Cereal Species Research Articles

Phenological Stages and Aluminum Presence Influences Arbuscular Mycorrhizal Fungi Communities in Roots of Plant Cereals

Globally, soil acidity is a restrictive condition for agricultural production in a large surface. The aim of this study was to assess arbuscular mycorrhizal fungi (AMF) diversity in cereal species roots exposed to aluminum (Al) phytotoxic level at different plant phenological stages. A microcosm experiment was conducted in a soil-less system. AMF communities were analyzed in root samples by using PCR-DGGE. Phenological stage has a significant effect on the diversity indices. Simpson diversity index indicated a significant dominance of some AMF operational taxonomic units (OTUs), which were present in higher proportion, presumably displaying functional roles influencing physiological processes within host plant cereal growing under acidic conditions. In addition, AMF-OTUs communities’ profiles showed a clustering trend related to Al presence. The present study suggests that AMF diversity based on OTUs analyses obtained from DGGE profiles depends on cereal plant phenological stage and Al supply, which seems to be a relevant AMF trait and it would be used for developing management strategies for acidic soils. However, more studies are needed related to Al effect on AMF communities of cereal species roots and AMF dynamics under cultivation conditions through the use of metagenomic techniques.

The Pros and Cons of Rye Chromatin Introgression into Wheat Genome

Rye is one of the most commonly used sources of elite genes in wheat improvement programs. Due to the high collinearity of the genomes of both cereal species, it is possible to obtain interspecific chromosomal translocations and substitution lines. Rye chromatin is used to transfer numerous genes for resistance to biotic and abiotic stresses into the wheat genome. Introgression has also resulted in improved agronomic traits. However, despite the numerous advantages, the transfer of large fragments or whole chromosomes has been quite often accompanied by a decrease in end-use quality. This paper presents an overview of the benefits and drawbacks of using rye as a source of variability in wheat breeding.

Identification of leaf rust resistance genes Lr34 and Lr46 in common wheat (Triticum aestivum L. ssp. aestivum) lines of different origin using multiplex PCR.

Leaf rust caused by the fungus Puccinia recondita f. sp. tritici is one of the most dangerous diseases of common wheat. Infections caused by fungal pathogens reduce the quantity and quality of yields of many cereal species. The most effective method to limit plant infection is to use cultivars that show rust resistance. Genetically conditioned horizontal-type resistance (racial-nonspecific) is a desirable trait because it is characterized by more stable expression compared to major (R) genes that induce racially specific resistance, often overcome by pathogens. Horizontal resistance is conditioned by the presence of slow rust genes, which include genes Lr34 and Lr46. This study aimed to identify markers linked to both genes in 64 common wheat lines and to develop multiplex PCR reaction conditions that were applied to identify both genes simultaneously. The degree of infestation of the analyzed lines was also assessed in field conditions during the growing season of 2017 and 2018. Simple sequence repeat anchored-polymerase chain reaction (SSR-PCR) marker csLV was identified during analysis in line PHR 4947. The presence of a specific sequence has also been confirmed in multiplex PCR analyses. In addition to gene Lr34, gene Lr46 was identified in this genotype. Lines PHR 4947 and PHR 4819 were characterized by the highest leaf rust resistance in field conditions. During STS-PCR analyses, the marker wmc44 of gene Lr46 was identified in most of the analyzed lines. This marker was not present in the following genotypes: PHR 4670, PHR 4800, PHR 4859, PHR 4907, PHR 4922, PHR 4949, PHR 4957, PHR 4995, and PHR 4997. The presence of a specific sequence has also been confirmed in multiplex PCR analyses. Genotypes carrying the markers of the analyzed gene showed good resistance to leaf rust in field conditions in both 2017 and 2018. Research has demonstrated that marker assisted selection (MAS) and multiplex PCR techniques are excellent tools for selecting genotypes resistant to leaf rust.

