Reciprocal influence of crops and shallow ground water in sandy landscapes of the Inland Pampas

In regions with shallow water tables, ground water may have a positive (water supply) or negative (waterlogging or salinization) impact on crops. Reciprocally, crops can influence ground water, altering water table depth and chemical composition. We quantified these reciprocal influences along natural gradients of groundwater depth in flat sedimentary landscapes of the Inland Pampas occupied by wheat, soybean, and maize during two growing seasons (2006/2007 and 2007/2008). We correlated crop yield and groundwater depth maps at the field level and made direct plant, soil and groundwater observations at the stand level across topographic gradients. Water table level largely accounted for spatial crop yield variation, explaining 20–75% of their variance. An optimum groundwater depth range, where crop yields were highest, was observed for all three crop species analyzed (1.40–2.45 m for maize, 1.20–2.20 m for soybean, and 0.70–1.65 m for wheat). The areas within these optimum bands had yields that were 3.7, 3 and 1.8 times larger than those where the water table was below 4 m for wheat, maize, and soybean, respectively. As groundwater levels become shallower than these depth bands, crop yields declined sharply (∼0.05 kg m⁻² on average for every 10 cm increase in water table level), suggesting negative effects of waterlogging, root anoxia and/or salinity. Groundwater levels below these depth bands were associated with gradually declining yields, likely driven by poorer groundwater supply.     

Yield response to plant density of maize and sunflower intercropped with soybean

Maize-soybean and sunflower-soybean intercrops have the potential for increasing yield per unit land area and time in fully mechanized farming systems. The objectives of this work were to measure the land equivalent ratio index of maize and sunflower intercropped to soybean, to assess the effects of plant density of its components, and to gain insight into ecophysiological processes affecting their yield determination. Maize-soybean and sunflower-soybean intercrops and their respective sole crops were grown at Balcarce, Argentina during two growing seasons. Treatments included a wide range of plant densities for sole and intercropped sunflower (2-9 plants m⁻²) and maize (4-12 plants m⁻²). Plants were harvested to determine shoot dry matter and grain yield per plot and at the individual plant level. Land equivalent ratio index (LER) increased 11% (mean of the two years) when plant density of sunflower was reduced from 6 to 3 plants m⁻²; and LER increased 5% (year 1) or it was maintained (year 2) when maize plant density was reduced from 8 to 4 plants m⁻². Yield response to plant density of sunflower and maize influenced LER. The response to plant density of intercropped sunflower and maize grain yield followed the same pattern than that in a sole crop, and grain yield of intercropped sunflower or maize were lower than those for the sole crops at each plant density except at the lowest sunflower plant density. Yield reductions from sole crop to intercrop at each plant density averaged 20% and were associated (i) with lower intra-row spacing in the intercrop and (ii) with a lower shoot production rather than to a change in the dry matter partitioning to reproductive structures; in addition, detrimental effects of soybean over maize or sunflower yield were undetectable.     

大豆籽粒重的遗传效应分析

以亲本、F1、F2三个世代为材料,采用混合模型方法,分析大豆百粒重的种子效应、细胞质效应和母体植株效应.结果表明,大豆籽粒重除受到种子直接加性和显性作用外,还有来自母体植株的加性和显性作用,这些效应均达到显著水平.其中母体显性效应方差最大,其次是种子直接加性效应,种子直接显性效应和母体加性效应的相对比例较小.从遗传体系来看,母体效应略高于种子直接效应.种子和母体效应的广义遗传率和狭义遗传率都达到显著水平,总的狭义遗传率达到40%.根据亲本育种值的预测,东农7819号和东农46号两亲本有利于提高籽粒重.     

