长期施肥和不同生态条件下我国作物产量可持续性特征

采用产量可持续性指数（SYI）法,研究了我国不同生态条件下20个长期试验点8个肥料处理的水稻、玉米和小麦产量的可持续性.结果表明：作物SYI值因施肥、作物种类和水热因子不同而呈显著差异.长期不施肥（CK）条件下,水稻、玉米和小麦的SYI值较低,分别为0.55、0.44和0.43;施肥尤其是NPK化肥配施有机肥可显著提高作物产量的可持续性,水稻、玉米和小麦的SYI值分别为0.66、0.58和0.57;单施N肥或NK肥的玉米和小麦的SYI值在0.36～0.47.SYI值大于0.55表明可持续性较好,小于0.45表明可持续性差.经纬度和气象因子对作物SYI也有不同程度的影响,3种作物不施肥时,水稻SYI变异较小,与各因子间没有显著相关性,玉米SYI变异最大且与各因子间存在显著的相关关系,小麦介于两者之间.因此,NPK配施有机肥有利于作物高产稳产,是维持系统可持续性的最优施肥模式.     

Domestication and crop physiology: roots of green-revolution wheat

BACKGROUND AND AIMS: Most plant scientists, in contrast to animal scientists, study only half the organism, namely above-ground stems, leaves, flowers and fruits, and neglect below-ground roots. Yet all acknowledge roots are important for anchorage, water and nutrient uptake, and presumably components of yield. This paper investigates the relationship between domestication, and the root systems of landraces, and the parents of early, mid- and late green-revolution bread wheat cultivars. It compares the root system of bread wheat and 'Veery'-type wheat containing the 1RS translocation from rye. METHODS: Wheat germplasm was grown in large pots in sand culture in replicated experiments. This allowed roots to be washed free to study root characters. KEY RESULTS: The three bread wheat parents of early green-revolution wheats have root biomass less than two-thirds the mean of some landrace wheats. Crossing early green-revolution wheat to an F(2) of 'Norin 10' and 'Brevor', further reduced root biomass in mid-generation semi-dwarf and dwarf wheats. Later-generation semi-dwarf wheats show genetic variation for root biomass, but some exhibit further reduction in root size. This is so for some California and UK wheats. The wheat-rye translocation in 'Kavkaz' for the short arm of chromosome 1 (1RS) increased root biomass and branching in cultivars that contained it. CONCLUSIONS: Root size of modern cultivars is small compared with that of landraces. Their root system may be too small for optimum uptake of water and nutrients and maximum grain yield. Optimum root size for grain yield has not been investigated in wheat or most crop plants. Use of 1RS and similar alien translocations may increase root biomass and grain yield significantly in irrigated and rain-fed conditions. Root characters may be integrated into components of yield analysis in wheat. Plant breeders may need to select directly for root characters.     

5. The use of genetic resources in breeding and breeding research

The dramatic increase in yields of agricultural crops over the last 40 years in developed countries has been attributed equally to improved genetic components and improved agronomic practices. The success of plant breeding is based partly on an increased understanding of the parameters involved, to a great extent on improved and more efficient methods of selection, to greater use of available genetic diversity and also to advances in a number of related disciplines including plant pathology, biochemistry, agronomy and genetics. Successes and problems associated with using various genetic resources in plant breeding are illustrated with examples from some of the world's major crops, including potatoes, barley and cotton.     

作物光能利用效率和收获指数时空变化研究进展

1972年Monteith提出的光能利用效率模型是当前大多数作物生长和产量形成模拟研究以及遥感估产所采用的主要方法.光能利用效率(radiation use efficiency, RUE)和收获指数(harvest index, HI)是其中的两个基本参量.鉴于目前作物RUE和HI研究与应用中仍存在着一些问题,本文综述了相关研究进展,总结了不同尺度上作物RUE和HI的研究方法;介绍了当前遥感估产应用中对RUE和HI两个关键参数的处置概况;建议今后研究应在点尺度开展作物RUE和HI研究的基础上,寻求其在区域尺度上定量评估的可行性途径,切实有效地发挥作物RUE和HI研究在作物实际生产管理中和遥感产量估算方面的应用价值及潜力.     

