Changes in radiation interception and R:FR over time and with canopy depth of two soybean cultivars with different branching characteristics

Because an outgrowth of auxiliary bud in plant is regulated by light quality detected by phytochrome, branching differences in various environment or cultivars in soybean would be the results of the responses to light environment. Therefore, we analyzed differences in the number of branches of two determinate soybean cultivars, ‘Hatsusayaka’ and ‘Sachiyutaka’, between low and high planting densities in relation to light quality within the canopy. We compared changes in the ratio of red to far red (R:FR) irradiance at the ground level over time and with canopy height with those in the fraction of intercepted photosynthetically active radiation (FIPAR) and leaf area index (LAI). Regardless of time or distance from the top of the canopy, the changes in R:FR were sigmoidal, and were symmetrical with those of FIPAR and LAI. The effects of density and cultivar on FIPAR, LAI, and R:FR could be modeled with a logistic function. The number of branches was greater at low density than at high density, and in Hatsusayaka than in Sachiyutaka. However, there were no notable differences in the dynamics of R:FR between planting densities or between cultivars. Close relationships between parameters of the dynamics of the changes in R:FR and of those in FIPAR and LAI suggest that FIPAR and LAI are major factors that regulate R:FR, regardless of time or canopy depth. We found no evidence of a causal relationship between the dynamics of R:FR within the canopy over time or with canopy depth and number of branches of either cultivar.     

Effect of plant density on growth and yield of new soybean genotypes grown under early planting condition in southwestern Japan

Soybeans planted in early to mid-June (early) are less affected by rainfall during rainy season than those conventionally planted in early to mid-July in southwestern Japan. Also, narrow row cultivation is expected to increase soybean yield and save labor for inter-tillage and ridging. Field experiments were performed in 2014 and 2015 to test the effect of plant density (high, middle, and low) under early planting condition on growth, yield, and several agronomical traits of Sachiyutaka A1 and three new genotypes (Sakukei 155, Kanto 127 and Shikoku 15). Early planting was performed in mid- to late June, even though rainy season started in early June. Higher plant densities produced 13% greater yield than low plant density through an increase in biomass accumulation, especially at R5. Among yield components, only pods m^?2 was significantly and positively correlated with yield, indicating that an increase in pods m^?2 led to a greater yield with higher plant densities. The yields of Sachiyutaka A1 were relatively stable for two years, but the lodging resistance should be further improved. Shikoku 15 had greater yield potential and lodging resistance, but its resistance to damping-off disease should be improved. Sakukei 155 with medium plant density produced relatively high and stable yield with less lodging. Although the yield of Kanto 127 fluctuated between experimental years, this genotype showed higher yield potential in higher plant densities with less lodging in 2015. Thus, Sakukei 155 and Kanto 127 with high or medium density may be suitable for early planting in this region.     

Effects of early planting and cultivars on the yield and agronomic traits of soybeans grown in southwestern Japan

Early planting contributed to increased soybean yields in the U.S. Because a double-cropping system dominates in southwestern Japan, early planting is not performed; it is thus unclear how much the yield potential could be increased by early planting. To address this question, we planted seven U.S. and five Japanese cultivars on around 20 May (early planting), measured the agronomic traits, including yield, yield components, and oil and protein contents, and compared these traits with those of the same cultivars planted on around 20 July (normal planting). In the early planting, the yields of the U.S. cultivars were 322–453 g m^?2, whereas the highest yield among the Japanese cultivars was only 315 g m^?2, which is significantly lower than those of the top five U.S. cultivars, indicating the adaptability of U.S. cultivars to early planting. The increases in yield obtained with early planting were 99–199 g m^?2 and ?26–144 g m^?2 for the U.S. and Japanese cultivars, respectively. The yield obtained by early planting was positively correlated with the pods m^?2, seeds pod^?1, and oil contents, but negatively correlated with the sterile pod rate, 100 seed weight and protein content. In the early planting, the U.S. cultivars had greater pods m^?2, seeds pod^?1 and oil content and less sterile pod rate, 100-seed weight, and protein content than the Japanese cultivars. These results suggest that early planting can increase the yield in southwestern Japan, if cultivars with agronomic traits observed in the U.S. cultivars of this study are grown.     

