Comparison of agronomic performance between inter-sub-specific hybrid and inbred japonica rice under different mechanical transplanting methods

Mechanical transplanting has been applied to rice cultivation to save labor costs and ease labor shortages in Asian countries, especially in China. However, little information is available related to the characteristics of agronomic performance when comparing inter-sub-specific hybrid rice (IHR) and inbred japonica rice (IJR) under mechanical transplanting method. In 2013 and 2014, field experiments were conducted using IHR (Yongyou 2640) and IJR (Wuyunjing 24) under two cultivation patterns, that is, pot seedlings mechanically transplanted (PS) and carpet seedlings mechanically transplanted (CS). Grain yield, yield components, leaf area index (LAI), leaf area duration (LAD), aboveground biomass, crop growth rate (CGR), nitrogen (N) uptake, and N accumulation were investigated. When compared with CS, PS displayed significantly increased grain yield for both varieties because the larger sink size allowed higher N accumulation from panicle initiation to maturity. Moreover, total aboveground biomass under PS increased significantly compared with that under CS; that is, higher photosynthetic productivity resulted from a greater LAI and higher LAD during the grain filling stage. Higher N absorption capacity in the middle and late growth periods resulted in significantly enhanced total N uptake under PS. When compared with IJR for both treatments, IHR generated 75.2% more grain yield. However, the characteristics creating high yield of IHR were different from those of IJR. Greater aboveground biomass production as well as higher N uptake and accumulation created higher grain yield in IHR than in IJR. These results suggest higher yield could be achieved using PS with IHR, attributing to exploit both yield superiority and productive potential.     

中国水稻种植机械化高产农艺研究现状及发展探讨

水稻种植机械化是中国作物机械化生产的难点。论文在回顾中国水稻机械化种植发展概况的基础上,重点总结与阐述水稻3种机械化种植方式下的高产规律与栽培农艺。（1）系统归纳了盘育毯苗机插水稻的生长发育特性,重点阐述了毯苗机插稻的高产形成规律,即以合理的茎蘖动态与LAI动态,提高群体中后期光合物质生产能力;以合理增加生育中期有效与高效生长量,提高抽穗后物质生产积累量与最终生物学产量;以足量穗数与较大穗型协调产出足够的群体总颖花量,并保持通常的结实率与粒重。同时介绍了相配套的高产栽培农艺：①培育标准化壮秧,提供构建高产群体起点的生物基础;②机械精确栽插,形成高质量群体起点;③前期及早促进,在有效分蘖临界叶龄期稍前群体茎蘖数够到高产适宜穗数值;④及早适度搁田,把群体高峰苗控制为适宜穗数值的1.4-1.5倍,为及早重施壮秆促花肥创造条件;⑤主攻中期优化生长,增加有效与高效生长量,以适量壮秆大穗构成高光效群体;⑥强化后期物质生产与积累,提高群体库容充实量。（2）系统介绍了钵苗机插水稻高产栽培具有的诸多优势：利于精确培育大秧龄带土钵壮秧;几乎无植伤地精确机插;可精确实现高产栽培设计的基本苗;利于培育适宜数量的壮秆大穗,改善群体通风透光条件,增强植株抗倒性;源库较协调,群体中后期光合生产能力强,利于稳定高产与创造超高产;同时可充分利用温光资源,利于多熟制周年高产。实施高产栽培的关键农艺为：①精确培育加大秧龄的壮秧;②精确定量机插;③适当重施分蘖肥与促花肥。（3）阐述了机直播稻生长发育特点与产量形成特征,介绍了合理确定机直播稻种植范围、选用相适生育期的抗倒大穗型品种、抢早机械精播、切实加强化学除草与肥水管理等增产增效的农艺措施。同时,进一步分析了中国水稻种植机械化存在的主要问题,紧贴国情,明确提出专业化培育标准化壮秧与机械精确移栽,并配套稳定高产高效农艺,应是中国多数稻区栽培机械化的基本方向,机械化直播可在稻季热量丰裕的部分地区应用。接着,指明了相应的研发重点与关键：①强调把毯苗机插高产栽培列为中国水稻主产区机械化主体方向加以重点研发,认为必须加强研发的重点是：增强毯苗秧龄弹性与秧苗素质;秸秆机械高质量还田整地与精确栽插秧苗;促进大田稳靠早发,培育适量壮秆大穗,增加群体总库容量。②降低机具成本,提高作业效率以及稳定超高产高效农艺的构建,则是水稻钵苗机插栽培研究的重点。③机直播稻高产栽培农艺发展应重点研究以高效的机械作业提高前茬秸秆还田质量与整地质量,提高机械精确播种质量与全苗早发的技术。文章最后还强调各水稻主产区,应据本区特点切实搞好当地主体机械化种植方式高产栽培全程机械化模式的技术集成与示范推广。     

