Archive

10 January 2021, Volume 35 Issue 1 Previous Issue    Next Issue
---
Review
Research Papers
Short communication


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Review

Select

Research and Progress of Bakanae Disease Resistance in Rice Zhijuan JI, Yuxiang ZENG, Yan LIANG, YANGChangdeng 2021, 35(1): 1-10.  DOI: 10.16819/j.1001-7216.2021.0511 Abstract ( )   HTML ( )   PDF (11416KB) ( )   Bakanae disease is a main disease in rice and it seriously affects rice production, resulting in critical yield loss. Rice bakanae disease is mainly seed-borne. Researchers focused onscreening resistant germplasm resources, resistance genetics, QTL mapping and gene miningto the disease. In this review,classification and characteristics ofthe pathogen causing rice bakanae disease werebriefly summarized. Different kinds of methods for evaluation of rice bakanae disease resistancewere compared.The number and chromosome distribution of resistance QTLs to rice bakanae disease wereanalyzed. The latest research results of transcriptomics and proteomics onresistancegene mining to rice bakanaewerediscussed. Finally, the future direction of this fieldwas expected. The review provides a reference for in-depth study and rice breeding on bakanae disease resistance.

Research Papers

Select

CRISPR/Cas9-mediatedEditing of AFP1Improves Rice Stress Tolerance Tianshun ZHOU, Dong YU, Ling LIU, Ning OUYANG, Guilong YUAN, Meijuan DUAN, Dingyang YUAN 2021, 35(1): 11-18.  DOI: 10.16819/j.1001-7216.2021.0503 Abstract ( )   HTML ( )   PDF (49348KB) ( )   【Objective】It is important to reveal the functions of rice AFP1 in response to abiotic stress, and createnewstress-resistant rice germplasm in innovative ways.【Method】Excellent indica restoring line Huazhan was used as transgenic receptor material to generate afp1 mutants usingCRISPR/Cas9 system, and abiotic stress tolerances of afp1 knockout lines were preliminaryanalyzed. 【Results】The editing efficiency of AFP1 in two targets were 66.67% and 75.00%, respectively.In all mutant plants, only insertions and deletions occurred.About 90% of mutant bases were small fragments,with a lengthless than 5bp.Six homozygous mutants without genetically modified ingredients were generated.Under normal conditions, plant height and seed setting rate of afp1 mutants were reduced, but effective tiller number per plant and panicle length were significantly increased. Interestingly, the yield per plant of mutants changed between-4.06%and +11.75%. Compared with the wild type, the ABA sensitivity and water loss rate of afp1 mutants were obviously decreased. Drought, heat and osmotic stress resistances were significantly improved.【Conclusion】MutationofAFP1genecouldimprovemultiple abiotic stress resistances in rice.

Select

Genetic Analysis and Gene Mapping of a Virescent and Panicle AbortionMutant vpa1in Rice Zhonghao WANG, Yan HE, Xiaobo ZHANG, Xia XU, WUJianli, SHIYongfeng 2021, 35(1): 19-26.  DOI: 10.16819/j.1001-7216.2021.0702 Abstract ( )   HTML ( )   PDF (9819KB) ( )   【Objective】Genes related to chloroplast development and panicle phenotype can be identified through the study onvirescent mutants and panicle apical abortion (paa) mutants in rice. 【Method】The main agronomic traits of vpa1 (virescent and panicle abortion 1) mutant and the wild-type were compared under conventional planting conditions in field. The virescent gene and paagene were mapped by bulked segregant analysis and map-based cloning.【Result】vpa1exhibited albino leaves at seedling stage andthe leaves graduallyreturned to normal. During heading stage,vpa1showed degeneration of spikelets at the tops of panicles. Except seed-setting rate, the agronomic traits including plant height, panicle length, number of filled grains per panicle and 1000-grain weight decreased significantly in vpa1as compared with the wild-type.Genetic analysis indicated that both the virescentphenotypeand the paa phenotype of vpa1are controlled by single recessive nuclear gene, and the virescentgene and paa gene were segregated independently.The virescent gene, Osv16, was mapped to a 125kb region between RM3441 and RM3029 on chromosome 3. Thepaagene, Ospaa10, was mapped to a 190kb region between RM11157 and RM5972 on chromosome 1.【Conclusion】mutations ofOsv16 and Ospaa10 causedsimultaneous variation of leaf color and spikelet phenotype in vpa1. Osv16 and Ospaa10are likely two new genes as no other virescent and paa genes have been identified in the related region, further cloning of both genes are currently underway.

