Responses of time of anthesis and maturity to sowing dates and infrared warming in spring wheat

Reliable prediction of the potential impacts of global warming on agriculture requires accurate data on crop responses to elevated temperatures. Controlled environments can precisely regulate temperature but may impose unrealistic radiation, photoperiod and humidity regimes. Infrared warming with automatic control of temperature rise has shown potential for warming field plots above ambient temperatures, while avoiding such biases. In a field experiment conducted at Maricopa, AZ, we assessed the utility of a temperature free-air controlled enhancement (T-FACE) approach by comparing phenology of wheat from a series of six sowing date treatments using T-FACE and an additional nine sowing dates that exposed crops to an exceptionally wide range of air temperatures (<0 °C to >40 °C). The T-FACE treatments were intended to achieve a warming of +1.5 °C during the daytime and +3.0 °C at night; the achieved warming averaged +1.3 °C during daytime and +2.8 °C at night. T-FACE and sowing date treatments had large effects on phenology. A regression-based analysis of simulations with the CSM-CROPSIM-CERES model showed that effects of T-FACE on phenology were similar to what would be expected from equivalent changes in air temperature. However, systematic deviations from the expected 1-to-1 relation suggested that assumed cardinal temperatures for phenology should be revised. Based on the single cultivar and location, it appeared that the base temperature for emergence to anthesis should be reduced from 0 °C to −5 °C, whereas the base temperature for grain filling should be increased from 0 °C to 4 °C and the optimal temperature, from 30 °C to 34 °C. Both T-FACE and extreme sowing date treatments proved valuable for improving understanding of high temperature effects on plant processes, as required for accurate prediction of crop responses to elevated temperatures under climate change.     

The chemical composition, digestibility and energy value of fermented and urea-treated whole crop wheat harvested at three stages of maturity

The metabolizable energy (ME) content, digestibility in vivo and chemical composition of fermented and urea-treated whole crop wheat (WCW) forage harvested were measured at different maturities. Over 2 years, twenty-four wheat forages (cv. Slepjner, Hussar and Cadenza) were harvested at 376, 516 and 632 g dry matter (DM) kg⁻¹ in Year 1 and 341, 467 and 544 g DM kg⁻¹ in Year 2 (Cuts 1, 2 and 3 respectively). Forages were conserved in 200−-ι barrels with or without a formic acid-based additive and with urea in Cuts 2 and 3 (20 or 40 g kg⁻¹ DM). Chemical compositions, digestibility in vivo and energy losses in faeces, urine and methane were measured in wethers fed 12 g DM kg⁻¹ live weight. Respective ranges in pH, crude protein, water-soluble carbohydrates, starch and neutral detergent fibre plus amylase (NDFA) contents were 3·8–8·5, 89–394, 2–43, 23–424 and 306–655 g kg⁻¹ DM. ME content, digestible organic matter content (DOMD) and digestibilities of starch and NDFA ranged between 8·4 and 15·7 MJ kg⁻¹ DM, 558 and 708 g kg⁻¹ DM, 0·901 and 0·999 and 0·362 and 0·693 respectively. Predicted methane energy losses were poorly correlated with measured values ( r ² < 0·45) in both years, but this accounted for less than 0.1 MJ ME kg⁻¹ DM. Significant ( P < 0.05) effects of maturity on the ME/DOMD ratio were observed and ascribed to differences in the extent of fermentation. Therefore, treatment application and maturity exert considerable influence on the ME content of WCW.     

今年我国茶叶生产有望继续增产增收

据农业部种植业管理司经作处消息：我国茶叶产销在连续5年取得年增长10%左右好成绩的基础上,2009年开局形势良好,春茶产销两旺,全年可望又是一个好年成。     

The Rht13 dwarfing gene reduces peduncle length and plant height to increase grain number and yield of wheat

