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.

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.

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.

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.

Identification of Quantitative Trait Loci for Cold Response of Seedling Vigor Traits in Rice

The quantitative trait loci （QTLs） for the seedling vigor traits under 12℃ cold water irrigation, such as the seedling height, the seedling fresh weight, the seedling dry weight, and their cold response index, were identified using an F2：3 population including 200 individuals and lines derived from a cross of indica and japonica ＂Milyang 23/Jileng 1＂ with microsatellite markers. All seedling vigor traits exhibited a continuous distribution near normal in F3 lines; these traits were quantitative traits controlled by multiple genes. Twelve QTLs conferring the seedling vigor traits under cold water irrigation were detected on chromosomes 1, 2, 7, 8, and 12, which explained the observed phenotypic variance from 5.2% to 17.9%. Among them, qCSH2 and qCSH12 were located in RM262-RM263 on chromosome 2 and RM270-RM17 on chromosome 12, respectively, which were associated with the seedling height, qSDW12 and qCSDW1 were located in RM19-RM270 on chromosome 12 and RM 129-RM9 on chromosome 1, respectively, which were correlated with the seedling dry weight and its cold response index, and the explained 16.6%, 17.9%, 15.9%, and 16.2% of the observed phenotypic variation, respectively. These QTLs alleles were derived from cold-tolerant parent Jileng 1; the gene actions of the two front genes showed their additive effect, and the two genes belind showed dominant and over dominant effects, respectively.

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.

Mechanization of irrigated rice cropping regions in China

The mechanization of rice production in China has experienced a comparatively long and an undulating process. The full-scale making of mechanization of irrigated rice cropping regions was started at the mid 1960’s, later than that of upland cropping and its average level of mechanization operation also lower than the average level of the country. During this peiod, however, a series of mechines were created, which adapted to the characteristics of rice cropping regions in China, and the foundation was laid for the later paddy field machinery. For example, transplanting machine (created in 1956), boat—shaped tractors (1961), paddy field ploughing and harrowing serial (1974), and single wheel plowing machines (1979) etc.

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.

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。

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。

冷水灌溉对水稻扬花期遭受短时高温危害的缓解效果

以灌溉水的温度处理(冷水初始温度20.0℃、常温水初始温度27.7℃)为主区,以气温处理(高温38.0℃、自然气温32.0℃)为副区,进行裂区实验设计,开展田间实验,探索高温与自然气温下水稻体温的变化特征及冷水灌溉和常温水灌溉对水稻剑叶、穗及节间温度的影响规律。结果表明:与自然气温相比,高温条件下水稻剑叶、穗及节间温度分别显著提高5.9℃、5.7℃和0.9℃。高温条件下使用两种温度的水灌溉时,冷水灌溉(LHT)处理的水温升高更快、升温幅度更大,10:00-15:00升温幅度达6.0℃;而常温水灌溉的水温变化缓慢,从10:00的27.7℃升至15:00的30.0℃,升温仅2.3℃。可见,高温条件下灌溉冷水比常温水吸收更多的热量。因此,高温条件下,与常温水灌溉处理相比,冷水灌溉处理使水稻剑叶、穗及节间温度显著降低了1.5℃、1.3℃和1.6℃,增大了气-叶温差、气-穗温差及气-节间温差。高温条件下,冷水灌溉能有效降低水稻体温,起到良好的避热效果,因此可以考虑作为缓解高温热害的一种技术手段。

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。

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。

土层厚度与灌溉方式对寒地水稻节水生长及产量的影响

【目的】探究不同土层厚度与灌溉方式对寒地水稻生长的影响。【方法】于2020年在兴安盟乌兰浩特市科右前旗袁隆平水稻试验基地开展水稻田间试验,试验设置15~20 cm(H1)、20~25 cm(H2)和25~30 cm(H3)3种土层厚度,设置控制灌溉(K)、常规灌溉(CK)2种灌溉方式,共计6个处理,探究不同土层厚度与灌溉方式对寒地水稻生长的影响。【结果】K处理下的水稻株高相比CK矮,根长、茎粗、每穴有效穗数、千粒质量及产量相比CK均有不同程度的增加,H2和H3土层厚度下的水稻产量相比H1增加30.49%~32.91%和63.74%~76.33%,K处理下的总灌水量相比CK减少55.04%~56.84%,K处理下的灌溉水生产率相比CK增加1.55~1.86倍,H2和H3土层厚度下的水稻灌溉水生产率相比H1增加35.61%~38.62%和73.07%~94.14%。【结论】25~30 cm土层厚度下采用控制灌溉的水稻节水增产效果最优,适宜当地水稻种植,研究结果可为寒地水稻种植提供理论依据与技术参考。

