Detection of head blight (Fusarium ssp.) in winter wheat by color and multispectral image analyses

The use of camera vision to automatically detect head blight (scab) on wheat ears could provide information about the severity of this dangerous disease and help meet future food traceability requirements. Fusarium spp. is dangerous for both human and animal consumption and the ability to monitor symptom location and severity before the harvested product is further processed or stored could help determine whether the grain is fit for human/animal consumption, for bio-conservation, or is completely unusable.To generate various infection levels, field trials were conducted in 2008 and 2009 using wheat varieties with differing levels of susceptibility to the disease; plots were artificially infected with a spore suspension. A color (red, green, and blue) and a multispectral (red, infrared) camera system with real-time image analysis software were developed and compared to detect disease symptoms in the plots.The chlorophyll defect of the infected wheat ears was classified against the image background by setting binarization thresholds. The result was a black and white image. Single pixels or tiny clusters of pixels not belonging to the symptoms were eliminated by setting an area threshold. For both systems, a linear correlation was found between the camera and the visually detected disease levels of the wheat ears in the plots.In the non-infected control plots without disease symptoms, the multispectral system accurately measured “no disease” even though the digital color system detected too much infection (i.e., a false positive). The multispectral system showed a superior calibration capacity. While the color system had to calibrate for each variety, the multispectral system used only one calibration step before starting the measurements.     

Influence of maize–wheat rotation systems on Fusarium head blight infection and deoxynivalenol content in wheat under low versus high disease pressure

Fusarium head blight (FHB) is one of the most destructive fungal diseases of small grain cereals resulting in a reduced grain yield and quality. FHB is the result of a complex interaction between weather conditions and agricultural practices including crop rotation, tillage, fungicide application and host resistance. This study deals with the results of field experiments conducted during the growing seasons 2009–2010 until 2011–2012 at Bottelare (Belgium). The experiments were set up to evaluate the influence of maize–wheat rotation on the visual symptoms of FHB and deoxynivalenol (DON) content in winter wheat. Using a randomised complete block design with four replications, we studied the impact of (a) maize variety as previous crop, (b) maize harvest method (grain or silage maize), (c) tillage method and (d) the influence of the wheat variety resistance on the FHB incidence and DON content. The experimental results showed that the susceptibility of the maize varieties for Fusarium and maize harvest method had only a minor effect on the FHB incidence and DON content of the wheat crop during the subsequent growing season. The tillage method and wheat variety resistance were more important; both factors had a significant influence on the FHB incidence and DON content. Furthermore, the quantitative effect of these factors depended on the disease pressure. The DON content reduction obtained by ploughing and by sowing moderately resistant wheat varieties was higher in case the weather conditions favoured FHB development. Furthermore, it was shown that repeated maize–wheat rotation in combination with favourable weather conditions for FHB could result in an accumulation of inoculum, which, for instance, led to DON contents up to 9.90 mg/kg in August 2012.     

Interactions between crop biomass and development of foliar diseases in winter wheat and the potential to graduate the fungicide dose according to crop biomass

Foliar pathogens such as Zymoseptoria tritici and Puccinia striiformis causing septoria leaf blotch and yellow rust respectively can cause serious yield reduction in winter wheat production, and control of the diseases often requires several fungicide applications during the growing season. Control is typically carried out using a constant fungicide dose in the entire field although there may be large differences in crop development and biomass across the field. The objective of the study reported in this paper was to test whether the fungicide dose response curve controlling septoria leaf blotch and other foliar diseases in winter wheat was dependent on crop development and biomass level. If such a biomass dependent dose response was found it was further the purpose to evaluate the potential to optimize fungicide inputs in winter wheat crops applying a site-specific crop density dependent fungicide dose. The study was carried out investigating fungicide dose response controlling foliar diseases in winter wheat at three biomass densities obtained growing the crop at three nitrogen levels and using variable seed rates. Further the field experiments included three fungicide dose rates at each biomass level, an untreated control, and 75%, 50% and 33% of the recommended fungicide dose rate and the experiments were replicated for three years. Crop biomass had a significant influence on occurrence of septoria and yellow rust with greater disease severity at increasing crop biomass. In two of three years, the interaction of crop biomass and fungicide dose rate had a significant influence on disease severity indicating a biomass-dependent dose response. The interaction occurred in the two years with high yield potential in combination with severe disease attack. If the variation in crop density and biomass level obtained in the study is representative of the variation found cultivating winter wheat in heterogeneous fields, then there seems to be scope for optimizing fungicide input against foliar diseases site-specific adapting the dose according to crop density/biomass.     

