不同水分管理模式和播后镇压对小麦干物质积累及产量的影响

为明确不同水分管理模式和播种后镇压对小麦干物质积累及产量形成的影响,以烟农19为材料,在大田条件下设置雨养（RI）、雨养+播后镇压（RC）、传统漫灌（TI）、传统漫灌+播后镇压（TC）、微喷灌（MI）和微喷灌+播后镇压（MC）处理,研究不同处理对小麦干物质积累及产量的影响。结果表明,与RI和TI处理比较,MI处理产量分别提高了44.2%和11.0%;RI处理产量最低,是由于穗数、穗粒数和粒重的显著下降所致,而TI处理产量较MI处理下降是由穗粒数和粒重显著降低导致。雨养和传统漫灌下播后镇压较其未镇压处理显著提升了产量,分别提高14.1%和6.2%。与TI和RI处理比较,MI处理开花期和灌浆期具有较高的群体叶面积指数（LAI）、旗叶叶绿素含量（SPAD值）,籽粒平均灌浆速率和成熟期干物质积累量;相比未镇压处理,镇压后,雨养和传统漫灌下LAI提升,雨养和微喷灌处理下灌浆期旗叶SPAD值显著增加,籽粒灌浆速率提高,从而促进了粒重增加和群体干物质积累。总之,微喷灌+播后镇压能促进小麦群体的形成,延缓叶片衰老,提高小麦的穗粒数及千粒重,从而增加小麦产量,为试验区推荐小麦栽培模式。     

氮素供应对春玉米产量及冠层部分指标的影响与相关分析

采用辽宁地区5个地方品种进行低、中、高3个氮素水平的比较试验(N0:不施氮、N1:112 kg/hm~2、N2:225 kg/hm~2),探究氮素对玉米冠层指标的影响及与产量因素的相关性。相关、逐步回归分析表明,随着施氮量升高,品种产量和穗粒数显著提高。不同氮素水平下,冠层指标与产量因素相关性有差异。穗粒数在N0处理下,与吐丝期叶氮比(SLN)和叶片氮浓度呈负相关,相关强度排序为吐丝期SLN吐丝期叶片氮浓度;N1处理下,与乳熟期LAI呈正相关,与吐丝期叶片氮浓度和吐丝期绿叶数呈负相关,相关强度排序为吐丝期叶片氮浓度乳熟期LAI吐丝期绿叶数;N2处理下,穗粒数与冠层指标相关性不显著。百粒重在N0处理下,与吐丝期穗位叶SPAD值呈正相关,与吐丝期LAI和乳熟期穗位叶SPAD值呈负相关,相关强度排序为吐丝期LAI吐丝期SPAD乳熟期SPAD;N1处理下,与乳熟期穗位叶SPAD值呈正相关,与乳熟期LAI呈负相关,相关强度排序为乳熟期LAI乳熟期SPAD值;在N2处理下,与吐丝期比叶面积(SLA)、SLN、乳熟期绿叶数呈负相关,相关强度排序为吐丝期SLN、SLA乳熟期绿叶数。     

吉林省大豆品种遗传改良过程中叶片性状的演变

以吉林省1923-2005年育成的30个大豆（Glycine max）品种为材料,通过2005和2006两年田间试验在R2﹑R4和R6期对叶部性状演化及其与产量的关系进行研究。结果表明,产量随育成年代呈线性增加,根据回归方程计算,产量从1923年的1197.80kg&;#8226;hm-2增加到2005年的2305.545 kg&;#8226;hm-2,82年来增加了1107.73kg&;#8226;hm-2,平均每年增加14.60kg&;#8226;hm-2;单株叶面积﹑单株叶片数目﹑长宽比和叶面积指数（LAI）随着育成年代的增加而增加,小叶面积随着育成年代的增加而降低;新品种的单株叶面积在生殖生长期均大于老品种,尤其在后期有较长的绿叶期;通过相关分析表明,产量与单株叶面积﹑叶面积指数均达到显著水平（P≤0.05）,在R2和R4期与单株叶片数目到显著水平（P≤0.05）,说明在遗传改良过程中叶部性状与产量关系密切,在品种选育和高产栽培过程中可以考虑作为选择的依据。     

Growth and yield potential of Oryza sativa and O. glaberrima upland rice cultivars and their interspecific progenies