留茬方式对小麦间作玉米产量和水分利用效率的影响

小麦/玉米间作是河西绿洲灌区主要间作模式,但传统间作和套种需水量大,使该地区水资源紧张.2010年在甘肃河西走廊石羊河绿洲灌区进行大田试验,研究传统小麦秸秆焚烧、秸秆翻还和秸秆立茬3种留茬方式对小麦/玉米间作作物籽粒产量、水分利用效率(WUE)和经济效益的影响.结果表明： 与焚烧和翻还的籽粒产量相比,立茬小麦单作分别增加7.2%和5.1%,立茬小麦间作分别增加6.2%和5.1%,立茬玉米单作分别增加4.7%和2.5%,立茬玉米间作分别增加7.2%和3.3%;与焚烧和翻还的WUE相比,立茬小麦单作分别增加20.4%和16.2%,立茬小麦间作分别增加17.9%和14.6%,立茬玉米单作分别增加16.7%和10.9%,立茬玉米间作分别增加11.8%和17.0%.就单作小麦、单作玉米和小麦/玉米平均值而言,焚烧、翻还、立茬处理的纯收益分别为10946、11471和13454元·hm^-2.从籽粒产量、水分利用效率和纯收益等方面考虑,立茬种植方式为甘肃省河西绿洲灌区小麦/玉米最佳种植模式.     

Waterlogging tolerance in the tribe Triticeae: the adventitious roots of Critesion marinum have a relatively high porosity and a barrier to radial oxygen loss

Nine species from the tribe Triticeae – three crop, three pasture and three ‘wild’ wetland species – were evaluated for tolerance to growth in stagnant deoxygenated nutrient solution and also for traits that enhance longitudinal O₂ movement within the roots. Critesion marinum (syn. Hordeum marinum) was the only species evaluated that had a strong barrier to radial O₂ loss (ROL) in the basal regions of its adventitious roots. Barriers to ROL have previously been documented in roots of several wetland species, although not in any close relatives of dryland crop species. Moreover, the porosity in adventitious roots of C. marinum was relatively high: 14% and 25% in plants grown in aerated and stagnant solutions, respectively. The porosity of C. marinum roots in the aerated solution was 1·8–5·4‐fold greater, and in the stagnant solution 1·2–2·8‐fold greater, than in the eight other species when grown under the same conditions. These traits presumably contributed to C. marinum having a 1·4–3 times greater adventitious root length than the other species when grown in deoxygenated stagnant nutrient solution or in waterlogged soil. The length of the adventitious roots and ROL profiles of C. marinum grown in waterlogged soil were comparable to those of the extremely waterlogging‐tolerant species Echinochloa crus‐galli L. (P. Beauv.). The superior tolerance of C. marinum, as compared to Hordeum vulgare (the closest cultivated relative), was confirmed in pots of soil waterlogged for 21 d; H. vulgare suffered severe reductions in shoot and adventitious root dry mass (81% and 67%, respectively), whereas C. marinum shoot mass was only reduced by 38% and adventitious root mass was not affected.     

断伤作物根系对籽粒产量与水分利用效率的影响研究现状及问题

就断伤作物根系对作物生长、产量形成及水分利用效率的影响方面的研究文献进行了评述,并提出了需要进一步探讨的若干问题。断根对作物地上、地下部生长状况及产量的影响与断根时问、程度直接相关。现有的能够与作物断根效果相联系的田问管理措施,以中耕为代表。但断根对作物产量的影响的报道是不一致的,有表现出正向效应的结果,也有表现出负向效应的结果。需要深入探讨的是可能存在的对于产量与水分利用效率具有正向效应的断根程度与时问的优化组合,揭示其在不同作物上的表现,并探讨其作用方式与内在机理。     

The pleiotropic ABNORMAL FLOWER AND DWARF1 affects plant height,floral development and grain yield in rice

