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10 May 2019, Volume 33 Issue 3 Previous Issue    Next Issue
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Review and Special Topic

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Analysis of the Eurytopicity of Super Hybrid Rice Liangyoupeijiu Chuangen LÜ, Xia LI, Shouyu ZONG, Jiangshi ZOU 2019, 33(3): 191-205.  DOI: 10.16819/j.1001-7216.2019.8132 Abstract ( )   HTML ( )   PDF (1180KB) ( )   The implication of eurytopicity of hybrid rice remains unclear, and the screening indicators and identification methods have not been reported in detail. A two-line super hybrid rice Liangyoupeijiu has been extensively grown in southern China for many years. Here, we reviewed the eurytopicity of Liangyoupeijiu and proposed methods of selection for rice better adaptability. Based on the characteristics of Liangyoupeijiu, the intrinsic mechanism and scientific implication of eurytopicity were summarized in two aspects. One is the wide adaptability to ecological factors including weak sensitivity to photoperiod, resistance to pathogens, as well as the plant height, leaf angle, and grain quality produced in the areas that can meet the requirements of agricultural ecology and economy. The other is the wide adaptability to environmental factors including tolerance to light intensity, air temperature, and moisture, nutrients, salinity, pH in soils, as well as resilience to planting date, planting density, and fertilizer management. Novel hybrid rice should be selected accordingly.

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Research Advances in the Effect of Heat and Drought on Rice and Its Mechanism Hua DUAN, Hui TONG, Yanqing LIU, Qingfen XU, Jun MA, Chunmin WANG 2019, 33(3): 206-218.  DOI: 10.16819/j.1001-7216.2019.8106 Abstract ( )   HTML ( )   PDF (1054KB) ( )   Heat and drought are two major environmental stresses that affect rice growth, productivity, and grain quality. a comprehensive understanding of which is critical to evaluate the impacts of climate change on crop production. We review the independent and combined effects of heat and drought on rice growth, yield, and grain quality, demonstrate the possible mechanisms involved from multiple perspectives, such as photosynthesis, antioxidant system, endogenous hormones, activities of the key enzymes involved in sucrose-to-starch conversion, and molecular profiling, proposes reasonable strategies to mitigate the stress of environmental heterogeneity, and provide considerable suggestions for future study.

Orginal Article

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Identification and Fine Mapping of a Narrow Leaf Mutant nal12 in Rice Yi WEN, Yunxia FANG, Peng HU, Yueying WANG, Linlin HOU, Yiqing TAN, Lixin ZHU, Xuemei DENG, Dali ZENG, Guangheng ZHANG, Longbiao GUO, Li ZHU, Guang CHEN, Deyong REN, Yuchun RAO, Dawei XUE, Qian QIAN, Jiang HU 2019, 33(3): 219-226.  DOI: 10.16819/j.1001-7216.2019.8125 Abstract ( )   HTML ( )   PDF (938KB) ( )   【Objective】Leaf is a vital component of ideal plant type in rice. Screening and identification of new leaf mutants can lay the foundation for studying leaf development and constructing ideal leaf morphology. 【Method】A novel rice mutant named narrow leaf 12 (nal12) was identified from an EMS mutagenized population of Wuyunjing 31. The leaf length, leaf width, numbers of large and small veins from flag leaf to the 4th leaf from the top were measured, and the histological section and microscopic observation were conducted at the maturity stage. The F2 segregating population was constructed from a cross between nal12 and indica variety TN1, and 1709 narrow-leaf individuals were selected for fine mapping of NAL12 with existing SSR, STS and developed molecular markers. 【Result】The nal12 showed narrow leaves at seedling stage, and exhibited dwarf, increased tillers and thinner stems at maturity stage. According to the anatomy observation of tissue sections, the narrow leaf phenotype of nal12 was caused by the decrease in the number of large veins and small veins compared with the wild type. Genetic analysis indicated that the narrow leaf trait was regulated by a single recessive nuclear gene, and NAL12 was finally mapped to a range of 64.7 kb between LC2-RF37 and LC4R-RF39 markers on chromosome 10. A total of 10 ORFs (open reading frames) were found and there were no narrow-leaf related genes reported in this region. qRT-PCR analysis revealed that the mutation of NAL12 was involved in the expression level of auxin synthesis and transport-related genes. 【Conclusion】NAL12 is a new leaf-shape regulatory gene, which lay a foundation for further research on rice leaf development and enrich its molecular regulatory network.

