Grain yield and nitrogen use efficiency of an ultrashort-duration variety grown under different nitrogen and seeding rates in direct-seeded and double-season rice in Central China

Nitrogen (N) and seeding rates are important factors affecting grain yield and N use efficiency (NUE) in direct-seeded rice.  However, these factors have not been adequately investigated on direct-seeded and double-season rice (DDR) in Central China.  The objective of this study was to evaluate the effects of various N and seeding rates on the grain yield and NUE of an ultrashort-duration variety grown under DDR.  Field experiments were conducted in 2018 in Wuxue County and 2019 in Qichun County, Hubei Province, China with four N rates and three seeding rates.  The results showed that the grain yield of the ultrashort-duration variety ranged from 6.32 to 8.23 t ha^–1 with a total growth duration of 85 to 97 days across all treatments with N application.  Grain yield was increased significantly by N application in most cases, but seeding rate had an inconsistent effect on grain yield.  Furthermore, the response of grain yield to the N rates was much higher than the response to seeding rates.  The moderate N rates of 100–150 and 70–120 kg N ha^–1 in the early and late seasons, respectively, could fully express the yield potential of the ultrashort-duration variety grown under DDR.  Remarkably higher N responses and agronomic NUE levels were achieved in the early-season rice compared with the late-season rice due to the difference in indigenous soil N supply capacity (INS) between the two seasons.  Seasonal differences in INS and N response should be considered when crop management practices are optimized for achieving high grain yield and NUE in ultrashort-duration variety grown under DDR.     

施氮对水稻茎秆抗倒伏能力的影响及其形态和力学机理

【目的】研究施氮对水稻茎秆抗倒伏能力的影响及其与茎秆形态性状和力学性状的关系及其作用机理,为水稻抗倒高产栽培调控提供依据。【方法】以常规籼稻银晶软占为材料,设置4个氮水平,进行大田试验,研究施氮对水稻茎秆基部节间形态和力学性状的影响及其与倒伏指数的关系。【结果】施氮影响水稻茎秆的形态和力学性状。随着施氮量的增加,株高增加,重心上移,基部节间长度增加,节间充实度下降,抗折力和弹性模量减小,茎秆倒伏指数增加,抗倒伏能力下降。倒伏指数与株高、重心高度及基部节间长度呈正相关,而与基部节间充实度、抗折力及弹性模量呈负相关,且相关系数大多达到显著或极显著水平。倒伏指数与单位面积有效穗数和每穗总粒数呈显著或极显著正相关,而与结实率和千粒重呈负相关趋势。【结论】株高、重心高度、基部节间长度和基部节间充实度等形态性状,以及弯曲力矩、抗折力等力学性状,是影响水稻茎秆抗倒伏能力的主要因素。     

不同栽培条件对杂交晚稻茎秆抗倒伏性状的影响

研究施氮量和栽插密度对水稻茎秆抗倒伏能力的影响及其与茎秆形态性状和力学性状的关系,为水稻抗倒伏高产栽培调控提供依据。以3种不同抗倒伏水平的籼型杂交晚稻品种为材料,设置3个氮水平、3种栽插密度,进行大田试验,研究施氮和栽插密度对水稻茎秆基部节间形态和力学性状的影响及其与倒伏指数的关系。结果表明,随着施氮量和栽插密度的增加,茎秆基部第1节间变细长,第2、3节间长度先增加后下降,茎壁变薄,秆型指数降低,从而提高茎秆的倒伏指数和降低抗倒伏能力;在高氮与高密栽培条件下,水稻的群体大,个体生长受抑制,使水稻植株茎秆的倾斜角度加大,倒伏指数加大,从而使水稻更容易倒伏;水稻基部茎秆的倒伏指数与株高、基部各伸长节间的长度呈正相关,与茎粗、茎壁厚、秆型指数呈负相关;增施氮肥与增加栽插密度,在一定程度上增加了茎长与植株茎秆的弯曲力矩,降低了壁厚、机械强度和折断弯矩(M),从而降低了茎秆的抗倒伏能力,提高了水稻茎秆的倒伏指数(LI)。施纯氮160 kg·hm^-2和栽插密度20.0 cm×16.6 cm时,水稻抗倒伏性能较好。     

Identification of tolerance to high density and lodging in short petiolate germplasm M657 and the effect of density on yield-related phenotypes of soybean

