春季追肥对冬小麦群体构建和籽粒灌浆进程的影响

为明确冬小麦春季合理追肥技术,以追肥时间（返青后10、25和40d）为主区,追肥量（90、120和150kg/hm²）为副区,研究春季追肥对冬小麦群体分蘖动态变化、籽粒灌浆进程、产量及氮效率的影响。结果表明,返青后25d较其他追肥时间显著提高了开花期分蘖数,追氮量为120kg/hm²时最高。返青后25d较其他追肥时间显著提高了籽粒灌浆起始势,籽粒达最大灌浆速率时间提高了1%~20%,提高灌浆过程中快增期和缓增期的灌浆速率,追氮量以120kg/hm²表现最好。返青后25d较其他追肥时间显著提高了成熟期植株干物质量及穗部结实性状,穗数、穗粒数、千粒重和产量分别提高8%~11%、7%~12%、3%~5%和8%~30%,且显著提高了氮肥偏生产力,以追氮量120kg/hm²最高。总之,返青后25d追肥可有效调控冬小麦春季分蘖消长,增加有效穗数,促进籽粒灌浆,提高粒重,且追施氮120kg/hm²实现了产量和氮效率同步提高。     

基于随机前沿分析的不同粮食生产规模农户生产技术效率差异及影响因素分析

本文以陕西省关中地区高陵县、泾阳县、岐山县三个地区不同经营规模农户为研究对象,运用超越对数生产函数对农户粮食生产的生产效率进行测度,并对影响农户生产技术效率的外生变量进行Tobit回归分析。结果表明:中等经营规模农户生产效率高于小规模农户和较大规模的农户;在影响因素中,劳动力年龄、农户家庭非农收入、农业与非农收入比例、农户播种面积、粮地租出比例、规模这些因素均对粮食生产技术效率有显著影响,而劳动力受教育年限和土地租出率均对生产技术效率无显著影响。     

全国种粮养牛发展分析

1951—2010年全国的粮食总产量是波动性增长。波动原因是粮食种植面积的波动,增长原因是粮食种植技术的进步。2010年全国粮食供给已是“北粮南运”。东北地区是全国的“粮仓”,黄淮海地区次之,长江中下游地区人均粮食产量只略高于全国平均水平。全国秸秆养牛已由畜力生产转为肉、奶生产,但人均水平较低。全国种粮养牛今后发展的目标应是人均粮食产量适度、粮食产量结构合理和秸秆养牛规模适量,其实现途径是科学化种粮养牛、综合开发种粮养牛乡村以及保证开发方针政策的正确。      

Thiamin (vitamin B1) and thiamin phosphate esters in five cereal grains during maturation

Non-phosphorylated thiamin (T), thiamin monophosphate (TMP), and thiamin diphosphate (TDP) were extracted from whole grains of wheat (Triticum aestivum, cv. Dekan), triticale (Triticosecale, cv. SW Talentro), rye (Secale cereale, cv. Agronom), oats (Avena sativa, cv. Dominik), and barley (Hordeum vulgare, cv. Merlot) at different growth stages (from inflorescence emergence to full ripeness of the grains) and determined with high-performance liquid chromatography and fluorescence detection. No thiamin triphosphate or adenosine thiamin triphosphate was found in these cereals. Total thiamin levels (the sum of T and its phosphate esters) determined on a dry matter (DM) basis were found to be quite similar in all grain samples throughout the analysis period, ranging from 5.59 (wheat) to 13.00 nmol/g DM (oats). In spikelets 3–5 days after flowering, the total thiamin content in all cereals was 40–75% T, 5–13% TMP, and 18–46% TDP. Generally, T increased and TDP decreased continuously with grain development, with maximum T (88–99%), and minimum TDP (2–10%) at ripeness. No TMP was detected in mature grains. The results indicate that variation in T, TMP, and TDP levels is probably due above all to the conversion of phosphorylated thiamin phosphate esters into less highly or non-phosphorylated forms.     

The Pinb-2 genes in wheat comprise a multigene family with great sequence diversity and important variants

The puroindoline genes Pina-D1 and Pinb-D1 located at the Ha locus on chromosome 5D of common wheat are considered the most important genetic determinants of grain hardness. The recent identification of Pinb-2 genes on group 7 chromosomes emphasises the need for detailed analysis of the genetics of this important trait. This study focussed on the analysis of Pinb-2 genes from accessions of hexaploid, tetraploid and diploid wheat, to address key questions related to their diversity and possible roles. Extensive DNA sequence heterogeneity was identified in the form of single nucleotide polymorphisms (SNPs), leading to seventeen reproducible haplotypes, of which thirteen are new. The results confirmed the known groups Pinb-2v1 to Pinb-2v5, identified a new group Pinb-2v6, and showed that the Pinb-2 genes comprised a small multigene family, at least in some genomes. The putative proteins exhibited changes at the important tryptophan-rich domain as well as basic and hydrophobic residues. A new Pina-D1 allele (at Ha locus) was also identified, designated Pina-D1t, with a premature stop codon at the TRD. Additionally, peptides designed on PINB-2 proteins displayed activity against bacteria and phytopathogenic fungi. The data strongly support the Pinb-2 genes being functionally relevant to roles including influencing grain texture.     