The green-revolution Rht-B1b and Rht-D1b dwarfing alleles are usually associated with increased wheat yields but are linked to reduced early growth and poor emergence if sowing conditions are unfavourable. Other dwarfing genes are available but not used in commercial breeding. The Rht13 bread wheat donor, Magnif M1, produces uniquely short peduncle and penultimate internodes to reduce plant height. A set of near-isogenic (NILs) and recombinant inbred (RILs) lines varying for height were developed from the cross of Magnif M1 and the Rht8c-containing Chuan-mai 18, and evaluated for a range of agronomic characteristics across favourable environments. Reductions in plant height were associated with increased grain number (r² = 0.35**) and harvest index (r² = 0.62**) in the NILs. Reduced-height RILs containing the Rht13-linked, Xgwm577_M microsatellite marker were significantly shorter, produced greater biomass, yield and harvest index, and increased spike and grain number than lines without the marker. Approximately 74 and 7% of the total phenotypic variance in plant height was accounted for by allelic differences in Xgwm577 and Rht8 loci, respectively. The peduncle and penultimate peduncle internodes of Rht13-containing lines were proportionately shorter than Rht8c-containing sibs and lines containing the Rht-B1b dwarfing allele. The unique height-reducing phenotype, increased grain number and yield associated with Rht13 indicate considerable potential for use of this dwarfing allele for improving wheat performance.     

Apparent digestibility and nitrogen utilization of diets based on maize silage harvested at three stages of maturity and fed to steers

Advancing maize crop maturity is associated with changes in ear‐to‐stover ratio which may have consequences for the digestibility of the ensiled crop. The apparent digestibility and nitrogen retention of three diets (Early, Mid and Late) containing maize silages made from maize of advancing harvest date [dry matter (DM) contents of the maize silages were 273, 314 and 367 g kg^?1 for the silages in the Early, Mid and Late diets respectively], together with a protein supplement offered in sufficient quantities to make the diets isonitrogenous, were measured in six Holstein–Friesian steers in an incomplete Latin square design with four periods. Dry‐matter intake of maize silage tended to be least for the Early diet and greatest for the Medium diet (P = 0·182). Apparent digestibility of DM and organic matter did not differ between diets. Apparent digestibility of energy was lowest in the Late diet (P = 0·057) and the metabolizable energy concentrations of the three silages were calculated as 11·0, 11·1 and 10·6 MJ kg^?1 DM for the Early, Medium and Late diets respectively (P = 0·068). No differences were detected between diets in starch digestibility but the number of undamaged grains present in the faeces of animals fed the Late diet was significantly higher than with the Early and Mid diets (P = 0·006). The apparent digestibility of neutral‐detergent fibre of the diets reduced significantly as silage DM content increased (P = 0·012) with a similar trend for the apparent digestibility of acid‐detergent fibre (P = 0·078). Apparent digestibility of nitrogen (N) was similar for the Early and Mid diets, both being greater than the Late diet (P = 0·035). Nitrogen retention did not differ between diets. It was concluded that delaying harvest until the DM content is above 300 g kg^?1 can negatively affect the nutritive value of maize silage in the UK.     

Recovery of nitrogen from different sources following applications to winter wheat at and after anthesis

The effects of applying nitrogen (30 or 40 kg N/ha) to wheat crops at and after anthesis, after 200 kg N/ha had already been applied to the soil during stem extension, were studied in field experiments comprising complete factorial combinations of different cultivars, fungicide applications and nitrogen treatments. Actual recoveries of late-season fertilizer nitrogen (LSFN), as indicated by ¹⁵N studies, interacted with cultivar and fungicide treatment, and depended on nitrogen source (urea applied as a solution to the foliage, or as ammonium nitrate applied to the soil) and year. These interactions, however, were not reflected in apparent fertilizer recoveries ((N in grain with LSFN − N in grain without LSFN)/N applied as LSFN), or in the crude protein concentration. Apparent fertilizer recovery was always lower than actual recoveries, and declined during grain filling. Fertilizer treatments with higher actual fertilizer recoveries were associated with lower net remobilisation of non-LSFN (net remobilised N = N in above ground crop at anthesis − N in non-grain, above ground crop at harvest). LSFN also increased mineral nitrogen in the soil at harvest even when applied as a solution to the foliage. These effects are discussed in relation to potential grain N demand.     

