Study on Effect of Iron in Anther Media of Early Japonica Rice in Cold Region

In this study, through vitro culturing anthers of 7 F1 progenies of early Japonica rice in cold region on medium with different Fe2+ contents, it was found that Fe2+ content generated greater impacts on the induction rate and green plantlet differentiation. The result demonstrated that if Fe2+ increased from 32 to 40 mg/kg, the induction rate of early Japonica rice anther culture in N6 culture media was more then 1.4 times higher than that in N6 culture media containing 5.6 mg/kg Fe2+. In this concentration range, the induction rate increased with the increase of Fe2+ content, while if the concentration was over this concentration range, the induction rate decreased with the increase of Fe2+, showing single peak distribution. When the Fe2+ was 40 mg/kg in differentiation medium, the differentiation rate decreased dramatically. The green plantlet differentiations of callus which were induced on culture media containing 32-40 mg/kg Fe2+ were different, when they were cultured on MS culture media, and 85.7% materials could increase green plantlet productivity to about 7.8%. Therefore, increasing Fe2+in induction media properly could increase anther culture efficiency of early Japonica rice in cold region.

Population Construction and Super-high Yield Characteristics of Japonica Super Rice in Cold Regions

[Objective] This study was conducted to construct a super-high yield population of Japnica rice in cold regions of North China and to explore its characteristics. [Method] The super rice variety Longjing 21 was selected as the experimental material. Different row spacing（two levels）, plant spacing（three levels） and seedling number per hill（three levels） were designed in field trials. Then, the growth stages,dry matter accumulation, leaf area, yield and yield components of these different treatments were measured. [Result] Rice yield had significantly negative correlation with plant spacing and row spacing, but no significant correlation with seedling number per hill. Rice yield was mainly affected by plant spacing, and less affected by seedling number per hill. The best recommended specifications for plant spacing of super rice variety Longjing 21 were 24 cm for row spacing, 12 cm for plant spacing and five seedlings per hill, and the expected yield was 10 473.0 kg/hm^2.The increased number of total spikelets（4.5×108hm2or more） in populations was the major reason for high yield. Super-high yield populations had fewer tillers at the early growth stage and achieved the expected number of productive tillers at critical leaf-age（June 25）, and tiller number peaked at jointing stage（July 6） and was about 1.2 times of the expected number. The percentage of productive tillers in total tillers of super-high yield population was more than 85% at heading stage. At middle growth stage（from jointing to heading stage）, the dry matter accumulation, leaf area index（LAI） at heading stage, effective leaf area, spikelet number of population,spikelet number per leaf area unit（cm2）, and culm-sheath weight per stem of super-high yield population were significantly higher than those of other populations.At late growth stage（from heading to maturity stage）, the leaf area decreasing rate of super-high yield population was significantly smaller than that of other populations. At late growth stage（from heading to maturity stage）, the leaf area decreasing rate, crop growth rate, net assimilation rate, biomass accumulation, number of filled grains per leaf area unit（cm^2） and grain weight per leaf area unit（cm^2） of high-yield population were significantly higher than those of other populations. Output and translocation of dry matter（weight per stem and sheath and total filling rate at maturity） from heading to milky stage of super-high yield population were significantly higher than those of other populations. [Conclusion] The characteristics of superhigh yield rice in cold region of North China are enriching the amount of actual filling of sink through improving photosynthetic efficiency from heading to maturity stage on the basis of enough panicle numbers.

Effects of Straw and Biochar Returned to the Soil on Soil Physical Properties and pH Value in Cold Rice Region

[Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly returned to the soil and charred straw(biochar)returned to the soil on soil bulk density,porosity,temperature and pH value of cold paddy soil were studied in this paper.[Results]The results showed that compared with conventional production,straw(6 t/ha),a small amount of biochar(2 t/ha)and a large amount of biochar(40 t/ha)returned to the soil reduced paddy soil bulk density at different growth stages by 6.02%-11.86%,2.69%-6.67%and 8.58%-11.32%,respectively,increased total porosity by 7.41%-14.93%,3.19%-8.38%and 9.81%-14.27%,respectively,and increased aeration porosity by 22.28%-192.11%,17.80%-92.11%and 52.44%-157.11%,respectively.Straw and a small amount of biochar returned to the soil had no significant effect on soil temperature and pH value of paddy field,but a large amount of biochar returned to the soil could significantly increase soil temperature by 5.13%-8.79%and pH value by 3.15%-5.96%in the later stage of rice growth.[Conclusions]The straw and biochar returned to the soil could reduce soil bulk density,increase total porosity and aeration porosity,and only a large amount of biochar returned to the soil could significantly increase soil temperature and pH value.