基于光谱反射率的寒地水稻叶片氮含量预测

为实现利用水稻叶片光谱指数实时预测叶片群体的氮素含量,采集了不同年份中氮素、品种差异下寒地水稻主要生育期(T_(1)穗分化中期、T_(2)拔节期、T_(3)孕穗期、T_(4)齐穗期、T5蜡熟期)顶部3片全展叶(上1、上2、上3叶分别记作L1、L_(2)、L_(3))的光谱反射率,探究其变化规律以及光谱指数与叶片氮素含量的关系,并用P-k、均方根误差(RMSE)、对称平均绝对百分比误差(SMAPE)、校正均方根误差(RMSEC)、交互验证均方根误差(RMSECV)、相对预测性能(RPD)对模型精度进行验证。结果显示:提高氮肥投入量,叶片反射率在可见光区域内呈降低趋势,在近红外平台叶片反射率上升。随着生育期的推进,在可见光区域内,不同品种L1叶反射率先降低后上升,L_(2)、L_(3)叶的反射率一直上升,与叶片氮素百分含量的敏感波段为500~550和650~700nm。对光谱指标和叶片氮素百分含量进行相关分析,生育前期以下位叶片的光谱指标相关系数高,生育后期则相反,筛选出T_(1)时期L_(2)叶指标FD-NDNI、T_(2)时期L_(2)叶指标GM2、T_(3)时期L_(2)叶指标Lic2、T_(4)时期L1叶指标MRESRI以及T5时期L1叶指标Ctr1适宜作为不同时期预测叶片氮素含量的最佳指标,预测叶片氮素含量的回归方程R2分别0.54^(**)、0.60^(**)、0.66^(**)、0.62^(**)、0.51^(**),均达到极显著水平;验证指标的P-k值分别为0.00、0.04、0.06、0.01、0.04;RMSE分别为0.39、0.58、0.22、0.54、2.56;SMAPE分别为1.11、1.41、1.03、1.64、3.89;RMSEC分别为0.17、0.15、0.13、0.13、0.13;RMSECV分别为0.18、0.14、0.12、0.12、、0.14;RPD分别为2.46、2.19、3.15、1.74、3.01,其中T_(3)时期L_(2)叶指标Lic2的预测效果表现最佳。借助筛选的光谱指标能够实现快捷、无损和实时预测水稻不同生育时期的氮素营养状况,促进高产优质的寒地水稻可持续发展。

孕穗期冷水灌溉对寒地粳稻籽粒灌浆及其氮素积累的影响

为探究孕穗期冷水灌溉下粳稻籽粒灌浆过程中的干物质、氮素形成积累规律及氮代谢关键酶调控效应，以东农428和松粳10为材料，设置6个冷水灌溉持续时间（0、3、6、9、12和15 d），分析孕穗期冷水灌溉对寒地粳稻籽粒灌浆过程中的干物质、氮素积累及氮代谢关键酶活性的影响。结果表明，与对照相比，孕穗期冷水灌溉下，寒地粳稻产量及籽粒干物质积累量的变化规律一致，冷水灌溉持续时间越长，产量及籽粒干物质积累量降幅越大。冷水灌溉下，寒地粳稻籽粒干物质积累量降低，除与籽粒干物质最大相对积累速率降低有关外，还与结实率降低、有效穗数和每穗总粒数减少有关。冷水灌溉可提高寒地粳稻籽粒全氮、蛋白氮、成熟期籽粒粗蛋白含量及灌浆前期籽粒谷氨酰胺合成酶（GS）活性。冷水灌溉6 d 可显著提高籽粒谷草转氨酶（GOT）及谷丙转氨酶（GPT）活性，冷水灌溉9~15 d 可显著降低其活性。短期冷水灌溉下（3~6 d），寒地粳稻通过增强有机氮同化过程，促进蛋白质合成，使籽粒氮素含量增加；长期冷水灌溉下（9~15 d），籽粒有机氮同化过程受到抑制，影响氨基酸和蛋白质的合成，最终导致籽粒氮素增幅下降。籽粒全氮、蛋白氮和淀粉颗粒态结合蛋白是不同耐冷性品种响应冷水胁迫的差异产物，其含量可作为耐冷性鉴定的指标。