Interaction between cultivar and crop management effects on winter wheat diseases, lodging, and yield

The breeding of winter wheat (Triticum aestivum L.) for resistance to major fungal diseases has been a priority over the last 15 years in France. During this period, integrated low-input strategies have been developed for winter wheat, to cope with falling grain prices and growing environmental concerns. We investigated the interactions between genotype and management for disease and lodging intensities, and analysed their effects on yield within an integrated crop management (CM) context.

A multi-environment experimental network (13 locations, studied in three seasons, between 1999–2000 and 2001–2002) comprising several combinations of cultivars and CM systems was carried out. Four rule-based CM plans were defined, with a decrease in input level from CM1 (a high-input CM plan designed to maximise the yield of a given cultivar) to CM4 (a low-input system with no fungicide protection, no plant growth regulator applications, a sowing density 40% lower than for CM1, and 90 kg ha⁻¹ less N fertiliser than for CM1). Cultivars were clustered into three groups (cultivar type (CT) CT1–CT3), according to their scores for resistance to diseases, for the analysis of yield, whereas the resistance cultivar rating (CR) for each disease and for lodging was considered for the analysis of disease and lodging intensities.

For all diseases, CM had a significant effect (P<0.0001), with disease intensity increasing from CM1 to CM4, whereas CR had a negative effect (P<0.005). An interaction between CR and CM was also detected for all diseases (P<0.005) except eyespot. Lodging intensity decreased significantly from CM1 to CM4 (P<0.0001), and significant increases in lodging resistance score (P<0.0001) were not associated with a genotype by management interaction.

Lastly, yield was significantly affected by CM (P<0.0001), CT (P<0.0003), and CM by CT interaction (P=0.0023). Cultivar ranking differed as a function of CM for yield, demonstrating that breeding programs focusing on cultivar evaluation in high-input environments do not result in the selection of cultivars suited to low-input environments.     

Effects of Fusarium culmorum and water stress on durum wheat in Tunisia

The effects of water stress on Fusarium foot and root rot in durum wheat were investigated in growth chamber, greenhouse and field tests in Tunisia. In the seedling stage, emergence of six durum wheat cultivars in the growth chamber was significantly reduced by inoculation with Fusarium culmorum and water stress (P<0.0001), with more disease under drier conditions. Additionally, the tiller number per mature plant, the 1000 grain weight and disease severity in mature stage were reduced by inoculation in greenhouse studies. In a field test, inoculation with F. culmorum significantly reduced the yield (P<0.001), by more than 17% for Om Rabiaa and 38% for Karim, the two cultivars tested. Yield was also significantly affected by precipitation and irrigation levels. The severity of the disease, estimated by the percentage of white heads, was separately affected by the cultivar (P<0.001) and inoculation (P = 0.0004). Percentage of white heads was 1.5 and 2 × higher in inoculated plants than non-inoculated for Om Rabiaa and Karim cultivars, respectively. Disease severity was highest in treatments with the greatest water stress. This is the first detailed study of water stress and F. culmorum on durum wheat in Tunisia, and indicates that cultivar resistance and irrigation management may be important in the management of Fusarium foot rot.     

Effects of crop rotation of soybean with corn on severity of sudden death syndrome and population densities of Heterodera glycines in naturally infested soil

Sudden death syndrome, caused by Fusarium virguliforme, and the soybean cyst nematode, Heterodera glycines, combined cause the highest yield losses in soybean. The objective of this study was to determine the effectiveness of corn rotated annually with soybean on reducing severity of sudden death syndrome (SDS) and if such crop rotation is beneficial to soybean root health and thus improves disease management strategies. Experiments were conducted from 2003 to 2006 through two cycles of a corn–soybean rotation on two commercial fields in Indiana. With one exception, the rotation of soybean with corn did not provide yield benefits compared to monoculture of soybean. Severity of foliar and root symptoms of SDS in rotation plots were never less than in soybean monoculture plots. At one location, soybean monoculture resulted in suppression of SDS compared to the corn–soybean rotation, while H. glycines reproduced freely. At the other location, monoculture of soybean resulted in suppressiveness against H. glycines, while SDS was limited in all treatments. The data suggest that soil suppressiveness can independently impact the pathogens that are important in SDS development. Because H. glycines can increase SDS symptoms, its suppression may also reduce severity of SDS. Current production systems consisting of yearly rotation of soybean with corn are highly vulnerable to the development of severe soil-borne disease complexes. The simple year-to-year rotation of corn and soybean is not considered sustainable. While monoculture of soybean resulted in some disease suppression in these trials, reliance on monoculture may be detrimental due to other environmental considerations beyond the scope of these trials. Including other crops may be beneficial in improving the sustainability of soybean and corn production systems.     

