Genetic control of dry matter,starch and sugar content in sweetpotato

Sweetpotato (Ipomoea batatas L. (Lam)) is a nutritious food security crop for most tropical households, but its utilisation is very low in Ghana compared to the other root and tuber crops due to lack of end-user-preferred cultivars. Knowledge on the genetic control of important traits such as dry matter, starch and sugar content of sweetpotato storage roots in a breeding population is critical for making breeding progress in developing sweetpotato varieties preferred by farmers and consumers. This study used diallel mating design to elucidate general combining ability and specific combining ability, to determine the gene action controlling storage root dry matter, starch and sugar content in sweetpotato and the heterotic potential of the traits to facilitate the crop’s improvement for increased utilisation. A general model for estimating genetic effects, GEAN II, was used to analyse the data. Genetic variability was seen for dry matter, starch and sugar content of sweetpotato and much of this genetic variation was additive in nature. The study also revealed significant heterosis in sweetpotato which offers opportunity for breeding non-sweet, high dry matter sweetpotato varieties that are preferred by farmers and consumers in Ghana.     

Nitrogen fertilization of strawberries: Nmin,leaf dry matter,and leaf sap analyses as control methods

In a three‐year survey several control methods of nitrogen (N) supply in strawberry were investigated. It was found that N_min analysis could be used as a measurement of control from the beginning of the season, indicating the need of additional N supply. Leaf dry matter analysis, taken during flowering, could be used as an indicator thus making it possible to make corrections within the season, if needed. When leaf dry matter analysis was compared to leaf sap analysis, correlations were evident for the majority of nutrients, N being an important exception. It was concluded that the use of N_min‐ and leaf dry matter analyses combined might make corrections in N fertilization within the same year possible.     

不同氮素形态配比对网纹甜瓜干物质分配和氮代谢的影响

该文研究了4种氮素形态配比(NO^-₃-N∶NH⁺₄-N分别为100∶0，75∶25，50∶50和25∶75)对基质栽培网纹甜瓜(品种为“春丽”和“蜜玲珑”)干物质积累和氮代谢的影响。结果表明,不同氮素形态配比影响了植株各器官干重占全株干重的百分比。随氮素形态中氨态氮比例的增加，叶片中硝酸还原酶、硝酸盐含量和可溶性蛋白质含量逐渐降低，而游离氨基酸含量则在NO^-₃-N∶NH⁺₄-N为50∶50的处理中最高。     

不同氮素形态配比对网纹甜瓜干物质分配和氮代谢的影响

该文研究了4种氮素形态配比(NO3--N∶NH4 -N分别为100∶0,75∶25,50∶50和25∶75)对基质栽培网纹甜瓜(品种为“春丽”和“蜜玲珑”)干物质积累和氮代谢的影响。结果表明,不同氮素形态配比影响了植株各器官干重占全株干重的百分比。随氮素形态中氨态氮比例的增加,叶片中硝酸还原酶、硝酸盐含量和可溶性蛋白质含量逐渐降低,而游离氨基酸含量则在NO3--N∶NH4 -N为50∶50的处理中最高。     

Influence of irrigation on dry matter production,leaf composition,and nutrient removal by turnip

Irrigation scheduling of leafy greens generally consists of applying 19 mm of water every four days, which leads to irrigation depths that exceed the soil water deficit, and requires fertilizer applications higher than recommended rates. We determined the influence of irrigation scheduled by class A pan evaporation and a variable crop factor on leaf tissue composition and nutrient removal by turnips using a continuous moisture gradient and different N fertilizer conditions. Irrigation maintained foliar concentrations of N, P, K, Ca, and Mg in the sufficiency range. During dry periods, increasing irrigation increased P, decreased Mg, and had little effect on N, Ca, or K foliar concentrations. Micro‐nutrient concentrations in the leaves responded to irrigation rates, but within a narrow range. Excessive water applications, due to rainfall or to irrigation rates higher than the model rate, consistently reduced nutrient crop removal. Since a combination of water applications that did not exceed soil water deficit and current fertilizer applications maintained adequate nutrient status and maximized nutrient crop removal, apparent need for N fertilization in excess of the recommended rate for turnips is due to excessive water applications.     

