Potassium-Use Efficiency in Upland Rice Genotypes

Potassium (K) uptake is greatest among essential nutrients for rice. Data related to yield, yield components, and K-use efficiency by upland rice genotypes are limited. A greenhouse experiment was conducted to evaluate influence of K on growth, yield and yield components, and K-use efficiency by upland rice genotypes. Potassium levels applied to an Oxisol were zero (natural K level) and 200 mg K kg¹ of soil and 20 upland rice genotypes were evaluated. Plant height, shoot dry weight, grain yield, 1000-grain weight, and spikelet sterility were significantly affected by K and genotype treatments. Genotypes Primavera and BRA 1600 were the most efficient and genotype BRAMG Curinga was most inefficient in producing grain yield. Plant growth (plant height and shoot dry weight) and yield components (panicle number, grain harvest index, 1000-grain weight, and panicle length) were significantly and positively associated with grain yield. However, spikelet sterility was significantly and negatively correlated with grain yield.     

籼稻保持系穗发芽抗性的改良

对籼稻32个保持系和40个恢复系收获时休眠性进行鉴定,在保持系中没有发现强休眠性材料,大多数恢复系休眠性也较弱。采用国际水稻研究所的4个强休眠品种IR64、IR112-12、IR13427、IR1529与生产上穗发芽严重的Ⅱ32A、冈46A及其保持系Ⅱ32B、冈46B组配,研究水稻收获时休眠性的遗传特点,并在F5和BC1F4世代中获得21个对Ⅱ32A和冈46A具有保持能力的强休眠材料。     

收获期和收割留茬高度对高羊茅种子产量和质量的影响

于2016年在上海交通大学闵行校区高羊茅(Festuca arundinacea)种子生产田实施了4个收获期和2个收割高度的两因素随机完全区组试验,以研究收获期和收割留茬高度对种子产量和质量的影响。试验结果表明:收获期从花后15 d至花后36 d,有籽粒脱落的穗子和有籽粒脱落的小穗的百分率和千粒重逐渐提高,而每小穗粒数逐渐下降,致使种子产量先增加后降低;在4个收获期处理中,最高籽粒产量出现在第2期,即花后22 d,其显著高于第1期(花后15 d)和第4期(花后36 d)的种子产量,而与第3期(花后29 d)收获的种子产量间没有显著差异;第2期收获的种子千粒重、种子发芽率和种子萌发苗株高与第3、4期收获的优质种子间没有显著差异;籽粒产量和质量在留茬高度16 cm(收割全株)和留茬高度58 cm(割穗)间差异不显著,该效应不随收获期的不同而异。据此推断:上海地区高产优质高羊茅种子的适宜收获期为首批开花穗的花后22～29 d,于全田尚有12%的嫩穗和59%的小穗顶部有1～3粒籽粒脱落时开始尽快收获;可以根据不同收获方式的需要在高于地面16 cm至穗颈节间(割穗留茬高度)范围内灵活确定植株收割高度。     

采收期对宁夏六盘山冷凉地区黄芪质量的影响研究

为建立不同采收期黄芪药材HPLC指纹图谱并测定5种成分含量,确定采收期对宁夏六盘山冷凉地区黄芪质量的影响,以乙腈甲醇混合液-醋酸缓冲盐梯度洗脱,检测波长260 nm,建立黄芪药材HPLC指纹图谱,以DAD检测器测定毛蕊异黄酮葡萄糖苷、芒柄花黄素、刺芒柄花苷、毛蕊异黄酮含量;以乙腈-水等度洗脱,ELSD检测器测定黄芪甲苷含量。结果显示,14批不同采收时间黄芪药材HPLC指纹图谱有15个共有峰,5月采收的黄芪毛蕊异黄酮葡萄糖苷与刺芒柄花苷含量较高,10月采收的黄芪毛蕊异黄酮葡萄糖苷与黄芪甲苷含量较高,5月与10月采收的黄芪指纹图谱共有峰总峰面积较大。在宁夏六盘山冷凉地区,黄芪宜在5月或10月采收,HPLC指纹图谱结合含量测定,能够客观、有效地评价不同采收时期黄芪质量。     