Contamination Assessment of Durum Wheat and Barley Irrigated with Treated Wastewater through Physiological and Biochemical Effects and Statistical Analyses

The present work focused on the impact of crop irrigation by treated wastewater (TWW) on soil fertility, in germination, and growth of two species of cereals (T. turgidum and H. vulgare). This investigation was conducted at the germination stage (controlled condition) and in pots containing a soil irrigated with wastewater in comparison with controlled soil. Germination rate, vigor index, seedling growth, total fresh mass, chlorophyll content, proline, ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT) activities were measured. Similar effects were shown on both species which emphasize the important role of antioxidant enzymes in the defense against oxidative stress induced by prolonged reuse of TWW. The disturbing effect of the reuse TWW on soil fertility, germination, and development of young plants (T. turgidum and H. vulgare) was linked to the presence of micropollutants in TWW. Data were analyzed by R language using a nonparametric statistical hypothesis test. These have caused the disorganization of many physiological mechanism targets, especially growth disorders observed under different abiotic stress conditions. In conclusion, high salt and heavy metal concentrations contained in the TWW are the major constraints related to the reuse of TWW. Hence, repetitive irrigation with this water can induce, at long term, soil contamination which can limit plant production and crop contamination.

K-means cluster analysis of the West African species of cereals based on nutritional value composition

The K-means algorithm was deployed to extract clusters within the prevalent cereal foods in West Africa. The West Africa Food Composition Table (WAFCT) presents all the 76 food sources in the cereals class as a single group without considering the similarity or dissimilarity in nutritional values. Using K-means clustering, the Euclidean distance between nutritional values of all cereal food items were measured to generate six sub-groups based on similarity. A one-way analysis to validate the results of the extracted clusters was carried out using the mean square values. For every nutrient, the “within groups” and “between groups” values of the mean squares were examined. This was done to ascertain how similar or dissimilar data points in the same or different clusters were to each other. It was discovered that the P values for all “between groups” and “within groups” mean squares for every nutrient was P < 0.01. Additionally, it was observed that in all cases, the mean square values of the “within groups” were significantly lower than those of the “between groups”. These outcomes are indications that clustering was properly done such that the variability in nutrient values for all food sources within the same clusters was significantly low,while those in different clusters were significantly high. Thus, the ultimate objective of clustering,which is to maximize intra-cluster similarity and minimize inter-cluster similarity was effectively achieved. Cluster analysis in this study showed that all food items within a particular cluster are similar to each other and dissimilar to food items in a different cluster.These findings are valuable in dietaries, food labeling, raw materials selection, public health nutrition, and food science research,when answering questions on the choice of alternative food items. Where original choices are not available or unaffordable, the clusters can be explored to select other similar options within the same cluster as the original choice.

On farm survival of Apulian legume and cereal landraces in relation to land cover/land use changes. A case study

Apulia (southeast of Italy) has always been an agricultural region in the Italian landscape. Nowadays, the countryside is a mix of natural environments and artificial landscapes. From 2014 to 2016, the region has been the object of a project aimed to collect information about geographic position and surface devoted to legume and/or cereal landrace cultivation. The collection missions carried out allowed the acquisition of 352 samples belonging to eight legumes and six cereal species. Chickpeas predominated among legumes, while durum and common wheat landraces prevailed among cereals. The cultivation of these landraces was mainly located in the marginal areas of central and southern Apulia region. The geographical information system technology, used in order to geo-reference the collection sites, allowed investigating the changes in land cover/land use (LCLU) occurred over the last three decades at each collecting site. In addition to the evidences collected at field level, the comparison of old ortho-photos and recent satellite images, available on Copernicus Land Monitoring Service of European Environment Agency, shown that very limited changes of LCLU have occurred. Near the collection sites, the agrarian landscape is remained highly fragmented as it was three decades ago. The cultivation side by side of irregular patches with legumes, cereals, olive trees, and grapevine characterise the agricultural landscape. Based on these evidences it can be infer that the absence of significant changes in LCLU has play a positive role in the safeguard of on farm conservation of Apulian landraces.
 Highlights - Analysis of present distribution of Apulian legume and cereal landraces. - Short description of the landscape of collection sites. - Comparison of present and past diffusion of landrace cultivation. - Changes in land cover/land use that occurred over the last three decades.