小麦黑胚病遗传力及气象因子与黑胚率的相关性分析

为了解气象因子对小麦黑胚率的影响,用48个小麦品种（系）于2016和2017连续两年在两个试验点自然条件下的黑胚率及气象数据,对小麦黑胚率的广义遗传力及气象因子与黑胚率的相关性进行分析。结果表明,小麦黑胚率的广义遗传力平均为49.9%,说明黑胚率约50%的表型变异来源于环境因素。大部分与温度相关的变量（日均温、高温天数等）在抽穗后11～15 d与26～40 d与黑胚率呈显著的负相关,低温天数与黑胚率呈显著正相关;与大气湿度有关的变量（日均相对湿度、日最低湿度等）多在抽穗后1～15 d与黑胚率呈显著的正相关（降雨量除外）;降雨天数与黑胚率的相关系数比降雨量与黑胚率的相关系数高;在研究的多数时间段内,日照时数与黑胚率呈负相关。抽穗后1～15 d潮湿、26～40 d低温、1～40 d寡日照气象条件对黑胚病的流行非常关键。     

苋菜、小麦和玉米对铯的吸收和积累差异

苋菜、小麦和玉米用石英砂和Hoagland营养液进行盆栽培养,3叶期时,向培养液中添加不同浓度铯(0、0.5、1、5、10、20 mmol/L CsCI),在处理后第7、14、21、28天取样,分析3种植物对铯的吸收富集差异.结果表明:苋菜、小麦和玉米中铯含量均与处理浓度和时间呈显著正相关,在20 mmol/L铯浓度下处理28 d后达到最大值;苋菜对铯的富集能力和富集系数远远高于小麦和玉米,在处理浓度小于1 mmol/L时,小麦和玉米对铯的吸收富集无显著差异,但随着处理浓度的增加和处理时间的延长,小麦对铯的富集能力显著高于玉米;苋菜、小麦和玉米的根、茎、叶对铯的吸收富集也存在显著差异,苋菜叶片是主要的富集器官,富集量表现为叶、茎、根依次减小,而小麦和玉米的根是主要富集器官,富集量表现为根、茎、叶依次减小;铯显著抑制苋菜、小麦和玉米的生长发育,随着处理浓度的增加,生物量显著降低,根冠比显著增加.本研究结果表明苋菜是一种铯富集能力强的具有较高潜在应用价值的铯污染修复植物,而小麦和玉米是铯低富集植物.     

Impact of pesticide seed treatments on aphid control and yield of wheat in the Sudan

Mixtures of imidacloprid and tebuconazole, were evaluated for three consecutive growing seasons, to determine the effects on plant stand, aphid control and wheat grain yield. At rates of 1.05/0.04 and 0.7/0.04 g a.i of pesticide, respectively, per kg of seeds, plant stand per unit area increased compared with their respective untreated control. Both rates of imidacloprid efficiently controlled the maize aphid (Melanaphis maidis) and suppressed the green bug (Schizaphis graminum) for 6–8 weeks after sowing. There were substantial differences among the different treatments in the number of grains/ear and the 1000-grain weight. These differences were reflected in 90% and 30% average increase in the total grain yield of the wheat crop raised from seeds treated with the mixture relative to the corresponding untreated control and a standard mixture of lindane plus thiram, respectively. This strategy of using imidacloprid as seed dressing allowed easy application, gave adequate reliable control of aphids and less hazardous to the environment.     

大豆籽粒大小的遗传及SSR标记分析

采用主基因+多基因混合遗传分离分析方法，联合分析J280082（小粒品种）×海系13（大粒品种），巴马九月黄（小粒品种）×海系13（大粒品种）2个组合的P1、P2、F1和F2四个群体，研究大豆籽粒大小的遗传规律，进而应用t测验和方差分析法分析并筛选与籽粒大小紧密连锁的SSR分子标记。结果表明：2个组合的大豆籽粒大小遗传都符合E-1模型，即籽粒大小性状均受两对主基因控制，并且有多基因效应，主基因效应表现为加性-显性-上位性效应；2组合主基因遗传率都较大，分别为74.3%、42.6%，多基因遗传率较小，分别为5.1%、14.4%。在J280082×海系13中有17个标记与大豆籽粒大小性状相关，在巴马九月黄×海系13群体中有12个标记与大豆籽粒大小性状相关；其中satt070（B2连锁群）、satt546（D1b连锁群）、satt302（H连锁群）、satt337（K连锁群）、satt373（L连锁群）、satt237（N连锁群）在两个群体中都表现出与大豆籽粒大小相关；satt302、satt070在两个群体中都有着较高的对籽粒大小性状变异的解释率(>8％)，可用于对大豆籽粒大小性状分子标记辅助育种选择。     