Analysis of yield-attributing traits for high-yielding wheat lines in southwestern Japan

Development of wheat cultivars that achieve high yields despite the short growing season is essential for increasing wheat production in southwestern Japan. The objectives of this study were to assess the genetic progress in grain yield and to clarify yield-attributing traits of high-yielding wheat lines in southwestern Japan. We conducted field experiments for two growing seasons (2012–2013 and 2013–2014) using three commercial wheat cultivars (Shiroganekomugi, Chikugoizumi, and Iwainodaichi) and four high-yielding wheat lines including Hakei W1380 developed in southwestern Japan. In an ancillary field experiment, we compared a commercial cultivar, Shiroganekomugi, and a high-yielding line, Hakei W1380, in the 2014–2015 season. Across the two seasons, grain yield of high-yielding lines was generally higher than commercial cultivars. Hakei W1380 achieved the highest grain yield across the two seasons, and successfully produced more than 900 g m^?2 in the 2013–2014 season. Correlation analysis showed that recent yield progress of wheat lines in southwestern Japan was derived from enhanced biomass production and grain number m^?2. Larger numbers of grains m^?2 in high-yielding lines than in commercial cultivars were associated with higher crop growth rate at the pre-anthesis stage, and therefore higher spike dry weight m^?2 at anthesis. Genotypic differences in crop growth rate from jointing to anthesis resulted mainly from differences in leaf area index. These results indicate that further improvements in grain yield in southwestern Japan could be achieved by increasing the amount of radiation intercepted at the pre-anthesis stage and grain number m^?2.     

不同水分处理对滴灌大豆干物质积累及生理参数的影响

研究滴灌大豆的干物质积累规律.设置295 mm、345 mm、395 mm、445 mm 4个不同的灌水处理,1个沟灌处理为对照对各处理的大豆株高、干物质积累、叶面积指数(LAI)、群体乍长牢(CGR)等参数进行分析结果表明:大豆株高随灌水量的增加而增加,LAI、CCR等随灌水量的增加而增加.滴灌大豆净同化率(NAR)在鼓粒期之后,随灌水量增加而降低;滴灌比沟灌更利于大豆干物质积累,在大豆生育期内较适宜的滴灌灌溉定额为395 mm～445 mm.     

超高产水稻的干物质生产特性研究

 以我国近年育成的超高产水稻品种为材料, 在福建龙海和云南涛源研究分析了超高产水稻品种的高产生理特性。结果表明超高产水稻品种积累了高额的生物量。 稻谷产量随干物质积累总量的增加而提高，产量主要取决于生物产量的高低，而收获指数对稻谷产量的贡献较小。超高产水稻干物质生产优势在中期和后期，产量随中期和后期干物质净积累量的增加而提高。中期和后期的群体生长率(CGR)与产量呈高度正相关，而前期CGR与产量的关系不密切。茎叶干物质输出量构成籽粒产量平均为24％（福建龙海）和33％（云南涛源），茎叶干物质输出量和抽穗后干物质积累量均与稻谷产量呈极显著正相关。在同一地点，对干物质积累的作用，CGR显著大于生长日数。     

盐粳228群体特征及对氮的响应

2010年对盐粳228进行氮肥试验,研究该品种高产群体特征及对氮的响应。结果表明:该品种抽穗后干物质积累占籽粒产量的71%~81%,茎叶的表观转运率少,容易获得高产。该品种抽穗期适宜的叶面积指数(LAI)为7.0~7.5,叶色呈"三黑三黄"节奏变化,后期生长速率(CGR)高,收获指数(HI)介于0.8~1.1之间。氮肥的适量施用(330kgN.hm-2)不仅可以保证叶色"三黑三黄"节奏变化,建立抽穗期适宜LAI的群体,还可以保持高产株型特征,提高抽穗后期的LAI、叶面积维持期、CGR和HI,最终实现高产。     

株行距配置对宽幅播种小麦产量形成的影响

为探明不同株行距配置对宽幅播种高产栽培下冬小麦产量形成调控的生理基础,选用高产冬小麦品种泰山28为材料,采用裂区设计,主区为种植密度（150×10⁴、225×10⁴和300×10⁴株·hm^-2）,副区为播种行距（25、20和15 cm）,研究了不同株行距配置下小麦干物质积累、转运及产量的影响。结果表明,在150×10⁴株·hm^-2种植密度下,小麦干物质积累量均处于较低水平,产量亦较低;在种植密度225×10⁴株·hm^-2配置20或25 cm行距和种植密度300×10⁴株·hm^-2配置25 cm行距时,小麦干物质积累量和产量均达到较高水平。在种植密度225万株·hm^-2和行距20 cm处理下,小麦开花前营养器官贮藏的同化物向籽粒的转运量、开花后光合产物在籽粒中的积累量及其对籽粒产量的贡献率均显著高于其他处理。泰山28在种植密度225×10⁴株·hm^-2配置20或25 cm行距和种植密度300×10⁴株·hm^-2配置25 cm行距下均可实现三者的协调,获得较高的产量。因此,合理的种植密度和行距配置是实现宽幅播种高产栽培小麦高产的重要技术途径。     