萌动小麦的干物质损耗与品质分析

对小麦籽粒经粒径分选和重力分选后获得的试样进行萌动发芽培养试验,从培养开始(0 h)到24 h之间以一定时间间隔对不同萌动状态的小麦进行干物质损耗测定和品质分析,结果表明：干物质的损耗随着萌动时间的增加而增加;容重(比重)越小,干物质的损耗呈现增大的趋势;各萌动时间段脂肪酸值则随着萌动时间的增加而增加;萌动籽粒的粗蛋白质含量较未萌动籽粒的低;萌动前期小麦籽粒的降落数值与未萌动籽粒相比基本上没有变化,而萌动后期的降落数值下降较快,表明此时淀粉酶的活性较高。     

Coupling of dry matter and nutrient accumulation in forage grass

Abstract

The logistic model has proven very useful in relating dry matter production of forage grasses to applied nitrogen. A recent extension of the model coupled dry matter and plant ? accumulation through a common response coefficient c. The objective of this analysis was to establish the validity of the extended model for each of the three major nutrients (?, ?, ?), with a common coefficient c between dry matter and each applied nutrient. Analysis of variance established the validity of this hypothesis. The model accurately described response of dry matter, plant nutrient removal, and plant nutrient concentration to applied nutrient, with overall correlation coefficients of 0.9928, 0.9972, and 0.9975 for applied N, P, and K, respectively. Furthermore, the model closely described the relationship between yield and plant nutrient removal, as well as between plant nutrient concentration and plant nutrient removal, for each nutrient. This work confirmed earlier results for applied ? with various grasses and established the validity of the model for applied ? and ? for the first time. The logistic equation is well‐behaved and simple to use on a pocket calculator. It can be used to describe yields and nutrient removal in evaluation of agricultural production and environmental quality.     

Coupling of dry matter and nitrogen accumulation in millet and ryegrass

Abstract

The logistic model has proven very useful in relating dry matter production of warm‐season and cool‐season forage grasses to applied nitrogen (N). A recent extension of the model coupled dry matter and plant N accumulation through a common response coefficient c. The objective of this analysis was to apply the extended model to both warm season pearl millet [Pennisetum typhoides (Burm.) Staph and C. E. Hubb.] and cool season ryegrass [Lolium multiflorum Lam.], and to establish a common response coefficient, c, between accumulation of dry matter and plant N for the two grasses in rotation. Analysis of variance established the validity of this hypothesis. The model accurately described response of dry matter, plant N removal, and plant N concentration to applied N, with an overall correlation coefficient of 0.9954. Furthermore, the model closely described the relationship between yield and plant N removal. The logistic equation is well behaved and simple to use on a pocket calculator. It can be used to estimate yield and plant N removal in evaluation of agricultural practices and the influences on environmental quality.     

用辐热积法模拟温室黄瓜叶面积、光合速率与干物质产量

依据温室黄瓜叶片生长与温度和辐射的关系,用辐热积构建了两种不同整枝方式下的叶面积模拟模型,并与已有的光合速率和干物质生产模型相结合,建立了适合中国种植技术的温室黄瓜光合速率与干物质生产模拟模型,并利用不同品种、基质的试验资料对模型进行了检验。结果表明,本模型比积温法和比叶面积法能更准确地预测温室黄瓜的叶面积和总干重,为温室作物生长模拟提供了新思路。     

温室黄瓜干物质分配与产量预测模拟模型初步研究

依据温室黄瓜(Cucumis sativus)器官生长与温度和辐射的关系,建立了基于分配指数和采收指数的温室黄瓜干物质分配与产量预测模拟模型,并利用不同品种和基质的试验资料对模型进行了检验。结果表明,模型对黄瓜地上部分干重、根干重、茎干重、叶干重、果实干重的预测结果与1∶1直线之间的R²分别为0.98,0.73,0.83,0.92,0.94;RMSE分别为232,6.8,157.6,173.9,196.8 kg/hm²。模型对黄瓜产量的预测结果与1∶1直线之间的R²为0.80,RMSE为7526.4 kg/hm²。本模型对不同基质、品种的黄瓜干物质分配和产量的预测值与实测值符合度均较高,说明本模型的普适性较好。模型不仅能较好地预测中国现有生产水平下温室黄瓜的干物质分配及产量,而且可以为实现中国温室黄瓜生产环境优化调控和模式化栽培管理提供决策支持。     

Atmospheric CO2 enrichment and plant dry matter content

Fresh and dry plant weights were measured throughout a number of different CO₂ enrichment experiments with six terrestrial plants and two aquatic species. Similar data were also extracted from the literature for 18 additional plants. In general, CO₂ enrichment had little effect on plant percentage dry matter content, except under conditions conducive to starch accumulation in leaves, and then it caused an increase in percentage dry matter content.     

