节水条件下不同播期密度设计对不同品种冬小麦群体生长特性和产量的影响

明确适应本地区气候变化和节水需要的小麦晚播适期范围,了解不同品种特性并确定其合理的播种期和种植密度,对充分挖掘小麦品种的产量潜力是非常重要的。利用随机区组试验研究‘泰山23’和‘泰山9818’在只浇底墒水和灌浆水的情况下,在4个播期、密度组合时的产量构成变化及群体发育动态变化。结果表明：适宜的晚播期限内通过增加播量来达到高产的同时,重要的是稳定其较高的千粒重。花期、灌浆期叶面积指数和产量存在正相关关系。‘泰山23’各播期的产量顺序为B1>B2>B3>B4,第四播期产量最低,且与其他播期产量有显著差异,在当前设计密度下,宜适期早播。‘泰山9818’产量顺序为B2>B1>B3>B4,且各播期产量无显著差异,各播期均可播种。     

四川地区彩色花生一年两熟种植时期研究

为解决四川花生新品种繁育加代慢、鲜食花生供应周期短的问题,试验探究了四川地区花生一年两熟的可行性。试验以‘蜀花1号(SH1)’、‘蜀彩花1号(SCH1)’、‘蜀彩花2号(SCH2)’3个彩色花生品种为材料,在四川攀西仁和试验基地对其在全年不同月份播种的生长发育状况、产量相关性状及繁殖系数进行了研究。结果表明：各个品种自身产量最高的种植时期有所不同,但时期差异不大,种植时间对各品种生长性状和产量性状均产生显著性影响,在1—9月播种期间出苗率、成熟株高、单株结果数、繁殖系数呈现先升高后降低的表现趋势,生育期则与之相反,因积温过低等气候条件限制,10—11月播种3个品种均未结果。进一步分析发现：5月播种‘SCH1’的单季繁殖系数为试验最高值,加权平均计算结果显示,3月播种‘SH1’和‘SCH2’时的全年繁殖系数最高,1月播种‘SCH1’的全年繁殖系数最高,最适宜一年两熟种植。结果证明：在攀西地区进行花生一年两熟种植可行,尤其是使用生育期较短的品种效果更好,可延长四川地区鲜食花生供应时长,同时为四川花生新品种本地快繁加代提供可能。     

山西夏播区适于机械化收获的甜荞品种及相关性状研究

为了筛选山西夏播区适于机械化收获的甜荞品种并明确其性状指标,通过对适宜寿阳县大面积种植的6个甜荞品种特征特性及产量水平试验的研究,初步筛选出山西夏播区适合于机械收获的品种为晋荞麦7号和晋荞麦8号,该区适合于机械收获的品种性状指标为倒伏级2级以下、茎粗2.1 cm以上、二级分枝3.0个以下,主茎第一分枝节位高度15cm左右、落粒率10%以下、生育期87≦d.     

两种除草剂对云南秋播苦荞田除草效应及其产量的影响

为了探讨除草剂对云南秋播苦荞田的防除效果、苦荞的安全性和产量的影响,以‘云荞1号’为材料,对云南秋播苦荞田进行不除草、人工除草、化学除草(金都尔、乙草胺)苗前土壤喷雾4个处理。试验结果表明,金都尔和乙草胺除草剂对秋播荞麦田的杂草有较好的防除效果,并且金都尔除草剂对阔叶杂草的防除效果大于禾本科杂草的防除效果,而乙草胺除草剂对禾本科杂草的防除效果大于阔叶杂草的防除效果;但两种除草剂对苦荞的出苗和幼苗生长都有一定的抑制作用,并且严重影响苦荞产量。因此在生产中,以阔叶杂草为主的苦荞田建议使用金都尔除草剂、以禾本科杂草为主的苦荞田建议使用乙草胺除草剂,但尚需进一步研究防除效果好又不影响产量的适合苦荞田除草剂浓度的筛选。     