Moderate plant height and successful establishment of reproductive organs play pivotal roles in rice grain production. The molecular mechanism that controls the two aspects remains unclear in rice. In the present study, we characterized a rice gene, ABNORMAL FLOWER AND DWARF1 (AFD1) that determined plant height, floral development and grain yield. The afd1 mutant showed variable defects including the dwarfism, long panicle, low seed setting and reduced grain yield. In addition, abnormal floral organs were also observed in the afd1 mutant including slender and thick hulls, and hull‐like lodicules. AFD1 encoded a DUF640 domain protein and was expressed in all tested tissues and organs. Subcellular localization showed AFD1‐green fluorescent fusion protein (GFP) was localized in the nucleus. Meantime, our results suggested that AFD1 regulated the expression of cell division and expansion related genes.     

Abscisic acid in developing grains of wheat and barley genotypes differing in grain weight

Two genetically related wheat lines growing in cabinets were given different temperatures during grain filling, and abscisic acid (ABA) was measured in whole grains by gas chromatography with an electron-capture detector. Three genetically related barley lines grown in the field were assayed for ABA content in endosperm and embryo fractions separately by radiommunoassay.Maximum grain growth rate and final weight per grain of the two wheat lines differed by 50–60% at low temperature and 30–40% at high temperature. During grain development two peaks in ABA level were observed at low temperature but only one at high temperature. At times when differences in grain growth rate between genotypes and between temperature treatments were large, the corresponding differences in ABA concentration were small. In barley, one line (Iabo 14) had 30% heavier grains than the other two (Onice and Opale). Endosperm ABA concentrations showed no clear differences between genotypes until grain filling was nearly complete. Embryo ABA levels were up to 10-times greater than those in the endosperm, with Opale having significantly less ABA in the embryo than the other two cultivars.Our experiments did not provide evidence for a causal relationship between ABA levels during grain filling and grain growth rate or final weight.Abbreviations ABA Abscisic acid - DAA days after anthesis - DW dry weight - FW fresh weight     

The effect of drought and heat stress on reproductive processes in cereals

As the result of intensive research and breeding efforts over the last 20 years, the yield potential and yield quality of cereals have been greatly improved. Nowadays, yield safety has gained more importance because of the forecasted climatic changes. Drought and high temperature are especially considered as key stress factors with high potential impact on crop yield. Yield safety can only be improved if future breeding attempts will be based on the valuable new knowledge acquired on the processes determining plant development and its responses to stress. Plant stress responses are very complex. Interactions between plant structure, function and the environment need to be investigated at various phases of plant development at the organismal, cellular as well as molecular levels in order to obtain a full picture. The results achieved so far in this field indicate that various plant organs, in a definite hierarchy and in interaction with each other, are involved in determining crop yield under stress. Here we attempt to summarize the currently available information on cereal reproduction under drought and heat stress and to give an outlook towards potential strategies to improve yield safety in cereals.     

The use of a principal axis model to examine individual plant harvest index in four grain legumes

BACKGROUND AND AIMS: A principal axis model (PAM) has been proposed to enable the selection of crop ideotypes. The PAM enables plant-to-plant variability within crops to be quantified and compared. The aim of this paper is to validate the PAM for four grain legumes. METHODS: Four grain legumes (Cicer arietinum, Lens culinaris, Lupinus angustifolius, Pisum sativum) were used to quantify the influence of plant-to-plant variability on crop yields. To create variability, populations of 10, 100 and 400 plants m(-2) were established 'on-the-square' with sowing depths of 2, 5 and 10 cm. Further, a central plant was treated with nitrogen and the impact of this on its four neighbouring plants was examined. Seeds were sown and plants harvested individually by hand. KEY RESULTS: Mean individual plant seed weight (SWT) and plant weight (PWT) decreased as plant population increased but there was a consistent and strong (R2 > 0.90) linear relationship between SWT and PWT, with a negative SWT-axis intercept in all species. These components form the basis of the principal axis model (PAM). The PAM was used to summarize the performance of individual plants within a crop and quantify the variability caused by N treatment and the lowest and highest yielding individual plants. A negative SWT-axis intercept indicated that a minimum plant weight (MPW) was required for seed production and therefore the relationship between plant harvest index (PHI) and PWT was asymptotic. The heaviest MPW was calculated for plants grown at the lowest plant population and it was species-dependent, being higher in the larger seeded species. CONCLUSIONS: Agronomic or physiological characteristics that lead to variability in PWT within a population will decrease PHI, and crop yield. The PAM may be useful in breeding programmes to identify plant phenotypes that minimize this plant-to-plant variability.     

