Changes in N Composition of Sugar Beet Varieties in Response to Increasing N Supply

The soluble nitrogen (N) components in sugar beet seriously impair sugar recovery. The only N component determined routinely in the sugar factory is amino N (the sum of amino acids in the beet), which is assumed to reflect all the other N components. Amino N is affected by N supply and variety, but only little is known about the other N components such as total soluble N, betaine and nitrate. This study aimed at investigating the effect of N supply on the N composition of sugar beet varieties with special emphasis on N supply by variety interactions. In 2001 and 2002, field trials with four varieties and four N treatments were carried out at six sites in Germany. Storage root yield and the concentrations of sucrose, sodium, amino N, betaine, nitrate and total soluble N in the beet were determined. With increasing N supply, the concentration of amino N increased considerably and that of nitrate slightly, whereas that of betaine remained rather constant. Thus, the N composition of sugar beet changed with increasing N supply and the percentage of amino N of total soluble N increased. Although amino N has the closest correlation with total soluble N, for quality assessment it may overestimate the effect of N supply on other N components. Varieties clearly differed in root yield and quality as well as in all N components. The variety with the lowest amino N had the highest betaine concentration. However, as related to the concentration of total soluble N in the beet, for all varieties amino N as well as betaine showed the same response pattern. This indicates that the N composition of sugar beet is determined by the level of total soluble N, irrespective of variety or N supply. All varieties required the same N supply for obtaining maximum yield or quality. N supply did not affect the ranking of the varieties for all parameters studied, consequently it need not be considered for variety choice.     

Nitrogen efficiency of canola genotypes varies between vegetative stage and grain maturity

There is no information on whether N efficiency in canola at maturity can be reliably determined by screening germplasm in the vegetative stage. Twelve canola genotypes identified in preliminary screening study as having either high or low N efficiency indices were tested for consistency in N efficiency between the vegetative stage and maturity. Plants were grown in a glasshouse under low or adequate N supply and N efficiency was assessed using the following criteria: dry weight at deficient N supply, relative yield at low vs. adequate N supply, and N utilisation efficiency. None of the 12 tested genotypes was classified as efficient or inefficient under all three criteria. One genotype (46C74) was classified as efficient under two criteria, and one genotype (Surpass 300 TT) was inefficient under two criteria. At maturity, three additional efficiency criteria were used: harvest index, N harvest index, and oil and protein concentration in seed. Two genotypes (Wesway and 46C74) (ranked as efficient at vegetative stage) remained efficient at maturity under most of the efficiency criteria used. On the other hand, genotype Surpass 603 CL ranked inefficient during the vegetative stage was ranked as efficient at maturity under two criteria. Overall, there was little consistency in the N efficiency ranking between vegetative stage and maturity in 12 tested genotypes. Screening canola germplasm for N efficiency for breeding purposes would therefore require an assessment at maturity.     

提高籼稻优质米品种成熟胚培养力的研究

以四个籼稻优质米品种的成熟胚为外植研究了培养基中的激素成分及琼脂浓度对培养力的影响。结果表明：（1）成熟胚组织培养力在品种间存在明显差异，99-WT15的诱导率最高，达93.0%，而中优早81仅为63.0%，相差30%；分化率以中早16最高，达62.0%，而中优早81和99-WTI15较低，分别为22.5%和15.6%。（2）基本培养基对诱导率无明显影响，但对分化率有后续效应，诱导培养基中以M8为基本培养基比以N6要高。（3）分化培养基中的激素配比对分化率的影响较大，2mg/L 6-BA与1mg/L NAA配比优于2mg/L KT与1mg/L NAA配比，分化率提高了11.9%。（4）提高琼脂浓度有利于成熟胚愈伤组织的变化，2%琼脂浓度的分化率比1%琼脂浓度的分化率提高4.3%～30.8%，平均提高13.2%。     

水稻品种种性研究 Ⅵ.晚籼稻优质品种数量性状遗传差异在选择亲本上的应用

35个华南地区水稻晚籼具有细长粒形的优质品种根据数量性状遗传差异进行系统聚类分析,分为6个类群。类群间差异比类群内大。表明水稻外观性状品质育种杂交亲本选配应在类群间进行。     