低播种量下杂交稻不同机械化种植方式的产量构成及特征

【目的】比较低播种量下杂交稻不同机械化种植方式的产量构成及特征,探索杂交稻机械化种植方法。【方法】在广东省肇庆市和江门市进行了早、晚稻毯状苗机插和麻膜毯状苗机插2种机械化种植方式对比试验,以钵苗人工手插为对照,采用低播种量精密播种培育壮秧,配合插秧机精准栽插。【结果】当播种量为每盘65 g芽种时,早、晚稻试验中2种机插与钵苗人工手插的实际产量差异为0.17%～0.66%和1.01%～3.24%,差异不显著;有效穗数是产量的主要影响因子,提高杂交稻产量的关键是保证适度有效穗数;不同种植方式穗部性状差异主要表现为二次枝梗数的差异,一次枝梗数差异较小。【结论】毯状苗机插可以在低播种量下通过提高中穗占比、大穗和中穗累计占比和协调结实率等因素实现高产栽培。     

Why high grain yield can be achieved in single seedling machine-transplanted hybrid rice under dense planting conditions?

This study was conducted to identify the factors associated with high grain yield in single seedling machine-transplanted hybrid rice under dense planting conditions. Field experiments were done in Yong'an Town, Hunan Province, China in 2015 and 2016. Two hybrid rice cultivars were grown under single seedling machine transplanting (SMT) and conventional machine transplanting (CMT) at a high planting density in each year. Grain yield and yield attributes were compared between SMT and CMT. Averaged across cultivars and years, grain yield was 12% higher under SMT than under CMT. Plant height, basal stem width, and shoot and root dry weights were higher in seedlings for SMT than those for CMT. SMT had less maximum tiller number per m² and consequently less panicle number per m² than did CMT. Branch number per panicle, especially the secondary branch number per panicle, and spikelet number per cm of panicle length were more under SMT than under CMT, which resulted in more spikelet number per panicle under SMT than under CMT. SMT had higher or equal spikelet filling percentage than did CMT. The difference in grain weight between SMT and CMT was relatively small and inconsistent cross years. SMT had higher or equal total biomass and harvest index than did CMT. Dry weight per stem under SMT was heavier than that under CMT. Larger leaf area per stem was partly responsible for the heavier dry weight per stem under SMT than under CMT. Our study suggests that improvement in seedling quality, panicle size, and dry weight per stem are critical to the high grain yield in single seedling machine-transplanted hybrid rice under dense planting conditions.     

Source-sink Characteristics and the Translocation of Assimilates in New Plant Type and Intersubspecific Hybrid Rice

Both new plant type (NPT) and intersubspecific hybrid rice (IHR) had large sink size (total number of spikelets per m2), however, poor grain filling limited their potential in the grain yield. Compared to the three-line indica hybrid of Shanyou 63 (CK), NPT and IHR showed higher photosynthetic potential,higher dry matter accumulation and higher ratio of dry weight to spikelets (total dry wt./total number of spikelets) from heading to harvest. But both exhibited a low export percentage and transfer ratio of assimilates, low partitioning of 14C to grains from labeled flag leaves, low harvest indices and low physiological activities (IAA content and activities of ATPase and starch synthase) of grains at early grainfilling stage. The physiological activities of grains at early filling stage were significantly correlated with the export percentage and transfer ratio of assimilates, ripened-grain percentage and grain plumpness (r = 0.85 *- 0.95* * ). The source-sink ratio (dry matter wt./spikelet and nonstructural carbohydrate/spikelet) at heading was positively correlated with physiological activities of grains (r = 0.84* - 0.97 * * ). It is suggested that low physiological activities of grains at early filling stage is attributed to low source-sink ratio at heading, and the low sink activity weakens the ability to remobilize assimilates into grains, and leads to poor grain filling in NPT and IHR.     