金银花采收期的试验研究

通过对秦岭山区金银花不同季节采收时期试验分析,研究结果表明,金银花以采收二白期和大白期花蕾入药质量最佳;叶以花期即初生花蕾时至花末期采摘,叶中的绿原酸含量最高,为最佳采叶期;藤中绿原酸含量嫩枝高于老枝,建议修剪时,应修剪枝条上部为最好;同株金银花植物中,药效成分绿原酸含量为：花蕾〉叶〉嫩叶〉老枝。这些为金银花最佳采收期提供了科学的依据。     

宁夏宜机收玉米品种的初步筛选

2015～2017年在宁夏扬黄灌区和引黄灌区开展239品/次适宜机械粒收玉米品种筛选试验。通过综合比较品种丰产稳产性、收获时子粒含水率等指标,筛选出3个适宜扬黄灌区机械粒收玉米品种,分别为银玉137、ZH846和先玉335。与对照郑单958相比,推荐品种早熟2～6.5 d,子粒含水率降低1.6～5.3个百分点,产量增加1.9%～12.2%。筛选出5个适宜引黄灌区机械粒收品种,分别是农华213、迪卡519、辽单575、登海605和先玉335。与对照郑单958相比,推荐品种早熟2～8 d,子粒含水率降低3.8～4.8个百分点,产量增加6.3%～18.7%。     

Fodder production of some shrubs and trees under two harvest intervals in subhumid southern Ghana

The study was undertaken to determine the relative performance of 13 fodder trees and shrubs in herbage production and quality under two forage regrowth periods six and 12 weeks. In primary growth assessment it was found that the species which achieved the most height growth were Cajanus cajan, Sesbania sesban and Gliricidia sepium. In terms of herbage dry matter production the species which performed best were Cajanus cajan, Flemingia macrophylla, Calliandra calothrysus, Codariocalyx gyroidesand Gliricidia sepium. In crude protein content the superior species were Albizia lebbeck, Cajanus cajan, Leucaena leucocephala and Sesbania sesban. Regrowth harvests in the second year showed Gliricidia sepium, Calliandra calothrysus and Flemingia macrophylla achieve the greatest herbage yields with yields in excess of 1 t/ha obtaining at the first 12 week regrowth harvest. Albizia lebbeck, Cajanus cajan, Leucaena leucocephala and Samanean saman produced consistently very high crude protein levels (more than 20%) in the regrowth harvests. Calcium contents of herbage of all test species in the regrowth harvests were in excess of the critical minimum requirement of 0.44% for ruminant feeding. This revised version was published online in June 2006 with corrections to the Cover Date.     

Konkurrenz und Ertragsvorteile in Gemengen aus Erbsen (Pisum sativum L.) und Hafer (Avena sativa L.)

In field trials on a fertile fluvisol in 1995 and 1996 near Göttingen, Germany, pea (Pisum sativum; cv. Messire/conventional leafed, cv. Profi/semileafless) and oats (Avena sativa; cv. Alf) were grown as sole crops and in substitutive mixtures. The sole crops were established at 80 pea seeds m^?2 and 300 oat seeds m^?2. The mixtures consisted of 67 % (pea) and 33 % (oats) of the monoculture densities, respectively. Interactions of cv. Messire or cv. Profi and oats were similar in 1995 and 1996. The mixtures outyielded the monocultures with respect to total above ground dry matter (RYT = 1.15) and grain yield (RYT = 1.09). Grain yield of pea and oats averaged 4.9 t ha^?1 in monocultures and 5.5 t ha^?1 in mixtures. Oats was relatively the stronger of the two competitors. Decreasing number of pods per plant could be highlighted as the factor for a lower pea seed frequency in the yield of the mixtures. For oats the number of panicles per plant and kernels per panicle were higher in the mixtures compared with the oat monocultures. The average amount of the harvest index (HI) was 0.52 for pea and 0.46 for oats. Favourable growth conditions increased HI values however, prolific vegetative growth in the mixtures resulted in lower HI values. The predicted RYT‐values estimate the maximum combined grain yield of 6.3 t ha^?1 in the mixture of 87 % pea (70 seeds m^?2) and 13 % oats (39 kernels m^?2).     