Proximal optical sensing of cucumber crop N status using chlorophyll fluorescence indices

Sustainable N management of intensive vegetable crops requires accurate and timely on-farm assessment of crop N status. Proximal fluorescence-based sensors are promising tools for monitoring crop N status, by providing non-destructive optical measurements of N-sensitive indicator compounds such as chlorophyll and flavonols. The ability of the Multiplex^® fluorescence sensor to determine crop N status was evaluated in two indeterminate cucumber crops grown in contrasting seasons (autumn and spring). Three fluorescence indices, leaf chlorophyll (SFR) and flavonols (FLAV) contents, and their ratio (Nitrogen Balance Index, NBI) were evaluated, and their consistency between the two crops compared. Actual crop N status was assessed by the Nitrogen Nutrition Index (NNI), calculated as the ratio between the actual and the critical crop N contents (i.e., the minimum N content for maximum growth). There were strong relationships between each of SFR, FLAV and NBI with crop NNI, for most weekly measurements made throughout the two crops. For the three indices, coefficients of determination (R²) were mostly 0.65–0.91 in the autumn crop, and 0.71–0.99 in the spring crop. SFR values were generally comparable between the two crops, which enabled the derivation of common relationships with NNI for individual phenological phases that applied to both cropping seasons. FLAV and NBI values were not comparable between the two crops; FLAV values were appreciably higher throughout the spring crop, which was attributed to the higher solar radiation. Consequently, phenological relationships of FLAV and NBI with NNI were established for each individual cropping season. Our findings suggested that SFR was the most consistent index between cropping seasons, and that NBI was the most sensitive index within each season. Regardless of the index and crops, all fluorescence indices were weakly related to crop NNI during the short vegetative phase while stronger relationships were found in the reproductive and harvest phases. This study also showed that the three fluorescence indices were sensitive to and able to distinguish deficient from optimal crop N status, but that they were insensitive to discriminate optimal from slightly excessive N status. Overall, this study demonstrated that fluorescence indices of chlorophyll content (SFR), flavonols content (FLAV) and nitrogen sufficiency (NBI) can be used as reliable indicators of crop N status in cucumber crops; however, there was variability in FLAV and NBI values between cropping seasons and a lack of sensitivity in the range of optimal to slightly excessive crop N status.     

Delayed permanent water rice production systems do not improve the recovery of 15N-urea compared to continuously flooded systems

Crop recovery of nitrogen (N) fertiliser in flooded rice systems is low relative to fertiliser N recoveries in aerobic crops, and the N losses have environmental consequences. Recent water shortages across the globe have seen a move towards alternative water management strategies such as delayed permanent water (DPW, also known as delayed flood). To investigate whether N fertiliser regimes used in DPW systems result in greater recovery of N fertiliser than traditional continuously flooded (CF) rice systems, we conducted a multi-N rate field trial using ¹⁵N-labelled urea. Around 27% of the ¹⁵N-labelled fertiliser was recovered in aboveground biomass at maturity, regardless of water regime or N fertiliser rate, and approximately 20% recovered in the soil to 300 mm depth. Plants in the CF system accumulated more total N at each rate of applied N fertiliser than plants in the DPW system due to greater exploitation of native soil N reserves, presumably because the earlier application of N fertiliser in the CF systems led to greater early growth and higher crop N demand. The greater crop biomass production as a result of higher N uptake in the CF system did not increase grain yields above those observed in the DPW system, likely due to cold weather damage. In the following season at the same site, a single N rate (150 kg N ha⁻¹) trial found no significant differences in crop N uptake, biomass yields, grain yields or ¹⁵N-labelled urea recovery in DPW, CF and drill sown-CF (DS-CF) treatments. However, owing to higher ¹⁵N fertiliser recovery in the 0–100 mm soil horizon, total plant + soil recovery of ¹⁵N was significantly higher in the CF treatment (63%) than the DS-CF and DPW treatments (around 50% recoveries). The loss of 40–50% of the applied N (presumably as NH₃ or N₂) in both seasons regardless of watering regime suggests that new fertiliser N management strategies beyond optimising the rate and timing of urea application are needed, particularly in light of increasing N fertiliser prices.     