Semiochemicals and habitat manipulation to support green lacewing activity to reduce aphid infestations in agroecosystems

Conservation biological control (CBC) is a promising tool for ecological intensification that aims to establish resilient natural enemy populations that contribute to pest management with reduced use of pesticides and at the same time support native biodiversity in agroecosystems. Yet the impact of natural enemies in CBC is often limited due to missing resources such as food, habitat, and hibernation shelters. Here, we studied a CBC strategy that incorporates these essential resources combined with semiochemicals, focusing on how the common green lacewing can enhance biological control of aphids.In a 4-year field study conducted at three locations in the region of East Norway, we developed a CBC strategy combining the three measures ATTRACT (a ternary attractant that increase lacewing egg laying), FOOD (floral buffer strips), and SHELTER (insect hotels for overwintering survival) to increase aphid biological control in spring barley. We recorded the number of lacewings, ladybirds, hoverflies, parasitized aphid mummies, and the two cereal aphid species Sitobion avenae and Rhopalosiphum padi. Our CBC strategy resulted in a significant increase in lacewing activity and significant aphid suppression. At all three locations and over the 4-year period, aphid infestation was below the economic damage threshold in the field plots using CBC measures. In contrast, during two of the years, the density of the aphid infestation in the control plots was significantly above the damage threshold. We found evidence that use of the ternary attractant supported green lacewings but led to loss of ladybirds, hoverflies, and parasitoids, even though flower strips were used as alternative resources.Our study shows a promising increase in lacewing activity in the agricultural landscape and high biological control of aphids in barley. Long-term field studies are needed to evaluate the impact on non-target species and the agroecosystem before practical application of this approach can be considered.

Excess Zinc Alters Cell Wall Class III Peroxidase Activity and Flavonoid Content in the Maize Scutellum.

Maize is one of the most important cereal crop species due to its uses for human and cattle nourishment, as well as its industrial use as a raw material. The yield and grain quality of maize depend on plant establishment, which starts with germination. Germination is dependent on embryo vigor and the stored reserves in the scutellum and endosperm. During germination, the scutellum epidermis changes and secretes enzymes and hormones into the endosperm. As a result, the hydrolysis products of the reserves and the different soluble nutrients are translocated to the scutellum through epithelial cells. Then, the reserves are directed to the embryo axis to sustain its growth. Therefore, the microenvironment surrounding the scutellum modulates its function. Zinc (Zn) is a micronutrient stored in the maize scutellum and endosperm; during imbibition, Zn from the endosperm is solubilized and mobilized towards the scutellum. During this process, Zn first becomes concentrated and interacts with cell wall charges, after which excess Zn is internalized in the vacuole. Currently, the effect of high Zn concentrations on the scutellum function and germinative processes are not known. In this paper, we show that, as a function of the concentration and time of exposure, Zn causes decreases in the radicle and plumule lengths and promotes the accumulation of reactive oxygen species (ROS) and flavonoids as well as changes in the activity of the cell wall Class III peroxidase (POD), which was quantified with guaiacol or catechin in the presence of H2O2. The relationship between the activity index or proportion of POD activity in the scutellum and the changes in the flavonoid concentration is proposed as a marker of stress and the state of vigor of the embryo.

Research of Aphididae of Cereals and Legumes of the Northeastern Ukraine.

