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18 December 2021, Volume 1 Issue 1 Previous Issue   
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Effects of Irrigation Regimes DuringGrain Filling Under Different Nitrogen Rates on Inferior SpikeletsGrain-Filling and Grain Yield of Rice Kuanyu ZHU, Mingfei ZHAN, CHENJing, Zhiqin WANG, Jianchang YANG, Buhong ZHAO 2018, 1(1): 155-168.  DOI: 10.16819/j.1001-7216.2018.7060 Abstract ( )   HTML ( )   【Objective】 To investigate the effects of water and nitrogen application on yield and grain filling,【Method】 an indica/japonica hybrid Yongyou 2640 with large-panicle and a japonica inbred Huaidao 5 with mid-panicle were grown in pots. After field seedling nursing then transplanting to pots, we designed three N rates, namely 0N (0 g N/pot), medium N level(MN, 2 g N/pot), and high N level(HN, 4 g N/pot), and three irrigation regimes post-anthesis consisting of conventional irrigation (CI, soil water potential was kept at 0 kPa), alternate wetting and moderate drying irrigation (WMD, rewatered when soil water potential reached -15 kPa), and alternate wetting and severe drying irrigation (WSD, rewatered when soil water potential reached -30 kPa). 【Result】 In the CI regime, MN showed the highest grain yield; in the WMD regimes, however, there was no significant difference in grain yield between MN and HN. Furthermore, in the WSD regime, grain yield under HN was the highest. In terms of grain filling, the superior spikelets present no significant difference in grain filling rate and final grain weight compared with all water-nitrogen treatments; Inferior spikeletsperforms better in grain filling rate and final grain weight at 0N and MN under CI and WMD regimes. However, in the WSD regime, 0N led to the lowest while HN showed the highest grain filling and final grain weight, but not significantly differentto MN. The above results showed that there was an obvious interaction between water and nitrogen. Among the varieties, grain filling rate and grain weight of inferior spikeletsof indica/japonica hybrid Yongyou 2640were lower than that ofjaponica inbred Huaidao 5, and the advantage of grain yield ofYongyou 2640 stemed from higher spikelet number per panicle. Finally, in the WMD+MN treatment, there was a higher nitrogen efficiency, creating higher grain yield with less nitrogen, and achieving the purpose of water and nitrogen saving. Secondly, it also eahanced the activity of root and leaves, improving the non-structural carbohydrate(NSC) remobilization, which promoted the upground biomass development and dry matter translocation in order to strengthen the inferior spikelets filling to induce an increase in grain yield. Therefore, it turns out to be the best water-nitrogen management in this research.

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Cloning and Expression Analysis of RsPhmGene inRhizoctoniasolani AG-1ⅠA of Rice Sheath Blight Pathogen Shaofeng JIANG, Chenjiaozi WANG, Canwei SHU, Erxun ZHOU 2018, 1(1): 111-118.  DOI: 10.16819/j.1001-7216.2018.7094 Abstract ( )   HTML ( )   PDF (818KB) ( )   【Objective】In order to elucidate the functions of phenol 2-monooxygenase(RsPhm)gene in melanization of RhizoctoniasolaniKühnAG-1ⅠA, the causal agent of rice sheath blight,【Method】the gene was cloned by routine PCR andRT-PCR techniques, and the bioinformatics analysis of this gene was conducted; furthermore, therelative expression levelunder catecholstresswas determinedby using fluorescence quantitative real-time PCR (qRT-PCR) technique.【Result】Bioinformatics analysis showed that the full-lengthDNA and cDNA sequences of RsPhmgene were 2628 bp and 1983 bp, respectively, which encode660 amino acids. The phylogenetic tree analysis showed thatRsPhm gene hada close relationship in different anastomosis groups (AGs) ofR.solani, and a certainevolutionary conservation amongdifferent fungal species. Results of qRT-PCR indicated that the exposure to exogenous catecholcould improvethe expression level ofRsPhm gene, and which peaked at 12.5 µg/mL of catechol,with a significant increase of 35.7 times, 19.1times and 28.4 timesup-regulated at 25 µg/mL and 50 g/mL,respectively, but only 2.1 times up-regulated at 100 g/mL.【Conclusion】The full-length sequence ofRsPhm gene was obtained, its basic biological information was understood, and its expression pattern under catechol stress was clarified.Thesefindings will lay abasis for the scientific and systematic elucidation of regulatorymechanism of melanin formation byRsPhmgene ofR. solaniAG-1ⅠA.