长江中下游杂交中籼水稻机插平衡栽培技术规程

杂交中籼水稻机插秧普遍存在秧龄弹性小、秧苗素质差、机械栽插植伤重、缓苗期长等不利因素,造成了机插水稻群体生育不平衡,严重限制了杂交中籼水稻产量潜力发挥和机插技术的推广。通过对江淮杂交中籼水稻机械化育栽技术连续8年的技术攻关,总结制定了杂交中籼水稻机插平衡栽培技术规程。该规程介绍了平衡栽培的定义,规定了长江中下游杂交中籼水稻机插的品种选用、育秧、整地、机插等技术指标、产量及其结构指标和不同目标产量施肥量,提出了平衡栽培的育秧技术、整地和机插技术和大田管理技术。     

不同移栽方式对水稻产量及效益的影响

[目的]就不同移栽方式对水稻产量及其效益的影响进行分析。[方法]以丹粳253、沈农6014为试材,采用乳苗抛栽、抛秧、插秧、大垄双行水和水直播(对照)5种移栽方式,比较研究了不同移栽方式对水稻群体的产量性状及其效益的影响。[结果]不同纬度地区不同栽培方式产量差异极显著。在沈阳地区,不同栽培方式水稻产量排序依次为插秧>抛秧>乳苗>大垄双行>水直播;在丹东地区,不同栽培方式水稻产量排序依次为大垄双行>抛秧>乳苗>插秧>水直播。乳苗抛栽的产量在不同纬度地区差异很大。丹东地区的乳苗抛栽水稻的产量较沈阳的高3 486.45 kg/hm2。乳苗抛栽平均可比插秧栽培节约1 018.5元/hm2,比抛秧栽培节约726.0元/hm2。[结论]不同栽培方式之间产量差异达到了极显著水平,产量与每公顷穗数、每穗颖花数、成粒率、千粒重的正相关达极显著水平。     

两系杂交稻穗颈节间维管束与籽粒充实特性的研究

对两系杂交稻穗颈节维管束特征及其籽粒充实进行了研究。结果表明，维管束数目与一、二次枝梗数及颖花数有密切关系。籽粒充实好的品种维管束和韧皮部的总面积显著高于籽粒充实差的品种，维管束的颖花负荷量与总库容负荷量明显低于充实率差的品种。扬两优6号不仅库容量大，而且籽粒充实率、充实程度良好，结实率正常。发达的维管束是其籽粒充实的前提。还讨论了育种、栽培技术问题。     

浙江省连作晚稻产量水平及其种植差异分析

2008年调查了浙江省余姚市、瑞安市和衢州市衢江区连作晚稻,主要品种有宁3-88、协优92和天优华占。栽插方式主要为抛秧、机插和手插3种方式,按不同产量水平选取代表样点,调查和测定不同产量水平的产量结构,共123个调查点。结果表明：晚稻平均单产为445.2 kg/667m²,最高产量和最低产量差异超过300 kg/667m²,有效穗数和穗实粒数与产量呈极显著正相关。移栽稻提高产量应保证足穗和结实率;抛秧应提高每穗实粒数;机插秧则应在保证穗数的基础上,提高千粒重。     

不同育秧方式对机插中籼水稻秧苗素质和产量性状的影响

[目的]为选择适应水稻机插作业的育秧方式和提高机插杂交中籼稻产量提供理论基础和技术支持。[方法]以徽两优6号为供试材料,研究营养土软盘育秧、流水线营养土硬盘育秧、淤泥软盘育秧3种育秧方式对机插秧水稻秧苗素质和产量性状的影响。[结果]流水线营养土硬盘育秧秧苗素质表现出较强的优势,成苗率较高,漏插率较低,茎基部较粗,根系盘接力较高,根系活力较强,缓苗期较短,产量优势明显,理论产量和实际产量分别高于其他育秧方式。[结论]在安徽省江淮地区,采取流水线营养土硬盘育秧有利于提高水稻机插秧的秧苗素质,建立合理的群体起点,形成较高的产量。     