包衣对大豆生长发育和产量的影响

通过用三种包衣剂对大豆种子包衣的研究,结果表明：大豆种子包衣后,种子的发芽势、发芽率、活力指数均优于不包衣种子,但包衣与不包衣种子的发芽率、发芽势、活力指数差异均未达显著水平。三种包衣剂都能协调大豆的营养生长和生殖生长的关系,增加百粒重,提高产量,其中2号包衣刺产量增加15．51％,差异达极显著水平,1号包衣刺产量增加1.31％,差异不显著,3号包衣剂增产4、49％,差异不显著。     

Effects of mechanical and chemical methods on weed control,weed seed rain and crop yield in maize,sunflower and soyabean

Eight field experiments with maize (Zea mays L.), sunflower (Helianthus annuus L.) and soyabean (Glycine max (L.) Merr.) were carried out in central Italy in order to evaluate the effects of mechanical and chemical methods (spring-tine harrowing, hoeing, hoeing-ridging, split-hoeing, finger-weeding, herbicides in the row + inter-row hoeing, herbicides broadcast) on weed control, weed seed rain and crop yield. The choice of chemical and mechanical treatments in maize and soyabean compared to sunflower, required to be managed more carefully in order to maximize the weed control reducing yield losses. A global rating of weed control methods, based on their weed control efficacy, was obtained as useful means to assist farmers and technicians to choose the more appropriate weed control method. The combination of herbicides intra-row and hoeing inter-row gave best efficacy (on average 99% of weed control), with a 50% reduction in the chemical load in the environment. Hoeing-ridging gave good results, both inter- and intra-row (on average 93% of weed control); this method was also effective in reducing competitive ability and seed production of uncontrolled weeds. Split-hoeing or finger-weeding showed some limitations giving satisfactory results only when combined. Harrowing gave lowest weed control, although when combined to other mechanical methods, can help achieve a better efficacy.     

桦川县优质高油大豆品种的筛选

通过10个优质大豆品种在桦川县的试种试验,从产量和生育期综合来看,结果表明合丰50为该县生产应用首推高油大豆品种,其次为黑农44、合丰45、绥农14-3、垦丰9等宜桦川县生产应用的高油品种。     

陕西关中小麦全麦粉SDS沉淀值与膨胀体积的遗传研究

为了给小麦品质育种早代选择指标的确定提供理论依据．选用5个品质性状不同的陕西关中小麦品种及其双列杂交的F1为材料，分析了全麦粉SDS沉淀值和膨胀体积的遗传特性。全麦粉SDS沉淀值和膨胀体积的平均值分别为67．66ml和6．09ml／g．其中沉淀值变异幅度较大，变异系数较高．而膨胀体积变异幅度较小，变异系数较低。SDS沉淀值的广义遗传力和狭义遗传力分别为98、42％和97．06％；膨胀体积的广义遗传力和狭义遗传力分别为54．75％和10．82％。对陕西关中小麦品质育种配制的组合而言，全麦粉SDS沉淀值可作为小麦育种分离早代蛋白质品质选择的指标，而全麦粉膨胀体积最好在育种高代进行选择。     

