果实膨大期不同施氮量对油桃产量和品质的影响

  【目的】  桃园施肥过量不仅导致资源浪费和环境问题,还会影响桃树的正常生长。在果实膨大期,果实体积和重量迅速增大,果实重量的增加占总果重的50%～70%,果实膨大期是影响果实着色和内在品质形成的关键期,探究此阶段适宜的施氮量,对降低氮肥施用量、提高果实产量和品质有重要意义。  【方法】  田间试验在北京市林业果树科学研究院果树生长良好的果园进行,试材为早熟油桃品种‘夏至早红’。设置0、100、200、400 kg/hm2 4个氮 (N) 水平,即N0、N1、N2和N3处理。2016年供试氮肥1/2为普通尿素,1/2为15N丰度为5.18%的尿素;2017年供试氮肥均为普通尿素。氮肥在果实膨大期于桃树两侧沟施。在果实成熟期取样,调查桃单株果实产量、单果重、果实可溶性固形物、果实还原糖和总酸、叶片SPAD值、新梢长度、各器官Ndff值。  【结果】  桃单株果实产量和单果重在施氮量200 kg/hm2(N2) 处理下最高,与N3处理没有显著差异,二者单果重均显著高于N0和N1处理。随着施氮量的增加,果实可溶性固形物含量先上升后下降。果实还原糖和总酸含量与果实膨大期施氮量呈正相关。2016年6月8日之后,N2和N3处理叶片SPAD值显著高于N0和N1处理 (除6月15日,N1与N2、N3处理无显著差异外)。2016年新梢长度随着施氮量的增加而增长,N3处理新梢长度显著高于其它3个处理;2017年N2和N3处理新梢长度显著高于N0和N1处理。随着施氮量的增加,叶片、枝条、果实的Ndff值均增加。  【结论】  适量施氮 (N 200 kg/hm2) 能够提高果实产量,在此基础上再增加氮肥用量 (N 400 kg/hm2),增产效果不明显。果实膨大期施氮可促进于新生器官 (新梢) 的建成,高施氮量能够加快新梢生长。     

亏缺灌溉对温室番茄产量与水分利用效率的影响

为了探讨西北旱区日光温室番茄节水高效灌溉模式,2008年进行了不同生育阶段水分亏缺对膜下沟灌番茄产量与水分利用效率的影响研究。结果表明,在番茄果实成熟与采收期亏水虽然可使果实早熟,增加收获期和市场高价位时期的重合度,但由于产量降低幅度较大,总体经济效益低,为不合理灌溉方案。相反,在对照处理灌水定额21 mm的基础上,苗期减少2/3灌水量、开花和果实膨大期减少1/3灌水量、果实成熟与采收期正常灌溉,是西北旱区日光温室番茄较适用的灌溉模式。即在番茄全生育期内灌水11～12次,灌溉定额为200～210 mm时,可实现市场产量170～180 t/hm2,毛效益31～34万元/hm2,水分利用效率和单方耗水毛效益分别为64～69 kg/m3和120～125元/m3,同时节约灌水量40～50 mm。     

早熟九叶青花椒主要特征特性分析

早熟九叶青花椒是重庆市农业科学院利用九叶青花椒实生变异单株,经多年选育而成的花椒新品种,具有早熟、早果、丰产等优良特征。在重庆地区开展的品比试验结果表明,早熟九叶青在海拔300～800 m地区生长结果表现良好:主要物候期提前5 d左右,果实早熟特性明显,在7月上旬成熟采收;树体矮化健壮特征明显,枝条短壮;早果丰产性能稳定,定植1年试花结果,第二年单株产量5 kg以上,定植3年丰产,丰产期667 m~2产量在1 000 kg以上;果实颗粒大,果型指数1.06～1.08,平均千粒重90.91～96.15 g。该品种是一个极具推广潜力的花椒新品种。     