Research Papers

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Identification of Brown Planthopper Resistance Genes in Broad-spectrum Blast Resistant Rice Germplasm 75-1-127 and Its Molecular Marker-Assisted Selection Breeding Haoyu JIANG, Gai ZENG, Ming HAO, Xianggui HUANG, Yinghui XIAO 2019, 33(3): 227-234.  DOI: 10.16819/j.1001-7216.2019.9005 Abstract ( )   HTML ( )   PDF (822KB) ( )   【Objective】Rice line, 75-1-127, which harbors the broad-spectrum blast resistance gene Pi9, has been widely used in rice variety improvement for blast resistance. Given that 75-1-127 shows strong resistance to brown planthoppers in our previous breeding projects, we identified its resistance genes to brown planthoppers and used it in molecular marker-assisted selection breeding. 【Method】The PCR products, which amplified from the genomic DNA of 75-1-127 with the primers designed according to the sequence of Bph14 and Bph15 genes in rice line B5, were sequenced and analyzed. The brown planthopper resistance of 75-1-127 and B5 were also identified with seedling bulk test method. A series of two-line genic male sterile lines derived from backcross with 75-1-127 as a donor parent, were screened with the molecular markers linked to Bph14 and Bph15 genes. The blast resistance, brown planthopper resistance and main agronomic traits of these progenies were also identified and evaluated. 【Result】The sequences of Bph14 and Bph15 in 75-1-127 were identical with those in B5. The resistance scores at seedling stage of 75-1-127 and B5 were both grade 1. In the progenies with 75-1-127 as resistance resource, the resistances to brown planthoppers of those monogenic lines of Bph14 or Bph15 and those Bph14/Bph15 pyramiding lines were all improved. That the seedling mortality of Bph14/Bph15 pyramiding lines was 8.5%, equivalent to the donor parents 75-1-127 and the positive control B5, further confirming that 75-1-127 contained resistance genes to brown planthoppers. 【Conclusion】Rice line 75-1-127, which carries the genes of Bph14 and Bph15, could be used as resistance resource in breeding.

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Characterization and Application of Antibodies Against a Small Heat Shock Protein OsHSP20 from Oryza sativa Jing HE, Han LIU, Liuming GUO, Jing LI, Hengmu ZHANG 2019, 33(3): 235-240.  DOI: 10.16819/j.1001-7216.2019.9009 Abstract ( )   HTML ( )   PDF (826KB) ( )   【Objective】In previous studies, OsHSP20, a gene encoding small heat shock protein, was cloned from Oryza sativa. Here its polyclonal antibodies were prepared and analyzed for their properties of immunological reactions and range of application. 【Method】 Synthetic peptide and recombinant protein of OsHSP20 were used to immunize the rabbits for preparing the polyclonal antibodies against the protein, respectively. Antigen-coated plate (ACP)- and dot-enzyme linked immunosorbent assays (ELISA) were used for comparing the titer and sensitivity of antibodies. Western blotting was used to determine the antibody specificity and the range of application. 【Result】In Western blotting assays, both antibodies were strongly reacted with a band of protein with an expected size of 37 kD, suggesting that they were specific against the OsHSP20. ACP- and dot-ELISA assays showed that the polyclonal antibody prepared from the recombinant protein had a higher titer and sensitivity than that of peptide. Further assays showed that the polyclonal antibody could be used for detection of the SHSP homologs of plants. 【Conclusion】The polyclonal antibodies were successfully prepared with high specificity, titer, and sensitivity and could be widely used to analyze the expression of HSP20 protein in a variety of monocotylous and dicotyledonous plants, which could contribute to the functional characterization of OsHSP20 and its homologs in different plants.