大豆不同亲本正、反交F2、F3、BC1F2主茎节数遗传规律研究

为深入理解大豆主茎节数的遗传规律,提高杂交组配及选择效果,以中、美大豆品种为亲本,对正、反交F2、F3、BC1F2后代群体的主茎节数遗传规律进行了比较研究.结果表明:不同大豆亲本杂交及回交后代群体的主茎节数变异度不大,分离强度表现中等;F3主茎节数的超亲优势较F2增强,而分离强度小于F2;大豆杂交及回交早世代主茎节数的遗传与其亲本值相关,以主茎节数少的品种为母本的组合,其杂交和回交早世代群体的平均值比以主茎节数多的品种为母本的组合偏小,而分离强度偏大,反之则异然;采用主茎节数少的品种回交不利于后代群体平均节数的增加,有利于回交后代群体分离强度保持在较高水平,扩大选择空间;而采用主茎节数多的品种回交虽有利于后代群体平均节数的增加,但回交后代群体分离强度偏低,选择空间缩小.研究还表明,主茎节数在F2、F3都具有较高的广义遗传力,且差异较小,在这2个世代进行选择是有效的;杂交早世代主茎节数的广义遗传力与组合配置有关,母本主茎节数多的组合,主茎节数广义遗传力大于母本主茎节数少的组合.     

我国北方玉米品种更替过程中产量杂种优势的演变

选用我国北方1970~2000s在生产中大面积推广应用的玉米单交种及其亲本为试材,在3个种植密度下比较分析品种更替过程中产量杂种优势的演变特征。结果表明,我国北方单交种更替过程中绝对杂种优势随年代的推进逐渐增加,低、中、高密度下绝对杂种优势平均增加比率分别为3.9%、7.9%和18.8%;相对杂种优势、中亲优势及杂种优势指数在低、中密度下略有降低趋势,在高密度下略有增加趋势;超高亲优势年代间变化较为平缓,1980~1990s品种超低亲优势显著低于1970s。分析表明,低密度下杂种优势对产量的贡献率较大,随着密度的增加,杂种优势越来越小,非杂种优势因素对产量的贡献率越来越大。     

超高产大豆主要群体生理参数与 经济产量关系的研究

以“新大豆1号”为供试品种，研究了超高产大豆在不同种植密度下的植株性状以及叶面积指数、光合势、干物质积累、光合生产率的动态及其与经济产量的相关关系。结果表明：收获株数在28.87万株/hm2时，产量达到5695.2kg/hm2；叶面积指数在出苗后84天达到最高，为5.29，总光合势达到2602269 m2.d/hm2；光合生产率在出苗后105天达到最大，为5.19 g/m2.d。“新大豆1号”在较低种植密度条件下，生长前期各项主要群体生理参数均优于较高种植密度；初花期和盛花期的叶面积指数、光合势和作物生长率与经济产量具有显著的相关性。     

利用小麦与玉米远缘杂交诱导小麦双单倍体的研究进展

利用小麦（Triticum aestivum L．）与玉米（Zea mays L．）进行远缘杂交,通过玉米染色体的消失而获得小麦单倍体胚,再经幼胚离体培养及染色体加倍诱导双单倍体（Double haploid,DH）,是小麦单倍体育种的一种重要途径,用这种方法创建的DH群体是进行小麦分子标记研究和QTL分析的重要遗传材料。本文对DH群体创建过程中影响单倍体胚产生、单倍体及双单倍体植株形成等因素以及双单倍体的应用进行了综述,重点探讨了亲本选配原则、花期调节技术、2,4-D处理、玉米花粉和小麦柱头发育状况以及环境因素等对诱导单倍体胚效果的影响等方面的研究状况,同时对利用小麦与玉米杂交诱导小麦双单倍体技术进行了展望。     