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CRISPR/Cas9-mediated Editing of GS3to ImproveFloweringTime injaponicaRice MENGShuai, Peng XU, Yingxin ZHANG, Hong WANG, Liyong CAO, Shihua CHENG, SHENXihong 2018, 1(1): 119-127.  DOI: 10.16819/j.1001-7216.2018.7112 Abstract ( )   HTML ( )   PDF (943KB) ( )   【Objective】Floweringtime asynchrony is one of the main factors limiting seed production of hybrid ricebetween male and female parents, and some studies have shown that flowering time is related to grainshape.Loss of function mutant ofGS3was used to study the difference of flowering timein this study so as to elucidate the impact of grain shape on flowering time.【Method】CRISPR/Cas9-mediated editing of GS3to achieve 13 pairs of near-isogenic line japonica varieties.Then the flowering time was investigated with visual methods. 【Result】T1 individuals derived from T0 generation were genotyped. The sequencing results show that some bases were mutatedwithsingle base insertion, includingChangbai25,Jijing102,Zhejing88,Wuyunjing27, J42 and otherswithbases deletion,including Kenjiandao6, Kongyu131, Zhejing22, Yangjing4227, Nanjing9108, J5933, J6167, J5938. For the grain shape of T1, the gs3 mutants conferred longer grain length compared to the wild type, and the gs3 mutants of Jijing102, Kongyu131, Zhejing88, Wuyunjing27 and Yangjing4227 were significantly earlier in flowering time thanthose of the wild type. The others were also earlier, but not significant.【Conclusion】 Long-grain japonica rice has an earlier flowering time than short-grainjaponica rice, which could provide referencesto study the grain-type breeding of japonicarice, and it would accelerate the breeding process of long-grainjaponica parents and promote the development of hybrid japonicarice.

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Effects of Exogenous Ethephon on Fertility of Thermo-sensitive Genic Male Sterile Rice Lines Under Low Temperature Inducement Linzhi LI, Jiaping WEI, Yanfeng JIA, Xiaolin LIU, Haiqing ZHANG, Ming WANG, Hao MA 2018, 1(1): 128-136.  DOI: 10.16819/j.1001-7216.2018.7045 Abstract ( )   HTML ( )   PDF (797KB) ( )   【Objective】Thisresearch aims toelucidate the mechanism behind sterility conversion(infertile convert into fertile)in low temperatureofthermo-sensitive genic male sterile ricein seed production in South China by applying exogenous ethephon.【Method】The thermo-sensitive genic male sterile rice cultivars Zhu 1S and Zhun S weretreated with artificial cooling water tank (low temperature, 22.5℃) induction for 7 days and sprayed withethephon (which promote synthesis of ethylene) and the chlorine dioxide solution (inhibitory substances)during fertility-sensitive period.Then the pollendyeing rate and the baggedseed-setting rate were calculatedand the quantitative real-time PCR was conducted.In addition, the promoters of OsACO5 and OsACS5, which are key enzymes of ethylene synthesis pathway, were isolated and analyzed.【Result】Under22.5℃for 7 days, the pollen rate of Zhu 1S and Zhun Swas 4.3% and 8.9%, and bagged seed-setting rate was 1.6% and 2.5%, respectively. Compared with the water spray control, the pollen rate of lines Zhu 1S and Zhun S was reduced by 3.3and 7.2 percent, respectively when spraying with 1600mg/L ethephon. When spraying with 1500 mg/L of chlorine dioxide solution, the pollen rate was increased by 3.5and 3.3 percent, and the bagged seed setting rate increased by 0.78and 0.52 percent, respectively. The expression of OsACO5 and OsACS5in young panicles was significantly increased at 1600 mg/L of ethephon under 22.5℃ inductionfor 7 days, which were 1.19, 1.24 (Zhu 1S) and 1.24, 1.1 (Zhun S) times of that of the control (water spray) respectively. When sprayed with 1500mg/L of chlorine dioxide solution for 7 days, the expression of OsACS5 gene in the Zhu 1S and Zhun S was significantly reduced, which were 0.93 and 0.89 times of that of the control (water spray), respectively, but the expression of OsACO5 was not significantly changed. Compared with normal field temperature (control) for 7 days, water spraying, 1600 mg/L of ethephon and 1500 mg/L of chlorine dioxide solution at22.5℃down-regulated the expression of OsACO5 and OsACS5 in young panicles of Zhu 1S and Zhun S.The promoters of OsACO5 and OsACS5contained multiple tissue-specific expression elements and ethylene-regulated cis-acting elements in addition to the basic structures such as TATA-box and CAAT-box. 【Conclusion】Under low temperature condition, spraying 1600mg/L ethephon in the sensitive period of thermo-sensitive genic male sterile rice had inhibitory effect on fertility conversion from sterility to fertility.