Soybean yield has been increased through high planting density, but investigating plant height and petiole traits to select for compact architecture, lodging resistance, and high yield varieties is an underexplored avenue to improve yield.  We compared the relationship between yield-related traits, lodging resistance, and petiole-associated phenotypes in the short petiole germplasm M657 with three control accessions over 2017-2018 in four locations of the Huang-Huai region.  The results showed M657 exhibited stable and high tolerance to high planting density and resistance to lodging, especially at the highest density (8×10⁵ plants ha^-1).  Regression analysis showed that shorter petiole length was significantly associated with increased lodging resistance.  Yield analysis showed that M657 achieved higher yields under higher densities, especially in the north Huang-Huai region.  There are markedly different responses to intra- and inter-row spacing designs among varieties in both lodging and yield related to location and density.  Lodging was positively correlated with planting density, plant height, petiole length, and number of effective branches, and negatively correlated with stem diameter, seed number per plant, and seed weight per plant.  The yield of soybean was increased by appropriately increasing planting density on the basis of current soybean varieties in the Huang-Huai region.  This study provides a valuable new germplasm resource for introgression of compact architecture traits amenable to high yield in high density planting systems and establishes a high-yield model of soybean in the Huang-Huai region.     

农作物倒伏及其影响因素分析

倒伏是由外界因素引发的植株茎秆从自然直立状态到永久错位的现象。倒伏是作物生产中普遍存在的问题,已成为高产稳产的重要限制因素之一。倒伏的严重性和对产量品质所造成的损失与作物生长环境和倒伏的发生时期有关。一般来说,适宜的生长环境、促进作物生长和产量提高的措施会引发倒伏或使倒伏程度加重。作物倒伏是一个综合的、复杂的现象,它受到外界风雨、栽培技术、植物本身特性以及支持土壤系统等的多重影响。鉴于倒伏性对产量、品质的严重影响,国内外学者对作物的抗倒伏性进行了广泛深入的研究。笔者综述了对倒伏的影响因素的分析,作物倒伏与否主要受到4个系统共同制约:气候因素、生态因素、栽培因素和植物内在遗传因素。     

农作物倒伏及其评价方法

倒伏是由外界因素引发的植株茎秆从自然直立状态到永久错位的现象。倒伏是作物生产中普遍存在的问题,已成为高产稳产的重要限制因素之一。倒伏的严重性和对产量品质所造成的损失与作物生长环境和倒伏的发生时期有关。一般来说,适宜的生长环境、促进作物生长和产量提高的措施会引发倒伏或使倒伏程度加重。鉴于倒伏性对产量、品质的严重影响,国内外学者对作物的抗倒伏性进行了广泛深入的研究。笔者综述了对倒伏类型的划分,归纳为茎倒(折)、根倒和根茎复合倒伏三种类型,并对评价抗倒性的方法和指标的进展情况进行了讨论。     

人工模拟机械开沟穴直播提高早籼稻茎秆抗倒伏能力及产量

【目的】研究机械开沟穴直播对早籼稻茎秆抗倒伏能力及产量的影响,为水稻机械化直播技术提供理论依据与技术支撑。【方法】试验以常规稻中嘉早17和杂交稻株两优171品种为材料,系统比较人工模拟机械开沟穴直播（MFP）、表面穴直播（SBP）与覆土穴直播（SCP）对直播早籼稻出苗率、植株抗倒性能及产量与产量构成的影响。【结果】与表面穴直播和覆土穴直播相比,人工模拟机械开沟穴直播可提高早籼稻供试品种的出苗率,增幅为5.19%—13.89%,且与表面穴直播处理差异显著（P<0.05）。同时,人工模拟机械开沟穴直播有利于提高直播水稻品种产量,两品种增产幅度为4.52%—11.20%;从产量构成因素分析,产量的提高主要得益于单位面积有效穗数、千粒重提高。此外,人工模拟机械开沟穴直播有利于提高供试品种植株抗折力,降低植株倒伏指数,尤其是第3节间;有利于增加株高、重心高度与第3节间（I3）茎壁厚度和节间粗度,提高不同节间的单位长度节间干重、单位体积节间干重以及木质素含量。大部分节间的节间干重与抗折力有显著的正相关,而与倒伏指数为显著的负相关。节间干重与单位长度节间干重是影响植株倒伏的主要因素,而株高、重心高度、节间长度和节间粗度并不能同时影响植株抗倒伏能力与倒伏指数,木质素与各节间抗折力有显著或极显著正相关。【结论】人工模拟机械开沟穴直播不仅有利于提高直播早籼稻产量,还显著提高植株抗倒伏能力,降低倒伏风险,可在生产中推广使用。     

小麦倒伏原因、机理及其对产量和品质影响研究进展

倒伏是制约小麦生产的关键因素,提高小麦抗倒性有利于提高小麦机械化收获和农业生产效率,进一步提高小麦产量和籽粒品质.为了明确倒伏原因、机理及其对产量和品质的影响,结合前人的研究,总结了小麦倒伏的影响因素、茎秆倒伏机理、倒伏对产量以及籽粒品质的影响.最后,从小麦育种和栽培两个方面,指出提高小麦抗倒性的关键措施以及未来研究方...     

