【作者】 秦建权；

【导师】 唐启源； 彭少兵； Krishna SV Jagadish；

【作者基本信息】 湖南农业大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 世界人口包括非洲和拉丁美洲食用水稻人口的快速增长,以及全球气候变化如高温、干旱和洪涝等不利气候条件的频发和强度增加,对稻米的需求、供给和水稻生产造成严峻的挑战。为了满足世界人口对稻米的需求,提高适宜生态条件下的水稻单产和增加水稻总产量日趋紧要。本研究以作物栽培调控技术(育秧、种植密度、水份管理、氮肥管理等)构建了不同栽培管理模式,于2009-2011年在中国湖南浏阳市永安镇大田条件下进行了定位试验,并于2011-2013年在国际水稻研究所(IRRI,菲律宾)大田进行了氮肥与品种的互作试验,系统研究了不同栽培模式和氮肥与品种互作下的水稻群体冠层结构、稻谷产量、产量构成因素、整精米产量、灌浆特性、氮肥利用率、辐射利用率等,主要研究结果如下：(1)不同栽培模式间的产量存在显著差异。稻谷产量在早季和晚季均以T4>T5>T3>T2(当地农民模式)>T1(氮空白模式),与对照T2模式相比,T4、T5和T3模式在早季和晚季3年平均分别增产32.7%、20.4%、15.7%和37.1%、28.8%、14.8%。究其增产的原因,从产量构成因素来看,T4、T5和T3模式的单位面积穗数和颖花数不论早季和晚季均显著高于T2模式,同时每穗粒数和结实率并没有显著降低或有所提高；从叶面积指数(LAI)和干物质生产来看,T4、T5和T3模式齐穗期的LAI在早季和晚季分别比T2模式增加51.0%、27.8%、16.9%和64.0%、49.2%、25.3%,总干物质积累量在早季和晚季分别增加30.3%、18.1%、14.2%和39.9%、32.7%、12.9%。(2)不同栽培模式间的氮素积累和氮肥利用率(NUE)存在显著差异。相对T2模式,T4、T5和T3模式的氮素积累量在早季和晚季分别增加42.1%、23.7%、18.2%和89.1%、75.5%、35.0%,氮肥农学利用率(AE)分别增加45.2%、46.0%和68.2%、127%、127.3%和97.8%,氮肥偏生产力(PFP)分别增加9.5%、19.1%、42.5%和16.0%、27.5%、38.5%。水稻氮素积累量和NUE显著提高的主要原因,一是氮肥后移使T4、T5和T3的花后总氮积累量在早季和晚季分别平均增加78.3%、54.8%、68.8%和74.0%、63.4%、31.8%,二是“干湿交替”水份管理及叶片化学调控等措施使T4、T5、T3的氮转运量在早季和晚季比T2模式分别增加22.0%、10.7%、2.8%和137.3%、104.6%、59.5%。(3)各栽培模式间的群体光合有效辐射截获量(IR)和辐射利用率(RUE)存在显著差异。相对于T2模式,IR在早季和晚季T4、T5和T3模式平均增加13.4%、9.6%、4.6%和14.1%、11.7%、4.4%,RUE在早季和晚季分别增加15.0%、8.0%、9.4%和16.7%、33.9%、8.4%。相关分析表明,不论早季和晚季,产量均与IR、 RUE呈极限著正相关(p<0.001),但是IR在早季的相关系数大于晚季,而RUE在晚季的相关系数大于早季。表明通过扩大群体的大小提高水稻群体IR,是早季提高产量的关键途径;而提高改善群体质量进而提高RUE是提高晚季产量的关键途径。(4)品种和氮肥施用对水稻籽粒灌浆特性各参数均产生较大的影响。提高施氦水平增加起始灌浆速率(GR0),延长第二次灌浆高峰时间(T2)和最大灌浆时间(Tmax),缩短第一次灌浆峰值时间(T1),从而导致平均灌浆速率降低；随施氮水平增加,前期(S1)的灌浆时间缩短,中期(S2)和后期(S2)的灌浆时间延长,导致前期灌浆速率变大和中后期灌浆速率减少。研究还表明,季节间灌浆特性的差异大于氮肥水平间的差异。灌浆特性对稻谷产量尤其是整精米产量产生显著影响,缩短第一次灌浆峰值时间(T1),延长第二次灌浆期时间(T2),增加前期的灌浆速率(MGR1)和降低中期和后期的灌浆速率(MGR2和MGR3)均能显著提高水稻整精米产量。(5)用ORZYA2000模拟可获得产量潜力与气候产量潜力进行了比较分析。结果表明,在雨季,当施氮水平在80kg N/ha和120kg N/ha条件下,各品种的可获得稻谷产量潜力分别比气候产量潜力降低了22%-33%和12%-21%,可获得干物质生产量潜力分别降低16-23%和3%-15%；但是在旱季,水稻可获得产量与气候产量潜力的差距较小,如在140kgN/ha和210kgN／ha条件下,可获得产量和干物质生产潜力分别比气候产量和干物质生产潜力降低仅为3%、1%和5%、3%。表明在没有环境胁迫的条件下(如旱季)培育新的高产量潜力的品种已经刻不容缓；同时有必要根据水稻不同种植区域的环境特点,利用气候产量潜力来指导水稻生产和氮肥管理,而不仅仅以对照品种产量的增减作为依据。(6)水稻不同群体对实际稻谷产量、气候产量潜力和整精米产量产生显著影响。随着氮肥水平的提高,稻谷产量有所增加,但是氮肥过高后,使部分品种的产量降低,凸显出水稻品种对氮肥效应的趋势不一致；但是整精米产量在氮肥增加的情况下均有所增加,同时高的稻谷产量并不一定具有较高的整精米产量,品种间具有显著的差异；本研究基于籼稻商品化条件下,将产量潜力定义为“在肥水充足、病虫杂草、倒伏及其他胁迫得到有效控制、适宜的生长环境下,水稻品种应具有较高的整精米率的气候产量”。综合考虑土壤和环境条件及具较高“整精米率”的“气候产量”可作为评估标尺来追踪随着时间的推移,水稻产量增加的幅度。更多还原

【Abstract】 The world population and the number of people depending on rice have been on a steep increase not just in Asia but also in Africa and Latin America. In addition, global climate changes.the increases in the frequency and intensity of extreme events like heat spikes, droughts or floods, will negatively affect rice production. All the above scenarios pose a serious challenge for meeting the global demand and supply of rice,under current and future climates. Thus, improving rice productivity under folly flooded non-stress conditions becomes especially important and timely. In this research, we systematically studied the physiological and agronomic responses of different crop management practices, nitrogen management and their interaction on population canopy structure, grain yield, yield components, grain quality, grain filling