不同氮肥运筹模式对冬小麦籽粒产量品质和氮肥利用率的影响

在高肥力条件下,研究了不同氮肥运筹模式对冬小麦籽粒产量、品质、氮肥利用率和土壤中硝态氮累积量的影响。结果表明,在本试验条件下,施用氮肥对籽粒产量、籽粒蛋白质含量和湿面筋含量无显著影响,而作为籽粒蛋白质质量指标的沉淀值、面团形成时间和面团稳定时间均明显改善。与分次施用（50%作底肥,50%作追肥）比较,拔节     

用叶面标记态15N研究冬小麦不同叶位氮素的运转

以叶面涂抹^15N方式对不同类型冬小麦品种不同叶位叶片氮素的吸收、运转进行了研究。结果表明,冬小麦生育后期不同叶位叶片对子粒品质的贡献不同,旗叶对子粒的贡献高于其他叶位叶片。不同蛋白含量类型中,普通子粒蛋白类型的京冬8后期叶片氮素含量下降快,植株氮素含量低,而其转运效率高;子粒高蛋白类型中优9507品种氮素收获指数低于京冬8,其子粒中高的蛋白质含量是由于其高吸收、高贮存的结果。中优9507茎秆贮存氮素的能力较强,京冬8子粒中氮素的积累更多地依赖于叶片氮素的供应。     

优质小麦新品种小偃503的选育及产业化示范初报

利用远缘杂交与常规育种技术相结合选育的优质小麦新品种——小偃503。该品种半冬性。株高80-85cm,抗倒伏性强。综合抗病性好。成熟早,产量高。蛋白质含量165g/kg,沉淀值46．4ml,湿面筋含量340g/kg,稳定时间13．0min。2000—2003年在岐山县进行产业化示范,在当地政府部门的协调下．组织农户、公司、企业相结合,建立小偃503繁殖生产基地。根据小偃503的特性,通过对土壤的平衡施肥,采用综合栽培技术及综合植保防治等配套体系,提高小偃503的产量,保证其种子的纯度。使农民从中增收,公司、企业从中获利。     

氮肥运筹方式对豫单2002产量及品质的影响

【研究目的】该研究旨在为豫单2002的推广应用提供施肥技术支撑,为高产高蛋白夏玉米氮肥合理运筹肥提供理论与技术依据。【方法】在豫北潮土区高产田块上,采用田间试验,设N0（不施氮肥）、N1（攻杆肥100%）、N2（攻穗肥100%）、N3（攻杆肥40%+攻穗肥60%）,N4（攻杆肥30%+攻穗肥50%+攻粒肥20%）五个处理开展研究。【结果】结果表明：氮肥不同运筹方式增产效果差异显著,其中N3处理增产效果最好,其次是N1处理和N4处理,N2处理增产效果最小;分次施肥有于提高籽粒粗蛋白含量,且随着施肥次数的增加,籽粒粗蛋白含量呈上升趋势;分次施肥亦有利于提高籽粒蛋白质产量,不同处理以N3最佳,其次为N4;氮肥不同运筹方式肥料利用率差异显著,其中N3处理最高,其次为N4和N1处理,而N2最低。【结论】N3处理由于有效地促进了植株对氮素的吸收利用,增加显著地产量和提高了籽粒蛋白质产量,一定程度上提高了籽粒蛋白质含量,因而为最佳氮肥运筹方式。     

施氮量对优质常规籼稻稻米品质的影响

为探讨施氮量对优质常规籼稻稻米品质的影响,以桂香18、桂育12、桂育9号、桂育11号、桂育18和桂育8号为材料,在4种不同施氮量下分析稻米品质指标。结果表明,糙米率和整精米率随施氮量的增加呈先升后降的趋势,供试品种在施氮150.0kg/hm²时其值较高;垩白粒率和垩白度随施氮量的增加而降低,供试品种在施氮150.0或187.5kg/hm²时其值较低,且在施氮150.0和187.5kg/hm²时,粒长和长宽比差异不显著;随施氮量的增加,直链淀粉含量呈上升趋势,蛋白质含量显著升高,供试品种在施氮150kg/hm²时直链淀粉含量均达到优质一等。综上,在本试验条件下,150kg/hm²是实现供试品种稻米品质较优的最适施氮量。     