不同播期对苦荞“黑丰1号”产量的影响

[目的]旨在研究不同播期对荞麦产量的影响,筛选适合青海东部农区荞麦种植的时间,[方法]以苦荞黑丰1号品种为试验材料开展田间试验,测定了5个播种时间下生育期及其构成因素等对产量的影响。试验结果表明：随着播期的延长,苦荞“黑丰1号”的产量呈现出先上升后下降的趋势,且在A3处理时理论产量达到最高,为408.9kg/亩。随着播种期的推迟,苦荞“黑丰1号”的生育期呈现出缩短的趋势,且各个阶段也表现出不同的差异性;地上部农艺性状中的主茎分支数处理间差异显著;同时与产量相关的构成要素差异性明显,最终产量在A3处理时最高。     

甜荞品种‘牡丹荞’季节性栽培对产量的影响

甜荞(Fagopyrum esculentum Moench)的生长生育过程受自然因素影响很大,光照、温度条件和水分条件的季节性变化对其产量影响明显。通过对‘牡丹荞’品种在不同季节的栽培种植,以播期、成熟期、全生育期、株高、主茎节数、主茎分枝、单株粒重、千粒重、小区产量为研究指标,通过数理统计的方法建立回归方程,揭示甜荞在某个区域的最适播期以及播期对主要产量性状的影响。研究结果表明：甜荞品种‘牡丹荞’在太原地区栽培对光照不敏感,对水分要求不严格,只对热量要求较严。出苗到开花期的 平均温度高则全生育期缩短,主茎分枝减少,单株粒数增加,单位面积甜荞产量提高。播种到出苗阶段,同其他作物一样,温度越高出苗越快。灌浆期最适温度为18~22℃。太原地区种植甜荞的最佳时期为7月7—20日。     

播种期对广东省晚稻产量及生育期的影响

为了研究出广东省5个典型稻作生态区晚稻最佳播种期,明确气候变化对近年来新育成并大面积推广晚稻品种产量的影响。2009年晚季,在韶关、肇庆、广州、汕头、湛江等5个代表性地点对超级杂交稻天优998、超级常规稻玉香油占及杂交稻天优428进行了分期播种试验,结果表明：播种期对广东晚稻产量及其构成因素的影响具有一定的地域性差异,其中,5个地点高产播种期分别为7月2日（B）、7月16日（D）、7月16日（D）、7月23日（E）、7月9日（C）。通过分析晚稻产量及其构成因素与温度、降雨、光照等气候生态因子的相互关系、构建逐步回归方程,结果表明,返青期至拔节期较低的日均最高气温、较低的日均最低气温、较高的日均气温及较高的积温,孕穗期至齐穗期较高的日均气温、较低的平均日照时数,以及齐穗后20天至收割期较大的累积日照时数,有利提高晚稻产量。     

冀西北冬麦北移适宜播期和品种的研究

为了进一步明确冀西北冬麦北移的适宜播期和品种,选用3个冬小麦品种（‘京冬1号’、‘苏引6号’和‘02铁品5’）,通过分期播种,研究不同播期对小麦越冬和产量的影响。结果表明,以2008年9月23日为播种期的小麦越冬性和产量最高,播期主要通过影响有效穗数多少决定产量高低,播种越晚影响越明显;‘02铁品5’与‘苏引6号’产量极显著高于‘京冬1号’。通过对2005-2010年的冬前积温进行分析,认为冀西北冬小麦适宜播期为9月20日至9月25日左右,同时,应根据气候及品种特性进行适当调整,即较暖地区可适当延后,冷凉地区要适当提前;生育期短、冬性弱的品种要适当晚播,生育期长和冬性强的品种可适当早播;播期推迟时,要适当加大播种密度,以弥补越冬性差造成的群体不足。     

Development of semidwarf breeding line with shattering resistance and preharvest-sprouting resistant in buckwheat (Fagopyrum esculentum)