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Development and Verification of a Functional Marker Associated with Resistance to ALS Inhibitor Herbicide Tao CHEN, Shanlei ZHANG, Ling ZHAO, Yadong ZHANG, Zhen ZHU, Qingyong ZHAO, Lihui ZHOU, Shu YAO, Chunfang ZHAO, Wenhua LIANG, Cailin WANG 2018, 1(1): 137-145.  DOI: 10.16819/j.1001-7216.2018.7091 Abstract ( )   HTML ( )   PDF (995KB) ( )   【Objective】Breedingrice varieties with resistance to ALS-inhibiting herbicide is the mosteconomical and effective method to preventweeds in direct-sowing field, and molecular marker-assisted selection canimprove its efficiency. 【Method】The dominant molecular marker, designed for genotypic detection in different varieties and an F2 population derived fromHuaidao5/Huanghuazhan M-1(mutant with resistance to ALS-inhibiting herbicide) was developed with Tetra-primer ARMS-PCR technique, based on the clarified mutation in CDS of ALS gene. 【Result】 The sequence alignment analysis of ALS gene encoding regionshowed that only the mutation from T1642G1643 to A1642T1643 leading to the 548th amino acid substitutionfrom tryptophan to methioninein highly conserved regionwas the critical factors to produce resistance to ALS-inhibiting herbicide inHuanghuazhan M-1, despitethe existence of multiplebase differencesbetween different indica and japonica rice varieties.The results of PCR detection indicated that three different genotypescould be accurately distinguished by electrophoretic bands, and it was exactly consistent with the phenotype of herbicide resistance at the seedling stage. 【Conclusion】 The genotype associated with two continuous base mutations could be rapidly detected by Tetra-primer ARMS-PCRtechnique, and the efficiency for varieties with resistance to ALS-inhibiting herbicidecould be improved in breeding process.

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Performance of Yield, Photosynthesis and Grain Quality of japonicaRice Cultivars UnderSalinity Stress in Micro-plots Genyou ZHOU, Caijiao ZHAI, Xianliang DENG, Jiao ZHANG, Zhenliang ZHANG, Qigeng DAI, Shiyou CUI 2018, 1(1): 146-154.  DOI: 10.16819/j.1001-7216.2018.7068 Abstract ( )   HTML ( )   PDF (781KB) ( )   【Objective】Rice growing is one of the widely utilized technologies for desalting, improving and exploiting tidal flat in Jiangsu coastal beach. The objective is to revealthe effects of salinity stress on rice yield,photosynthetic parameters, grain quality and starch viscosity, providing a reference and laying a theoretical basis for developing rice production in Jiangsu coastal beach.【Method】Four japonica rice varieties with better salt tolerance, Tongjing 981, Yandao 12, Yandao 10 and Nanjing 5055 were used to investigate theyield and its components, photosynthetic parameters, rice quality and starch viscosity under salinity stress (S1, 1.112 dS/m for EC1:5) and no salinity stress (S0, 0.207 dS/m, control).【Result】Compared with the control, rice yield decreased significantly under salinity stress, was only 40.5% of that of the control, panicle number per unit area had no significant difference, while grain number per panicle and 1000-grain weight also decreased significantly. The photosynthetic rate and intercellular CO2 concentration decreased significantly, but stomatal induction and transpiration rate had no significant difference between S0 and S1. The processing quality of rice, together with amylose content decreased significantly, the appearance quality almost remained unchanged, while protein content increased significantly. The peak viscosity, trough viscosity, final viscosity, breakdown value, consistence value showed no significant changes, the setback value and pasting temperature increased significantly.【Conclusion】Salinity stress had adverse effects on yield, photosynthetic parameters and grain quality of rice.During the critical period of salt stress on yield and quality, such as booting stage and filling stage, measures should be taken to alleviate salt stress.