温室黄瓜光合生产与干物质积累模拟模型

根据“源-库”理论及黄瓜生理学和作物生态学的基本原理,建立了温室黄瓜冠层光合生产和干物质积累模拟模型,模型由叶面积动态、光合作用、呼吸作用、干物质积累等子模型组成,模型中参数由相关文献和试验资料确定。通过收集国产温室黄瓜各生育时期干物质积累量对模型进行检验。结果表明,以光合作用为基础的干物质积累量模拟值与实测值的相对误差在-3.0%～10.0%之间,说明所建立的模拟模型具有较高的精确性、机理性和实用性。     

Dynamics of dry matter and nitrogen distribution in transplanted rice on mollisols

We studied the dynamics of dry matter (DM) and nitrogen (N) distribution in different plant parts (leaf, stem, and panicle) and grain yield of transplanted rice due to N management practices through neem coated urea (NCU). The results indicated that application of NCU at 125% recommended dose of N (RDN) with 50:25:25 split schedule at basal (B), active tillering (AT), and panicle initiation (PI) stages resulted in higher DM and N distribution to leaf, stem, and panicle at 60 and 90 days after transplanting and harvest than the application of prilled urea at 100% RDN with the same split schedule (existing practice). Further, the increment in grain yield was 10.95% than the existing practice. Hence, we suggest the application of NCU at 125% RDN with 50:25:25 split schedule at B, AT, and PI stages for achieving higher DM and grain yield on Mollisols.     

Distribution and dynamics of soil organic matter in an Antarctic dry valley

Terrestrial ecosystems in the Antarctic dry valleys function under extremely cold and dry climatic conditions that severely constrain C and N cycling and, like other polar regions, are likely to be sensitive to environmental change. To characterize the distribution and dynamics of soil organic C (SOC) and N in the various landscape elements of an Antarctic dry valley, we measured soil profile organic C and organic N stocks, inorganic N (NH₄-N and NO₃-N), soil CO₂ effluxes, water contents and soil temperatures in the Garwood Valley, a relatively small valley in southern Victoria Land. We also conducted laboratory measurements of basal respiration on soils collected from the Valley. SOC and respiration rates were low and SOC was highly stratified in the soil profile, with the largest values observed near the surface. Significant variations of SOC stocks and soil CO₂ effluxes were observed between landscape elements and spatial variability was closely related to the distance from the lake, the major site of primary production. The fastest rate of SOC turnover (residence time c. 30 years) was found in the soils at the lake edge, slower rates were found in landscape elements close to the lake (c. 52-67 years), and the slowest rates in other landscape elements (c. 84-123 years) further away. A mass balance of organic C indicates that the quantity of C fixed in the lake, accumulated on the lake edge, exposed and subsequently displaced on a 14-year basis can explain the near-surface SOC turnover within the entire valley. We conclude that the displacement of organic matter derived from the lake is an important external source for the microbial processes in these soils at a landscape scale. However, further investigations are needed in order to evaluate the importance of displaced C compared to other nutrients (e.g. N) on the spatial control of observed soil respiration rates.     

Analysis of dry matter and protein contents in fresh yam bean tubers by near‐infrared reflectance spectroscopy

Abstract

Fast screening methods are needed for plant breeding. The objective of this research was to evaluate the potential of near‐infrared reflectance spectroscopy (NIRS) for the simultaneous analysis of dry matter and protein contents in intact discs of fresh yam bean (Pachyrhizus spp.) tubers. Discs from 210 tubers were extracted with a punch few hours after harvesting and scanned by NIRS using a specially designed adapter. External validation revealed a close relationship between NIRS and reference methods for dry matter content (r²=0.94; standard error of performance, SEP=1.2%) and protein content (r²=0.87; SEP=1.94%). The calibration for protein content was compared with another one developed using dried‐ground tuber samples (r²=0.97; SEP=0.97%). These results suggested that NIRS can be used to determine dry matter and protein contents in fresh tuber samples of yam beans with acceptable accuracy. Further research will have to determine if additional traits can be incorporated into this scheme.     