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Analysis of Rice Blast Resistance Genes in japonica Rice Varieties in Liaoning Province Zhengyan PAN, Fulin QIU, Guilan LÜ, Xiufang MA, Wenqi SHANG, Yuanjun BAI, Zhengjin XU 2019, 33(3): 241-248.  DOI: 10.16819/j.1001-7216.2019.8071 Abstract ( )   HTML ( )   PDF (945KB) ( )   【Objective】To clarify the rice blast resistance genes in 260 japonica rice varieties in Liaoning Province, evaluate their utilization value, and provide reference for rice breeding,【Method】specific primers of nine rice blast resistance genes were selected to analyze the species, the quantity and the geographical distribution of resistance genes of 260 japonica rice varieties in Liaoning, and the cluster analysis of varieties was based on the detection bands of disease resistance genes. The disease resistance of the nine resistant mongenic rice lines was evaluated by seedling-spray inoculation, natural disease investigation during the active tillering stage and ripening stage.【Result】The number of blast resistance genes in japonica rice from Liaoning varied from 0 to 7, and the frequency of Pikh gene ranked highest, followed by the Pikm and Pi1. Pi9 gene was not detected in all tested varieties, and Pi40 gene was only detected in Liaojing 421 bred by the Liaoning Academy of Agricultural Sciences. There were 62 gene combinations in the rice varieties tested, and based on the clustering analysis of the results of the resistance gene detection, 260 japonica rice materials can be divided into 11 groups. Among the nine resistant mongenic lines, Pi40 showed the best resistance, followed by Pi9, Pigm and Pita.【Conclusion】The resistance genes Pi9, Pi40, Pita, and Pigm have important application potential in breeding in Liaoning Province. 80.38% of the tested varieties concentrate in groups V, VI, VII and IX. There is no obvious geographical difference; the types of disease resistance gene combinations of the tested varieties are relatively less abundant and the genetic relationship is relatively close.

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Effects of Different Soil Texture on Root Growth and Distribution of Rice Seedlings Under Drip Irrigation Qiang XU, Xiaopeng MA, Tingbo LÜ, Dongwang WANG, Meng BAI, Zelin WANG, Jingran NIU 2019, 33(3): 249-256.  DOI: 10.16819/j.1001-7216.2019.8096 Abstract ( )   HTML ( )   PDF (949KB) ( )   【Objective】The effects of different soil textures on root growth and distribution of drip-irrigated rice during seedling stage were studied, and the important role of soil environment on rice seedling growth under drip irrigation was revealed.【Method】A potted soil column experiment was conducted in the experimental site of the Shihezi University. Three treatments, heavy loam, light loam and sandy soil, were designed. Each treatment was repeated for five times. Samples were taken 10, 20, 30 and 40 days after sowing. The seedling emergence rate, root morphology, biomass, root activity and root distribution under different treatments were compared and analyzed. Effects of soil conditions on root growth and distribution of rice seedlings under drip irrigation were analyzed. 【Result】The average seedling emergence rate in sandy soil was 15.21% higher than that in heavy loam soil and 4.6% higher than that in light loam soil, respectively. The root volume in heavy loam soil was 18.53% and 43.15% higher than that in light loam and sandy soil respectively; the longest root length in sandy soil treatment was 38.44% and 12.69% higher than that in heavy loam and light loam, respectively; the total biomass in heavy loam soil was 19.76% and 41.48% higher than that in light loam and sandy soils, respectively. The root biomass of heavy loam soil increased by 14.98% and 35.83% compared with that in light loam and sandy soils. The root activity in seedling stage followed the following trend: heavy loam soil > light loam soil > sandy soil, and the average root activity within 40 days in heavy loam soil was 3.54% and 13.91% higher than that in light loam soil and sandy soil, respectively. The proportion of roots in the soil at depth from 0 to 5 cm in each period was always the largest. 【Conclusion】 The results showed that different soil textures had significant effects on rice seedling emergence rate, root morphology, biomass, root activity and root distribution under drip irrigation. Therefore, in order to achieve the goal of high quality, high yield and high efficiency, different sowing amounts and corresponding cultivation practices should be taken in the process of popularizing drip irrigation.