Control of Rhagoletis indifferens using thiamethoxam and spinosad baits under external fly pressure and its relation to rapidity of kill and residual bait activity

Control of western cherry fruit fly (Rhagoletis indifferens Curran) using thiamethoxam in sucrose bait (sucrose only) and spinosad bait (GF-120, spinosad in a mix of sugar, protein, ammonium acetate, and other ingredients) in cherry orchards with external fly pressure and the residual activity of these baits were studied in Washington state and Utah, U.S.A., in 2010 and 2011. Thiamethoxam baits applied weekly controlled larval infestations better than spinosad bait applied weekly in one of four trials and did not differ from spinosad bait applied weekly in the remaining trials. Thiamethoxam baits applied every two weeks controlled larval infestations better than spinosad bait applied every two weeks in two of three trials, and did not differ statistically from spinosad bait applied weekly. Thiamethoxam bait that was aged on sweet cherry leaves in the field for 0, 7, 14, and 21 days killed flies more rapidly than spinosad bait that was aged for the same periods and reduced oviposition more than spinosad bait in the laboratory. Thiamethoxam bait retained activity up to 21 days of aging whereas spinosad bait lost activity after 14 or 21 days of aging. Results suggest that when there is external fly pressure, the potentiality of thiamethoxam bait to kill mature R. indifferens more rapidly than spinosad bait may not always translate to better fly control. However, when sprays are applied every two weeks, the longer residual activity of thiamethoxam than spinosad bait does appear to translate to better fly control. This study presents thiamethoxam with sucrose as a new option for an effective bait spray against R. indifferens.     

Use of dry-moist heat effects to improve the functionality,immunogenicity of whole wheat flour and its application in bread making

Whole wheat flour samples having protein content of 8.9% and 10.6% were subjected to dry and moist heat conditions to improve the functionality. Dry heat treated flours (DHTF) had higher values of falling number and SDS sedimentation values when compared to moist heat treated flour (MHTF). MHTF showed decrease in water absorption from 75.4 to 56.7%, increase in dough development time from 3.3 to 11.9 min, increase in peak viscosity and cold paste viscosity from 467 to 778 BU and 678 to 1017 BU respectively when compared to untreated flour. MHTF lost its elasticity, SDS-page gel electrophoresis indicated the change especially in the region of gliadin and ELISA indicated 41% reduction in immunogenicity against gliadin. The specific volume of breads prepared from MHTF was significantly lower whereas the crumb firmness value was higher than breads from untreated flours. Breads from treated flours also showed reduction in immunogenicity against gliadin.     

Genetic resistance to and effect of leaf rust and powdery mildew on yield and its components in 50 soft red winter wheat cultivars

Effects of leaf rust (caused by Puccinia triticina f. sp. tritici Eriks.) and powdery mildew [caused by Blumeria graminis (DC.) E. O. Speer f. sp. tritici Em. Marchal], on performance of 50 soft red winter (SRW) wheat (Triticum aestivum L) cultivars were evaluated under natural field conditions. Widely grown cultivars released from 1919 to 2009 with varying disease resistance were grown in split-plot experiments in 2010 and 2011. Treated replications received seed treatments of triadimenol, captan and imidacloprid and foliar applications of propiconazole and prothioconazole + tebucanazole fungicides. Non-treated replications received only tebucanazole + metalaxyl + imazalil seed treatments. Final mean disease severity, agronomic, yield-related traits, yield components and spike characteristics were analyzed to determine individual and combined effects of leaf rust and powdery mildew on the cultivars. Yield losses as high as 54% were observed in the susceptible cultivar Red May. Average yield losses ranged from 1% to 21%. Yield losses primarily due to powdery mildew were as high as 14%, and losses primarily due to leaf rust were as high as 33%. Powdery mildew had the largest negative correlation with harvest index and seeds/spike. Leaf rust was most negatively correlated with plant biomass and harvest index, with a less consistent negative relationship with kernel weight.     