characteristics, nitrogen use efficiency and radiation use efficiency. Field experiments were conducted continuously during the early season and late season of2009-2011in Liuyang County, Hunan Province, China and during the2011wet season (WS) to2012dry season (DS) at the experimental farm of IRRI, Philippines, respectively. The main results of the study are listed below:1. The results of different crop management practices recoeded significant differenceswith in rice grain yield among the different management practices.The ranking for grain yield among different treatments across different years and seasons was as follows: T4> T5> T3> T2> T1. Grain yield averaged across all three years in T4, T5and T3was32.8%,20.4%,15.7%and37.1%,28.8%,14.8%higher than the normal farmers’practice (T2) in early season rice (ESR) and late season rice (LSR), respectively. Reasons behind the yield increase can be explained by yield components, leaf area index (LAI) and dry matter production. T4, T5and T3produced significantly higher panicles m-2and spikelet number m-2compared to T2during both ESR and LSR, and spikelets panicle-1and the grain-filling percentage were slightly decreased in ESR and especially slightly increased in LSR compared with T2. In addition, LAI averaged across all three years in T4, T5and T3was51.0%,27.8%,16.9%and64.0%,49.2%,25.3%higher than with T2during ESR and LSR, respectively.The total biomass averaged across all three years in T4, T5and T3was30.3%, 18.1%,14.2%and39.9%,32.7%,12.9%higher than with T2in ESR and LSR, respectively. Facilitating better N uptake2. The total nitrogen content and nitrogen use efficiency (NUE) varied significantly among the different management patterns. The total nitrogen content of plants in ESR and LSR was higher by42.1%,23.7%,18.2%and89.1%,75.5%,35.0%in T4, T5and T3than in T2, respectively. Nitrogen agronomic efficiency (AE) in ESR and LSR was increased by45.2%,46.0%,68.2%and127%,127.3%,97.8%and partial factor productivity of applied nitrogen (PFP) in ESR and LSR was increased by9.5%,19.1%,42.5%and16.0%,27.5%,38.5%in T4, T5and T3compared with T2, respectively. Significant increase of the total nitrogen content and NUE was mainly due to the total nitrogen content after heading in ESR and LSR was increased by78.3%,54.8%,68.8%and74.0%,63.4%,31.8%in T4, T5and T3compared with T2, as a result of postponement of the N fertilizer application. On the other hand, combination with shallow wetting and drying and KH2PO4application as foliar spray resulted in the increase of nitrogen translocation, and nitrogen translocation during ESR and LSR by22.0%,10.7%,2.8%and137.3%,104.6%,59.5%in T4, T5and T3compared with T2, respectively.3. Intercepted radiation (IR) and radiation use efficiency (RUE) differed significantly among the different management practices. IR averaged in ESR and LSR of T4, T5and T3was13.4%,9.6%,4.6%and14.1%,11.7%,4.4%higher than that in T2, respectively. RUE averaged in ESR and LSR of T4, T5and T3was15.0%,8.0%,9.4%and16.7%,33.9%,8.4%higher than that in T2, respectively. Both IR and RUE were significantly positively correlated with grain yield (p＜0.001) in both seasons, while r of intercepted radiation in ESR was greater than in LSR, and r of RUE in LSR greater than