Characterization of Reverse Thermo-sensitive Genic Male Sterile Lines in Cold Regions of China

Yannong S, a reverse thermo-sensitive genic male sterile （TGMS） line, is sterile at high temperature and fertile at low temperature. In the present study, the fertility of Yannong S and the japonica reverse TGMS lines derived from it was in- vestigated in Harbin, Heilongjiang from 2013 to 2015. The results showed that Yan- nong S was completely male sterile in July and August （the hottest months of the year in Harbin）, and the seed setting rate of bagged panicles was 0. We also in- ferred that the critical temperature for inducing the sterility of Yannong S was higher than 28 ℃. Most of the japonica reverse TGMS lines derived from Yannong S were completely aborted in July and August, with a seed setting rate of 0. It can be con- cluded that the reverse TGMS lines derived from Yannong S are genetically stable lines that have a long period of sterility in cold regions, so they may be the ideal genetic materials for the development and in-situ seed production of japonica hybrid rice.

Effect of Cold-Water Irrigation on Grain Quality Traits in japonica Rice Varieties from Yunnan Province,China

The response of grain quality traits to cold-water irrigation and its correlation with cold tolerance were studied in 11 japonica rice varieties from Yunnan Province, China. The results indicated that the response of grain quality traits to the cold-water stress varied with rice varieties and grain quality traits. Under the cold-water stress, grain width, chalky rice rate, whiteness, 1000-grain weight, brown rice rate, taste meter value, peak viscosity, trough viscosity, breakdown viscosity and final viscosity significantly decreased, whereas grain length-width ratio, head rice rate, alkali digestion value, protein content and setback viscosity markedly increased. However, the other traits such as grain length, amylose content, milled rice rate, peak viscosity time and pasting temperature were not significantly affected by the cold-water stress. Significant correlations were discovered between phenotypic acceptability and cold response indices of taste meter value, protein content, peak viscosity and breakdown viscosity. Therefore, it would be very important to improve the cold tolerance of Yunnan rice varieties in order to stabilize and improve their eating quality.

Effect of Salt Stress on Nitrogen Assimilation of Functional Leaves and Root System of Rice in Cold Region

The aims were to investigate the effect of salt stress on key enzyme activity of nitrogen metabolism and the concentration of nitrate nitrogen and ammonium nitrogen response to salt stress.Two rice cultivars,Mudanjiang 30(sensitive cultivar)and Longdao 5(salt-tolerant cultivar),were treated with different salt concentrations(CK 0%,S10.075%,S20.15%,S30.225%and S40.3%).The results showed that the activities of nitrate reductase(NR),glutamine synthase(GS),glutamate synthase(GOGAT)and glutamate dehydrogenase(GDH)in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with those of the CK,the activities of NR,GS and GOGAT of rice in cold region decreased,but the activity of GDH increased in the heading stage under salt stress.The variation for key enzyme activity of nitrogen metabolism was the highest under S4 treatment.The activities of NR,GS and GOGAT in the functional leaves significantly decreased compared with those in roots;the concentrations of nitrate nitrogen and ammonium nitrogen in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with that of the CK,the concentration of nitrate nitrogen decreased in leaves and roots,the concentration of ammonium nitrogen decreased and the concentration of ammonium nitrogen in roots increased under salt stress.The variations for the activities of NR,GS and GOGAT in the functional leaves and roots of Longdao 5 were less than those of Mudanjiang 30 under the same concentration of salt stress.

Standardized Cultivation of Cold Region Rice in Heilongjiang Reclamation Area

The paper analyzes the characteristics of rice production in Heilongjiang Reclamation Area(HRA)and the achievements made through innovative research and practice,evaluates the standardized mode of rice cultivation and technical standards for rice production,which play a key role in guaranteeing the growth of grain total output in Heilongjiang reclamation area and make great contributions to the national grain safety.

Design and Research on Virtual Display of Whole Process Mechanization for Rice Production in Cold Region

With the development of society,the virtual reality technology and multimedia technology have been applied to modern large-scale agriculture. The paper describes the design ideas for animation display of mechanized rice production in cold region,and elaborates the design of major part of each scene. By animation display,we can know about the whole process of rice production,as well as the benefits of mechanized operation.