Select

Effects of Water Stress on Yield Formation and Root Morphological and Physiological Characteristics of Water-saving and Drought-resistantRice Danping HOU, Jinsong TAN, Qingyu BI, Anning ZHANG, Yi LIU, Feiming WANG, Guolan LIU, Xinqiao YU, BIJunguo, Lijun LUO 2021, 35(1): 27-37.  DOI: 10.16819/j.1001-7216.2021.0507 Abstract ( )   HTML ( )   PDF (46462KB) ( )   【Objective】To explore the characteristics of yield formation and changes inroot morphology and physiology of water-saving and drought-resistant rice under different irrigation conditions.【Method】Three water treatments (conventional irrigation, light water stress and heavy water stress) were set in the root canal experiment of water-saving and drought-resistant rice Hanyou 73 and high-yield rice H You 518.The plant height, tillering, root morphological and physiological characteristics, yield components were investigated, and theirrelationshipswere analyzed to elucidatethe effect of water stress on yield formation, root morphology and physiologyof water-saving and drought-resistant rice and the difference tohigh-yield rice.【Result】The results of thetwo-year experiment showed that compared with conventional irrigation, the grain yield and its components of Hanyou 73had no significant change under light water stress, and the grain yield of H You 518 decreased by 25.6% on average in two years, and the number of grains per panicle, seed setting rate and 1000-grain weight were also significantly decreased.Under heavy water stress, the grain yield and its components of the two varieties decreased significantly, among which the grain yield of Hanyou 73decreased by 28.8% on average within two years, and that of H You 518decreased by 46.1%.Compared with conventional irrigation, there were no significant changes in total absorption surface area, active absorption surface area, root volume, root diameter, root tip number and antioxidant enzyme activitiesof Hanyou 73 under mild water stress, while the above mentioned traits were significantly decreased under heavy water stress; the root morphological and physiological indexes of H You518 were significantly decreased under the two water stress.【Conclusion】The water-saving and drought-resistant rice Hanyou 73 can maintainhigh yield under light water stress, and the yield decline under heavy water stress is significantly lower than that of high-yield rice H You 518.Soundroot morphology and strong root activity are the important reasons for its stable yield and drought resistance.

Select

Effects of Drought Stressat Grain Filling Stage on Rice Physiological Characteristics and Yield Xiaolong YANG, Jianping CHENG, Benfu WANG, Yang LI, Zhisheng ZHANG, Jinlan LI, Ping LI 2021, 35(1): 38-46.  DOI: 10.16819/j.1001-7216.2021.0401 Abstract ( )   HTML ( )   PDF (13358KB) ( )   【Objective】Itis very important to reveal the effects of drought stress at grainfilling stage on physiological characteristics of flag leaves and yield of different genotypes of rice, and provide the reference for rice cultivation under soil drought conditions.【Method】The water-saving and drought resistant rice variety Hanyou 113 (HY113) and hybrid rice variety Yangliangyou 6(YLY6) were cultured as materials under two water treatments (conventionalflooding and drought stress at grainfilling stage). The yield and itscomponents, rice quality (processing quality, appearance quality and nutritional quality), dry matter production and distribution, leaf physiological activity (leaf water potential, air-leaf temperature gap and photosynthetic rate) were determined.【Result】Compared with conventionalflooding, the leaf water potential and air-leaf temperature gap significantly decreased under drought stress duringgrainfilling, which resulted in decreased photosynthetic ratesofflagleaves. However, from the 2nd to the 15th day after rehydration, the physiological activities of the flagleaves could be restoredto the normal level, and no significant difference was observed as comparedto controlgroup. There wasno significant change in grainyield, which was mainly due to accumulation of dry matter in the early growing stage and significantly increasedfilled grain number. The rice millingquality was not changed significantly, but the appearance quality of YLY6 was just the opposite, the appearance quality of HY113 was improved. In addition, the nutrition quality was improved due to increased protein content.【Conclusion】Moderate drought at grainfilling stage can improve rice quality and stabilize grain yield. Therefore, moderatereduction of water input at late growing stages can not only save agricultural water and stabilize yield, but also help improve rice quality.