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Effects of Rape Straw Retention and Water and Nitrogen Management on Population Quality and Yield of Hybrid Rice Under Rice-rape Rotation Yaozhu YIN, Changchun GUO, Yongjian SUN, Yunxia WU, Huaqing YU, Zhibai SUN, Qiao ZHANG, Haiyue WANG, Zhiyuan YANG, Jun MA 2019, 33(3): 257-268.  DOI: 10.16819/j.1001-7216.2019.8102 Abstract ( )   HTML ( )   PDF (1057KB) ( )   【Objective】It has great significance to investigate the interaction mode between straw returning and water-nitrogen (N) management on rice population quality and yield.【Method】Hybrid rice (Yixiangyou 2115) was used as experimental materials with two straw retention ways as main plot (crop straw composting and direct straw returning) and conventional irrigation and alternate irrigation as split plot and four N rates as split-split plot. The relationship between population quality and yield of hybrid rice were also analyzed.【Results】Straw returning and water-nitrogen (N) management exert significant or extremely significant effects on biomass accumulation of hybrid rice, LAI and grain yield. Correlation analysis indicated that there existed significantly or highly significantly positive correlations between population quality index and yield. The straw composting had a highly significant effect on population growth rate and grain yield compared with direct straw returning, the high valid leaf area index at the full heading stage increased by 4.71%-6.50%, Dry matter weight of population during maturity increased by 9.22%-13.30%, and the effective panicle number increased by 5.9%-9.8%, the spikelet number by 1.5%-5.2%, the yield by 9.5%-13.4%. Compared with conventional irrigation, controlled alternative irrigation could ensure sufficient panicle number, increase dry matter accumulation, slow down leaf area attenuation rate from jointing stage to full heading stage, accelerate population growth rate at seed-setting stage, and increase grain number per panicle and yield significantly. With the increase of nitrogen rate, the number of tillers, dry matter accumulation, effective leaf area ratio and effective leaf area rate all increased at first and then decreased. 【Conclusion】 From the perspective of the effect of the three factors, straw composting, alternative irrigation, 150 kg/hm2 nitrogen level were the optimum treatment of water saving and N reduction in this experiment. It can significantly improve efficient LAI of full heading (4.80-5.32), enhance the high dry matter accumulation rate during filling stage (6.94-7.36 t/hm2), notely increase effective panicle number (181.6×104-220.9×104/hm2) and grain number per panicle(180-200), achieving grain yield of hybrid rice of 10328.1-12464.1 kg/hm2.