不同生育期芝麻根系分泌物对连作障碍的响应及其自毒作用

为探讨芝麻根系分泌物中可能导致连作障碍的化感物质,以江西主栽品种金黄麻为材料,设置正茬与连作处理,研究芝麻现蕾期、盛花期和成熟期根系分泌物的组分变化与差异。结果表明：正茬芝麻根系分泌物对芝麻种子的发芽表现出“低促高抑”现象。正茬和连作芝麻在现蕾期、盛花期和成熟期的根系分泌物中鉴定出18～28种有机物。现蕾和盛花期芝麻根系分泌物均含有酯类、烃类、酸类、酚类、胺类、醇类和酮类物质,以反式-（2,3-二苯基环丙基）-苯亚砜甲酯相对丰度为最高;成熟期比现蕾和盛花期多醚类物质,以辛乙烯二醇单正十二烷基酯相对丰度为最高。酯类物质是芝麻根系分泌物的重要组分,尤其在现蕾期其总相对丰度达到75.12%（正茬）、52.96%（连作）。其中,邻苯二酸二异辛酯和辛乙烯二醇单正十二烷基酯的相对丰度在连作芝麻根系分泌物比正茬中高9.48和5.73个百分点。酸类物质在芝麻成熟期根系分泌物中含量最高,总相对丰度在正茬与连作芝麻根系分泌物中分别达17.53和42.71个百分点。其中,连作芝麻根系分泌物中棕榈酸、亚油酸和硬脂酸的相对丰度依次提高15.78、1.33和1.15个百分点;油酸、肉豆蔻酸仅在连作芝麻根系分泌物中检测到,相对丰度为10.66和1.62个百分点。与正茬相比,芥酸酰胺在现蕾期和盛花期的连作芝麻根系分泌物中相对丰度分别提高21.68和11.51个百分点;油酸酰胺相应提高2.16和7.44个百分点。综上,连作改变了芝麻根系分泌物组分。     

Effect of field history on the cereal leafminer Syringopais temperatella Led. (Lepidoptera: Scythrididae) and its preference to different wheat and barley cultivars

Due to the importance of wheat and barley production in Jordan, prevention of the cereal leafminer, Syringopais temperatella Led. (Lepidoptera: Scythrididae) is of vital importance. The insect is a severe pest and plays an important role in limiting the production of these crops. The use of insecticides is neither economic nor sustainable, so that there is an urgent need to initiate a viable alternative to chemical control. Therefore, this study aimed at investigating the effect of crop rotation on S. temperatella and its preference to different wheat and barley cultivars. The field history experiment was conducted using five different crop rotations. For the preference experiments in the laboratory, two major experimental groups were conducted. The first was set up to measure the consumed leaf area and the second one to record the number of larval attaches. Each group consisted of four different subgroups; 6 wheat cultivars, 6 barley cultivars, two and one cultivar of each crop. The results indicated that the infestation percentage and number of larvae were significantly the lowest in the crop rotation, wheat/chickpea/wheat while the highest were recorded for barley/barley/barley. The preference results showed that wheat cultivar, Horani Nawawi is significantly the most preferred while Horani 27 is the least cultivar. In case of barley, Mutah was the most preferred cultivar and the least preference was recorded for Athroh. Also, wheat was significantly less preferred than barley. The wheat cultivars, Sham, Em-Qees and Acsad 65 had the highest number of attaches and Deer Alla the least. In contrast, the barley cultivar, Acsad 176 had the highest and Athroh and Rum 1 had the least attaches. Barley cultivars had higher attaches than wheat ones. There was a positive relation between the infestation percent and number of larvae, as well as the consumed area and number of attaches in all of the four subgroups. In conclusion, the crop rotation, wheat/chickpea/wheat should be followed and there is a preference variation among the tested wheat and barley cultivars.     