A recent breakthrough in generating fertile progeny from Oryza sativa×O. glaberrima crosses gives rice breeders access to a broader range of germplasm. Interspecific crosses might provide new solutions to the low productivity of upland rice systems prone to weed competition. Two field and one pot experiments conducted during 1995 and 1996 served to characterize growth and yield potential of CG14 (O. glaberrima), WAB56-104 (O. sativa) and their progeny. During the 1995 wet season and the 1996 dry and wet seasons, the lines were seeded in a well-drained upland field in Ivory Coast with supplemental sprinkler irrigation. A randomized complete-block design with three replications was used, with cultivar and nitrogen levels as sub-plots. Specific leaf area (SLA), leaf area index (LAI), leaf chlorophyll content (SPAD method) and tiller number were measured at 2-week intervals until flowering. Grain yield and yield components were measured at maturity. In all environments, CG14 produced two to three times the LAI and tiller numbers as WAB56-104. This was associated with a high SLA and low leaf chlorophyll content. Grain yields of CG14 did not respond to N inputs, although the sink potential did. The difference was mainly caused by grain shattering. The progenies had intermediate LAI, SLA and leaf chlorophyll content, but their grain yields, tiller numbers and resistance to lodging and grain shattering were similar to WAB56-104. Across lines, LAI and SLA were significantly correlated. A paddy field experiment confirmed the relationship between LAI and SLA for a wider range of rice cultivars and interspecific progenies. A pot experiment demonstrated that leaf net CO₂ assimilation rates (A_max) followed a common linear function of areal leaf chlorophyll content across cultivars. The main common cause of differential LAI and A_max appeared to have been genotypic patterns of SLA, which might be an important determinant of growth vigor and competitiveness with weeds. The possibility is discussed of combining, in a single line, high SLA during vegetative growth (for weed competitiveness) with low SLA during the reproductive growth phase (for high yield potential), to produce an efficient plant type for low-management conditions.     

Factors in the Reduction in Grain Number in Winter Wheat by Early-Sowing in Yamaguchi

Abstract

Grain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike.     

氮肥运筹对郑单1002和郑单958冠层特征和产量的影响

以郑单1002和郑单958为材料,0(N0)、150(N1)、300(N2)kg/hm2氮肥水平,常规尿素和一次性基施掺混控释肥两种氮肥类型,研究不同氮肥运筹对夏玉米冠层特征、干物质积累与分配和产量的影响。结果表明,增加施氮量,两个品种穗位层和近地表叶面积指数(LAI)比N0处理增加25.7%~52.5%,开花期和成熟期干物质积累、千粒重、穗粒数、穗长和产量显著增加,农学利用效率降低22.0%~40.0%。与常规尿素相比,掺混控释肥增加玉米生长后期穗位层和近地表的透光率和成熟期干物质积累,提高了千粒重、穗粒数、产量和氮肥农学效率,降低子粒含水率。在相同施肥条件下,与郑单958相比,郑单1002的LAI和穗粒数分别提高7.5%~14.8%和2.3%~11.5%,千粒重降低1.4%~6.2%,产量提高0.8%~6.2%。     

Agronomic and physiological contributions to the yield improvement of soybean cultivars released from 1950 to 2006 in Northeast China

Increasing yield is a high priority in most breeding programs. Approximately 600 soybean cultivars had been released by the end of the last century in Northeast China. Understanding the agronomic and physiological changes is essential for planning further plant breeding strategies in soybean. In this study, 45 representative soybean cultivars, from maturity groups 00 and 0, released from 1950 to 2006 in Northeast China were compared in field conditions for 3 consecutive years. A positive correlation between seed yield and year of cultivar release was indicated with a 0.58% average annual increase. Seed number per plant was the most important contributor to yield gain, with a 0.41% increase per year. Pod number per plant and seed size varied slightly with the year of cultivar release. Although variation in protein was from 37.0% to 45.5%, and oil concentration was from 16.7% to 22.0%, their concentrations were not consistently related to year of cultivar release. A 33% increase in the photosynthetic rate, 10.6% increase in plant dry weight and 19.0% increase in harvest index (HI) were found, while leaf area index (LAI) decreased by 17.3%. Modern cultivars have higher photosynthetic rates than their predecessors. The reduced plant height gave increased resistance to lodging, with the lodging score dropping from 3.2 in 1951 to 1.0 in 2006. Seed resistances to disease and pest infestation were also improved. Yield stability was enhanced over years, which could be attributed to the stable pod production across different environments. A flow diagram to explain the contributors to genetic improvement of soybeans in Northeast China was developed.     