Introduction. The article presents the results of research to establish the species composition of aphids –pests of cereals and legumes of agricultural farm of Kharkov region and analyzes their ecological and biological features. The research was conducted for several years in the spring and summer in the Kupyansk district, Kharkov region. A study of constant changes in the species composition of aphidofauna and recommendations for regulating the number of pests is very relevant today.Purpose.The purpose of the study is to investigate the composition of aphidofauna species of cereals and legumes today and to study the dynamics of the abundance of common species in the field of research.Methods.Inspection of infected plants, determination of the degree of colonization by aphids of each plant. Collecting aphids and determining their species.Results. Thirteen species of aphids of the family Aphididae have been collected and identified. Among the cultivated plants, fields sown with 14 species of cereals and legumes were surveyed. By type of food, certain species of aphids are conditionally divided into oligophages (5 species) and polyphages (8 species). In the aphidofauna of Ukraine, monoecious (non-migratory) life cycles are typicalfor 6 species (46% of the total number), dioecious (migratory) for 7 species (54%) of aphids. The largest number of aphid colonies was recorded on cereals and legumes at the edges of fields bordering on separate strips of woody-shrub and herbaceous vegetation, which serves as an additional forage base or primary host in the dioecious life cycle of some species. Significant aphid damage to cereals was observed during the end of milky –the beginning of waxy ripeness of grain, on the tops of shoots on corn, and in legumes –during the entire growing season on young leaves and stems. As for climatic factors, there was an increase in the number of aphids on cereals in hot dry weather, and on legumes –in moderately warm and humid. Heavy rains suppressed the rapid reproduction and development of all species of aphids. Conclusion.As a result of research, 13 species of aphids of the family true aphids Aphididae were found and identified.The most numerous were polyphagous aphids: the large cereal aphid Sitobion avenae Fabricius, 1775, the common cereal aphid Schizaphis graminum Rondani, 1852, the barley aphid Brachycolus noxius Mordvilko, 1913, the bird-cherry-cereal aphid Rhopalosiphum padi Linnaeus, 1758, elm-cereal, or corn aphid Tetraneura ulmi Linnaeus, 1758, beet-leaf aphid Aphis fabae Scopoli, 1763, pea aphid Acyrthosiphon pisum Harris, 1776.Key words: aphids; aphid fauna; cereals; legumes; oligophagеs; polyphagеs

Heterogeneous Expression and Purification of the Wheat VRN1 K-Box Domain Suggest the Formation of a Tetramer of the VRN1 Protein

In cereal species such as wheat (Ttiticum aestivum) and barley (Hordeum vulgare), many studies have indicated that VERNALIZATION 1 (VRN1) functions as a flowering promoter, which activates florigen gene expression. The wheat florigen gene Wheat FLOWERING LOCUS T (WFT, which is identical to VRN3) is an integrator of the vernalization, photoperiod and autonomous pathways in wheat flowering, and the WFT expression is correlated with the VRN1 expression. VRN1 encodes an APETALA1/FRUITFULL-like MADS-box transcription factor which expression is induced by vernalization, leading to flowering thorough up-regulation of WFT. In Arabidopsis, it has been reported that protein-protein interactions are keys for MADS-box protein function and MADS-box transcription factors must dimerize to bind to the target gene. In this study, by using gel permeation chromatography (GPC) with purified VRN1 protein, we indicated the possibility that VRN1 protein exists as tetramer-like as flowering homeotic MADS-box proteins in Arabidopsis.

Genomics of grain quality in cereals

Rapid advances in genomics are providing the tools to determine the genetic basis of quality (both nutritional and functional) in cereals. This promises to allow increased rates of genetic gain in breeding by reducing the need for extensive end-product testing of new varieties. Many quality traits are the result of relatively recent human selection and are thus likely to be controlled by only a few major genes. This makes identification of these genes for use in breeding selection an attractive target for breeders. Examples of the discovery of genes that are major contributors to key grain quality attributes include, fragrance and cooking temperature in rice (identified by re-sequencing) and loaf volume and milling yield in wheat (identified by transcriptome analysis). Extension of genomic tools to an analysis of the wider gene pool including wild relatives will enable the identification of alleles that may contribute to improved or novel grain quality in the future and may be critical to ensuring quality is retained in a changed climate. Completely new cereal species might be produced.

Root system characteristics under different water regimes in three cereal species

Root system characteristics under different water regimes in three cereal species

Modification of starch composition, structure and properties through editing of TaSBEIIa in both winter and spring wheat varieties by CRISPR/Cas9.