夏玉米植株干物质、 氮磷钾养分积累速度和时间的动态分析

用Logistic方程及导出的速度方程, 探讨夏玉米植株干物质和氮、 磷、 钾养分积累速度与时间的数量关系,以期为动态过程分析提供一些新的资料。田间肥料试验结果表明,夏玉米植株干物质与养分积累速度的动态变化呈现不对称钟形曲线,根据曲线走向可将其划分为低速期（I）、快速期（II）和降速期（III）。三期时长各占夏玉米全生育期的1/3,但不同处理各期时长不同步。夏玉米出苗后30天左右内（I期）植株干物质和养分积累速度很低,与其后的II、 III期相比,速度相差一个数量级; 其后的II期速度最高,III期积累速度逐步下降,平均速度低于II期。植株干物质与养分的分期积累量取决于分期时长与速度两个参数。     

覆膜对玉米间作豌豆干物质积累与分配的影响

分别对玉米、豌豆带进行覆膜、不覆膜处理做大田试验,研究豌豆-玉米间作体系的产量和干物质积累与分配的变化。结果表明:覆膜比不覆膜显著提高了作物的籽粒产量和生物学产量。单作覆膜比不覆膜玉米增产9%,豌豆增产21%;间作经济产量,玉米覆膜豌豆不覆膜处理的玉米比间作无膜处理的玉米增产11.70%,全膜覆盖比间作无膜处理的豌豆增产24.40%。土地当量比(LER)除玉米不覆膜豌豆覆膜的小于1外,其他处理LER为1.09~1.24,表现出明显的间作优势。两作物养分向籽粒的转移率和贡献率均为茎大于叶,覆膜提高了干物质向籽粒的转移率和贡献率。玉米覆膜豌豆不覆膜处理是本研究中间作优势最明显的覆膜方式,而玉米不覆膜豌豆覆膜处理会造成资源浪费,不利于豌豆-玉米间作体系的产量积累。     

牧草干物质产量的时空变异及其制图研究

以英国Hillsborough农业研究所附近的一块7.9 hm²的牧草田为研究区，采用地统计方法研究分析连续3年的牧草干物质产量在3个收割季节的空间变异，并研究了第一、二季其空间分布的变异在时间上的稳定性，在此基础上制作了牧草干物质产量分级管理地图。第三季由于天气原因未能收集到2001年的数据而未做时间稳定性研究。结果表明，牧草产量在第一季的空间变异最小且在时间上基本稳定，因此，在第一季，根据牧草干物质产量分级管理地图对该牧草地进行精确管理，特别是精确肥料管理，是可行的；而在第二季，牧草产量的空间分布非常零散，且在时间上表现为不稳定，目前还很难对该牧草地进行精确管理。     

Effects of phosphorus and drought stresses on dry matter and phosphorus allocation in wheat

The effect of phosphorus (P) and soil water availability (W) on the growth and development of wheat plants (Triticum aestivum L. cv. Minaret) was studied in a pot experiment. Four levels of P supply (0, 15, 30, and 100 μgP/g soil) were applied before sowing. Thirty‐four days after sowing (DAS), the pots were kept near 100% of field capacity (FC). From 34 DAS until one week before anthesis (67 DAS), half of the pots were maintained between 60–70% FC. Control pots were kept at 85–95% FC by weighing and watering the pots every two to three days. Shoots were harvested four times before anthesis and twice after. At each harvest, dry matter and P accumulation were measured in leaves, stems, and ears. In this study, thermal time until anthesis was inversely related to the level of P application. Phosphorus additioning affected the allocation of biomass and P in aerial plant organs. Plants growing only with soil P showed a delay in the allocation of dry matter and P into leaves and stems with respect to plants fertilized with 100 μg P/g of soil. In this study, the final composition of the grain depended on re‐mobilization from other plant organs. Evidence of independent re‐mobilization of carbohydrates and P towards the ear is presented, and the pattern of plant development as well as the relationships between development and dry matter and P allocation are discussed.     

不同产量类型水稻基因型干物质积累与磷素吸收利用

以27份中稻和29份晚稻亲本材料为供试材料,采用系统聚类方法将供试材料按产量分为高、 中、 低产三个类型,通过大田试验比较了不同产量类型、 不同生育阶段的干物质生产和磷素吸收利用的差异。结果表明,1）不同生育类型水稻产量、 磷吸收及利用效率存在极显著的基因型差异,中稻和晚稻最高产量分别是最低产量的3.24和2.15倍; 晚稻高产类型产量较中稻高12.69%,但磷利用效率差异不显著。2）中稻高产类型磷积累量在分蘖拔节期最大,晚稻高产类型在拔节抽穗期最大; 中稻和晚稻高产类型干物质量均在分蘖拔节期最小,拔节抽穗期最大,出现前小、 中强、 后高的现象。3）中稻干物质量和磷积累量均在分蘖拔节期对产量贡献率最大,分别为42.38%和58.09%; 晚稻磷积累量在抽穗成熟期对产量贡献率最大,为39.35%,干物质量在此阶段也较高,为16.16%。因此,营养生长阶段的干物质积累和磷的吸收对中稻产量影响较大,而对晚稻产量影响较大的是在生育后期。