安徽沿淮和淮北地区小麦穗粒重研究

为给重穗型小麦新品种选育及高产育种提供参考依据,以24个小麦品种(系)为材料,对穗粒重与产量、产量三要素及其他18个性状间的关系进行了分析。结果表明,供试品种间穗粒重、收获指数、产量及产量三要素存在着极显著差异;穗粒重与产量呈显著正相关,与穗粒数、收获指数、单茎生物产量、单茎草重呈极显著正相关,与倒三叶的面积呈显著正相关,与穗数、籽粒容重呈极显著负相关。根据穗粒重把小麦品种划分为三大类:重穗型,穗粒重≥1.8g;中穗型,穗粒重为1.4～1.8g;轻穗型,穗粒重≤1.4g。沿淮和淮北地区可通过着重提高穗粒数、同步提高单茎生物产量与收获指数的途径提高穗粒重。     

不同春生叶龄期追氮对冬小麦产量形成和抗倒性能的影响

为明确兼顾冬小麦高产和抗倒伏的春季最佳追氮时期,设置品种、追氮期二因素裂区试验,其中,2015-2016年以山农16（SN16）和石新828（SX828）2个品种为主区,2016-2017年以藁优2018（GY2018）、科农2009（KN2009）和石4366（SH4366）3个品种为主区,两年均以春3、4、5、6叶伸出时分别追施总施N量240 kg·hm^-2中的50%氮肥（分别用N3～N6表示）为副区。在关键生育时期调查群体总茎数,成熟期调查茎秆抗倒伏相关性状及产量构成因素。结果表明,拔节至孕穗期一般以N3或N4处理总茎数最多,开花至成熟期一般以N4处理的穗数最多,N5处理的成穗率最高;孕穗期至开花后24 d,N4处理的叶面积指数（LAI）最大,N6处理的最小;大部分品种以N4处理的株高最高,不同叶龄期追氮处理的重心高度则因品种而异;N4处理小麦基部第2节间最长,节间充实度和机械强度最小,N3和N4处理的抗倒指数最低。抗倒指数和机械强度与株高、重心高度、节间长度均呈极显著负相关,与节间直径、茎壁厚度和充实度均呈极显著正相关。不同叶龄期追氮对每公顷穗数和穗粒数的影响较小,大部分小麦品种以N4处理的穗数最多,且施氮处理间的差异一般不显著。石新828和藁优2018各施氮处理千粒重的差异不显著,另外3个品种N4处理的千粒重高于其他处理。5个品种中除藁优2018以N5处理的籽粒产量最高外,其他品种均以N4处理的籽粒产量最高,且均与N5处理的差异不显著。综合来看,春4叶期追氮产量性状最优而倒伏风险最大;春5叶期追氮的籽粒产量与春4叶期追氮的差异不显著,但其抗倒能力显著提高,可以兼顾高产和抗倒伏,因此,春5叶期为河北平原春季最佳追氮时期。在灌水条件常成为限制因素的该地区小麦生产中,春4叶至春5叶期根据水源情况灌水和随水追施氮肥,都是比较适宜的。     

High Yielding Performance of Soybean in Northern Xinjiang,China

Abstract

The experimental site (Shihezi, Xinjiang, China) is located in an arid area of central Asia with abundant solar radiation of almost 10 daily sunshine hours from April to September. The yield potential in this area appears to be high if sufficient water is supplied. The yields of five soybean (Glycine max (L.) Merr.) cultivars including three semi-indeterminate Chinese cultivars (Shidadou 1, Xindadou 1 and Suinong 11) and two determinate Japanese cultivars (Toyomusume and Toyokomachi) were evaluated over three years. These cultivars were grown under drip irrigation, a high planting density (22.2 plants m^-2) and heavy applications of farmyard manure (15 t ha^-1). Each cultivar showed a high leaf area index (LAI). In particular, the maximum LAI was greater than 7 over the three years in Shidadou 1 and Toyokomachi. The three Chinese cultivars with a high plant height had a low LAI in the upper layers of the canopy, but the two Japanese cultivars with a short plant height had a higher LAI in the middle or upper layers. Toyokomachi and Shidadou 1 had the highest seed yield, followed by Toyomusume. In particular, the seed yield of Toyokomachi was as high as 8.67 t ha^-1 on the average of the three years. These high-yielding cultivars had more than 60 pods per plant (1350 m^-2). The high yields in this experiment could be due to the large amount of intercepted radiation owing to the high LAI and abundant solar radiation, frequent and sufficient irrigation by the drip irrigation, and large number of pods as a sink.     