SummaryFoods high in amylose content and resistant starch (RS) offer great potential to improve human health and lower the risk of serious noninfectious diseases. Common wheat (Triticum aestivum L.) is a major staple food crop globally. However, the RS contents in the grains of modern wheat varieties are low. Here, we report the generation of high‐amylose wheat through targeted mutagenesis of TaSBEIIa in a modern winter wheat cv Zhengmai 7698 (ZM) and a spring wheat cv Bobwhite by CRISPR/Cas9, respectively. We generated a series of transgene‐free mutant lines either with partial or triple‐null TasbeIIa alleles in ZM and Bobwhite, respectively. Analyses of starch composition, structure and properties revealed that the effects of partial or triple‐null alleles were dosage dependent with triple‐null lines demonstrated more profound impacts on starch composition, fine structures of amylopectin and physiochemical and nutritional properties. The flours of triple‐null lines possessed significantly increased amylose, RS, protein and soluble pentosan contents which benefit human health. Baking quality analyses indicated that the high‐amylose flours may be used as additives or for making cookies. Collectively, we successfully modified the starch composition, structure and properties through targeted mutagenesis of TaSBEIIa by CRISPR/Cas9 in both winter and spring wheat varieties and generated transgene‐free high‐amylose wheat. Our finding provides deep insights on the role of TaSBEIIa in determining starch composition, structure, properties and end‐use quality in different genetic backgrounds and improving RS content with multiple breeding and end‐use applications in cereal crop species through genome editing for health benefits.

Ранние свидетельства производящей экономики в материалах гиссарской культуры: обзор исследовательских концепций

The transition to farming is a revolutionary step in human history. Domesticated species of cereals and small ruminants which spread from the territory of the countries of the Fertile Crescent appear in Central Asia during the early Neolithic period (the 6th — 5th millennium BC). In the middle of the 20th century several Neolithic cultures prominent for the Central-Asian region were defined: Jeitun, Kelteminar and Hissar. This publication is devoted to the consideration of the Hissar culture and the existing reconstructions of its economic structure. The Gissar culture is widespread on the territory of the Gissar-Alai and dates from the 6th to the 2nd millennium BC. Since the late 1950s the researchers tried to determine the type of economy of the carriers of the Hissar culture: the early stage of agriculture and cattle breeding; hunting and gathering; nomadic cattle breeding. This article examines the main arguments “for” and “against” the existence of a productive economy in the Hissar culture, namely, cattle breeding. Based on a number of signs, such as the presence of long-term and short-term camps, a large number of bones of small ruminants, the availability of year-round pastures at the site, the absence of hunting tools in the toolkit, the team of authors agrees with the point of view of V. A. Ranova and G. F. Korobkova about the use of early cattle breeding by the Hissar people. However, this hypothesis requires additional elaboration using bioarchaeological research methods. Keywords: Central Asia, Hissaro-Alay, Hissar, Neolithic, pastopalism Acknowledgements: The analysis of the general problems was carried out with the support of the project of the Russian Science Foundation No. 19–78–10053 “Origin of the Industrial Economy in the Mountainous Part of Central Asia”, the analysis of materials from the Hissar culture was carried out within the framework of the research program No. 0329–2019–0002 “Ancient Cultural Processes in the Territory of Central Asia”.