An important breeding issue in buckwheat is to increase its resistance to lodging, which can result in the loss of yield and quality of buckwheat foods. We developed the semidwarf buckwheat ‘Kyukei 50’, which has a short plant height and a strong lodging resistance. The internode length of ‘Kyukei 50’ was shorter than that of the summer-sown standard variety ‘HITACHIAKISOBA’. Progeny analysis revealed that the semidwarf trait was dominated by at least one recessive gene. Compared with ‘HITACHIAKISOBA’, in ‘Kyukei 50’, the time of maturation was earlier, and the pre-harvest sprouting resistance was the same, indicating that ‘Kyukei 50’ is suitable for sowing in both spring and summer. ‘Kyukei 50’ exhibits the ‘green flower type’ shattering resistance trait and, therefore, has a thick pedicel; breaking tensile strength is approximately two-fold stronger than that of ‘HITACHIAKISOBA’. The yield of ‘Kyukei 50’ is the same as that of ‘HITACHIAKISOBA’. In addition, the lowest seed height of ‘Kyukei 50’ was >17 cm. These results indicate that the ‘Kyukei 50’ is a promising breeding line for lodging resistance and loss of harvesting machinery.     

施氮量对荞麦产量及品质的影响

本试验以两个荞麦品种为试验材料,研究了5个施氮水平对荞麦产量及品质的影响。结果表明：随着施氮水平的增加,两种荞麦品种在产量和品质上均表现出先上升后下降的趋势,且在施氮量为90 kg.hm-2时表现最佳。其中,苦荞“黑丰1号”的株高、主茎分支数和主茎节数与对照相比显著(P&;amp;lt;0.05)提高,分别增加了23.21%,15.63%,9.80%；甜荞“六桥1号”分别提高了8.48%,15.29%,14.00%。与产量相关的构成要素也有大幅度的上升,90 kg.hm-2施N处理下为最高,产量表现也最高,且品种间产量差异较大。品质方面,90 kg.hm-2处理增加了两个荞麦品种的蛋白质含量、淀粉含量、粗脂肪含量和总黄酮含量,显著(P&;amp;lt;0.05)高于对照。因此,在本试验条件下,适宜的施N量(90 kg.hm-2)对荞麦的产量和品质有很好的促进作用,值得推广应用。     

Crop and Weed Growth in a Sequence of Spring Barley and Winter Wheat Crops Established Together from a Spring Sowing (Relay Cropping)

A relay cropping system of cereals, whereby winter wheat (Triticum aestivum L.) was undersown in two‐row spring barley (Hordeum distichum L.), was established in a field trial in central Sweden in 1999 and continued until 2000. The purpose of the study was to examine crop and weed responses to different plant densities of the undersown winter crop. Winter wheat was sown at four seed rates (187, 94, 47 and 0 kg ha^?1) immediately after the sowing of barley. Barley was harvested in the first autumn after sowing and winter wheat in the second autumn. The grain yield of barley was not affected by the seed rate of wheat, and averaged 4580 kg ha^?1. Winter wheat did not vernalize during the first growing season but remained at the vegetative stage. The grain yield of wheat was 1990 kg ha^?1 for the lowest and 5610 kg ha^?1 for the highest seed rate of wheat. Whilst the undersowing process itself stimulated weed emergence in this experiment, increasing the undersowing seed rate reduced the population of perennial weeds by 40–70 %. In the second growing season, the total biomass of weeds was 66 % higher at the highest seed rate compared with the lowest seed rate.     

Growth and Yield Response of Facultative Wheat to Winter Sowing, Freezing Sowing and Spring Sowing at Different Seeding Rates