Peanut leaf area index,light interception,radiation use efficiency,and harvest index at three sites in Texas

Stability of parameters describing crop growth of peanut (Arachis hypogaea L.) is important because of the diversity of climatic conditions in which peanuts are grown and is valuable when developing simulation models for this species. In contrast, variability in the same parameters is desirable for plant breeders working to develop improved cultivars. This study seeks to quantify key parameters for biomass and yield production of some common peanut cultivars at three sites in Texas. We measured leaf area index (LAI), light extinction coefficient (k) for Beer's law, and harvest index (HI) for four cultivars at Stephenville, TX and one cultivar near Gustine, TX, and for LAI and biomass on four cultivars at Seminole, TX. Mean radiation use efficiency (RUE) values were 1.98 g MJ⁻¹ at Stephenville, 1.92 at Gustine, and 2.02 at Seminole. Highest RUE values were for the Low-Energy Precise Application (LEPA) irrigation treatment at Seminole. Maximum LAI values ranged from 5.6 to 7.0 at Stephenville, from 5.0 to 6.2 at Seminole, and was 5.3 at Gustine. Mean k values ranged from 0.60 to 0.64 at Stephenville and was 0.77 at Gustine. The overall mean HI was 0.36, with a mean of 0.33 for Stephenville, 0.44 for Gustine, 0.53 for spray irrigation at Seminole, and 0.58 for LEPA irrigation at Seminole. Values of RUE, k, and HI for the cultivars in this study and similarities between this study and values reported in the literature will aid modelers simulating peanut development and yield and aid breeders in identifying key traits critical to peanut grain yield improvement.     

阴雨寡照条件下密度对夏玉米叶面积和产量的影响

选用玉米品种郑单958和金海5号,设不同种植密度,研究阴雨寡照条件下种植密度对夏玉米叶面积、干物质积累及产量的影响。结果表明,在整个生育期,郑单958和金海5号群体叶面积指数(LAI)均随密度的增加而增大,但LAI增长率和单株叶面积逐渐减小,表明随着密度提高,LAI增加是单株叶面积减少和群体数量增加共同作用的结果。随着密度增加,两个品种单株干物质积累量均呈下降趋势。郑单958和金海5号在52 500株/hm2的密度下产量最高,分别为7 358.3 kg/hm2和7 016.7 kg/hm2。     

不同密度春玉米叶面积系数动态特征及其对产量的影响

研究了两个品种吉单209(JD209)、郑单958(ZD958)不同密度群体各生育期LAI动态变化特征,并分析了主要动态特征参数与产量及产量构成的关系,探讨春玉米高密度高产群体叶面积系数(Leafarea index,LAI)动态变化特征对产量的效应。结果表明:各密度群体LAI动态变化呈单峰曲线趋势,随密度增加峰值增大,相同密度下ZD958群体LAI大于JD209,表现较强的耐密性。两个品种高产的适宜密度范围是6万～9万株/hm²,群体的最大LAI在5～7;各生育期的群体LAI与密度呈显著线性正相关,其中抽雄吐丝期LAI对密度的增长率最大,分别为0.583和0.679;灌浆期群体LAI对产量的影响最大,表明此时期是产量形成的关键期。大喇叭口期LAI对穗数、穗粒数影响最大。密度是通过调控群体的LAI和穗数来影响产量构成和最终产量。     

Impact of elevated CO2 concentration on inter-subspecific hybrid rice cultivar Liangyoupeijiu under fully open-air field conditions

Hybrid rice cultivar plays an important role in rice production system due to its high yield potential and resistance to environmental stress. Quantification of its responses to rising CO₂ concentration ([CO₂]) will reduce our uncertainty in predicting future food security and assist in development of adaptation strategies. Using free air CO₂ enrichment (FACE), we measured seasonal changes in growth and nitrogen (N) uptake of an inter-subspecific hybrid rice cultivar Liangyoupeijiu grown under two levels of [CO₂] (ambient and elevated by 200 μmol mol⁻¹) and two levels of N fertilization in 2005–2006. Average across the 2 years, FACE increased crop growth rate similarly by 22%, 24% and 23% in the periods from transplanting to panicle initiation (PI), PI to heading and heading to maturity, which was mainly attributed to an increase in green leaf area index rather than the greater net assimilation rate. Grain yield increased greatly under FACE as a result of similar contributions by panicle number per unit area, grain number per panicle and individual grain yield. Final aboveground N acquisition showed a 10.4% increase under FACE, which resulted from enhanced N uptake at both vegetative and reproductive growth stages. Compared with previous FACE studies on final productivity of two inbred japonica cultivars, inter-subspecific hybrid cultivar appears to profit more from elevated [CO₂], which mainly resulted from its greater enhancement in photosynthetic production during reproductive growth due to a lack of N limitations late in the season.     