黄冠梨果实和叶片钾素积累特征及其对施钾的响应

【目的】 本研究通过研究黄冠梨果实和叶片钾素积累特征及其对不同施钾量的响应,探讨施钾对梨果产量和品质的影响,为梨园合理施钾提供依据。 【方法】 选取同一区域 14 年生不同产量水平的高 (60～70 t/hm2)、中产 (30～40 t/hm2) 两个黄冠梨园开展田间施钾试验。设置 K₂O 0、150、300、450 kg/hm2 四个施钾水平(K0、K150、K300、K450),分别在幼果期、膨大Ⅰ期、膨大Ⅱ期、成熟期和果实收获后一个月采集叶片与果实样品,研究施钾对产量、果实品质、叶片和果实钾含量及钾积累量、钾肥利用率的影响。 【结果】 随施钾量增加高产园产量增加显著,K450 处理比对照提高了 16.9%;在中产园 K300 处理产量达到最高值,较对照提高了 27.2%,K450 与 K300 处理之间无显著差异。果实中可溶性糖含量和糖酸比随施钾量增加而提高,可滴定酸变化规律与之相反。从幼果期至成熟期,叶片与果实钾含量均呈下降趋势,施钾在不同程度上提高了钾素含量。叶片钾积累量在膨大Ⅰ期达到最大,随后积累量逐渐下降。果实钾在整个膨大期积累最多,占全生育期钾积累量的 60%～79%;膨大期后高产园果实仍在迅速积累钾素,中产园积累减缓。落叶前叶片钾回流,高产园回流力度大于中产园。高产园果实收获和落叶移走钾量为 258～314 g/plant,中产园为 166～192 g/plant。在高产园 K450 处理和中产园 K300 处理下,果实和叶片内每积累 1 kg 钾素,高产园可增产 414.0 kg,中产园增产 405.2 kg。 【结论】 施钾促进了树体对钾素的吸收,果实产量和果实品质随施钾量增加有不同程度提高。膨大期是树体吸收钾素的最大效率期,建议在膨大期前追施钾肥。综合产量、肥料利用率及果实品质等各项指标,建议产量为 60～70 t/hm2 的高产园适宜施钾量为 450 kg/hm2,产量为 30～40 t/hm2 的中产园适宜施钾量为 300 kg/hm2。      

不同播期对紫云英生长及物质养分积累的影响

在大田试验条件下,设置了自2009年9月25日—11月6日共7个播种时期,研究不同播期对紫云英生长、产量及养分吸收的影响。试验结果表明,紫云英的密度、株高、单株复叶数、表观叶面积和单株重均随播期推迟而下降。鲜草产量随播期推迟显著降低,9月25日播种的鲜草产量最高,达31833 kg/hm2,种子产量则以10月2日播种的最高,为227 kg/hm2。地上部N、P、K、Cu含量均随播期推迟呈下降趋势,10月30日之后播种处理的Fe、Mn含量则显著增加,而不同播期对Ca、Mg、Zn含量无影响。各养分积累量均随播期推迟而下降。研究表明,播期显著影响紫云英生长及物质养分积累,本试验条件下宜在9月下旬至10月上旬期间播种。     

不同水氮组合对全立架栽培伽师瓜产量与品质的影响

全立架露地栽培伽师瓜（Cucumis melo var. saccharinus Naud）是一种集高密度、 覆膜、 立架于一体的立体种植新模式。本文在极端干旱的喀什地区灌溉条件下,研究不同水氮组合对全立架栽培伽师瓜产量、 品质、 水氮资源利用效率的影响,结果表明,施氮肥能使全立架栽培伽师瓜单果重增加而使产量提高31.0%。而当施氮量增至375 kg/hm2 且灌水8250 m3/hm2 时,又显著增加烂果率。灌水量为67507500 m3/hm2时氮素利用效率最高,并随施氮量的增加而降低。施氮量为225 kg/hm2 时灌水利用效率最高。施氮量375 kg/hm2时的果肉维生素C含量较不施氮肥降低11.3%~25.6%。不同灌水量对果实果肉比例及果皮比例无显著影响,而施用氮肥可增加果实的果肉比例、 降低胎座子粒的质量百分比。当全立架露地栽培伽师瓜的产量达81745 kg/hm2时,适宜的水氮组合为全生育期施氮303 kg/hm2、灌水7405 m3/hm2,且能保证果实品质。     