Yield and water use of wheat (Triticum aestivum) in a Mediterranean environment: Cultivar differences and sowing density effects

Yield of eight wheat cultivars was evaluated under rainfed and irrigated conditions in a Mediterranean environment. Variation in grain yield resulted from variation in both aboveground biomass production and in harvest index. Under rainfed compared to irrigated conditions, grain yield, biomass and days to heading were decreased, whereas harvest index was increased. Grain yield of the different cultivars under rainfed conditions correlated with that under irrigated conditions in one of the two years. Among cultivars, harvest index under rainfed and irrigated conditions were correlated in both years.Water was used more efficiently for biomass production, and equally efficiently for grain production, under irrigated compared to rainfed conditions. Under rainfed conditions, crop water use efficiency was higher for cultivars developed for rainfed environments than for those developed for high-rainfall or irrigated environments. Cultivars with low-rainfall target environments had the lowest evapotranspiration under rainfed conditions. Under rainfed conditions, differences between the cultivar groups in crop water use efficiency corresponded with trends in water use efficiency of individual plants and with the ratio of photosynthesis to transpiration, measured on plants grown in a growth room.Early in the season, water was used more efficiently for biomass production at high sowing densities than at low sowing densities. Through faster biomass production and ground cover a smaller proportion of the evapotranspired water was lost in soil evaporation and a larger proportion was transpired. However, the net effect was a greater water use in the early phases of growth and consequently a lower water availability later in the season, leading to similar yields regardless of sowing density.     

灌浆期水分亏缺条件下二、四、六倍体小麦收获指数和水分利用效率的演化

为揭示不同倍性小麦生长发育、产量性状及水分利用对灌浆期水分亏缺响应的差异,选用二倍体野生一粒小麦(Triticum boeoticum)、栽培一粒小麦(T.monococcum),四倍体野生二粒小麦(T.dicoccoides)、栽培二粒小麦(T.dicoccon),和两个普通六倍体小麦(T.aestivum)品种‘长武134’和‘陕253’6个小麦品种作为供试材料。采用盆栽控水的方法,测定和分析了不同灌浆期土壤水分条件下小麦株高、旗叶叶面积、穗长、根干重、地上生物量、根冠比、千粒重、粒数、产量、收获指数、蒸腾耗水量和水分利用效率等性状的变化。在小麦染色体倍体由二倍体向六倍体进化的过程中,小麦地上生物量、千粒重、穗粒数、产量、收获指数和水分利用效率都显著增加。随着土壤水分从正常→中度亏缺→重度亏缺的减少,收获指数先增大后减小,分别为41.26%、42.48%和38.19%;生物量水分利用效率逐渐增大,分别为2.39、2.43和2.53g·kg–1;产量水分利用效率分别为1.05、1.10和1.04g·kg–1。在灌浆期水分条件是影响收获指数和水分利用效率的关键因素之一。灌浆期的水分亏缺有利于六倍体小麦的收获指数和四倍体的生物量水分利用效率的提高。中度的水分亏缺有利于四倍体和六倍体产量水分利用效率的提高。     

A genome-wide analysis of single nucleotide polymorphism diversity in the world's major cereal crops