The effect of nitrogenous fertiliser application on leaf traits in durum wheat in relation to grain yield and development

Nitrogen (N) fertilisation boosts the grain yield of wheat through its influence on yield components, phenology and leaf traits. Both crop growth and senescence are dependent on N supply, as are the number of kernels set per unit area and per ear, and the mean kernel size. A two-season trial of four semi-dwarf durum wheat cultivars, grown at two levels of N, was used to illustrate the effects of N on canopy temperature, leaf resistance and flag leaf senescence pattern under irrigated conditions in a Mediterranean climate, and to explore the consequences of these effects on the crop phenology, its yield and its yield components. The well-fertilised crop developed a larger leaf area index at anthesis and a lower leaf resistance, thus generating a lower canopy temperature and delayed anthesis. Its grain fill duration was shorter, in spite of its lower canopy temperature, presumably because the increased N availability resulted in the development of a stronger sink (more kernels per unit area and per ear), which was associated with earlier senescence, thereby shortening the duration of grain fill, and led to reduced kernel weight.     

吉林省不同年代大豆品种某些株型性状的演变

对吉林省1923年以来生产上主推的9个大豆品种的产量、叶面积、叶面积指数(LA I) 、叶柄长度、茎直径 和比叶重( SLW)等参数的研究表明:大豆产量、叶面积、叶面积指数(LA I) 、茎直径和比叶重( SLW)随着年代的增 加而增加;老品种的冠层结构呈伞型,新品种的冠层结构呈宝塔型;大豆产量与单株叶面积、叶面积指数(LA I)和茎 直径呈显著相关( P≤0. 05) ,株型可以作为大豆高产、高光效育种的重要依据。     

灌溉模式对不同密度小麦群体质量和产量的影响

为明确灌溉模式对不同密度小麦群体的调控效应,在大田条件下设置了不灌水（W0）、灌1水（W1j,拔节期灌水;W1b,孕穗期灌水）、灌2水（W2,拔节期和孕穗期灌水）、灌3水（W3,拔节期、孕穗期和灌浆期灌水）5种灌溉模式和基本苗180万.hm-2（D1）、300万.hm-2（D2）、450万.hm-2（D3）3种密度的二因素试验,研究了灌溉模式对不同密度小麦群体质量指标和产量的影响。结果表明,在灌溉拔节水的基础上增加灌溉显著提高了群体总茎数、叶面积指数和成穗率,三个指标基本上均表现为W3〉W2〉W1j〉W1b〉W0。花后干物质积累量高低表现为W2〉W1j〉W1b〉W3〉W0。产量则随着灌溉次数的增多呈低-高-低的变化趋势,表现为W2〉W3〉W1b〉W1j〉W0。密度从D1增加到D3,总茎数、叶面积指数和干物质积累量显著增加,籽粒产量则呈低-高-低的变化趋势。因此在春季降雨较少的条件下,灌溉模式W2即灌拔节水和孕穗水,就可以满足小麦正常生长发育、群体合理构建和高产的需要,其适宜密度为300万.hm-2基本苗。     

Does higher yield potential improve barley performance in Mediterranean conditions?: A case study