Intra-specific variation of wheat grain quality in response to elevated [CO2] at two sowing times under rain-fed and irrigation treatments

In order to investigate the intra-specific variation of wheat grain quality response to elevated atmospheric CO₂ concentration (e[CO₂]), eight wheat (Triticum aestivum L.)cultivars were grown at two CO₂ concentrations ([CO₂]) (current atmospheric, 389 CO₂ μmol mol⁻¹vs. e[CO₂], FACE (Free-Air CO₂ Enrichment), 550  ±  10% CO₂ μmol mol⁻¹), at two water levels (rain-fed vs. irrigated) and at two times of sowing (TOS₁, vs. TOS₂). The TOS treatment was mainly imposed to understand whether e[CO₂] could modify the effects of timing of higher grain filling temperatures on grain quality. When plants were grown at TOS₁, TKW (thousand kernel weight), grain test weight, hardness index, P, Ca, Na and phytate were not significantly changed under e[CO₂]. On the other hand, e[CO₂] increased TKW (16%), hardness index (9%), kernel diameter (6%), test weight (2%) but decreased grain protein (10%) and grain phytate (11%) at TOS₂. In regard to grain Zn, Mn and Cu concentrations and some flour rheological properties, cultivar specific responses to e[CO₂] were observed at both sowing times. Observed genetic variability in response to e[CO₂] in terms of grain minerals and flour rheological properties could be easily incorporated into future wheat breeding programs to enable adaptation to climate change.     

苗期渍水对直播冬油菜产量和农学利用率的影响及油菜在不同氮肥施用下的响应

在轻简化施肥背景下,为减少渍害损失,解决长江流域冬油菜产区生产面临的重要问题,开展氮肥施用 对油菜渍害的缓解作用研究。设置三因素田间试验,分别为不同氮肥用量（0、60、120、180、240和300 kg N/hm2）、氮 肥类型（油菜专用控释尿素和普通尿素）和水分处理（苗期渍水和正常排水）,测定各处理产量和氮肥农学利用率, 明确苗期渍水对不同氮素供应水平油菜的影响,并比较油菜专用控释尿素一次性施用和普通尿素分次施用下油菜 对苗期渍水的响应。结果表明,直播冬油菜产量随氮肥施用量增加而提高,至240 kg N/hm2时不再增加。油菜专用 控释尿素一次性施用,在氮肥用量为60～180 kg N/hm2时产量高于普通尿素分次施用;在氮肥用量为240～300 kg N/hm2时,两种氮肥类型产量基本相当。氮肥施用通过增加收获密度、单株角果数和每角粒数提高产量。苗期渍水 导致直播冬油菜产量损失1.1%～41.9%,随氮肥用量增加,渍水引起的产量损失率呈先增加后降低趋势。0～60 kg N/hm2处理时,渍水使收获密度显著降低（降幅达29.4%~45.0%）,单株角果数增加;施氮量为120~180 kg N/hm2时, 渍水导致收获密度和单株角果数分别降低19.5%~33.7%和1.4%~17.7%;施氮高于180 kg N/hm2时,收获密度和单 株角果数降幅减小（降幅分别为5%~30.9%和3.6%~9.5%）。普通尿素分次施用和油菜专用控释尿素一次性施用, 分别在施氮量为120和180 kg N/hm2时产量损失率最高,分别达29.8%和41.9%。相同氮肥用量下油菜专用控释尿 素一次性施用的产量损失率大于普通尿素分次施用。渍水显著降低氮肥农学利用率,降幅为8.4%～51.9%,施氮充 足（240～300 kg N/hm2）时氮肥农学利用率降幅低于氮素用量较低处理（120～180 kg N/hm2）,油菜专用控释尿素一 次施用处理的农学利用率平均降幅（36.5%）高于普通尿素分次施用（17.3%）。综上可知,苗期渍水时,油菜专用控 释尿素一次施用,会加重油菜受渍影响;土壤氮素供应能力较低时,渍害逆境解除后,适量追施速效氮肥可有效缓 解产量损失,实现油菜稳产。     

Contribution of main stem and tillers to durum wheat (Triticum turgidum L. var. durum) grain yield and its components grown in Mediterranean environments