Starch RVA Profile Properties for Cold Tolerant and Sensitive Cultivars of Japonica Rice at Different Altitudes

[Objective] By investigating of change rule rice starch RVA profile properties and the influence of cold tolerance on rice quality,the aim was to provide scientific references to the breeding of new cold-tolerant japonica rice varieties with high quality in the Yunnan plateau.[Method] Four cold-tolerant and five cold-sensitive japonica rice cultivars were grown at three locations with different altitudes in Yunnan plateau to investigate rice starch RVA profile characteristics.[Result] The results showed that with increasing altitude,the setback viscosity in cold-sensitive cultivars increased significantly,while the peak viscosity and breakdown viscosity decreased significantly.However,the peak viscosity and breakdown viscosity in cold-tolerant cultivars initially decreased and then gradually increased with rising altitude,whereas the setback viscosity initially increased and then decreased.[Conclusion] The starch RVA parameters of cold-tolerant cultivars were less sensitive to different environments than those of cold-sensitive cultivars.Cooking and eating quality of cold-tolerant cultivars had relatively stable trends with rising altitude,whereas cooking and eating quality of cold-sensitive cultivars had a trend toward inferior.

Effect of Low Temperature and Sparse Light Conditions on Cold Tolerance of Different Rice Lines at Seedling Stage

Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of 36 parents and 423 rice lines from 68 hybrid groups were investigated at seedling stage under low tempera- ture and sparse light conditions in field. There were 10 parent accessions with strong cold tolerance of level 1. Among them, 3 were common wild rice accessions; 4 were japonica rice cultivars; 2 were indica rice; 1 was offspring from hybrid be- tween indica and japonica.There were 33 lines with strong cold tolerance of level 1 from the hybrid groups of common wild rice,and 15 from the hybrid groups of IRBB5, and only 3 from the hybrid groups of BPHR96. There were abundant cold tolerance resources in rice germplasm. It was feasible to develop cold tolerance cul- tivars from the hybrids among common wild rice, japonica cultivars and indica culti- vars.

Effects of Plant Spacing,Row Spacing and Seedling Number Allocation on the Growth Dynamics of Different Populations of Two Types of Rice Varieties

[Objectives]This study was conducted to construct high-yielding,high-quality,and high-light-efficiency population structures of different types of rice varieties.[Methods]The effects of plant spacing,row spacing and seedling number allocation on stems and tillers,leaf area and dynamic traits of high-yielding rice populations(more than 9750 kg/hm^(2))and low-yielding populations(less than 9750 kg/hm^(2))were studied by two kinds of representative rice varieties with different tiller ability and panicle sizes in cold regions.[Results]Decreasing the plant and row spacing and increasing the number of planted seedlings per hole advanced the heading date and made the number of stems and tillers in the population increase.The impact on the super rice variety with fewer tillers and heavier panicles was greater than that of conventional variety with more tillers and lighter panicles.The stems and tillers of the high-yielding high-quality populations grew steadily in the early stage of development,until an appropriate number of panicles was reached at the critical leaf age for productive tillers(June 25),and the peak seedlings should appear in the jointing stage(July 9)with a small number(that value of Longjing 21,the super rice variety with fewer tillers and heavier panicles,was about 1.2 times the expected panicle number,and that of the conventional variety with more tillers and lighter panicles,Kongyu 131,was about 1.1 times the expected panicle number).The populations gradually declined since then,until reaching an appropriate number of panicles at the heading stage.The high-yielding high-quality populations had a higher leaf area index at the heading stage.The value of Longjing 21,the super rice variety with fewer tiller and heavier panicles,reached about 6.0,and that of Kongyu 131,the conventional variety with more tillers and lighter panicles,reached about 4.5.The values decreased thereafter.At the maturation stage,the leaf area index of Longjing 21 remained above 2.5,and that of Kongyu 131 remained above 2.0.[Conclusions]This study has an important guiding role and significance for their high-yielding and high-quality supporting cultivation in cold regions.

水稻籼粳亚种间rDNA的ITS(internal transcribed spacer,ITS)序列分析

为探讨水稻亚种间的遗传背景及亲缘关系 ,运用PCR技术扩增并测序了水稻籼亚种的南京 11号、9311、广陆矮 4号三个品种和粳亚种的秋光、日本晴、爪哇稻三个品种的完整ITS区 (包括 5 .8S区 )。供试材料的 5 .8SrDNA的长度和G C含量完全一致。ITS1的长度为 193- 195bp ,G C含量为 72 .31% - 74 .38;ITS2的长度为 2 2 4 - 2 32bp ,G C含量为 74 .4 6 % - 76 .86 %。序列的相似性为 94 .4 % - 99.3%。CLUSTAL .W软件排序及分析表明 :1)存在 4个信息位点把 6个品种分为籼粳两大类群 ;2 )籼稻之间的ITS序列的同源性小于粳稻之间的同源性。由此可见 ,水稻核糖体DNA的ITS序列的变化规律与其传统的分类具有高度的一致性。