水稻核心种质资源茎秆抗倒伏性研究

为了探究不同株高、重心高度及基部茎秆性状对水稻抗倒伏能力的影响,以533份水稻核心种质资源为试验材料,在2种栽培条件下,对10个性状进行相关分析和通径分析,结果表明:低株高水稻基部第1节间壁厚和基部抗折力对倒伏指数有协同作用,低株高水稻抗倒伏茎秆性状改良应集中在基部第1节间茎粗、壁厚,高株高水稻倒伏性更易受株高和重心高度的影响,高株高水稻抗倒伏性状改良应集中在基部第2节间茎粗,增强水稻茎秆基部抗折力是提高不同株高水稻抗倒伏能力的途径之一。     

水稻抗倒伏能力与茎秆物理性状的关系及对产量的影响

研究了不同肥力条件下的水稻抗倒伏能力与茎秆物理性状的关系及对产量的影响。以成熟期植株倾斜角度代表的抗倒伏能力与茎秆第1伸长节间长度呈极显著负相关,与基部茎秆粗度、厚度分别呈极显著正相关。不同株高品种的抗倒伏能力存在着品种间差异;施氮对水稻群体倒伏具有重要影响。就产量来说,最高产群体一般出现在750kg/hm2的中肥区。研究认为,通过降低第1和第2伸长节间长度,适当加强茎秆基部物理性状的强度、降低穗位、增加穗长和穗颈长度等,可以提高水稻植株的抗倒性,使倒伏与株高和生物产量的矛盾在更高产水平上得到统一。     

谷子育成品种的抗倒性评价

倒伏对谷子产量和品质以及机械化收获均有显著影响。为了筛选适宜机械化收获的谷子品种,以近几年通过国家鉴定、省级审定和参加国家区试的22个谷子育成品种为试材,利用倒伏系数评价了参试谷子品种的抗倒性;通过分析茎秆性状（株高、单茎鲜重、根量、茎秆抗折力、基部4节的长度、茎秆机械强度）与品种倒伏系数的相关关系,明确了影响谷子抗倒性的关键性状指标;并以抗倒性有显著差异的几个谷子品种为代表,探讨了这些关键性状指标如何影响谷子的抗倒伏能力。结果表明：济谷14、济谷16和冀谷31的倒伏系数均＜0.15,抗倒伏能力很强; M2173、济谷13、衡0950和济谷12的倒伏系数均＞0.29 ,抗倒伏能力较弱。本研究条件下,谷子株高和单茎鲜重与倒伏系数呈正相关,基部4节的长度与倒伏系数呈负相关,但关系程度均不密切;根量、茎秆抗折力和茎秆机械强度与谷子抗倒性有非常密切的关系。将抗倒性明显不同的7个谷子品种进行了3个关键性状指标的对比分析,结果发现,根量越大,茎秆抗折力越大,茎秆的机械强度越大,谷子品种的抗倒伏能力越强,越适合机械化收获。     

Nitrogen management improves lodging resistance and production in maize (Zea mays L.) at a high plant density

Lodging in maize leads to yield losses worldwide.  In this study, we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics, culm mechanical strength, lignin content, root growth, lodging percentage and production in maize at a high plant density.  We compared a traditional nitrogen (N) application rate of 300 kg ha^–1 (R) and an optimized N application rate of 225 kg ha^–1 (O) under four N application modes: 50% of N applied at sowing and 50% at the 10th-leaf stage (N1); 100% of N applied at sowing (N2); 40% of N applied at sowing, 40% at the 10th-leaf stage and 20% at tasseling stage (N3); and 30% of N applied at sowing, 30% at the 10th-leaf stage, 20% at the tasseling stage, and 20% at the silking stage (N4).  The optimized N rate (225 kg ha^–1) significantly reduced internode lengths, plant height, ear height, center of gravity height and lodging percentage.  The optimized N rate significantly increased internode diameters, filling degrees, culm mechanical strength, root growth and lignin content.  The application of N in four split doses (N4) significantly improved culm morphological characteristics, culm mechanical strength, lignin content, and root growth, while it reduced internode lengths, plant height, ear height, center of gravity height and lodging percentage.  Internode diameters, filling degrees, culm mechanical strength, lignin content, number and diameter of brace roots, root volume, root dry weight, bleeding safe and grain yield were significantly negatively correlated with plant height, ear height, center of gravity height, internode lengths and lodging percentage.  In conclusion, treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics, culm mechanical strength, lignin content, and root growth, so it improved the production of the maize crop at a high plant density.     