Barley is one of the most widely cultivated crops in rainfed areas of the Mediterranean, where drought is the main factor that limits yield. Knowledge of the physiological traits responsible for adaptation of barley cultivars to Mediterranean environments may be relevant for future breeding strategies. Yield potential versus drought tolerance is an open debate. Here, we studied two barley cultivars (Graphic and Kym), of similar time to anthesis and crop duration, that are widely cultivated in the western Mediterranean. Grain yield was evaluated in 41 field trials and ranged (averaged for the 16–32 cultivars assayed in each trial) from 0.7 to 9.1 Mg ha⁻¹. Yield components and carbon isotope discrimination (Δ¹³C) of grains was analysed in another two trials. Graphic production was greater than Kym in all conditions. This greater yield was sustained mainly by more ears per unit ground area, which may be attributable to higher growth potential during tillering. Moreover, Graphic showed greater Δ¹³C of kernels, indicating improved water status even at the end of the crop cycle. To examine differences in early growth, these cultivars were grown in optimal conditions and then photosynthetic activity and biomass analysed at the end of tillering. Graphic showed greater above-ground and root biomass as well as total leaf area per plant and per tiller than Kym, and also tended to have more tillers per plant, but its shoot-to-root biomass ratio was lower. Nitrogen content per unit leaf area was correlated negatively with plant and with tiller leaf area and positively with the shoot-to-root biomass ratio. Photosynthetic rate per unit leaf area was lower in Graphic and positively related to a lower nitrogen content, whereas stomatal limitation of photosynthesis and water use efficiency was similar in the two cultivars. Ribulose 1,5-biphosphate regeneration capacity contributed to the lower photosynthetic rate of Graphic. Moreover, quantum yield of photosystem II (PSII) electron transport was also lower in Graphic than Kym, which suggests that mechanisms other than leaf structure also contributed to the higher photosynthetic capacity of the former. Nevertheless, as result of differences in leaf area, total plant photosynthesis was greater in Graphic.The results indicate that the higher yield of Graphic under a wide range of Mediterranean conditions may be sustained by increased plant growth and total photosynthesis during tillering, although the photosynthetic capacity per unit leaf area is lower than that of Kym. Graphic has a more extensive root system than Kym, subsequently improving its water status in later stages of the crop cycle. Nitrogen content per unit leaf area is a good indicator of the growth and photosynthetic activity of barley plants in the early stages of the crop cycle.     

不同类型化控剂对春玉米产量及生长发育的调控效应

以紧凑高抗玉米品种中单909为试验材料,种植密度为67 500株/hm2,研究拔节期至大喇叭口期分别喷施"增产胺"、"吨田宝"及"DA-6"3种不同类型化控剂对玉米产量及生长发育的影响。结果表明,喷施3种不同类型化控剂均可提高玉米子粒产量,"增产胺"和"吨田宝"的增产最为显著,较对照分别增产6.9%和6.6%;化控剂处理对行粒数和穗长影响不明显,明显缩短了秃尖长度,"增产胺"、"吨田宝"、"DA-6"处理分别较对照缩短23.9%、16.6%和28.3%;喷施"增产胺"同时增加穗粒数和千粒重,"吨田宝"增加玉米穗粒数,"DA-6"提高玉米的千粒重;"增产胺"与"吨田宝"处理后收获指数均明显高于对照,"DA-6"处理收获指数与对照差异不显著。与对照相比,化控处理后叶面积指数、各生育期生物总量均明显增加;对叶片SPAD值的影响存在差异,"增产胺"和"吨田宝"均提高穗位叶的SPAD值,"DA-6"对穗位叶SPAD值的影响不显著。     

Role of early vigor in adaptation of rice to water-saving aerobic culture: Effects of nitrogen utilization and leaf growth

Early vigor and rapid canopy development are important characteristics in aerobic rice culture, where they are highly susceptible to soil water deficits. To elucidate the response of rice's vegetative growth to water management regimes, we evaluated the leaf growth and the concomitant nitrogen (N) utilization of nine cultivars grown in flooded and aerobic culture in 2 years. In aerobic culture, the soil water potential at a depth of 20 cm frequently reached −60 kPa in 2007, but remained above −30 kPa in 2008. The average leaf area index (LAI) in the middle of the vegetative growth stage, N uptake and leaf N content per unit leaf area (specific leaf N; SLN) in aerobic culture were comparable to those in flooded culture. However, there was a significant cultivar × water regime interaction in LAI: cultivars with higher LAI during the vegetative growth stage achieved higher yield in aerobic rice culture. IR72 and Takanari (high-yielding cultivars of flood-irrigated rice) showed poor leaf growth as well as lower N uptake and higher SLN in aerobic culture compared with flooded culture. Our results show that early vigor is closely associated with yield stability to the soil moisture fluctuations in aerobic rice culture, even if weeds are properly controlled. Greater N uptake from aerobic soil and better balancing between the N demand for leaf growth and the N supply to the leaves under fluctuating soil moisture would be, at least in part, relevant to a rice cultivar's adaptation to aerobic conditions.