Select

PopulationGrowthCharacteristics and Cultivation Strategies of Mechanically Transplanted Rice in Late Seeding and Planting Conditions Jingtao QIU, Xiaojia REN, Tianhao JIANG, GUXueyi, Zujian ZHANG 2021, 35(1): 47-58.  DOI: 10.16819/j.1001-7216.2021.9139 Abstract ( )   HTML ( )   PDF (6932KB) ( )   【Objective】It is of great importance to knowthe long-term special application value of mechanically transplanted rice in late seeding and planting conditions.【Method】Anexperiment was conducted in southern Jiangsu to analyze the yield performance and population growthcharacteristics of mechanically transplanted rice in late seeding and planting conditions. Further, the impact of cultivation measures on population development and yield of mechanically transplanted rice in late seeding and planting conditions was analyzed at different plantingdensitiesand panicle-promoting fertilizer application level.【Result】Due to the decrease in the number of panicleand grain number per panicle, and slightly-affected seed setting rate and thousand-grain weight,the yield of mechanically transplanted rice in late seeding and planting conditions decreased to some extent. peak seedling number of mechanically transplanted rice in late seeding and planting conditions was relatively advanced, and the productive tiller percentage decreased significantly. The accumulation and translocationof assilimateswere affected to some extent. NSC accumulation in the stem and sheath decreased during heading stage, and the export rate and conversion rate instem and sheath also showed a downward trend. It can be seen that there was an inevitable disadvantage in production and yield formation of the mechanically transplanted rice in late seeding and late planting conditions. By increasing the density, the number of panicleper unit area increased significantly, the performance of above-ground dry matter accumulation increased, and the yield increased significantly. Atthe same density, with the increase of the nitrogen application level of panicle-promotingfertilizer, the yield first increased and then decreased. However, seed setting, excessive panicle-promotingfertilizer application was not conducive to the dry matter accumulation of mechanically transplanted rice in late seeding and planting conditions. The combination of higher density with the appropriate level of panicle-promoting fertilizer could increase the percentage of productive tillers, and maintain the leaf activity during seed setting and good production capacity in the middle and late phases.【Conclusion】With higher transplanting density, the late seeded and mechanically transplanted rice can gain strong growth momentum at early growth stage and favorable population quality.The unproductive tiller number decreasesby reducing fertilizer application in the middle and late growth stages so as to achieve relatively high yield and production efficiency.

Select

Effects of Seedling-raising Substrate and Water Spraying Interval on Seedling Quality and Grain Yield of MechanicallyTransplantedRice LIRui, DONGLiqiang, SHANGWenqi, MALiang, Xianju WANG, WANGZheng, LIYuedong 2021, 35(1): 59-68.  DOI: 10.16819/j.1001-7216.2021.0714 Abstract ( )   HTML ( )   PDF (23876KB) ( )   【Objective】To explore suitable water management method formechanicallytransplantedrice seedlingsunder the mode of mechanized sowing and dry seedbed nursing.【Method】Two substrates(organic substrate andnutrient soil) were used and three water treatments(with water spraying intervalsof 24 h,48 h,72 h) were set at 1.5-leaf age to reveal the changes of the seedling quality, mechanical transplanting quality and rice yield, with Liaojing 401 as test material.【Result】Compared with the water treatments with a water spraying interval of 24 h, the 72 h-interval water spraying treatment could increase SPAD of seedlings, decrease the height of the seedlings, increase the number of the roots, the ratio of root to shoot, improve the quality of the seedlings. The injured seedling percentageand unplantedhillrate in the72 h-interval water spraying treatment was low and it took less time for seedlings to recover after transplanting, and the seedlings produced many new roots. The seedlings under the72 h-interval water treatment were more adaptable to the field environment, the chlorophyll fluorescence parameters of the seedlings in the72 h-interval water treatment were at a high level. The performance of productive panicle number, seed setting rate and actual yield of the 72 h-interval water treatment was the best.【Conclusion】The method of the 72 h-interval water treatment could improve the quality of the seedlings and machine-transplanted quality. The seedlings recover fast after mechanical transplanting, and the tillers transform into more productive panicles, thusthe actual yield of the 72 h-interval water treatment was increased.