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Effects of Combined Biochemical Inhibitors and Fertilization Models on Rice Population Quality in Yellow Clayey Field Xuan ZHOU, Rong JIN, Lianghuan WU, DAIFeng 2018, 1(1): 169-180.  DOI: 10.16819/j.1001-7216.2018.7041 Abstract ( )   HTML ( )   PDF (1019KB) ( )   【Objective】Application of biochemical inhibitors is one of the effective ways to improve fertilizer use efficiency of rice. The objective of this study is to reveal rice population heterosis as affected by combined inhibitors and fertilization models, and find a suitable high-yield and efficient application method for rice growing region in yellow clayey soil. 【Method】The experiment was conducted to study the interaction effect of biochemical inhibitor combinations and fertilization models (one-off and three-time fertilization) on population quality of rice in yellow clayey field using two factor randomized block design. 【Result】Three-split urea fertilization significantly increased number of productive tillers, effective leaf area index(LAI), dry matter accumulation from heading to maturity, SPAD value at heading stage and grain yield of rice by 0.8%, 24.0%, 9.3%, 1.5% and 14.2% compared withthose of one-off fertilization treatment, respectively. On the other hand, addition of biochemical inhibitor (NBPT/NPPT+CP) significantly increased number of productive tillers, panicle setting rate, dry matter accumulation after heading, efficient LAI, and SPAD value at heading stage of rice, and also improved the grain to leaf ratio, enhanced the source-sink relationship among different fertilization models. Correlation analysis showed that dry matter accumulation from heading to maturity was significantly positively related with rice grain yield. Application of new urease inhibitor NPPT alone or combined with CP had the same effect on population quality in paddy field with NBPT. 【Conclusion】The integration and optimization of fertilization technique and combined inhibitors application can improve population quality of rice, photosynthetic product transformation and grainyield in yellow clay field.

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Impacts of Ozone Stress on Dry Matter Accumulation and Distribution of Rice Genotypes with Different Ozone Sensitivity Zaisheng SHAO, Hairong MU, Yipeng ZHAO, Bin PENG, Yulong WANG, Yunxia WANG, Lianxin YANG 2018, 1(1): 181-188.  DOI: 10.16819/j.1001-7216.2018.7097 Abstract ( )   HTML ( )   PDF (880KB) ( )   【Objective】The dry matter accumulation and distribution of rice with different ozone sensitivity in response to ozone stress were studiedin order to provide reference for ozone-tolerant rice breeding.【Method】Twenty-three rice cultivars or lines were grown in glasshouse-type fumigation chambers with low ozone concentration as control (C-O3, 10 nL/L) and high ozone concentration as elevated O3 treatment (E-O3, 100 nL/L) from a week after transplanting until maturity.The effects of ozone stress on dry matter accumulation and distribution of rice genotypes were determined, as well as the relationships between their responses to ozone stress and the ozone-induced changes in the above-ground biomass at maturity stage. Based on the ozone-induced changes in the above-ground dry weight, these rice genotypes were clustered into three types by the MinSSw (dynamic clustering method-minimum sum of squares within groups) method.【Result】Compared to the control, ozone stress decreased the above-ground dry weight of three rice types A, B and C at maturity by 19%, 39% and 52%, respectively, and significant treatment effects were detected in B and C. Ozone stress slightly increased the leaf dry weight of rice type A, but significantly decreased that of B (-11%) and C (-25%). Ozone stress significantly decreased stem dry weight by 26%, 41% and 57%, panicle dry weight by 34%, 59% and 62% of rice types A, B and C, respectively.Ozone stress significantly increased the ratio of leaf to above-ground dry weight (+46%), but significantly decreased that of stem (-8%) and panicle (-24%). Ozone level and rice eype interacted with the measured parameters to various degress, which gave rise to small changes in rice type A compared to type B and C.【Conclusion】The above results indicated that, ozone concentration of 100 nL/Lseriously inhibited the growth of rice organs, decreasedassimilatesallocation to stems and panicles, but greatly increased assimilates allocation toleaves, resulted in the decrease of mechanical strength of rice stems. In general, theseozone-induced changes in ozone-sensitive rice genotypes were more obvious thanthosein ozone-resistant rice types.