in ESR. The above results indicated that increasing IR of rice population was the key approach of ESR yield improvement, and improving RUE via optimizing rice population quality was the main approach of LSR yield improvement in double-season rice.4. Nitrogen treatments and cultivars had significant effects on grain filling parameters. GRo increased, T2and Tmax extended and T1decreased with increasing N supply, resulted in lower mean grain rate. On the other hand, S1shortened and S2and S3increased with increasing N supply, resulted in higher grain filling rate at early filling stage and lower grain filling rate at mid and later filling stage. The grain filling characteristics across cultivars was significantly different between dry season (DS) and wet season (WS), differed more than that between different N treatments. The grain filling characteristics had significantly effect on rice grain yield and especially head rice yield. Shortening T1and extending T2to accelerate MGR1and decelerate MGR2and MGR3can improve head rice yield.5. Comparative analysis between the actual observed yield (AY) and the climatic yield potential (PY) derived using ORYZA2000indicated that AY across current elite cultivars supplied with80kg N ha-1were up to22%-33%lower than PY, and AY with120kg N ha-1were12%-21%lower than PY during WS. Dry matter production with80kg N ha-1and120kg N ha-1was16-23%and3%-15%lower than potential dry matter production during DS, respectively. AY across current elite cultivars supplied with adequate N (140and210kg N) was close to100%of the climatic yield potential derived using ORYZA2000during DS Our results demonstrated the immediate urgency in incorporating new and diverse germplasm into ongoing breeding programs targeted toward enhancing yield under fully flooded non-stress conditions. On the other hand, the use of a derived climatic yield potential as an unbiased reference for rice yield potential studies will help account for climatic and edaphic variability across different rice-growing geographies and it allows for cross cutting meta-analysis of genetic yield gains over time.6. Different populations in rice had significant effects on grain yield, climate yield and especially head rice yield. Grain yield was improved with increasing N application, except for some cultivars with lower yield under high N, which indicated response to N supply varied with cultivars, while head rice yield increased with increasing N supply. Even with similar paddy yield, the cultivars differed significantly in head rice recovery, and head rice yield.Based on our results, we redefine rice yield potential as "the climatic yield of a cultivar with superior head rice yield recovery when grown in environments to which it is adapted, with nutrients and water non-limiting and with pests, diseases, weeds, lodging, and other stresses effectively controlled." The inclusion of "climatic" yield would allow establishing a measuring stick for tracking yield gains over time after accounting for edaphic and environmental conditions and "with superior head rice recovery," which determines the actual gain in terms of ecollllnomic units that determine cultivars’marketability, consumer preferences, and wider farmer adoption.更多还原