Select

Effect of Spraying Methyl JasmonateDuring Heading Date on Floret Opening Time and Plant Type of japonica Rice from Different Ecological Areas Yuchen YANG, Yuanye XIA, Zhiqiang YAN, Lei WANG, Bingchun YAN, Jingbo WANG, Yiwei WANG, Jinhua LUAN, Hai XU 2021, 35(1): 69-77.  DOI: 10.16819/j.1001-7216.2021.0516 Abstract ( )   HTML ( )   PDF (25032KB) ( )   ：【Objective】This work tends to clarify the effect of MeJAspraying on floret opening time and plant type of japonica rice from diverse ecological areas and lay a scientific basis for utilizing MeJA to regulate the floret opening time of hybrid parents, increase seed production of intersubspecies hybrid rice【Method】Thirty fivejaponica rice cultivars from diverse ecological areas were used as test materials and subjected to different concentrations of MeJA treatment during heading date. Difference in response to MeJA exposure of the tested materials and its effect on plant type traits were analyzed.【Result】MeJA spraying had a significant promoting effect on the floret opening time of japonica rice from different ecological areas. Compared with the control, the floret opening time of japonica rice treated with different concentrations of MeJA was significantly advanced on the first day after treatment.With the rising MeJA concentration, the initial flowering time, full flowering time, and terminal flowering time of japonica rice were significantly advanced. The duration from initial flowering to full flowering, duration from initial flowering to terminal flowering were significantly shortened, duration from full flowering to terminal flowering was significantly extended. On the second and third days after treatment, MeJA spraying was out of function quickly. Flowering could be found under low concentration MeJA treatment and it was opposite under high- and medium-concentration MeJA treatment. Japonica rice cultivars from different ecological areas showed different sensitivity to MeJA regulation. The japonica rice cultivars from Liaoning rice growing region are the most sensitive in the floret opening time and those from the third accumulated temperature zone of Heilongjiang Province was the least sensitive. MeJA spraying exerted a significant effect on the plant type traits of japonica rice. Plant height and panicle curvature were significantly decreased with the increase of MeJA concentration as compared with the control. The length of the flag leaf and the second leaf from the top increased with the increasing MeJA concentration.【Conclusion】MeJA has significant promoting effect on the floret opening traits of japonica rice from different ecological areas. MeJA regulation has more obvious effect on early flowering with the rising concentration of MeJA. With the increase of MeJA concentration, the sensitivity of japonica rice to MeJAd differs. MeJA has a certain effect on plant type traits of japonica rice. Plant height, panicle curvaturesignificantly decrease with the increase of MeJA concentration. MeJA spraying exerts no significant effect on other plant type traits.

Select

Effects of Tillage Methods on Distribution Characteristics of CH4 and N2O in Soil Profile ofDouble-cropping PaddyField Tong YANG, Junnan WU, Ting BAO, Fengbo LI, Jinfei FENG, Xiyue ZHOU, Fuping FANG 2021, 35(1): 78-88.  DOI: 10.16819/j.1001-7216.2021.0509 Abstract ( )   HTML ( )   PDF (33049KB) ( )   【Objective】Exploring the spatial and temporal variation of the concentrations of CH4 and N2O in soil profile is beneficial to understanding the mechanism behind the effects of agronomic measures on the production and diffusion of greenhouse gas from paddy fields.【Method】A field experiment with different tillage treatments [rotary tillage (RT) and no tillage (NT)] and fertilization measures, including no fertilization (CK), only chemical fertilizer (F), and fertilizer + straw returning (FS), was conducted to reveal the distribution characteristics of CH4 and N2O in the surface water and soil profile.【Result】The concentration of CH4 in the surface water in the early and late rice growing seasons was significantly lower than that in the soil profile. On the contrary, the concentration of N2O in the surface water was higher than that in the soil profile. The concentration of CH4 in the soil profile decreased with the increase of soil depth. Whereas no obvious trend was observed for N2O in the soil profile. Tillage methods significantly affected the concentrations of CH4 and N2O in the soil profile. RT significantly increased the concentration of CH4, especially in 0-5 cm and 5-10 cm soil layers, while significantly reduced the concentration of N2O in the soil profile at some growth periods, as compared with NT. The correlation indexes between net CH4 flux rate and CH4concentration in upper soil layers was higher than that in the deep soil layers and field surface water. The net flux rate of N2O in the early rice growing season was primarily affected by the concentration of N2O in the surface soil layer; while the net flux rate of N2O in the late rice growing season was mainly affected by the concentration of N2O in the middle and deep soil layers.【Conclusion】The concentrations of CH4 and N2O in soil profile presented great spatial-temporal variation during the early and late rice growing seasons. Tillage method significantly affected the concentrations of CH4 and N2O in soil profile.