Lodging resistance and yield potential of winter wheat: effect of planting density and genotype

Improved lodging resistance is important for achieving high yield in irrigated environments. This study was conducted to determine genotypic variation in lodging resistance and related morphological traits among winter wheat cultivars planted at two densities, and to identify key traits associated with lodging resistance. Lodging performance of 28 genotypes, including 24 released cultivars and four advanced lines, was evaluated at 250 plants per square meter and 500 plants per square meter in Shandong province during the 2008–2009 and 2009–2010 crop seasons. At the higher density, the average grain yield was 2.6% higher, even though lodging score rose by as much as 136%. The higher planting density increased lodging through increased leaf area index (LAI), plant height, center of gravity and length of basal internodes, and reduced grain weight per spike and diameter of the lower two stem internodes. LAI, center of gravity and diameter of first internodes, as the important indicators for lodging resistance, were significantly correlated with lodging score, with R= 0.62, 0.59 and −0.52 (P<0.01), respectively. Plant pushing resistance was significantly associated with diameter and length of the first internodes (R = 0.71–0.77, P<0.01), indicating it could be used to assess the strength of the lower stem. Higher planting density could be used to select genotypes with lodging resistance in irrigated environments. Cultivars carrying high plant density tolerance and high yield potential, such as Jimai 22 and Liangxing 66, were recommended as leading cultivars for production as well as elite crossing parents for further increasing yield potential in the Yellow and Huai Valleys Winter Wheat Zone in China.     

立丰灵对水稻抗倒性和产量性状的影响

观察水稻施用立丰灵后的节间形态、抗倒性及产量性状的生理效应,结果表明:①立丰灵抑制节间伸长期的纵向伸长,促进节间伸长期的横向生长,使节间外径增粗,秆壁加厚;②立丰灵通过矮缩节间减少弯曲力矩和增进节间粗厚度提高抗折力的双重作用,来降低倒伏指数,即增加抗倒力;③水稻倒4、倒3节间是最易倒伏的部位,因而,倒4、倒3节间的倒伏...     

偏高秆偏大穗杂交粳稻屉优418和 辽优5218的抗倒伏能力分析

文章对偏高秆、偏大穗杂交粳稻屉优418、辽优5218组合在随机区组三次重复、较高肥力条件下的抗倒伏能力进行了分析。研究认为偏高秆、偏大穗杂交粳稻屉优418、辽优5218组合具有抗倒伏能力强的理想茎秆物理形状:地上部第一伸长节间长度很短,地上部第二伸长节间长度也较短,基部茎秆截面椭圆长轴、短轴长和面积大,壁厚宽和茎壁截面积大,植株表现出抗倒伏能力强;在育种和栽培实践中,通过减少第一和第二伸长节间长度,适当加强茎秆基部物理性状的强度,降低穗位,增加穗长和穗颈长度等,可以提高杂交粳稻植株的抗倒性,使倒伏与株高和生物产量的矛盾在更高产水平上得到统一。     

杂交中籼新品种筛选

[目的]筛选出适合安徽省种植的杂交中籼新品种。[方法]通过对12个杂交中籼新品种进行比较试验,调查各品种的生育性状、抗性及产量等指标。[结果]从产量和主要农艺性状表现筛选出综合表现好的品种有两优502、丰两优688、两优392;综合表现较好的品种有Y两优5836、荃优金1号;两优8号、两优3451这2个品种的综合表现较差。[结论]降低株高可以提高品种的抗倒能力,但产量并不低;增加穗粒数、提高结实率,可以有效提高水稻品种的产量。     

苏州市晚粳型水稻新品种综合评价研究

[目的]筛选适宜苏州地区种植的晚粳型水稻(Oryza sativa L.)新品种。[方法]对5个常规粳稻和2个杂交粳稻新品种进行随机区组试验,综合鉴定各品种的农艺性状、产量性状、米质等。[结果]参加试验的品种中,苏10-100的生育期较迟,达到172 d,不适合当地种植。嘉47尽管产量水平较高,但条纹叶枯病较重,推广种植风险较大。通粳981植株偏高,且产量水平较低。常粳11-5与常优09-3产量中等,外观米质一般,可继续鉴定比较一年。E282和武运粳29号的综合性状较优,生育期适宜,产量分列第1和3位,增产均达到极显著水平。E282株高适中,茎秆粗壮,抗倒性强,抗病性较强,穗型大,外观米质较优;武运粳29号种植过程中应注意控制氮肥施用,增施磷钾肥,减小倒伏风险。[结论]武运粳29号和E282综合性状优良,丰产性好,适应性强,较适合在苏州地区进行更大面积推广示范种植。     