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Scanning Electron Microscopic Analysis of Grain Cross-section from Rice with Different Transparency Yan LU, Xiaomin ZHANG, Yan QI, Changquan ZHANG, Yuping LING, Qiaoquan LIU 2018, 1(1): 189-199.  DOI: 10.16819/j.1001-7216.2018.7107 Abstract ( )   HTML ( )   PDF (1625KB) ( )   【Objective】 The objective of this study was to set up an ideal method of observation of a single starch granule cross-section, to clarify the relationship between rice transparency and amylose content and to find the structure foundation that caused the poor rice transparency. 【Method】 The pre-treated rice grain cross-section and isolated starch were observed under a scanning electron microscopy.【Result】The transparency of both indica and japonica soft rice with amylose contentbelow 15%was significantly decreased. By comparingdifferent methods of grain cross-section pre-treatments, we found that the direct mechanical fracture method can’t break a single starch granule and the mechanical fracture with glass scraping method could break down an individual starch granule, however, it will cause rough surface and thus difficult to be analyzed quantitatively. As for the liquid nitrogen fracture method, we found it’s an ideal way to break a single starch granule and the cavity in starch granule can be easily observed. We then further analyzed the starch granule arrangement and the internal structure of an individual starch granule in paddy rice from both indica and japonica rice cultivars. We found that all the starch granules arranged tightly and obvious air containing space was observed in an individual starch granule from grains of all dark endosperm rice. Also, we found that the number and area of starch granule cavity in glutinous rice was significantly higher than those in dark endosperm rice. Furthermore, we proved that the number and area of starch granule cavity increased as the grain moisture content decreased.【Conclusion】The direct liquid nitrogen fracture treatment of rice grain cross-section is an ideal method for the single starch granule cross-section observation. Besides, the rice grain transparency showed a close relationship with the moisture content and also the number and size of cavity in the middle of a starch granule but not the starch granule arrangement. Moreover, the size and number of cavities increased as the amylose content decreased.

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Effects ofBiochar Amendment to Soil on Life HistoryTraits of Laodelphaxstriatellus(Hemiptera: Delphacidae) on Rice Plants Qiang FU, Baoping LI, Ling MENG 2018, 1(1): 200-206.  DOI: 10.16819/j.1001-7216.2018.7113 Abstract ( )   HTML ( )   PDF (954KB) ( )   【Objective】To investigate the potential of biochar application in the control of crop pests, weevaluated the effect of biochar amendment to soil on the small brown rice planthopper(Laodelphaxstriatellusas)on rice. 【Method】Laboratory experiments were conducted using a 2 × 3 factorial design to explore the effect of the two independent variables (biochar type and application level) on developmental and reproductive performances of the insect on potted rice plants.【Result】1) Biochar type and application level had an interactive effect on the nymphal duration, which though did not vary with application levels when corn or rice biochar was applied, yet significantly prolonged by 1.54 days when wheat biochar was applied at 30 g/kg compared to 18.70±0.30 d in the control. 2) Biochar type and application level did not have interactive effects on longevity of female adults. Biochar application level did not influence female adult longevity, but corn biochar significantly increased the longevity by 2.13 d compared to 23.70±0.48d with addition of rice biochar, for wheat biochar,by 3.10 d. 3) There was abiochar type × application levelinteraction effect on fecundity. Biochar amendment decreased lifetime fecundity of L. striatellusbut the effect varied with biochar type and application level. At 30 g/kg biochar level, the fecundity increased for corn biochar by 22.80 and 18.95 eggs compared to those, for rice and wheat biochar respectively. At 50 g/kg biochar level, the fecundity decreased for corn biochar by 16.90 and 21.60 eggs compared to thosefor rice biochar and wheat biochar.【Conclusion】Biochar amendment to soil can have a negative impact on fecundity of L. striatellus, yet theimpact varies with biochar type and application level.