Select

Correlation Between SPAD Value of Flag Leaf and Rice Quality of High Quality indica Rice Zhidong WANG, Yibo CHEN, Rong GONG, Shaochuan ZHOU, Chongrong WANG, Hong LI, Daoqiang HUANG, Degui ZHOU, Lei ZHAO, Yangyang PAN, Yiqiang YANG, LIXiaofang 2021, 35(1): 89-97.  DOI: 10.16819/j.1001-7216.2021.0508 Abstract ( )   HTML ( )   PDF (22788KB) ( )   【Objective】 To reveal the relationship between SPAD value of flag leaf and rice quality characters in keygrowth period of high quality indica rice, and to lay a theoretical basis for breeding and production of high eating qualityindica rice in the future. 【Method】 Twelve good quality indica rice varieties including Meixiangzhan 2, Huanghuazhanand Wushansimiao were used to determine the rice quality characters, such as cooking and eating quality, starch RVA andthe SPAD values of flag leaf at different growth stages. And the correlation between SPAD value and rice quality characterswere further analyzed. 【Result】 The SPAD value of flag leaf in waxy ripening stage and yellow ripening stage hadsignificantly or extremely significantly positive correlation with rice eating value, peak viscosity and breakdown value,whereas an extremely significantly negative correlation with rice protein content. 【Conclusion】 The correlationcoefficients between SPAD value of flag leaf in yellow ripening stage and food taste value and protein content of indica riceare greater than those in waxy ripening stage. The higher SPAD value in yellow ripening stage, the lower protein content ofrice and the better eating quality. The SPAD value of flag 1leaf in yellow ripening stage can be used to predict the eatingvalue and protein content of indica rice. The linear fiting equation between SPAD value Qx) of flag leaf in yellow ripeningstage and eating value (y) of rice is y=0.0901x+65.76(R2=0.687); the linear ftting equation with protein content (y) isy=-0.098x+9.217(R2=0.602).

Short communication

Select

Population Dynamics and Yield Loss Evaluation of Heterodera elachistain Single-cropping Late Rice in Changsha,China Yongchun HUANG, Shan YE, Tao YUAN, Jianyu ZHOU, Deliang PENG, Wenkun HUANG, Zhong DING 2021, 35(1): 98-102.  DOI: 10.16819/j.1001-7216.2021.9118 Abstract ( )   HTML ( )   PDF (15035KB) ( )   ：【Objective】It is very important toclarify population dynamics and the economic threshold of Heterodera elachista【Methods】Soil and root samples were periodically collected in a single-cropping late rice field inChangsha, Hunan Province from2016 to 2018.Effects of population density of H. elachista on agronomic traits and yield loss of rice were determined by artificial inoculation. 【Result】The population density of cysts mainly showed three obvious peaks, occurring at the late tillering stage, booting stage and yellow maturity stage, respectively. It was deducedthat H. elachistahad three generations in single-cropping late rice inChangsha. The plot test indicated that H. elachista had adverse effects on agronomic traitsofrice such as plant height, effective panicle number, solid grain weight and seed setting rate. Whenthe inoculationamount of H. elachista was ≥4eggs/mL, the damages of H. elachistawererelatively serious andthe weight loss of the damaged plant was more than 19.4%, so that corresponding control measures should be recommended. 【Conclusion】We analyzed the influential factors behind generation number and control index. It will lay a solid basis for H. elachista control in Changsha.