Comparison of disease severity caused by four soil-borne pathogens in winter cereal seedlings

In Australia, crown rot of cereals is predominantly caused by Fusarium pseudograminearum and Fusarium culmorum, and common root rot by Bipolaris sorokiniana. Fusarium graminearum is an important pathogen causing Fusarium head blight worldwide and has also been reported to cause crown rot of wheat. The comparative ability of F. pseudograminearum, F. culmorum, F. graminearum and B. sorokiniana to cause crown rot and common root rot across a range of winter cereal species requires investigation. In glasshouse trials, we inoculated one cultivar each of barley, bread wheat, durum wheat, oat and triticale with two strains of each of the four pathogens. At 21 days after inoculation, the sub-crown internode and leaf sheaths of each plant were visually rated for brown discoloration. Shoot length and dry weight of inoculated plants were compared with those of non-inoculated controls. Barley and bread wheat had the highest disease severity ratings on leaf sheaths and sub-crown internode (64.7–99.6%), whereas oat had the lowest disease severity ratings across all pathogens (<5%). The shoot length of all cultivars was significantly reduced (by 12.2–55%, P < 0.05) when exposed to F. pseudograminearum. This study provides a comparison of pathogenicity of crown rot and common root rot pathogens and demonstrates significant variation in visual discoloration and host response across a range of winter cereals.

Fast developing Russian wheat aphid biotypes remains an unsolved enigma.

Diuraphis noxia, commonly known as the Russian wheat aphid, is an economically important cereal pest species, highly invasive and reproduces mostly asexually. Remarkably, many new virulent populations continue to develop, despite the lack of genetic diversity in the aphid. Russian wheat aphid is a phloem feeder and is therefore engaged in a continuous arms battle with its cereal host, with the acquisition of virulence central to the breakdown of host resistance. In the review, most attention is given to recent topics about mechanisms and strategies whereby the aphid acquires virulence against its host, with special reference given to the role of noncoding RNA elements, bacteria, and the epigenetic pathway in possibly directing virulence.

The Effect of Foliar Fertilization with Micronutrients on the Incidence and Severity of Leaf and Stem-base Diseases in Winter Triticale (x Triticosecale Witmm.) and Winter Rye (Secale cereale L.)

Winter triticale (Triticale) cv. Dinaro and winter rye (Secale cereale L.) cv. Dankowskie Diament were grown in 2012 and 2013 in a field-plot experiment in Tomaszkowo near Olsztyn (NE Poland). The experiment consisted of 7 treatments: absolute control (without fertilizers or the growth stimulator), control-NPK fertilizer, NPK fertilizer + micronutrients applied alone or in combination (4 treatments), NPK fertilizer + Nano-Gro growth stimulator. The severity of disease symptoms on the leaves and stem-bases of triticale and rye was evaluated throughout the growing season. Symptoms of powdery mildew on the leaves of winter triticale and winter rye were noted only in the growing season of 2013, and disease severity remained at a low level. In the growing season of 2012, weather conditions were conducive to the spread of Septoria tritici blotch (STB) and brown rust on triticale (the highest values of infection index were 41.6 and 23.8%, respectively), and scald and brown rust on rye (29.0 and 38.1%, respectively). Foliar application of micronutrients influenced the rates of infections caused by Zymoseptoria tritici and Puccinia recondita f. sp. tritici on triticale leaves. Symptoms of eyespot and Fusarium foot and root rot were noted on the stem-bases of both cereal species, whereas symptoms of take-all disease and sharp eyespot were observed sporadically. Significant differences were found between treatments in the severity of infections caused by Gaeumannomyces graminis on the stem-bases of triticale, and by Tapesia spp. and Rhizoctonia spp. on the stem-bases of rye.

Scavenging and recycling deep soil nitrogen using cover crops on mid-Atlantic, USA farms