不同海拔对藜麦生长及产量的影响

为研究不同海拔对藜麦生长及产量的影响，为藜麦产业发展提供依据，以陇藜1号和陇藜4号为指示品种，在海拔分别为2 912、2 730、2 151、1 980 m的临潭县城关镇、天祝县松山镇、通渭县马营镇和平川区种田乡进行了多点试验。结果表明，总体上随海拔升高，藜麦灌浆期至成熟期延长，生育期也随之延长；随着播期的推迟，藜麦生育期呈缩短趋势，产量也降低。单株重、千粒重是直接影响藜麦产量的主要性状。产量变异系数陇藜1号 < 陇藜4号，说明陇藜1号综合性状表现良好，且产量稳定。     

施氮与灌水对夏玉米产量和水氮利用的影响

通过田间裂区试验,研究了不同灌水量（900、 1200和1500 m3/hm2）和施氮量（0、 150、 210和270 kg/hm2）对夏玉米生长状况、 产量构成及水、 氮利用效率等的影响。结果表明: 当灌水量超过最低量 900 m3/hm2、 施氮量超过150 kg/hm2时,二者对玉米产量、 产量构成因素（穗粒数、 百粒重及穗粒重）和收获指数（HI）以及各生育期干物质积累量等均没有明显影响; 氮肥农学效率和氮肥偏生产力随氮肥用量的增加呈明显降低趋势; 灌水生产效率和水分利用效率随灌水量的增加也显著降低,二者均表现为900 m3/hm21200 m3/hm21500 m3/hm2。因此,在本试验条件下,以W900N150处理的水、 氮利用效率、 产量及其构成因素等较高,并且对环境造成潜在危害最小,为当地地域气候条件下夏玉米生产中节水减氮的较为适宜的水氮配比。     

不同移栽方式、密度和采摘期对甘草生长、产量及种子质量的影响

以野生乌拉尔甘草为试验材料,以种子直播为对照,测定了在平栽、斜栽(35°～45°)、直栽3种移栽方式及12、15、18、21株/m~2等4种移栽密度条件下,甘草的全根长、主根长、株高等生长指标及单株产量、小区产量2项产量指标,统计并测定了乳熟期、褐熟期和黑熟期3个不同采收期甘草种子直径、数量、空瘪率等外观指标,以及种子干质量、吸水率、萌发率等质量指标,分析了不同移栽方式和采收期对甘草生长、产量和种子质量的影响。结果表明:斜栽方式和15株/m~2移栽密度处理各项生长指标和产量指标均显著优于其他处理,更能促进甘草植株生长并提高产量;黑熟期采收的甘草种子外观及种子质量各项指标均比乳熟期和褐熟期差,生产中宜选择在乳熟期和褐熟期之间采收甘草种子。     

基于Hybrid-maize模型的吉林省不同生态区 玉米产量潜力研究

为挖掘玉米产量潜力,进一步提升玉米综合生产能力,利用在东北地区已验证的Hybrid-maize模型及多年气象数据对吉林省不同生态类型区[东部湿润生态区(桦甸)、中部半湿润生态区(公主岭)、西部半干旱生态区(乾安)]不同品种、播期和密度及其相互组合下的玉米产量潜力进行模拟,并对影响玉米高产稳产的因素进行定量分析,同时考虑产量潜力变异情况及品种本身的生产特性,构建了吉林省不同生态区玉米高产体系。研究结果表明:1)改变播期是一项重要的增产措施,不同生态区的表现不同,湿润区应选择早播,播种日期在4月20日左右较适宜,而半湿润和半干旱地区应尽量晚播,适宜播期应在5月中旬左右。2)不同生态区对密度的容纳能力表现为湿润区(桦甸)半湿润区(公主岭)半干旱区(乾安),3个地区的适宜密度分别为90 000株·hm~(-2)、80 000株·hm~(-2)和75 000株·hm~(-2)左右。3)选用生育期更长的品种表现出了较高的增产潜力,生产上应根据不同区域生态条件,尽量选择晚熟品种,在当前播期条件下半湿润和半干旱地区品种生育期内需要的有效生长积温(GDD)可增至1 600℃以上。4)与当前生产技术相比,将播期、密度、品种三者优化组合,高产体系长期平均产量潜力可增产14.39%~29.23%。本研究可为吉林省玉米高产措施的正确应用提供理论依据,为玉米产量大面积提升提供技术参考。     