秧龄和播量对水稻机插秧苗素质及产量的影响

[目的]研究秧龄和播量对水稻机插秧苗素质及产量的影响。[方法]以优质粳稻品种南粳46为材料,研究不同秧龄和播量对水稻机插秧苗苗高、叶龄、成苗率、成苗数、素质、茎蘖动态、产量及其构成因素的影响。[结果]秧龄和播量对机插秧苗素质及产量有显著影响。其中,20 d秧龄和80 g/盘播种量时机插秧苗素质最好,实测产量最高,达10 263.45 kg/hm~2。[结论]该试验为进一步完善机插育秧技术,加快水稻种植机械化发展提供理论依据。     

成都平原稻麦两熟区机插秧育秧技术研究

在成都平原稻麦两熟种植制度区,以川香9838为材料,从播种期、播种量、育秧材料和育秧方式4个方面对水稻机插秧育秧技术进行了研究。结果表明:4月5~10日播种,选用透水膜作育秧的衬垫,每平方米播种300 g,按照旱育秧苗床管理技术进行苗床管理,即使45 d秧龄,秧苗也生长整齐,适于机插。以塑料机插秧盘为衬底,每盘播种量从90g降到50g,采用塑盘旱育秧管理技术,既大幅降低了播种量,又能培育出秧龄30~35 d,满足早茬口机插的秧苗。蔬菜茬采用机插秧比人工插秧全程节本增效2967.65元/hm2,小麦茬节本增效2037.60元/hm2。     

水稻机械插秧增苗减肥技术研究

[目的]进一步提高水稻生产技术水平和肥料利用率,减少农业面源污染,在水稻产量不降低的前提下,减少化学肥料的投入量。[方法]以模拟水稻机械插秧的方式,通过田间小区试验,研究水稻增苗减肥技术对产量的影响。[结果]在增加基本苗的前提下,适当减少化肥的用量完全可以建立高产的结构,达到增产、稳产的目的。[结论]该研究可为农业机械插秧大面积推广应用提供科学的理论指导。     

杂交中稻超多蘖壮秧超稀高产栽培技术的研究

 以5个杂交中稻品种为材料,对作者提出的“杂交中稻超多蘖壮秧超稀高产栽培技术”的高产原理及技术进行了5年的研究。结果表明,使用该技术不仅能获高产,而且能节省种子、劳力等生产成本,是多熟制地区特别是迟栽田及发挥重穗型品种增产潜力的一条重要的高产途径。“两超”栽培高产的直接原因是颖花数量的增加和籽粒的良好充实。“两超”栽培高素质的“超多蘖壮秧”和本田期健壮的个体生长是其穗足、穗大粒多的前提,而其高质量的群体结构和明显的后期生长优势是其籽粒灌浆结实良好和单穗重提高的物质保证。     

耕作和育秧方式对机插水稻群体质量和产量的影响

用3因素裂区设计,研究了耕作方式、品种和育秧方式对机插稻群体质量和产量的影响.结果表明,免耕机插栽插质量整体差于常规翻耕机插,群体质量与常规翻耕机插差异不大,产量低于常规翻耕机插.塑料软盘育秧与钵形毯状育秧对水稻生长和产量的影响较小,生产上可因地制宜选用.     

不同秧龄移栽对烟后稻影响试验

研究不同机插秧龄对烟后稻生长及产量的影响,结果表明:机插秧龄以13~17 d为宜,烟后稻主要性状表现较优,产量较高.     

亚种间杂交稻产量源库特征

 对大量典型的籼粳亚种间杂交种组合的产量源库特征进行了研究，获得了如下如果：亚杂组合的物质生产的优势主要表现在出穗后经济产量形成期，这与籼型三系杂交稻物质生产的优势主要表现在出穗前迥然不同；亚杂组合的库容优势也十分明显，就其总体而言全生育期物质生产量与库容的比例高于汕优63；大多数亚杂组合的光合产物向穗的运转不良，这是部分亚杂组合籽粒充实不良的成因，也是限制亚种间杂种优势充分利用的带普遍性的问题。对这一问题的研究展望及提高亚种间杂交稻籽粒充实度的栽培途径进行了讨论。     

杂交稻低播量精准条播育秧机插提高群体均匀度和产量的效应分析

[目的]明确杂交稻低播种量下精准条播(precision drill sowing,PS)育秧提高机插群体均匀度和产量的效应,创建杂交稻毯苗稀播少本机插理论与技术.[方法]选用籼粳杂交稻甬优1540为供试品种,在余杭区崇化村和富阳区中国水稻研究所试验基地开展试验.以传统撒播(broadcast sowing,BS)育秧...     