Over 3.5 million expressed sequence tags from the major cereal taxa were used to electronically mine over 176 000 putative single nucleotide polymorphisms (SNPs). The density, distribution and degree of linkage between these SNPs were compared among the different taxa. The frequency of sequence polymorphism was lowest in diploid taxa (rice, barley and sorghum), intermediate in tetraploid maize and highest in allohexaploid wheat and octoploid sugarcane. SNPs were further categorized as either intravarietal (differences between gene family members and homoeologues) or varietal (differences between two varieties), and as either co-segregating or non-co-segregating with neighbouring polymorphisms. Varietal co-segregating SNPs represent the best candidates for molecular markers as they show variation between varieties and have a high probability of being validated, as sequencing errors are unlikely to co-segregate with one another. This elite class of SNPs was most abundant in barley and least abundant in wheat and rice. Despite the large number of observed sequence polymorphisms in allohexaploid wheat, only a fraction of those available are likely to make good molecular markers. In addition, we found that rice SNPs up to 10 kb apart were in linkage disequilibrium (LD), but that high levels of LD attributable to population structure confounded the tracking of LD over greater distances.     

黄淮海平原玉米施氮量对后茬小麦土壤剖面硝态氮和产量的影响

在冬小麦-夏玉米一年两熟模式下,玉米品种“郑单958”（植株密度9株/m^2）和小麦品种“93-9”（基本苗704株/m^2）,冬小麦基施144kg N/hm^2,研究了玉米5个施N量（0、90、180、270和360kg/hm^2）对后茬小麦期间土壤剖面硝态氮含量、无机氮总量,以及小麦氮素吸收利用和产量的影响.结果表明：（1）与不施氮相比,玉米施氮显著增加小麦季0～200cm土壤硝态氮含量;自拔节起,0～40cm、0～130cm和0～200cm硝态氮含量均随施氮量增加而递增,在硝态氮含量较高的小区增幅也大.（2）轮作一周期后,不施氮和施氮360kg/hm^2显著影响0～130cm和0～200cm无机氮总量,但在90～270 kg/hm^2之间,施氮量的影响不明显.（3）施氮小于180kg/hm^2时,成熟期小麦植株氮素和籽粒氮素积累量、氮肥利用率均随施氮量增加而递增,但不明显.（4）与不施氮相比,施氮90kg/hm^2的小麦产量和麦玉轮作总产均增加但不明显,施氮180 kg/hm^2均显著增加,施氮270kg/hm^2与180kg/hm^2无明显差异.本试验条件下,夏玉米施氮90～180 kg/hm^2是适宜的.     

Elucidating the genetic basis of biomass accumulation and radiation use efficiency in spring wheat and its role in yield potential

One of the major challenges for plant scientists is increasing wheat (Triticum aestivum) yield potential (YP). A significant bottleneck for increasing YP is achieving increased biomass through optimization of radiation use efficiency (RUE) along the crop cycle. Exotic material such as landraces and synthetic wheat has been incorporated into breeding programmes in an attempt to alleviate this; however, their contribution to YP is still unclear. To understand the genetic basis of biomass accumulation and RUE, we applied genome‐wide association study (GWAS) to a panel of 150 elite spring wheat genotypes including many landrace and synthetically derived lines. The panel was evaluated for 31 traits over 2 years under optimal growing conditions and genotyped using the 35K wheat breeders array. Marker‐trait association identified 94 SNPs significantly associated with yield, agronomic and phenology‐related traits along with RUE and final biomass (BM_PM) at various growth stages that explained 7%–17% of phenotypic variation. Common SNP markers were identified for grain yield, BM_PM and RUE on chromosomes 5A and 7A. Additionally, landrace and synthetic derivative lines showed higher thousand grain weight (TGW), BM_PM and RUE but lower grain number (GM2) and harvest index (HI). Our work demonstrates the use of exotic material as a valuable resource to increase YP. It also provides markers for use in marker‐assisted breeding to systematically increase BM_PM, RUE and TGW and avoid the TGW/GM2 and BM_PM/HI trade‐off. Thus, achieving greater genetic gains in elite germplasm while also highlighting genomic regions and candidate genes for further study.     