Boron fertilization improves seed yield and harvest index of Camelina sativa L. by affecting source-sink

The impact of soil (1, 2 kg ha^?1) and foliar (100, 200 mg L^?1) boron (B) with control (no B) was evaluated on phenology and yield formation of Camelina each applied at stem elongation and flowering stages. Foliar (200 mg L^?1) or soil B (2 kg ha^?1) resulted in earlier flowering and maturity, increased fruit bearing branches (19.68%), number of siliqua, seeds per siliqua (4.6%), biological yield (15%), seed yield (24%), harvest index (11.4%) and oil contents (23%) than no B. Increased fruit bearing branches, seed filled siliqua or seed numbers, harvest index and oil quality can be attributed to changes in dry matter accumulated of stem with simultaneous increase in siliqua dry weight with foliar or soil applied B. In crux, foliar (200 mg L^?1) or soil applied (2 kg ha^?1) B seems promising to improve seed and oil yield, harvest index of Camelina sativa under B deficient condition.     

Patterns of diversity in pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millsp.) germplasm collected from different elevations in Kenya

Pigeonpea germplasm accessions collected from low (<500 m), medium (501–1000 m), high (1001–1500 m) and very high elevation zones (>1500 m) of Kenya were evaluated for 15 agronomic traits and seed protein content at ICRISAT, Patancheru, India. There were significant differences (P < 0.001) among elevation zones for the number of primary and secondary branches, days to 75% maturity, pod length, seeds per pod, 100-seed weight and seed yield. Mean values indicated that the accessions from low elevation zone were significantly different from those collected in higher elevation zones for early flowering and maturity, number of primary branches, pod length, number of pods per plant, seeds per pod, 100-seed weight, seed yield and harvest index. None of the accessions collected in Kenya belonged to extra early (<80 days to 50% flowering) and early (80–100 days to 50% flowering) maturity groups, as defined by time to flowering at Patancheru, India. Mean diversity index based on all characters indicated that accessions from the low elevation zone are more diverse than those from the higher elevation zones. Frequency distribution for trait extremes indicated that the accessions from the low elevation zone were early to flower and mature, short statured, produced more primary and secondary branches with high pod bearing length, long pods, more pods per plant, more seeds per pod, a high seed yield and harvest index. Accessions from the very high elevation zone were late flowering, with a large number of tertiary branches, large seeds and a high shelling percentage and could be a source for cold tolerance and the breeding of vegetable types. Results suggest that the elevation of collection sites is therefore a very important determinant of variation patterns of pigeonpea in Kenya.     

Seasonal critical concentration and relationships of leaf phosphorus and potassium status with biomass and yield traits of soybean

Analysis of uppermost fully expanded leaves is useful to detect a deficiency of mineral nutrients such as phosphorus (P) and potassium (K) in soybean. Although, the leaf P or K status aids in fertilizer management, information on nutrient seasonal relationships with growth and yield traits at maturity are limited. To investigate this, soybean was grown under varying P or K nutrition under ambient and elevated CO₂ concentrations. Results show significant relationships of the relative total biomass and yield‐related traits with the foliar P and K concentrations measured several times in the season across CO₂ levels. However, the relationships established earlier in the season showed that the growth period between 25 and 37 d after planting (DAP), representing the beginning of flowering and pod, respectively, is the best for leaf sampling to determine the foliar P or K status. The leaf P and K status as well as the critical leaf P (CLPC) and K (CLKC) concentrations for traits such as seed yield peaked around 30 DAP (R2 stage) and tended to decline thereafter with the plant age. The CLPC and CLKC of seed yield indicate that the leaf P and K concentration of at least 2.74 mg g^?1 and 19.06 mg g^?1, respectively, in the uppermost fully expanded leaves are needed between 25 and 37 DAP for near‐optimum soybean yield. Moreover, the greatest impact of P and K deficiency occurred for the traits that contribute the most to the soybean yield (e.g., relative total biomass, seed yield, pod and seed numbers), while traits such as seed number per pod, seed size, and shelling percentages were the least affected and showed smaller leaf critical concentration. The CLPC or CLKC for biomass and seed yield was greater under elevated CO₂ 24–25 DAP but varied thereafter. These results are useful to researchers and farmers to understand the dynamics of the relationship of pre‐harvest leaf P and K status with soybean productivity at maturity, and in the determination of suitable growth stage to collect leaf samples.     