直播栽培对双季早稻生育期、抗倒伏能力及产量效益的影响

【目的】探究直播栽培方式对不同类型水稻品种生育期、抗倒伏能力、产量和经济效益的影响,以期为机械化直播稻的应用推广提供理论基础。【方法】2020年和2021年早稻,以广西生产上推广面积较大的常规稻品种桂育9号、桂育11号、桂野丰、广粮香2号和杂交稻Y两优1号等5个品种为供试材料,以人工移栽为对照,进行大田精量直播。试验采用裂区设计,以栽培模式为主区,品种为副区,设置3个重复。记录各生育周期,测定主茎形态、基部茎秆特征以及抗折力、弯曲力度和倒伏指数等抗倒伏指标,成熟期测定产量及其构成因素,并计算成本和经济效益。【结果】（1）直播稻的生育期缩短2—6 d,主要表现在播种到幼穗分化期之间;（2）直播稻的抗倒伏能力低于移栽稻,其株高、重心高度与穗干重均较低,第二节间的茎粗、壁厚、鲜重和干重亦较低,茎秆长度则高于移栽稻,这是导致直播水稻抗倒伏能力弱的主要原因;（3）在产量表现方面,除Y两优1号外,其余4个水稻品种的产量表现为直播稻低于移栽稻。生育期相对短的品种,直播稻的产量明显低于移栽稻,而生育期较长的品种,产量差异不显著,在产量构成因素中,每穗粒数增加和结实率的提高是直播稻增产的主要因素;（4）...     

水稻新品种丰优293抗倒超高产栽培技术研究

[目的]为丰优293的大面积推广提供技术指导。[方法]以水稻品种丰优293和11838（对照）为材料,研究不同施肥水平（施纯氮225、150、75kg／hm^2）对2品种抗倒性（株高、重心高度、节间壁厚和倒伏指数）和产量及产量构成因素的影响。并总结了丰优293的高产栽培技术要点。[结果J3种肥力水平下,丰优293的倒伏指数、株高、重心高度均低于11838,而基部3个节间的厚度明显厚于11838;3种肥力水平下,丰优293的穴穗数低于11838,但其穗粒数、结实率、千粒重、理论产量和实际产量均高于11838。[结论]相同肥力水平下。丰优293的抗倒性和产量均优于11838。丰优293的最适播期为4月中下旬,最适移栽时问为5月中下旬,秧田用种量和扦插密度分别为180kg／hm^2和16．5cm×23．1cm。     

不同耕作模式下施硅量对垦粳7号抗倒伏性能的影响

以垦粳7号水稻为材料,采用田间小区试验方法,在垄作和平作两种耕作模式下,设置4种硅肥量D1(0 mL·hm^-2)、D2(150 mL·hm^-2)、D3(375 mL·hm^-2)、D4(600 mL·hm^-2),研究不同处理下水稻株高、重心高、基部第1节间（N1）、第2节间（N2）、第3节间（N3）、第4节间（N4）抗倒伏能力和主要物理性状的差异,并对倒伏指数、抗折力与茎秆主要物理性状进行相关分析。结果表明：在两种耕作模式下,适当的硅肥处理使水稻株高、重心高降低,N1、N2节间长缩短,N3、N4节间长伸长,各节间粗度、单位节间干重、茎壁厚度、抗折力和弯曲力矩都增加,倒伏指数减小,抗倒伏能力增强。两种耕作模式均在D3处理时倒伏指数最小,垄作模式下D3处理N1、N2、N3、N4节间倒伏指数较D1分别降低了15.35%、5.18%、5.89%、10.61%,平作模式下D3处理N1、N2、N3、N4节间倒伏指数较D1分别降低了12.20%、6.59%、6.29%、8.70%。基部各节间倒伏指数与节间粗度、单位节间干重、茎壁厚呈负相关,与株高、重心高呈正相关。基部各节间抗折力与节间粗度、单位节间干重、茎壁厚呈正相关,与重心高呈负相关。不同耕作模式下,适当硅肥用量处理均使水稻抗折力、抗倒伏性能增加。硅肥施用量为375 mL·hm^-2时,水稻抗倒伏性能最好。