大豆粒茎比的遗传及其与其它农艺性状的相关研究

本试验是在前人研究基础上,利用未经选择的大豆F3、F4世代为试材,研究大豆粒茎比的遗传及与相关性状的关系,明确粒茎比的遗传规律、选择效果和它在产量选择中的作用,探索在哈尔滨生态条件下,适合的大豆粒茎比类型,为高产育种提供理论依据。大豆粒茎比于F3、F4代呈明显分离,各组合单株粒茎比的次数分布呈为单峰曲线,呈正态分布;大豆粒茎比的遗传是以加性为主的数量性状,早期世代遗传力低,不易选择,随着世代增加,遗传力增大,可在F4代和以后世代进行选择;大豆亲本粒茎比的中亲值与F3、F4代粒茎比的均值呈显著的正相关,中亲值可做为大豆杂交育种中亲本选配的一个指标;大豆粒茎比与植株高度、主茎节数、分支数、分支荚数、生物产量、收获重、茎重呈负相关,与主茎荚数、株粒数、百粒重呈正相关,长叶型株系粒茎比高于园叶型株系粒茎比;有限类型株系高于亚有限类型,说明随着进化程度提高大豆粒茎比值有提高的趋势;大豆粒茎比与单株产量的关系较复杂,在一定范围内大豆粒茎比值的提高产量会提高,超过一定的范围,产量会有所降低。说明在一定生态条件下,都有一定的适应大豆粒茎比类型,粒茎比大小反应了一定生态条件下所形成的生态类型。在哈尔滨田间条件下,大豆粒茎比值在0.9左右的品种类型,可望获得高产。     

Profiling and geographical distribution of seed oil content of sunflower in Ukraine

The sunflower has the potential to be a highly competitive crop owing to its diversity market and the valuable oil it produces. Nevertheless, the amount of sunflower seed oil – a key factor for the crushing industry – is affected by genotype and environment, which sometimes is difficult to predict. The paper analyzes the theoretical principles of sunflower growth in Ukraine, highlights the current trends in the sowing of this crop, the influence of climatic factors of the environment on the pros...     

茶种系间的亲缘关系及进化的酯酶同工酶分析

采用聚丙烯酰胺凝胶电泳法测定了103个茶树种质资源材料的酯酶同工酶(EST)。结果表明,EST 与茶形态分类特征有密切关系;茶树的进化途径为大叶茶→中叶茶→小叶茶,乔木型→小乔木型→灌木型。不同形态类型材料间亲缘关系分析表明,大叶茶与中、小叶茶间的关系较远,中叶茶与小叶茶之间的关系较近,进化水平相似,应属同一聚居群。形态学上的大叶茶实际上是一个亲缘关系相当复杂的类群。乔木与灌木型茶树间亲缘关系疏远,小乔木与灌木型茶树间的关系次之,而乔木与小乔木间的关系接近。     

EMS诱导的盛农1号小麦突变体筛选与鉴定

突变体诱导是创造小麦遗传材料和选育新品种的重要途径之一。通过甲基磺酸乙酯（EMS）处理高产、抗白粉病品系盛农1号,从4 500个M₂代穗系中筛选出174个突变体穗系,突变率为3.86%。其中,穗部突变体32个,突变率为0.71%;叶部突变体47个,突变率为0.89%;茎部突变体22个,突变率为0.49%;育性和成熟期突变体12个,突变率为0.27%;其他类型突变体11个,突变率为0.24%;农艺性状优于对照盛农1号的突变体57个,突变率为1.27%。经过M₃代验证及生物学性状和农艺性状调查,获得可稳定遗传的株系18个,其中,穗部突变体6个,茎秆突变体1个,叶部突变体6个,早熟突变体3个,晚熟突变体2个。农艺性状分析表明,穗部突变体SS4、SS5、SS6和SS16的小穗性状优于盛农1号。这些新突变体为小麦品种改良和遗传研究提供了新的材料。     

小麦×玉米产生的小麦单倍体植株的染色体加倍研究

为了研究秋水仙素对小麦×玉米产生的小麦单倍体的染色体加倍效果,分别用浓度为250、500、750、1 000 mg/L的秋水仙素溶液对单倍体植株进行浸根加倍处理.结果表明,单倍体植株的平均加倍率分别为51.9%、83.2%、86.4%、82.9%,平均加倍处理效率分别为46.1%、68.8%、71.7%、70.9%,均以浓度为750 mg/L的秋水仙素溶液处理效果最好.用浓度为500 mg/L的秋水仙素溶液浸根处理时持续供应O2,可获得79.9%的平均加倍率,高于没有O2供应的处理(72.7%);有O2供应的加倍处理效率(66.1%)也高于无O2供应的处理(62.2)%.