Switchgrass from North Dakota – an adaptable and promising energy crop for northern regions of Europe

Searching for novel energy crops, an interest in C4-type plant switchgrass (SWG) has increased worldwide. The present research was aimed to study SWG genetic resources for most important agrobiological traits with a view of extending the range of energy plants in the Nemoral zone of Europe. SWG was studied for the peculiarities of developmental stages, winter hardiness, and dry matter (DM) yield. SWG regrowth in spring started one month later compared to the reed canary grass (variety ‘Chiefton’). All investigated genotypes matured seeds in the second half of September. The most winter-hardy SWG accessions (0–20% winter damage) were the majority of wild ecotypes and the variety ‘Dacotah’ from North Dakota (2–4 hardiness zone) as well as the variety ‘Summer’ from South Nebraska (4, 5 hardiness zone). Ecotypes from North Dakota exhibited a high breeding potential and prospects in Northern regions of Europe due to genotypic variation of winter hardiness trait. The varieties ‘Alamo’, ‘Falcon’, ‘Grenville’, ‘Shawnee’, and ‘Trailblazer’ that originated from warmer climate zones (6–9 hardiness zone) were heavily damaged or completely killed. The worst overwinter survival of plants was recorded after the first winter. DM yield was estimated at two regimens of cutting. When grass was cut once at seed maturity stage, DM yield in the first harvest year was 249 g per plant, in the second harvest year 349 g per plant, and in the third harvest year 493 g per plant. When grass was cut twice per season (at the beginning of anthesis and after regrowth of aftermath), DM yield was significantly lower: in the first harvest year the DM yield was 203 g per plant (18.4% less), in the second harvest year 182 g per plant (47.9% less), and in the third harvest year 272 g per plant (44.7% less).     

Influence of harvest time on the quality of oil-based compounds in sea buckthorn (Hippophae rhamnoides L. ssp. sinensis) seed and fruit

The effect of the harvest time on oil-based bioactive compounds in sea buckthorn berries ( Hippophae rhamnoides L. ssp. sinensis) was investigated. Sea buckthorn berries were collected at early maturity (September), maturity (November), and postmaturity (January) during the 2003-2004 harvest year. Whole berries were analyzed for physical characteristics, and fruit and seed fractions were analyzed for bioactive content. November-harvested berries yielded the highest values for berry sizes, CIELab factor a*, and total carotenoid content in the fruit fraction ( p < 0.05). September yielded significantly higher ( p < 0.05) levels of major compounds, alpha-tocopherol and beta-sitosterol, in the fruit fraction. Seed characteristics and bioactive compounds did not vary significantly with respect to the harvest time ( p > 0.05). These results have identified the most suitable level of maturity for the optimization of certain compounds and the losses that may occur with winter harvest, commonly practiced in cold climates.     

密度和留叶枝对棉株产量的空间分布和熟相的影响

在山东临清、夏津和惠民的大田条件下研究了不同密度与整枝处理下棉花产量分布、库源比例和熟相, 探讨种植密度和留叶枝对棉株产量空间分布和熟相的影响。结果表明, 产量在棉株空间分布的总体趋势是, 去叶枝棉株的产量全部来自果枝, 留叶枝棉株的产量主要来自果枝(85%), 叶枝所占份额较低(15%); 无论去叶枝还是留叶枝, 产量主要分布在下中层(72%)和内围(74%), 上层(28%)和外围(26%)产量分布较少。密度和整枝对棉花产量空间分布有显著影响, 但两者的互作效应不显著。密度主要影响产量在棉株上的内外分布, 随密度升高, 产量向内围集中; 而整枝则主要影响产量在棉株上的垂直分布, 留叶枝使产量上下分布更加分散。整枝对棉花熟相影响不大; 但密度显著影响熟相和库源比例, 低密度下库源比例大、轻度早衰, 高密度下库源比例小、轻度晚熟, 中等密度(5.25株·m^-2)下库源比例适宜, 熟相较好。     

海岛棉资源自然复合盐胁迫综合评价

为筛选适合盐碱地种植的海岛棉品种,本试验以203份海岛棉进行自然复合盐胁迫筛选及评价.结果 表明,株高、始节高、果枝数、蕾铃脱落数、蕾铃脱落率及单铃籽棉产量耐盐系数呈现下降,衣分、铃数、始节数、有效铃数、有效果枝数、单铃皮棉产量、单株籽棉产量及单株皮棉产量耐盐系数略有上升.变异系数表现为单株皮棉、籽棉产量最高.相关分析...     