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Effects of Interaction Between Nitrogen Application Rate and Direct-sowing Density on Yield Formation Characteristics of Rice Pei WU, Tianye CHEN, Jiaqi YUAN, Heng HUANG, Zhipeng XING, Yajie HU, Ming ZHU, Dejian LI, Guolin LIU, Hongcheng ZHANG 2019, 33(3): 269-281.  DOI: 10.16819/j.1001-7216.2019.8112 Abstract ( )   HTML ( )   PDF (974KB) ( )   【Objective】To reveal the effects of interaction between nitrogen application rate and direct-sowing density on yield formation characteristics of rice, 【Method】 Nanjing 9108, a japonica cultivar with good taste, was used as the experimental material. We designed four nitrogen application rates, namely N1(0 kg/hm2), N2(150 kg/hm2), N3(225 kg/hm2), N4(300 kg/hm2), and five direct-sowing densities, namely D1(90×104/hm2), D2(180×104/hm2), D3(270×104/hm2), D4(360×104/hm2), D5(450×104/hm2). 【Result】The rice yield increased with the increase of nitrogen rate. Under the nitrogen application rate of N1, N2, N3, the grain yield of rice was first increased and then decreased with the increase of direct-sowing density. Under these nitrogen application rates, the highest yield was 6.74 t/hm2, 7.78 t/hm2, 8.93 t/hm2, respectively, which was obtained at the direct-sowing densities of D4, D3, D2. Under the nitrogen rate of N4, the yield decreased with the increase of direct-sowing density, and the highest yield was 9.55 t/hm2, which was obtained at the direct-sowing density of D1. Appropriate direct-sowing densities under different nitrogen application rates can improve rice yield, among which the yield of N4D1 was the highest, due to its moderate number of stems and tillers, large panicle type and LAI in the mid- and late-growth stages, high photosynthetic potential and crop growth rate, superior net assimilation rate and dry matter weight in the later growth. 【Conclusion】Under the high nitrogen rate of 300 kg/hm2, mechanical direct-sowing rice can easily achieve high yield, and appropriate direct-sowing density can further improve rice yield. However, given green production and cost saving and efficiency increasing, to reduce the nitrogen rate to 225 kg/hm2, and the direct-sowing density to 180×104/hm2 can still obtain yield around 9 t/hm2, which is also worthy of promotion.

Short Communication

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Sensitivity Changes of Rice Stem Borers to Insecticides After Feeding on Vetiveria zianioides Ruixue SONG, Han LU, Yanhui LU, Xusong ZHENG, Zhongxian LÜ 2019, 33(3): 282-286.  DOI: 10.16819/j.1001-7216.2019.8025 Abstract ( )   HTML ( )   PDF (532KB) ( )   【Objective】Previous studies showed that vetiver grass (Vetiveria zizanioides) can effectively attract female adults of Sesamia inferens (Walker) and Chilo suppressalis (Walker) to lay eggs, while hatched larvae will die after feeding on vetiver grass for a certain time. Therefore, vetiver grass is recommended for field control of rice stem borers. However, the combination of various measures is always used for field control. At present, chemical control is still an irreplaceable measure. Nevertheless, the sensitivity change of rice stem borers after feeding on vetiver to commonly used insecticides is still unclear. 【Method】Seedling dipping bioassay method was used to investigate the toxicity of eight insecticides, including indoxacarb, chlorantraniliprole, spinosad, emamectin benzoate, sulfluramid, metaflumizone, abamectin and chlopyrifos to both S. inferens and C. suppressalis, and the sensitivity changes of these two insect species to these insecticides after feeding on vetiver grass. 【Result】 LC50 to S. inferens were as follows: metaflumizone 1.04 mg/L, emamectin benzoate 1.40 mg/L, chlorantraniliprole 2.67 mg/L, sulfluramid 3.48 mg/L, spinosad 7.59 mg/L, abamectin 13.03 mg/L, indoxacarb 16.57 mg/L, chlorpyrifos 23.28 mg/L; and to C. suppressalis were metaflumizone 1.94 mg/L, emamectin benzoate 2.07 mg/L, chlorantraniliprole 4.20 mg/L, sulfluramid 8.93 mg/L, indoxacarb 9.51 mg/L, spinosad 9.72 mg/L, abamectin 17.63 mg/L, chlorpyrifos 64.68 mg/L. The sensitivity of the two kinds of rice stem borers fed on vetvier grass was increased as compared with the stem borers fed on rice. Three days after feeding on vetiver grass, the sensitivity of S. inferens larvae to eight pesticides was improved, and the mortality was also increased by 13.3%-22.2%. The sensitivities of S. inferens to chlorantraniliprole, spinosad, sulfluramid, metaflumizone and chlorpyrifos were significantly increased, while the sensitivity of C. suppressalis larvae to all the tested pesticides was significantly increased after feeding on vetiver grass with an increased mortality by 26.7%-33.3%. Overall, the sensitivity of C. suppressalis larvae was obviously increased more than that of S. inferens. 【Conclusion】The sensitivity of rice stem borers to eight commonly used insecticides was dramatically increased after feeding on vetiver grass.