Performance of a High-Yielding Modern Rice Cultivar Takanari and Several Old and New Cultivars Grown with and without Chemical Fertilizer in a Submerged Paddy Field

Abstract

A high nitrogen-uptake capacity and effective use of absorbed nitrogen for dry matter and grain production are required to improve the production cost and environmental pollution. We characterized grain yield, dry matter production and nitrogen accumulation in six rice cultivars: Sekitori (released in 1848) and Aikoku (1882), referred to as SA cultivars hereafter; Koshihikari (1956); Nipponbare (1963) and Asanohikari (1987), referred to as NA cultivars hereafter; and Takanari (in 1990) as a high-yielding modern cultivar. The plants were grown with and without chemical fertilizer in a submerged paddy field. When plants were supplied with manure and chemical fertilizer, Takanari consistently produced the heaviest grain and dry matter, followed by the NA cultivars, and the SA cultivars the lightest. Dry matter production before heading was greater in Takanari and the NA cultivars due to the longer duration of vegetative growth. Dry matter production after heading was greatest in Takanari, with a larger crop growth rate (CGR), and smallest in the SA cultivars with a shorter ripening time. Greater dry matter production during ripening was accompanied by the greater accumulation of nitrogen by Takanari and NA cultivars. These plants developed a larger amount of roots. The smaller light extinction coefficient of the canopy was also attributed to the higher CGR in Takanari. When plants were grown without chemical fertilizer, Takanari also produced heavier grain and dry matter, followed by the NA cultivars. The heavier grain in these cultivars resulted from the greater dry matter production before heading, which was due to the longer period of vegetative growth. The greater dry matter production and nitrogen accumulation by Takanari and NA cultivars were evident when plants were grown with chemical fertilizer. Koshihikari was characterized by a higher CGR and greater nitrogen accumulation during ripening in the absence of chemical fertilizer which should be noted in efforts to decrease rates of nitrogen application.     

Effects of Nitrogen Fertilizer Application Time on Dry Matter Accumulation and Yield of Chinese Potato Variety KX 13

Application time of nitrogen (N) fertilizer can significantly influence the yield and quality of potato tubers. The objective of this experiment was to assess the effects of N application time on dry matter accumulation in foliage and tubers, as well as on marketable tuber ratio, dry matter concentration, and specific gravity of the Chinese cultivar KX 13. The four treatments were as follows: all the 150 kg?N?ha^?1 applied at planting (T1); 100 kg N ha^?1 applied at planting and 50 kg N ha^?1 applied 1 week before tuber initiation (20 days after emergence, DAE) (T2); 100 kg N ha^?1 applied at planting and 50 kg N ha^?1 applied 1 week before tuber bulking stage (35 DAE) (T3); and 100 kg?N?ha^?1 applied at emergence and 50 kg N ha^?1 applied 1 week before tuber bulking stage (35 DAE) (T4). For all treatments, 90 kg P₂O₅ ha^?1 ((NH₄)₂HPO₄) and 150 kg K₂O ha^?1 (K₂SO₄) were applied at planting. Thirty tons per hectare of marketable tuber yield was achieved with T3, while 23 t ha^?1 marketable yield was achieved by applying all 150 kg N ha^?1 at planting (T1). Relative to treatment T1, T3 also significantly increased harvest index (HI) from 0.76 to 0.86 and marketable tuber ratio from 64.8% to 79.2%. Applying N at planting in conjunction with dressing at 20 DAE (T2) gave a high marketable tuber ratio (74%) and HI (0.86), but the lower total tuber yield led to a lower marketable tuber yield. Without N application at planting (T4), N dressing did not increase the yield and HI. Treatments with N dressing had no significant effect on specific gravity or dry matter concentration of tubers.     