Growth and yield of wheat are affected by environmental conditions and can be regulated by sowing time and seeding rate. In this study, three sowing times [winter sowing (first week of September), freezing sowing (last week of October) and spring sowing (last week of April)] at seven seeding rates (325, 375, 425, 475, 525, 575 and 625 seeds m^?2) were investigated during the 2002–03 and 2003–04 seasons, in Erzurum (Turkey) dryland conditions, using Kirik facultative wheat. A split‐plot design was used, with sowing times as main plots and seeding rates randomized as subplots. There was a significant year × sowing time interaction for grain yield and kernels per spike. Winter‐sown wheat produced a significantly higher leaf area index, leaf area duration, spikes per square metre, kernel weight and grain yield than freezing‐ and spring‐sown wheat. The optimum time of sowing was winter for the facultative cv. Kirik. Grain yields at freezing and spring sowing were low, which was largely the result of hastened crop development and high temperatures during and after anthesis. Increasing seeding rate up to 525 seeds m^?2 increased the spikes per square metre at harvest, resulting in increased grain yield. Seeding rate, however, was not as important as sowing time in maximizing grain yield. Changes in spikes per square metre were the major contributors to the grain‐yield differences observed among sowing times and seeding rates. Yield increases from higher seeding rates were greater at freezing and spring sowing. We recommended that a seeding rate of 525 seeds m^?2 be chosen for winter sowing, and 575 seeds m^?2 for freezing and spring sowing.     

Influence of Sowing Dates on Yield and Oil Quality in Sunflower

Effect of sowing dates (temperature regimes) on growth, yield oil content and quality in sunflower ( Helianthus annuus L. ) was studied. Plants of early sowings which had received low temperature during 0–45 days of growth grew very poorly in height. Plant height significantly correlated with temperature at all the three growth stages. Plants sown in March produced highest yield and January sown plants recorded lowest yield. Protein content of seeds decreased where as the oil content increased with delay in sowing dates. Oil content in the seeds collected from different sowing dates showed significant differences. However, oil content was not significantly correlated with temperatures at any growth stages. Incorporation of ¹⁴C-acetate into lipids of developing seeds was increased as the sowing was delayed. Early sown plants had higher percentage of oleic acid and late sown plants had higher percentage of linoleic acid. Effect sowing dates on oil content and oil quality were discussed on the basis of temperature variation during different growth stages.     

Management of Italian and Perennial Ryegrasses for Seed and Forage Production in Crop Rotations

Italian ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (L. perenne L.) can be grown for seed and forage in cold winter regions provided the stand persists well over winter. Seed yield and plant characteristics during primary growth, and forage yield during regrowth, were determined for two Italian and one perennial ryegrass cultivars in Atlantic Canada. Establishment methods and dates included sowing ryegrass in cultivated soil alone or with barley in mid‐May and, after harvesting the barley crop, by sowing ryegrass following conventional or reduced cultivation and by no‐till drilling into barley stubble in mid‐August and early September. Despite some winterkill, particularly in Italian ryegrass, seed and forage yields were adequate in post‐establishment growing seasons. Seed yield for Italian ryegrass was greatest (1270 kg ha^?1) when it was sown into cultivated soil in mid‐August and least (890 kg ha^?1) when sown alone in May. Italian ryegrass yielded 15–17 % more seed when plots were established in mid‐August rather than in mid‐May or early September. Italian ryegrass cv. Lemtal had a greater density of fertile tillers (1030 m^?2) in the sward than cv. Ajax (860 m^?2) and its tiller density was greater when seeded into cultivated soil in September than in mid‐August. There were fewer spikelets per seed head for sowing Italian ryegrass with barley in May than for the other methods of establishment. Forage yield in regrowth was greater for Italian ryegrass cv. Ajax (2770 kg ha^?1) than for cv. Lemtal (2480 kg ha^?1). Seed yield of perennial ryegrass was greater when seeded in mid‐May than in mid‐August or early September. The seed yield of perennial ryegrass was greater when it was sown with barley in May and harvested for grain, than when it was sown alone or with barley harvested at late milk stage. The establishment methods for mid‐August and early September sowing had little effect on seed yield. However, the no‐till and reduced tillage methods resulted in a greater tiller density than sowing into the cultivated seedbed. Fertile tillers tended to be denser under reduced cultivation for sowing in August. Forage yield of perennial ryegrass regrowth was not influenced by the sowing method and timing. In conclusion, Italian and perennial ryegrasses produce adequate seed and forage regrowth under different establishment methods and timing. However, the poor persistence of Italian ryegrass may limit commercial production after the establishment year in Atlantic Canada.     