Estimating index of population trend by re-sampling techniques (jackknife and bootstrap) and its application to the life table study of rice leaf roller, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

Taking a published natural population life table of rice leaf roller, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), as an example, we estimated the population trend index, I, via re‐sampling methods (jackknife and bootstrap), determined its statistical properties and illustrated the application of these methods in determining the control effectiveness of bio‐agents and chemical insecticides. Depending on the simulation outputs, the smoothed distribution pattern of the estimates of I by delete‐1 jackknife is visually distinguishable from the normal density, but the smoothed pattern produced by delete‐d jackknife, and logarithm‐transformed smoothed patterns produced by both empirical and parametric bootstraps, matched well the corresponding normal density. Thus, the estimates of I produced by delete‐1 jackknife were not used to determine the suppressive effect of wasps and insecticides. The 95% percent confidence intervals or the narrowest 95 percentiles and Z‐test criterion were employed to compare the effectiveness of Trichogramma japonicum Ashmead and insecticides (powder, 1.5% mevinphos + 3% alpha‐hexachloro cyclohexane) against the rice leaf roller based on the estimates of I produced by delete‐d jackknife and bootstrap techniques. At α= 0.05 level, there were statistical differences between wasp treatment and control, and between wasp and insecticide treatments, if the normality is ensured, or by the narrowest 95 percentiles. However, there is still no difference between insecticide treatment and control. By Z‐test criterion, wasp treatment is better than control and insecticide treatment with P‐value < 0.01. Insecticide treatment is similar to control with P‐value > 0.2 indicating that 95% confidence intervals procedure is more conservative. Although similar conclusions may be drawn by re‐sampling techniques, such as the delta method, about the suppressive effect of trichogramma and insecticides, the normality of the estimates can be checked and guaranteed, and the correlation among sequential life stages of rice leaf roller is also considered in the estimation. Judged by the P‐values from Z‐test, the delta method is more conservative.     

Physical map of the wheat high-grain protein content gene Gpc-B1 and development of a high-throughput molecular marker

Grain protein content (GPC) is important for human nutrition and has a strong influence on pasta and bread quality. A quantitative trait locus, derived from a Triticum turgidum ssp. dicoccoides accession (DIC), with an average increase in GPC of 14 g kg(-1) was mapped on chromosome 6BS. Using the wheat-rice colinearity, a high-density map of the wheat region was developed and the quantitative trait locus was mapped as a simple Mendelian locus designated Gpc-B1. A physical map of approx. 250 kb of the Gpc-B1 region was developed using a tetraploid wheat bacterial artificial chromosome library. The constructed physical map included the two Gpc-B1 flanking markers and one potential candidate gene from the colinear rice region completely linked to Gpc-B1. The relationship between physical and genetic distances and the feasibility of isolating genes by positional cloning in wheat are discussed. A high-throughput codominant marker, Xuhw89, was developed. A 4-bp deletion present in the DIC allele was absent in a collection of 117 cultivated tetraploid and hexaploid wheat germplasm, suggesting that this marker will be useful to incorporate the high GPC allele from the DIC accession studied here into commercial wheat varieties.     

The ecology and agronomy of Miscanthus sinensis, a species important to bioenergy crop development, in its native range in Japan: a review

Among several candidate perennial taxa, Miscanthus × giganteus has been evaluated and promoted as a promising bioenergy crop. Owing to several limitations, however, of the sterile hybrid, both at the taxon and agronomic production levels, other options need to be explored to not only improve M . × giganteus , which was originally collected in Japan, but to also consider the development of other members of its genus, including Miscanthus sinensis , as bioenergy crops. Indeed, there is likely much to be learned and applied to Miscanthus as a bioenergy crop from the long history of intensive interaction between humans and M. sinensis in Japan, which in some regions of the country spans several thousand years. Combined with its high amount of genetic variation, stress tolerance, biotic interactions with fauna, and function as a keystone species in diverse grasslands and other ecosystems within its native range, the unique and extensive management of M. sinensis in Japan as a forage grass and building material provides agronomists, agroecologists, and plant breeders with the capability of better understanding this species in terms of potential contribution to bioenergy crop development. Moreover, the studies described in this review may serve as a platform for future research of Miscanthus as a bioenergy crop in other parts of the world.