低温胁迫下水稻孕穗期幼穗的转录组动态分析

为深入了解寒地水稻孕穗期耐低温机理,明确低温应答的分子机制,本研究对孕穗期耐冷性强的水稻品种龙粳25(LG25)的幼穗进行低温胁迫转录组动态分析。通过测序,共获得515.26 Mb的Clean Reads,筛选获得6927个差异表达基因(DEGs)。其中,低温处理2 d时,获得6784个DEGs;低温处理4 d后,DEGs显著减少,仅获得1149个。GO富集分析表明,韦恩图各部分的上调和下调基因分别显著富集到33个生物进程GO类别,其中包含基因数最多的类别为单生物代谢过程,低温应答和高温应答在LG25的韦恩图各部分富集最多。KEGG富集分析表明,韦恩图各部分DEGs共富集到32条信号通路,其中植物激素信号转导通路在韦恩图各部分显著富集最多,共包含83个DEGs,分布在脱落酸、生长素、油菜素内酯、细胞分裂素、赤霉素、乙烯、茉莉酸、水杨酸等8个激素通路中,以生长素、脱落酸和水杨酸等激素包含的DEGs较多,分别为26个、17个和15个。

辽宁稻区水稻新品系抗寒性鉴定

冷害被认为是影响水稻生产的重要因素之一,为促使科研成果尽快转化为现实生产力,提高水稻综合生产力,加大新品种的抗逆性研究,特别是抗寒性研究,筛选抗寒资源,为加速良种推广与合理布局提供科学依据,试验对来自辽宁稻区的81个粳稻品系采用冷水灌溉法进行抗寒性鉴定。结果表明:冷水处理后各品系的农艺性状和产量性状均呈现下降趋势,其中株高降低1.3~39 cm;穗长减少0.3~10.6 cm;每穗总粒数减少2~89粒;结实率降幅为34.5%~96.6%;正常结实品种千粒重降低0.9~16.9 g;产量降幅为47%~100%。综合来看,北粳G1、YJ6、北粳G12、辽优86、北粳G5、北粳G6、辽粳香3号、铁粳2114、KH12这9份材料抗寒性较好,属于第一层次,可为粳稻耐寒育种提供利用价值。

寒地水稻孕穗期低温胁迫响应的转录组分析

水稻是世界重要的口粮作物,其整个生育周期都会受到低温冷害的威胁。为探究寒地水稻孕穗期低温胁迫应答基因的发掘及其低温应答调控机制,本研究对孕穗期低温下寒地水稻孕穗期耐冷品种龙粳25(LG25)和不耐冷品种龙粳11(LG11)的幼穗颖花展开转录组测序分析。结果表明,龙粳11中共筛选得到11 269个差异表达基因(DEGs),龙粳25中仅有1 148个DEGs。GO富集分析表明,龙粳11中差异基因多显著富集在光合作用相关的GO条目中,龙粳25多富集在低温、热响应及花粉发育相关的GO条目中。低温胁迫下,二者共同显著富集到低温响应及花粉发育GO条目。KEGG富集分析表明,龙粳11中差异基因多显著富集在光合有机物中的碳固定、光合作用等KEGG通路中,龙粳25多显著富集在淀粉蔗糖代谢、氨基糖和核糖代谢等KEGG通路中。

减氮增密对寒地水稻产量及氮素吸收利用的影响

基于2017年开始的秸秆还田下寒地水稻减氮增密长期定位试验[CK:常规密度(30 cm×13.3 cm),不施氮肥;T1:常规密度(30 cm×13.3 cm),常规施氮量(180 kg/hm^(2));T2:增加密度32%(30 cm×10 cm),常规施氮量(180 kg/hm^(2));T3:增加密度32%(30 cm×10 cm),穗肥减少常规施氮总量的20%(总施氮量144 kg/hm^(2));T4:增加密度32%(30 cm×10 cm),基肥减少常规施氮总量的20%(总施氮量144 kg/hm^(2))],利用2023年监测的试验数据,研究减氮增密对水稻产量及氮素吸收利用的影响。结果表明,T4处理产量最高,显著高于CK、T1、T2处理,增幅分别为39.6%、9.8%、13.3%;T3处理次之,与T4处理差异不显著。二者产量的提高主要归因于有效穗数的提高,其中T4处理有效穗数分别较CK、T1处理显著提高64.0%、18.5%。T3、T4处理收获指数较高,两者差异不显著,但均显著高于其他处理,其中,T4处理分别较CK、T1、T2处理提高30.4%、53.3%、15.6%。拔节期—成熟期,总体上以T4处理叶片SPAD值最高,SPAD衰减率最低,地上部干物质积累量较高。T1—T4处理植株总吸氮量较CK显著增加53.6%~94.2%,以T4处理增幅最大。与T1处理相比,T4处理氮肥吸收利用率、氮素吸收率、氮肥农学利用率、氮肥偏生产力分别显著提高36.1%、30.1%、82.4%、37.3%,而土壤氮素表观盈亏量和氮素盈余率则分别显著降低87.5%和103.8%;T3处理氮肥吸收利用率显著降低22.5%,而氮肥农学利用率、氮肥偏生产力分别显著提高71.2%、34.9%。氮肥偏生产力、氮肥农学利用率、氮素吸收率与产量均呈极显著正相关,而氮素盈余率和土壤氮素表观盈亏量与产量均呈显著或极显著负相关。综上所述,在减少基肥中氮肥施用量的同时增加移栽密度可提高水稻产量及氮素吸收利用率,适合寒地水稻生长。