Genotypic yield responses of lowland rice in high-altitude cropping systems

Rising global mean temperatures open opportunities in high-altitude production systems for temperature-sensitive crops such as lowland rice. Currently, the cropping window for rice in higher altitudes is still narrow, and thus, genotypes that tolerate a certain degree of chilling are needed to achieve their potential yield. Final yield depends on the interaction between genotype and environmental conditions. Exposing the genotype to a wide range of environments is a way to evaluate its adaptability into an expanding cropping calendar. Over a 2-year period, an experiment was conducted in lowland rice systems in Madagascar at two locations differing in altitude. Twenty genotypes with contrasting levels of tolerance to low temperature were sown monthly in a non-replicated rice garden trial. Plant development was monitored and yield and yield components were determined. Yield stability across the different growing environments was investigated. While crop duration was affected by sowing dates and altitude, yield was mainly determined by sowing date. Panicle number per m² and number of spikelets per panicle were the most limiting factors for yield potential in mid-altitude, while in high altitude, yield was mainly limited by spikelet fertility. Resulting cropping calendar and genotype recommendations are discussed.     

Incidence of and yield loss caused by maize rayado fino virus in maize cultivars in Ecuador

Three sowing date trials, each planted with one cultivar, were performed to measure the natural incidence of the Maize rayado fino virus (MRFV). The lowest incidences (1–6%) were obtained at the sowing dates normally practised in the tested regions. Earlier or later sowing dates had higher to much higher incidences (up to 18 and 32%). Two cultivar trials, one with four cultivars and one with eight cultivars, showed significant differences in incidence, ranging from 14.0% in ‘Iniap-160’ to 2.0% in ‘Cadet-2’. In one trial with plots of 1000 m², the cultivar Iniap-122 was sown at three sowing dates. In each plot, plants that developed MRFV symptoms at the 8–10 leaf stage, at the 12–14 leaf stage and at the emergence of tassels were marked. Marked MRFV-affected plants were compared with non-MRFV-affected plants in their neighbourhood to estimate yield loss due to MRFV. The yield losses at the three sowing dates were 2.5, 1.6 and 4.8%, respectively. It was concluded that the yield loss due to MRFV is quite small provided sowing is restricted to the normal sowing period.     

Grain yield and quality: does there have to be a trade-off?

The effect of agronomic practices and cultivars on grain yield, grain protein and small grain sievings was examined in field experiments over four years in the winter rainfall wheatbelt of Western Australia. Rotation with legume crops and pastures was the main factor responsible for increasing grain protein percent. Grain proteins were increased by 4-5% for crops grown in good legume pasture rotations compared to continuous wheat rotations, but only by 1-2% by factors such as delayed sowing time, applied nitrogen, cultivar or grass weed control. In legume based rotations, wheat crops sown at their highest yielding times produced proteins in the appropriate ranges for premium paying grades. Applying N fertilisers up to the optimum rates for yield did not result in proteins below the levels required for premium paying grades, except for hard wheats at >11.5% grain protein. Legume rotations and appropriate soil types were required for hard wheats to exceed 11.5% at economic N rates. The yield penalty often associated with high quality cultivars has been reduced or eliminated in the modern cultivars used in the experiments. Some longer season cultivars only produced grain proteins >10% if sown after their optimum time for yield, but sowing at optimum time reduced the probability of producing small grain sievings. Some cultivars were more susceptible than others to producing excessive sievings, especially those with inherently smaller than average seed size. Seed rates up to the optimum for grain yield did not result in excessive small grain sievings except where the site was highly fertile, where the crop was sown too late for optimum yield or where too much N fertiliser was used. This revised version was published online in August 2006 with corrections to the Cover Date.     