Under terminal drought conditions, cereal varieties with limited tillering have been suggested to be advantageous, because they have fewer nonproductive tillers, thereby limiting water consumption prior to anthesis. In this study, four field trials were conducted over two growing seasons in southern Spain, under rainfed and irrigated conditions. Twenty-five genotypes were studied to evaluate the contribution of the main stem (MS) and tillers to grain yield and its components. Significant differences were found among genotypes for these contributions under non-stressed environments, but these differences were not significant under water-stress conditions. The contribution of the MS to plant grain yield was higher than that of tillers (68% vs. 32%) and was stable between years in irrigated trials. However, in the rainfed trials, MS contributed differently depending on year-to-year climate variations. Thus, under favorable weather conditions the contribution of MS to grain yield was higher than in the unfavorable year (85% vs. 59%). In irrigated environments, MS and tiller grain yield depended on the number of grains per spike, spikelets per spike, and thousand kernel weight (TKW). Under water-limited conditions, MS yield depended on the number of grains per spike and grains per spikelet, whereas the number of spikelets and TKW had less influence on MS grain yield. Furthermore, under water-stress conditions, high tillering genotypes showed yield levels similar to the genotypes with restricted tillering. Additionally, there was no significant evidence of a positive or negative effect of maximum tiller number on grain yield under rainfed conditions.     

水稻灌浆期耐热性的品种间差异及其与剑叶光合特性和内源多胺的关系

对65个不同来源的早籼稻品种进行了灌浆期耐热性的鉴定研究,并比较了耐热性相差很大的品种灌浆期高温胁迫前后的生理反应。结果表明：秕粒率、实粒重、整精米率、垩白度、蛋白质含量的胁迫指数可作为水稻品种灌浆期耐热性田间直接鉴定的 5个指标,可采用隶属函数值法对各品种的耐热性进行综合评价;不同品种的耐热性存在相当大的差异,筛选出了几个耐热性很强的品种;高温胁迫严重影响水稻的光合能力,但耐热性强的品种剑叶的光合速率高温胁迫后下降幅度明显较小,胁迫解除后恢复的程度也更高,叶绿素含量、RuBPc 活性及内源多胺含量的变化趋势与光合速率相一致,是水稻耐高温逼熟的重要生理特征。     

水稻灌浆期耐热性的品种间差异及其与剑叶光合特性和内源多胺的关系

 对65个不同来源的早籼稻品种进行了灌浆期耐热性的鉴定研究,并比较了耐热性相差很大的品种灌浆期高温胁迫前后的生理反应。结果表明：秕粒率、实粒重、整精米率、垩白度、蛋白质含量的胁迫指数可作为水稻品种灌浆期耐热性田间直接鉴定的 5个指标,可采用隶属函数值法对各品种的耐热性进行综合评价;不同品种的耐热性存在相当大的差异,筛选出了几个耐热性很强的品种;高温胁迫严重影响水稻的光合能力,但耐热性强的品种剑叶的光合速率高温胁迫后下降幅度明显较小,胁迫解除后恢复的程度也更高,叶绿素含量、RuBPc 活性及内源多胺含量的变化趋势与光合速率相一致,是水稻耐高温逼熟的重要生理特征。     

Matrix-fibril morphology development of polypropylene/poly(butylenes terephthalate) blend fibers at different zones of melt spinning process and its relation to mechanical properties

Different shapes of dispersed phase such as sphere, laminar and fibrillar can form in the matrix phase of polymer blends. Production of blend fibers in melt spinning process can result more effective in fibrillar phase morphology formation than in other processes. In this research, the matrix-fibril morphology development during the melt spinning of polypropylene/poly(butylenes terephthalate) was studied. The shapes of blend dispersed phase collected from different zones of the melt spinning line were evaluated by scanning electron micrographs (SEM) and rheological mechanical spectra (RMS). The results showed that fibrillar shape could not be created in the PP/PBT blend fiber samples exited from the spinneret orifice (gravity spun fibers) at low contents (5 percent) of the PBT dispersed phase. However, a complete fibrillar structure was formed in all the as-spun PP/PBT blend fiber samples (melt drawn). The rheological evaluations confirmed a network structure resulting from fibril formation for the samples with high contents (20–40 %) of the PBT dispersed phase and the formation of spherical shape with low contents (5–10 %) of the PBT dispersed phase in matrix of the blend fibers. It was observed that the flow fields of processing zones and blend ratio, in producing the blend fibers, have intensive effects on morphological variations; besides there was a strong relation between the mechanical and morphological properties.