Root System Size Influences Water‐Nutrient Uptake and Nitrate Leaching Potential in Wheat

Environmental and economic considerations require the effective use of water and nutrients to elevate grain production in bread wheat (Triticum aestivum L.) with concomitant reduction in nitrate leaching to minimize contamination of underground water. We determined the effect of the root system on leaching fraction, leachate N concentration, and N, P and K uptake using bread wheat ‘Pavon 76’ and its three near‐isogenic translocation lines: Pavon 1RS.1AL, Pavon 1RS.1BL and Pavon 1RS.1DL. These genotypes were grown in sand‐tube experiments under optimum and low level of nutrients for 2 years. Root, stem and leaves, and grain N, P, and K content, and agronomic characters were measured. Leaching fraction and leachate nitrate concentration were measured at early tillering, booting and early grain filling. Significant main effects for year, nutrient level and genotype were found for the characters. Genotype × N interaction was significant only for root P content. Genotype × year interaction was significant only for plant N content, root P content and plant P content. Genotype × year × N interaction was significant only for root N uptake efficiency. Thus, genotypic means averaged across years and nutrient levels are reported. Low levels of nutrients (1330, 235 and 793 mg vs. 1915, 375 and 1268 mg N, P and K, respectively) reduced mean root biomass, plant biomass and grain yield by 27 %, 25 %, and 19 %, respectively. The translocation lines produced 31–46 % more root biomass, 11–14 % heavier grains and 6–8 % greater grain yield than Pavon 76. Leaching fraction was higher under low level of nutrient at booting and grain filling. Leaching fraction at tillering, booting, and grain filling was 67%, 42% and 25%, respectively. Leaching fraction at early tillering was lower for Pavon 1RS.1AL (39 %) and Pavon 1RS.1DL (40.5 %) than for Pavon 76 (45.3 %). Leachate nitrate concentration was lower for two translocation lines at all three stages of plant growth compared to Pavon 76. The correlation coefficient between plant N content and root biomass, between plant N content and plant biomass, and between grain yield and root biomass was positive and significant. Significant positive correlation was found between root biomass and P and K uptake. Multiple small applications of N fertilizer during early plant growth with adequate irrigation water are recommended. Wheat genotypes with superior root characteristics for efficient nutrient uptake, especially during tillering and booting, should be developed in breeding programmes to increase grain yield and to minimize the nitrate leaching.     

The FishPath approach for fisheries management in a data- and capacity-limited world

Successful fisheries management systems tend to be underpinned by harvest strategies, specifying formally agreed data collection systems, assessment approaches and management measures used to regulate fishing pressure. While harvest strategies can be effective even in data- and capacity-limited (DCL) situations, their development remains challenging in such contexts. We present a process and decision-support tool, FishPath, to guide the identification of suitable harvest strategy component options given often debilitating conditions: (i) resource limitations and lack of technical management capacity; (ii) ‘uniqueness’ of DCL fisheries; (iii) the concept of harvest strategies is unfamiliar to managers and scientists, and the universe of options is hard to navigate; and (iv) the lack of an effective participatory process to identify solutions tailored to local contexts. These conditions can lead to either management paralysis or generic solutions that may be poor fits to specific conditions. The FishPath Tool uses a diagnostic questionnaire that elicits the key characteristics and specific circumstances of a fishery. It compares these with the requirements of alternative options from an inventory of possible harvest strategy components, identifies where these requirements are met and provides customised, transparent guidance on the appropriateness of component options of a harvest strategy, specific to the fishery of interest and its governance context. The FishPath Process is a facilitated multi-stakeholder, participatory engagement process aimed to set fisheries on the path to develop a harvest strategy. The FishPath Process and Tool combine to ensure a bottom-up, documented, transparent, replicable and efficient process.