不同氮效率玉米自交系对氮素供应的反应

以对氮反应有典型差异的玉米自交系自330和陈94—11为材料,研究了不同供氮水平对其生物量和氮素吸收、利用的基因型差异。结果表明,植株的株高、叶片数、氮浓度、含氮量以及地上部生物量随着供氮水平的降低而降低,但根系的生物量、根冠比和氮素的根冠比却呈上升趋势。自330在氮素胁迫的条件下,具有较高的耐低氮能力。两个基因型玉米自交系吸氮量表现出的差异不是由于其氮含量造成的,而是由于根系生物量的差异造成的。     

耐低氮烟草基因型的筛选及氮效率分析

筛选耐低氮及氮高效的烟草基因型是提高氮素利用效率,减少氮污染的一种有效途径。本文采用营养液培养方法,于苗期以低氮(0.5 mmol L–1)和正常氮(5.0 mmol L–1)处理74个不同基因型烟草,通过指标统计、因子分析、聚类分析来确定评价指标及筛选出耐低氮基因型,并结合氮效率综合值分析表明,在低氮和正常氮条件下,不同基因型烟草的根系体积、根系生物量、茎叶氮累积量、地上部生物量变异系数均较大,分别为0.37~0.68和0.38~0.64。低氮和正常氮的主成分基本相似,在不同供氮条件下茎叶氮累积量、地上部生物量均起主要作用。筛选出15个耐低氮基因型,占供试材料的20.3%,其中8个属于低氮高效正常氮低效型,占耐低氮基因型的53.3%,6个属于低氮低效正常氮低效型,占40.0%,1个属于低氮高效正常氮高效型,占0.7%;筛选出8个低氮敏感基因型,其中6个属于低氮低效正常氮高效型,占75.0%,2个属于低氮低效正常氮低效型,占25.0%。初步确定14P9为耐低氮、氮高效基因型,中烟100和K394为低氮敏感、氮低效基因型。     

肥料氮在塑膜覆盖生态系统中的循环

应用~(15)N示踪技术研究了塑膜覆盖生态系统中肥料氮的循环。结果表明,在覆盖及玉米秸秆还田条件下氮的18.56％被第一季玉米所吸收,59.09％残留在土壤中。第二季小麦和第三季夏谷又分别回收秸秆氮4.0％和2.9％。玉米对硫酸铵氮的利用率为38.4％,其中15.8％分布在茎叶和根茬中,参与养分再循环,但氮素损失大,接近施肥量的50％。残留在土壤中的秸秆氨3.4％存在于未分解的秸秆中,3.5％移动到土壤下层(30～50cm),45.8％与土壤矿物结合。化肥氮残留很少,大部分进入土壤有机无机复合体中,而部分土壤氮被活化。     

A moving block evaluation technique for improving the efficiency of pedigree selection

Summary Pedigree seletion on the basis of moving block adjustment encompasses a two-phase cycle per year, i.e. family selection at a number of sites representing production environments for which adaptation is sought, and individual plant selection wihtin selected families at an extra site. Family selection within sites is based on moving blocks consisting of sets of contiguous plots, the number of which varies according to the chosen selection pressure. Families are unreplicated within each site and family selection across sites is based upon the family selection index F, i.e. the number of sites at which a particular family has been selected. The use of moving blocks for control of variation in growing conditions wihtin sites, and of the index F for exploiting genotype-site interaction early in the program, is expected to increase efficiency and to save time required to release a cultivar, as regional tests become unnecessary. In addition, the procedure allows screening an unrestricted number of families at any number of sites, in both self-and cross-fertilizing crops.     

Utilization of molecular markers for improving the phosphorus efficiency in crop plants

Phosphorus (P) is the second most growth limiting macronutrient after nitrogen and plays several important roles in all organisms including plants. In soil, P is available in both organic and inorganic forms. P deficiency reduces the growth and yield of several crop plants. Plants respond to P deficiency by the phenotypic changes especially by the modification of root architecture. Molecular marker‐assisted breeding (MAB) has been proposed as an important tool to identify and develop improved varieties of crop plants with efficient P‐use efficiency (PUE). Identification of quantitative trait loci (QTLs) for traits related to PUE has been considered as the first step in marker‐assisted selection (MAS) and improvement of crop yield programmes. In this review, we describe in detail on architectural changes of roots under P deficiency that are reported in various crops and discuss the efforts made to improve PUE using molecular marker tools. Details on QTLs identified for low P‐stress tolerance in various crop plants are presented. These QTLs can be used to improve PUE in crop plants through MAS and breeding, which may be beneficial to improve the yields under P‐deficient soil. Development of new and improved varieties using MAB will limit the use of non‐renewable fertilizers and improve PUE of key crop plants in low input agriculture.     