0.01%28-高芸苔素内酯·吲哚丁酸对寒地水稻生长及产量的影响

为明确0.01%28-高芸苔素内酯·吲哚丁酸对寒地水稻生长调节作用,采用随机区组试验设计,研究不同施药量对寒地水稻生长及产量的影响。结果表明,于分蘖期施用0.01%28-高芸苔素内酯·吲哚丁酸颗粒剂,能明显促进水稻分蘖,缩短始穗期至齐穗期天数,促进干物质积累,增强抗倒伏能力,提高水稻产量,对水稻生长安全。药剂施用量为22.5 kg/hm^(2)时,水稻穗粒数、结实率、千粒重最大,产量最高,是最佳施用量。

寒地水稻全程绿色防控技术探析

寒地水稻全程绿色生产技术立足北方高寒地区,依托水稻绿色食品生产基地,筛选优良水稻品种,将农业、物理、生物与化学防治有机结合,通过使用标准施药器械,规范施药作业标准,有效提升了寒地水稻全程绿色防控的质量和效益,实现了对大米“生态、安全、营养、健康”的要求。

水稻耐冷研究现状与黑龙江省粳稻耐冷生物育种策略

随着全球气候变化,极端天气事件发生概率显著上升。作为我国水稻商品粮重要生产基地,黑龙江省是低温冷害频发地区,黑龙江省粳稻在苗期和生殖生长期(含孕穗期、开花期和成熟期)都容易遭遇低温胁迫。低温胁迫是黑龙江省粳稻生产的重要限制因素,提高黑龙江省粳稻品种耐冷性对保障我国粮食安全生产具有重大战略意义。本文在回顾水稻耐冷鉴定方法和遗传研究同时,通过分析黑龙江省粳稻近20年(2006-2023年)育成品种的耐冷数据发现,随着近年来审定品种数量“井喷”,品种耐冷性呈现整体下降趋势;其次,通过基于参考基因组的比较作图发现,苗期和生殖生长期耐冷性大多受独立的位点或染色体区段控制,遗传重叠(包括一因多效位点和连锁区段)比例在21%左右,其中负调控位点占比20%。对当前黑龙江省粳稻耐冷育种工作而言,针对上述遗传重叠位点/区段和负调控位点开展深入研究,将有利于进一步提高育种工作效率。在此基础上,本文提出了黑龙江省粳稻耐冷生物育种策略以及苗期与生殖生长期耐冷性同步改良的具体建议。

播量和插秧密度互作对寒地水稻生长发育和产量的影响

试验在大田条件下,以垦稻1725为试验材料,设置干籽125 g/盘(S1)、干籽70 g/盘(S2)两个水平及行株距为30 cm×12 cm(P1)、30 cm×10 cm(P2)、25 cm×12 cm(P3)和25 cm×10 cm(P4)四个水平,分析不同播量和插秧密度互作下寒地水稻秧苗素质、茎蘖动态、干物质积累和产量构成特征及其关系。结果表明:不同播量下,S2处理秧苗素质高于S1处理。播量与插秧密度交互作用下,各处理组合对水稻干物质积累量、产量及其构成因素的影响存在明显或显著互作效应,以播量70 g/盘、行株距30 cm×10 cm(S2P2)处理产量最好,产量达748.62 kg/667 m^(2)。在同一密度下,S2处理产量高于S1处理。在同一播量下,稀播处理产量最好的为S2P2处理,密播处理产量最好的为S1P3处理。综合分析表明,种植垦稻1725稀播育壮秧,稀播建议30 cm×10 cm插秧密度,提高后期分蘖及干物质积累量,增加产量;如是密播弱苗,建议25 cm×12 cm插秧密度,增加平方米基本苗数,提高产量。