黑龙港流域玉米不同生育阶段气象因子对产量性状的影响

明确玉米生长发育不同阶段气象因子与产量的关系,有助于确定区域最适播期。通过调整播期来改变玉米生育期内气候条件,对于抵御阶段性不良气象因子的胁迫并最终实现高产目标有重要意义。本研究以郑单958为试验材料,于2009年至2010年在黑龙港地区中国农业大学吴桥试验站进行分期播种试验,分析产量及产量构成因素与不同阶段气象因子的关系。结果显示: (1)由于年际间气象条件的差异,产量及其构成因素并非简单地随播期变化而变化。(2)在试验设定的高密度条件下,产量提升主要受千粒重的制约,穗粒数次之。(3)产量性状与不同生育阶段的多个气象因子显著相关。穗期、抽雄吐丝阶段的光照条件对穗粒数以及产量有影响;苗期、营养生长阶段气温日较差与产量显著正相关;抽雄吐丝前后的温度条件影响穗粒数;生育期总降水量影响穗粒数和千粒重的提升。该地区在调整播种时间、改进栽培措施时,上述关系应是考虑的重点。生产中可适当早播晚收,选用适宜的中晚熟品种,既可避开生育前期及籽粒形成阶段不利气象因子的影响,又可延长籽粒灌浆时间,充分利用该地区生育后期丰富的光热资源。     

播期对大豆生长状况及产量的影响

了解不同播期对大豆生长状况及产量的影响,对寻求适宜播期及优质高效生产有重要意义。以黑龙江省哈尔滨市大豆主栽品种为试验材料,通过3个播期处理(S1为5月1日,S_2为5月10日,S_3为5月21日),研究不同播期条件下大豆生长状况及产量的变化规律。结果表明:S_1、S_2处理生育期日数延长;S_1、S_2处理在鼓粒期—成熟期干物质积累与分配及生长率明显高于S_3处理,干物质积累向果实转移量增大,其产量分别增加230.6、317.7 kg/hm~2;S2处理在3个处理中最优,水热等气候资源利用程度高。哈尔滨市大豆适宜播期为5月8—10日,但适播期应考虑春季土壤水分或春季首场透雨,促进大豆生长发育,显著提高产量。     

DROUGHT STRESS: Soil Water Availability Alters the Inter‐ and Intra‐Cultivar Competition of Three Spring Wheat Cultivars Bred in Different Eras

Competition for water generates a classic aspect of the tragedy of the commons, the ‘race for fish’, where crops must allocate more resource to acquisition of the limiting resource than is optimal for crop yield allocation. A pot experiment using a simple additive (target–neighbour) design was conducted to examine the above‐ground and below‐ground growth of three spring wheat (Triticum aestivum L.) cultivars when grown alone and in mixtures at three levels of water availability. The effects of competition and water availability were compared by observing patterns of growth, biomass allocation and below‐ground outcomes. Competitive interactions were investigated among cultivars ‘HST’, ‘GY602’ and ‘LC8275’, target plant of each cultivar grown without neighbouring plants are referred to herein as control plant and one target plant of each cultivar sown surrounded either by same or another cultivar as intra‐ or inter‐cultivar competition. Competitive ability was assessed as the response ratio (lnRR) between the target plant surrounded by six other plants and the target plant in isolation. Our results showed that the cultivar ‘HST’, released over a century ago, produced a higher biomass and grain yield than the more recently released cultivars ‘LC8275’ and ‘GY602’ when grown as isolated plants with sufficient water supply. However, competition for resources from neighbours led to target plant biomass and grain yield being significantly reduced relative to controls in all three cultivars, particularly in ‘HST’. When subjected to intra‐cultivar competition, the two recently released cultivars ‘LC8275’ and ‘GY602’ had higher grain yields and water use efficiency for grain than ‘HST’ in all three water regimes. The landrace ‘HST’ had better and significantly linear relationships between biomass and biomass allocation, root length and specific root length, whereas the recent and modern cultivars had much more water‐related species‐specific changes in root morphology and allocation patterns. These results suggest that crop traits that influence competitive ability, such as biomass allocation to roots and root plasticity in response to drought have changed in modern wheat cultivars because of breeding and selection.