氮、磷肥配施对青引1号燕麦产量和品质的影响

为探明西藏海拔4 300m地区种植燕麦的氮、磷肥需求及其对燕麦产量和品质的影响,以青引1号燕麦为材料,在西藏拉萨墨竹工卡县斯布村进行了燕麦的氮、磷肥配施试验。结果表明：该区种植燕麦可正常成熟,生育期114~124d;施用氮、磷肥对燕麦产草量、植株高度、养分含量均影响显著。在相同施磷水平下,随着氮肥的增加,干草产量、乳熟期植株高度和粗蛋白呈现先增后减趋势,并以施氮（纯N）75kg/hm ²、磷（P₂O₅）60kg/hm ²的处理组合产量最高,为11 573kg/hm ²,比不施肥对照组增产4 718kg/hm ²,且净收益最高。粗脂肪、酸性洗涤纤维和中性洗涤纤维含量随着氮肥施用量的增加而有不同程度的降低。纯N 75kg/hm ²和P₂O₅ 60kg/hm ²可作为该区草地建植的推荐施肥量。     

不同产地不同玉米品种营养品质差异性分析

为了解河南省小区域范围内不同产地不同玉米品种所含主要营养物质含量的差异,在河南省3个不同的产地对其广泛推广的3种玉米品种进行扦样,对其所含蛋白质、脂质、淀粉含量进行测定并进行差异性分析。结果表明,不同产地不同玉米品种间营养品质差异性较为显著,同一产地不同玉米品种间营养品质差异较小,同一玉米品种不同产地间的营养品质存在着显著性差异,表明在适宜的环境和合理种植下,这3种玉米品种均可以表现出其优良品质,可以进行混合种植。     

一种检测荷载pGMCSF-SS质粒的 减毒沙门氏菌数的方法学研究

以荷载pGMCSF-SS质粒的减毒沙门氏菌为参考菌，连续培养13h，间隔1h连续采样，用紫外分光光度计检测OD600值，同时用平板计数计算活菌数。根据所测数据，建立细菌对数与细菌浊度之间的直线回归数学模型，即Y=1.5568x+7.0944, R2=0.9543，并对相关关系进行了显著性检测︱r︱>r0.01，表明此回归方程可信度很高。为进一步检测该模型的可靠性，在培养时间内随机取样，检测OD600值，比较利用平板计数与回归方程所得细菌对数Y，二者差异不显著（p>0.05）。通过探讨细菌浊度与细菌计数之间的相关性建立的回归方程，可以有效地克服传统计数方法的不足，便于应用     

20年来我国自育棉花品种纤维品质分析

从“六五”到“九五”期间 ,我国自育陆地棉品种的纤维主体长度或 2 .5 %跨距长度主要集中在2 7～ 30 mm,断裂比强度集中在 1 7～ 2 3c N· tex- 1,麦克隆值集中在 3.7～ 4.9。总体来讲 ,品种品质在纤维长度的阈值、比强度平均值和上限值几个指标上在不断进步 ,麦克隆的阈值呈加宽趋势。与美国棉花品种相比 ,我国品种的纤维长度占有优势 ,比强度略有逊色 ,麦克隆值分布较宽。我们的最大缺陷在于缺少长度在 31 mm以上 ,比强度在2 5 c N· tex- 1以上的陆地棉品种。为满足纺织工业的多种需求 ,迎接日益激烈的国际竞争 ,我们必须及时地调整我们的品种与种植结构 ,尤其要重点培育和推广一批 2 .5 %跨长在 31 mm以上 ,比强度在 2 5 c N· tex- 1以上 ,麦克隆值在 3.7～ 4.2之间的特优质品种