Changes in Quality Attributes during Growth of Leek (Allium porrum L.) for Industrial Processing

Abstract

A field experiment with leek was conducted in 1990 and 1991. Plant weight and the contents of nitrate and dry matter of the leek were measured on ten successive harvest dates each year. The yield of dry matter per square metre was calculated and related to harvest time. A maximum and virtually constant average plant weight was obtained from the beginning to the end of October (weeks 41–44). After this time the plant weight decreased. The yield of dry matter per square metre was virtually constant during the last two weeks of October and the first week of November.

The content of nitrate decreased steadily during the harvest period, while the content of dry matter was at a minimum in the middle of October (week 43).

The changes in nitrate and dry matter during growth could be explained by results from analyses of the different composition of the fractions of the leek. The content of nitrate and dry matter decreased from the outer to the inner part of the leek, in which the major part of the growth takes place during the weeks up to harvest.

A maximum yield of fresh weight and dry matter can be obtained after harvest in October or November (weeks 43–45) when the content of nitrate has decreased to a low and almost stable level.     

Quantitave evaluation of Ethiopian landraces of lentil (Lens culinaris)

Summary One hundred and fifty-six landrace populations of lentil (Lens culinaris Medikus) collected from 10 provinces in Ethiopia were evaluated for a set of six quantitative traits at three sites contrasting in altitude. Consistent regional differences among landraces were found for time to flower and maturity, 100-seed weight, number of seeds/pod and plant height. The regional differences were clarified by a discriminant analysis based on 100-seed weight, time to flower and plant height. The lentil of the West Highlands was early and short, that of the North Highlands was large-seeded, whereas lentils from the Central Highlands were the least distinctive group. Selection for seed size was the result of local human preferences. Humans were probably also responsible for the lack of adaptive value of plant phenology in relation to altitude. Selection for seed yield at the low and middle elevation sites gave a positive response to selection at both sites. However, selection for yield at the highland site did not give a positive response elsewhere, indicating that adaptation to highland conditions differed from that at lower elevations.     

Influence of Potassium Rates and Sources on Seed Cotton Yield and Yield Components of Some Elite Cotton Cultivars

Abstract

A field experiment was conducted at Central Cotton Research Institute, Multan, Pakistan on Miani soil series, silt loam soil (Calcaric, Cambisols and fine silty, mixed Hyperthermic Fluventic Haplocambids) to assess the response of four cotton (Gossypium hirsutum L.) cultivars to potassium (K) fertilization. The treatments consisted of four cotton cultivars (CIM-448, CIM-1100, NIAB-Karishma, S-12), four potassium rates (0, 62.5, 125, 250 kg K ha^?1), and two sources of potassium fertilizer [muriate of potash (KCl) and sulphate of potash (K₂SO₄)]. The cotton cultivars differed significantly in response to various potassium fertilizer levels and its sources with respect to seed cotton yield and its components. The highest yield was obtained with the application of 250-kg K ha^?1, however, it was economical to add 125 kg K ha^?1. Seed cotton yield of cv. CIM-448 was considerably greater than that of the other cultivars in K-unfertilized treatments, which was related to cultivar differences in K uptake efficiency in utilizing native potassium nutrient. Potassium added as muriate of potash caused a significant depression in seed cotton yield than that of sulphate of potash. The increase in yield seemed to have resulted largely from the higher K concentration of leaf tissues at bloom stage and available soil-K because of potassium application. A significant relationship between the yield and number of bolls per plant (r = 0.92**) and boll weight (r = 0.85**) indicated that these two growth attributes were responsible for enhancing the quantum of final harvest of seed cotton.