钵苗机插水稻群体动态特征及高产形成机制的探讨

【目的】旨在阐明钵苗机插水稻产量构成特征和群体动态特征以及高产形成机制。【方法】2010年选用24个不同单穗重粳稻品种统一高产栽培,以成熟期平均单穗重聚类分析划分3种穗型,并每种穗型筛选2个具有代表性品种。2011-2012年采用大穗型品种甬优8号和甬优2640,中穗型品种武运粳24号和宁粳3号,小穗型品种淮稻5号和淮稻10号为试验材料,在江苏省兴化市钓鱼镇进行大田试验,以毯苗机插水稻为对照,系统研究钵苗机插水稻产量及其产量构成、群体茎蘖动态、叶面积指数动态和干物质积累动态特征,并从秧苗素质、栽后物质积累、阶段光合物质生产、光合势、群体生长率、净同化率、株型特征、茎鞘物质输出与转运、根系活力等方面深入探讨钵苗机插水稻高产形成机制。【结果】钵苗机插水稻产量显著或极显著高于对照,大穗型品种增产8.71%-11.11%,中穗型品种增产6.85%-7.89%,小穗型品种增产5.30%-6.34%。钵苗机插水稻产量的提高主要原因是在足够穗数的基础上,显著或极显著增加每穗粒数,进而提高群体颖花量,同时保持稳定的结实率和千粒重。与对照相比,钵苗机插水稻群体茎蘖数栽后增长快,高峰苗适宜,拔节后群体茎蘖数消减缓慢,最终有效穗数足,成穗率高;群体叶面积指数和干物质积累量,有效分蘖临界叶龄期钵苗机插水稻显著高于对照,拔节期两者相当,孕穗后钵苗机插水稻显著或极显著高于对照,成熟期叶面积指数钵苗机插水稻较对照高出5.17%-11.00%,干物质积累量钵苗机插水稻较对照高出5.36%-9.20%。钵苗机插水稻高产形成机制为带土带蘖栽插,秧苗素质高,群体起点质量优,活棵早,分蘖快,低位分蘖多,栽后地上和地下部物质积累多,为争足穗、促壮秆和攻大穗奠定生物学基础;抽穗期株型紧凑,叶系配置优,叶面积大,比叶重高,基部茎秆粗壮,粒叶比高,形成高光效高质量群体;生育后期根系活力强,叶面积衰减慢,光合势大,群体生长率和净同化率高,干物质积累多,灌浆充实量大,茎鞘物质输出与转运合理。【结论】钵苗机插水稻群体起点质量高,栽后分蘖早生发快,群体生长优势明显,特别是生育中后期光合生产能力强,物质积累多。钵苗机插水稻产量构成特征表现为“穗数足、穗型大、粒数多”。     

Yield characteristics of japonica/indica hybrids rice in the middle and lower reaches of the Yangtze River in China

Although a lot of researches have been done on yield characteristics of japonica/indica hybrid rice, there is little information on differences of yield characteristics between different types of hybrid. To determine common characteristics of japonica/indica hybrid rice(JIHR) and identify the differences between different types of JIHR, the present study assessed yield characteristics, such as panicle trait, leaf area index(LAI), above-ground biomass accumulation, and nitrogen absorption and utilization, among three types of cultivar of JIHR. In our field experiments, three types of JIHR, e.g., Yongyou, Chunyou and Jiayouzhongke, were divided, and each of them has two cultivars, which were used as materials, meanwhile, using conventional japonica rice(CJR) Wuyingjing 31 and Sujing 9 were as controls. The results showed that the mean yield of those JIHR was above 12 t ha–1 in 2017 and 2018, and was 31.9 and 32.2%, respectively higher than that of CJR in the two years. Spikelet number per panicle of JIHR resulted in high yield. Higher yield of JIHR was likely contributed to greater panicle number and more spikelets per panicle. Higher yielding JIHR showed stronger tillering capacity, larger LAI and above-ground biomass accumulation from jointing to heading stages, which likely contributed to the higher number of spikelets per panicle. The long duration from heading to maturity stages allowed more nitrogen accumulation of higher yielding JIHR.