选育高产花生的几个生理指标

用花生高产品种与农家品种、多粒型PI259747 比较分析,高产品种叶绿素含量多,光合速率高,固氮活性较高,单位叶面积干重较大,干物质积累多且分配到荚果的比例大。这些性状与产量或生物产量成显著的正相关。高产育种时,可选择叶绿素含量高,叶片厚,根瘤较大而多,经济系数高的植株。     

花生新品种泉花327的选育与生育特性研究

泉花327系泉州市农科所育成的花生新品种。经多年试验示范，该品种表现高产、稳产、优质等优良特性。生育特性研究结果，泉花327表现开花集中、结荚性好、叶面积指数（LAI）较大、净同化率（NAR）高、干物质积累多、库大、源大、库源协调等，表明该品种具有高产花生的生育特性。     

耐密植大豆品种沈农12叶片性状研究

以耐密植大豆沈农12和普通大豆辽豆11为试材,在不同种植密度(7.5、15.0、22.5、30.0、37.5、45.0万株.hm-2)下,比较了2个品种的叶片性状。结果表明:耐密植品种沈农12叶形指数较高、叶柄较短、叶倾角较小,有利于密植栽培;随着种植密度增加,在一定密度范围内叶形指数、叶柄长度均随密度增加而增大;耐密性不同的品种叶柄长度随密度而增加的幅度不同,沈农12增幅较小;叶倾角也有随密度增加而减小的趋势。沈农12叶片性状有利于叶片的受光态势,因而,该品种的净光合速率较高,并且随着密度增加其叶片的净光合速率下降幅度较小。     

宽幅播种条件下行距对小麦产量及干物质积累和转运的影响

为了确定小麦宽幅播种的适宜行距,在高产地块以高产小麦品种泰农18为材料,设置20 cm、25 cm、30 cm三个行距处理,研究了宽幅播种条件下行距对小麦产量、群体动态、干物质积累与分配的影响。结果表明,相同行距下,宽幅播种的小麦产量较常规条播提高11.0%。在宽幅播种条件下,行距过大时小麦群体数量较小,成穗不足,干物质积累减少,产量降低;缩小行距可提高群体数量和干物质积累;但行距过小时穗粒数、千粒重下降,群体边际效应减弱,产量降低;适宜行距可协调产量构成因素,提高群体在花后维持较高光合能力,提高花后干物质同化量和对籽粒的贡献度。在本试验的条件下,泰农18以宽幅播种、行距25 cm、播量120 kg·hm~(-2)为宜。     

Characteristics of growth and quality,and factors contributing to high yield in newly developed rice variety ‘Akidawara’

The newly developed rice variety ‘Akidawara’ (AKI) combines the traits of high yield and highly palatability, and its cultivation is expected to spread. We examined characteristics of growth and quality, and factors contributing to high yield in AKI by comparing with ‘Nipponbare’ (NIP). Grain yield for AKI were 703 g m^?2 (9% more than NIP) and 781 g m^?2 (14% more than NIP) under the standard and heavy fertilizer regimes. It was also suggested that increase in the sink capacity was the key contributors to the high yield in AKI resulting from a conspicuous increase in the number of spikelets, which is likely due to introgression of the high-yielding variety allele. Furthermore, AKI achieved the similar degree of sink filling in spite of its larger sink capacity. In this point, panicle dry weight increase during ripening (ΔP) was significantly higher for AKI than for NIP despite the fact that no differences in shoot dry weight increase were observed between varieties. The greater ΔP in AKI might be derived from its larger sink capacity and the difference between varieties involves the translocation of nonstructural carbohydrate. In the grain quality, the reduction in perfect grain ratio was negligible and regarded as a small trade-off for AKI’s 14% increase in yield, and grain protein content increased to a lesser degree in AKI at the same yield level. These results suggest that over 700 g m^?2 high yield can be achieved with relative high grain quality and lower protein content in AKI.     

不同月份播种对红壤甘蔗干物质与养分积累的影响

甘蔗是广西重要的经济作物.为促进甘蔗高效生产,以甘蔗品种'桂糖42号'为材料,在田间条件下,依据广西甘蔗主要播种月份,设置2月15日、3月15日、4月15日及5月15日4个播种期,分析新植蔗和宿根蔗干物质积累、养分积累及养分经济效率.结果表明,随播期推迟,新植蔗各器官干物质积累量减少;宿根蔗根、叶干物质积累量增加,茎干...     