In the mid-Atlantic USA region, nitrogen uptake by crops ceases about four weeks prior to harvest maturity, leaving substantial mineral N in the soil profile, which is prone to leach during the winter. Deep-rooted cover crops planted by early-September can potentially take up residual N and recycle some of it for following cash crops. We performed experiments on 19 minimum-tillage, grain farms investigating four unfertilized cover crop systems (forage radish (Raphanus sativus L.), winter cereal or grass, forage radish + winter cereal + crimson clover (Trifolium incarnatum L.), and a no cover crop control). We measured cover crop biomass, N uptake, and inorganic N distribution within the upper 210 cm of soil in late-fall and early-spring, and the following corn (Zea mays L.) crop’s growth and yield. In late-fall, radish reduced soil NO3 in the upper 90 cm by 66 %, while winter cereal or mix cover crops reduced NO3 in the upper 60 cm by 67 % and 56 %, respectively, compared to a no cover crop control. In the spring, the radish and mix cover crops resulted in comparable nitrate levels to the no cover crop control in the topsoil layer (> 30 kg ha−1) and less nitrate than the no cover crop control in subsoil layers. The winter cereal cover crop had low nitrate levels in the topsoil (∼20 kg ha−1) layer and subsoil layers. The biomass and N content of corn seedling (5 leaf) were influenced by the previous cover crop treatment in the order radish (4.0 g biomass plant−1) > mix (3.0 g biomass plant−1) = control (3.5 g biomass plant−1) > winter cereal (2.4 g biomass plant−1). At the farmers’ standard N fertilizer application rate, corn yield following radish was higher than following the winter cereal or mixed species cover crop but corn yield following radish was not different than following no cover crop. Corn yield following the winter cereal cover crop was lower than following no cover crop. Cover crops can be fit within the framework of existing cropping systems to scavenge residual N, therein reducing subsoil inorganic N. Radish and mixed species cover crops can be used prior to corn without reducing the overall short-term N use efficiency of the cropping system.

Incidence of Cereal Cyst Nematode Prevailing in Wheat-rice Growing Regions of Punjab Province, Pakistan

Background: Cereal Cyst Nematodes (CCN) are prevailing in all type of agricultural lands and responsible for enormous losses of cereal crops. The understandings on population densities and management of these nematode are required to improve crop health and productivity.Methods: A study was designed to assess the incidence of cereal cyst nematodes in wheat and rice monoculture cropping regions of eight districts of Punjab province, viz., Jhang, Khushab, layyah, Hafizabad, Sheikhupura, Narowal, Gujranwala and Sargodha in Pakistan. Population densities of cereal cyst nematodes were studied by extracting the cysts and second stage juveniles from soil samples and identified the nematode species. Result: The CCNs were found in 80% of the total 250 samples collected from wheat and rice monoculture fields of at least one crop. In the soil samples collected from wheat fields, an average of 7 to 38 cysts/100g of dry soil with eggs and J2 population of 142-771 were recorded. Whereas from the soil samples of rice fields, 17 to 25 cysts/100g soil were found with 345 to 508 eggs and juveniles. Among the wheat fields, the lowest incidence of 5.5% was recorded in kot–momin and highest incidence of 16.88% was recorded in Silanwali tehsils of Sargodha region. In rice fields, 24.69 to 27.00% incidence of CCNs was noticed in soil samples of various surveyed regions. Three different species of Heterodera genus were morphologically identified from the collections. The species includes Heterodera oryzae, Heterodera avenae and Heterodera graminophila. H. oryzae was more abundant in rice growing regions while H. avenae and H. graminophila were present dominantly in wheat growing regions. This study provides an inclusive information regarding cereal cyst nematode densities and species in wheat-rice growing regions of Punjab province of Pakistan.

The origins of agriculture: Intentions and consequences

We synthesise the results of a large programme of plant ecological research to investigate the selective pressures driving crop domestication and the origins of agriculture in western Asia. We explore this primarily through a series of experiments, comparing the ecological characteristics of: (1) domesticated cereal and pulse species with their wild progenitors and (2) the wild progenitor species with other west Asian grasses and legumes that did not become domesticated during the emergence of agriculture. In particular, we consider the balance between deliberate human selection and unintended consequences of human actions in driving the domestication process. Taken together, our results provide the first empirical evidence to suggest that ecological processes, and unintended selection due to competition between growing plants within anthropogenic environments, may have played a more significant part in the emergence of agriculture than previously supposed. Such human-plant co-evolutionary mechanisms would render unnecessary the search for ‘push’ or ‘pull’ factors, dependent on deliberate human invention to solve a problem or to satisfy a need, as prime movers to explain why hunter-gatherers switched to an agricultural way of life.