IR36 and TN1). The present investigation proved that the leaf morphology viz., leaf length and width, plant height and trichome density and length may play a vital role in resistance against rice leaffolder.