窄行密植对半矮秆大豆产量及性状的影响

在窄行密植栽培模式下选用半矮秆大豆品种合农60,并以大垄栽培为对照,研究窄行密植技术对大豆产量及品质、农艺性状的影响,结果表明：窄行密植栽培模式下大豆的产量显著地高于大垄栽培的产量,并且除了百粒重、蛋白质和脂肪含量,其他各性状都以窄行密植的大豆表现最好;不同时期窄行密植和大垄栽培大豆的SPAD值、单株叶面积和叶干重变化趋势基本一致。     

不同肥密处理对超高产大豆氮素吸收和产量的影响

以超高产大豆品种辽豆14和普通品种辽豆11为试材,在不同磷酸二铵施用量和种植密度处理下,对其氮素积累和产量进行了比较.结果表明:施用磷酸二铵可以促进大豆茎秆、叶片、荚皮、籽粒和全株氮积累,随着种植密度的增加,植株各器官和全株氮积累量呈下降趋势.在生殖生长期,超高产品种叶柄中氮积累量均高于普通品种.随着磷酸二铵施用量和种...     

Potato Crop Response to Genotype and Environment in a Subtropical Highland Agro-ecology

Potato response to environment, planting date and genotype was studied for different agro-ecological zones in Lesotho. Field experiments were conducted at four different sites with altitudes ranging from 1,655 to 2,250 m above sea level during the 2010/2011 and 2011/2012 summer growing seasons. Treatments consisted of three cultivars that varied in maturity type, two planting dates and four sites differing in altitude and weather patterns. Various plant parts were measured periodically. To understand and quantify the influence of abiotic factors that determine and limit yields, the LINTUL crop growth model was employed which simulated potential yields for the different agro-ecological zones using weather data collected per site during the study period. Observed actual crop yields were compared with model simulations to determine the yield gap. Model simulations helped to improve our understanding of yield limitations to further expand potato production in subtropical highlands, with emphasis on increasing production through increased yields rather than increased area. Substantial variation in yield between planting date, cultivar and site were observed. Average tuber dry matter (DM) yields for the highest yielding season were above 7.5 t DM ha^?1 or over 37.5 t ha^?1 fresh tuber yield. The lowest yield obtained was 2.39 t DM ha^?1 or 12 t ha^?1 fresh tuber yield for cultivar Vanderplank in the 2011/2012 growing season at the site with the lowest altitude. Modelled potential tuber yields were 9–14 t DM ha^?1 or 45–70 t ha^?1 fresh yield. Drought stress frequently resulted in lower radiation use efficiencies and to a lesser degree harvest indices, which reduced tuber yield. The site with the lowest altitude and highest temperatures had the lowest yields, while the site with the highest altitude had the highest yields. Later maturing cultivars yielded more than earlier maturing ones at all sites. It is concluded that the risk of low yields in rain-fed subtropical highlands can be minimised by planting late cultivars at the highest areas possible as early as the risks of late frosts permit.     

Salinity reduces radiation absorption and use efficiency in soybean

The potential rate of plant development and biomass accumulation under conditions free of environmental stress depends on the amount of radiation absorption and the efficiency of utilizing the absorbed solar energy to drive photosynthetic processes that produce biomass materials. Salinity, as a form of soil and water stress, generally has a detrimental effect on plant growth, and crops such as soybean are usually sensitive to salinity. Field and greenhouse experiments were conducted to determine soybean growth characteristics and the relative impact of salinity on radiation absorption and radiation-use efficiency (RUE) at a whole plant level. Cumulative absorption of photosynthetically active radiation (∑APAR) was estimated using hourly inputs of predicted canopy extinction coefficients and measured leaf area indices (LAI) and global solar radiation. On 110 days after planting, soybean plants grown under non-saline conditions in the field accumulated 583 MJ ∑APAR m⁻². A 20% reduction in ∑APAR resulted from growing the plants in soil with a solution electrical conductivity (EC) of about 10 dS m⁻¹. Soybeans grown under non-saline conditions in the field achieved a RUE of 1.89 g MJ⁻¹ ∑APAR for above-ground biomass dry materials. The RUE reached only 1.08 g MJ⁻¹ ∑APAR in the saline soil, about a 40% reduction from the non-saline control. Salinity also significantly reduced ∑APAR and RUE for soybeans in the greenhouse. The observed smaller plant and leaf sizes and darker green leaves under salinity stress were attributed to reductions in LAI and increases in unit leaf chlorophyll, respectively. Reductions in LAI exceeded small gains in leaf chlorophyll, which resulted in less total canopy chlorophyll per unit ground area. Analyzing salinity effect on plant growth and biomass production using the relative importance of ∑APAR and RUE is potentially useful because APAR and total canopy chlorophyll can be estimated with remote sensing techniques.