Puroindolines are associated with decreased polar lipid breakdown during wheat seed development

The wheat Hardness (Ha) locus consists of Puroindoline a (Pina) and Puroindoline b (Pinb) and controls whether wheat is soft or hard textured. PINA and PINB act cooperatively to create grain softness and are associated with increased polar lipids at seed maturity. Here we examined developing seeds varying in PINA or PINB content to identify when polar lipid differences occur. One population carried Wild Type (WT) PINA while varying for the presence of PINB, while the other population carried a WT PINB and segregated for PINA. For the PINB segregating population, polar lipids were maximal on a per mg dry weight basis at 7–14 days after anthesis (DAA) while for PINA segregating population, total polar lipids were maximal at 7–21 DAA. The most abundant polar lipids at maturity were mono- and di- galactosyldiglyceride. No individual polar lipid species were specific to PINA or PINB. The effect of both PINA and PINB increased throughout seed development with greater decreases in the most abundant polar lipids in genotypes lacking either PINA or PINB. The results indicate that PINA and PINB act cooperatively to prevent polar lipid breakdown during seed maturation and that this process is central to the development of grain softness.     

育秧方式和壮秧剂对抛栽晚稻生长及产量的影响

以杂交水稻“桂两优2号”为试材,设土床旱育秧（A1）、编织布旱育秧（A2）、塑盘旱育秧（A3）、塑盘湿润育秧（A4）4种方式,在不同育秧方式基础上设置施用壮秧剂和不施壮秧剂2个处理水平,研究育秧方式对抛栽晚稻生长及产量的影响。结果表明：抛栽后立苗最快的是A2,其次是A3,A1和A4最慢;分蘖最快、数量最多的是A2,其次是A3和A1,A4分蘖最慢、数量最少;干物质积累A2和A3具有明显优势,其次是A1,A4积累最少;A2的产量最高,产量性状较好,其次是A3,A4产量最低、产量性状较差。施用壮秧剂可促进晚稻生长,改善产量性状,提高产量。育秧方式与壮秧剂交互作用对晚稻产量及主要性状有显著影响。综合晚稻生长和产量及性状看,本试验条件下最适合的育秧方式是编织布与施壮秧剂组合旱育秧。     

黄淮海区域小麦、玉米双机收籽粒:实施措施及建议

针对黄淮海区域冬小麦、夏玉米一年两熟的耕作制度,为整体提高该地区粮食生产效率,降低人力成本,实现小麦玉米双机收籽粒,提出了通过晚播小麦10~15天,为玉米机收让出籽粒脱水时间,同时提出配套使用适宜机收籽粒的早熟、脱水快玉米新品种及栽培管理措施。通过制定小麦、玉米全程机械化技术体系,开展全方位协作攻关,进行小麦、玉米双机收品种筛选和培育,改进籽粒收获配套机械,开发配套烘干籽粒设备,并通过政府的农业扶持项目帮助产业升级,促进该地区粮食生产的全面提升。     

不同播期条件下京单68和郑单958的籽粒灌浆特性

（北京市农林科学院玉米研究中心,北京100097） 摘要：研究不同播期条件下京单68和郑单958的籽粒灌浆特性。以京单68和郑单958为试材,设置春播（5月14日）和夏播（6月13日）2个播期处理。结果表明：春播条件下玉米灌浆期间的平均温度、最高温度、最低温度和积温分别比夏播条件高1.22 ℃、0.54 ℃、2.37 ℃和480.54 ℃。春播条件下京单68和郑单958的最终百粒干物重分别为43.03 g和39.02 g,夏播条件下分别为41.17 g和34.80 g。不同播期间,参试品种灌浆速率最大时的生长量（Wmax）和活跃灌浆期积温（P）均表现为春播高于夏播;而最大灌浆速率（Gmax）、灌浆起始势（Ro）、到达最大灌浆速率时的积温（TGDD）呈相反趋势。同一播期不同品种间,TGDD和P表现为郑单958高于京单68,而Wmax、Gmax、Ro表现为京单68高于郑单958。该研究表明,京单68较郑单958灌浆启动早,积累起始势大,最大灌浆速率高,达到最大灌浆速率、活跃灌浆期积温少,京单68最终百粒干物重高于郑单958。     

施氮深度对旱地小麦耗水特性和干物质积累与分配的影响

为确定黄淮冬麦区旱地小麦施氮技术的最佳施肥深度,2010-2012连续两年度在大田条件下设置氮肥表面撒施(D1),施氮深度10 cm (D2)、20 cm (D3)和30 cm (D4) 4个处理,研究了施氮深度对旱地小麦山农16和烟农0428耗水特性和干物质积累与分配的影响。与D1和D2处理相比,D3和D4处理在拔节至开花期和开花至成熟期的耗水量显著提高,40~120 cm土层土壤贮水消耗量显著增加,在降水量较丰富的2011-2012年度,D3和D4处理120~160 cm土层土壤贮水消耗量也显著高于D1和D2处理(高4.0~5.3 mm), 说明20~30 cm施氮肥有利于提高土壤水分的利用, 尤其是土壤深层贮水的利用,满足小麦拔节后的水分需求; D3和D4处理拔节至开花期和开花至成熟期干物质积累量均显著高于D1和D2处理,成熟期和开花后干物质积累量分别高642.1~2006.8 kg hm^-2和394.5~723.1 kg hm^-2。D3的籽粒产量和氮肥偏生产力与D4无显著差异,均显著高于D1和D2,水分利用效率较高。因此,20 cm是黄淮冬麦区旱地冬小麦的适宜施氮深度。