小麦品种冬春性、抗寒性与广适性的关系

为给我国冬小麦的冬、春性遗传改良提供参考,结合"济麦"系列小麦品种(济南17、济麦19、济麦20、济麦21、济麦22)及1996年以来年推广面积最大的冬小麦品种的特性及作者多年育种经验,分析了目前小麦冬春性的分类、鉴定方法(常规田间鉴定方法及分子标记鉴定法)及与抗寒性、广适性的关系。小麦冬春性鉴定应将2种方法有机结合,冬春性与抗寒性无必然联系。冬小麦在其他特性相当的情况下,抗寒性强的偏春性品种往往表现出广泛的适应性,冬春麦杂交可作为提高小麦品种广适性的一条重要途径。     

Effects of supplemental irrigation based on soil moisture levels on photosynthesis,dry matter accumulation,and remobilization in winter wheat (Triticum aestivum L.) cultivars

Two winter wheat (Triticum aestivum L.) cultivars, namely Jimai22 (JM22) and Zhouyuan9369 (ZY9369), were used to study the effects of a new irrigation policy, supplemental irrigation (SI) based on soil moisture levels, photosynthesis, dry matter accumulation, and remobilization from 2009 to 2011 in Northern China. Two SI treatments were designed based on relative soil moisture contents in the 0–140 cm soil layer: (1) the target soil relative water contents were 75% of field capacity (FC) at jointing and 65% of FC at anthesis (W1), 75% and 70% (W2) in 2009–2010, and (2) the target soil relative water contents were 75% at jointing and 75% at anthesis (W1′), 75% and 80% (W2′) in 2010–2011. Rain-fed treatment (W0) was used as control. Results showed that SI significantly improved the biomass, grain yield and water use efficiency (WUE) of both wheat cultivars. The biomass and grain yield of W1 and W1’ treatments were higher than those of others. The net photosynthetic rate, the actual photochemical efficiency of flag leaf, the accumulation of dry matter, and its remobilization from the vegetative parts to the grains after anthesis in W1 and W1’ treatments were significantly higher than in the other treatments. By contrast, the WUE and irrigation efficiency of W2 and W2’ were significantly lower than those of W1 and W1’. Under the experimental conditions, ‘JM22’ showed higher photosynthetic rate in the last stage of grain filling, more spike number per ha, more kernels per spike, higher 1000-kernels weight and eventually higher WUE than ‘ZY9369’.     

Effect of herbicide and cover crop on weed control in no-tillage jack-o-lantern pumpkin (Cucurbita pepo L.) production

Field experiments were conducted to evaluate cover crop (none, winter wheat, or winter rye) and pre-emergence (PRE) applications of clomazone plus ethalfluralin alone or with halosulfuron [PRE or post-emergence (POST)] for smooth crabgrass [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl.] and redroot pigweed (Amaranthus retroflexus L.) control in no-tillage ‘Aspen’ jack-o-lantern pumpkin (Cucurbita pepo L.). At pumpkin harvest, cover crops had reduced smooth crabgrass density, but not redroot pigweed. Although PRE or POST applications of halosulfuron alone were more effective at reducing redroot pigweed density than clomazone plus ethalfluralin PRE, the combination of halosulfuron plus clomazone and ethalfluralin PRE reduced redroot pigweed density to the greatest extent. Pumpkin yields were not affected by cover crop, although average pumpkin sizes were greater with the inclusion of cover crop residues. Pumpkin fruit sizes and yields were the greatest with clomazone and ethalfluralin PRE in combination with halosulfuron applied PRE or POST. Overall, cover crop had relatively little influence on pumpkin yields compared with herbicide treatments. The addition of halosulfuron to clomazone and ethalfluralin provided greater broadleaf weed control resulting in greater jack-o-lantern pumpkin yields.     

A reliable assay for the detection of soft wheat adulteration in Italian pasta is based on the use of new DNA molecular markers capable of discriminating between Triticum aestivum and Triticum durum

Italian pasta must be prepared using exclusively durum wheat. According to current Italian rules, only a maximum of 3% Triticum aestivum is allowed to account for cross-contamination that may occur during the agricultural process. Efficient methods for the detection of accidental or intentional contamination of common wheat to durum wheat products are therefore required. This article describes a novel approach for the detection and quantification of soft wheat adulteration in whole grain durum flours and dried pasta. The assay relies on the presence of intron-specific DNA length polymorphisms in the plant β-tubulin gene family, which can be highlighted through the PCR-based TBP (Tubulin-Based Polymorphism) method. In wheat, the TBP method produces species-specific amplification products, which can be either directly used as new DNA molecular markers capable of discriminating between T. aestivum and Triticum durum or analyzed at the sequence level for the design of species-specific probes. The latter approach allowed the development of new sequence-specific targets that can be exploited in RT-PCR assays for a rapid and accurate quantification of soft wheat adulteration in durum wheat pasta.     

The effect of tillage practice,input level and environment on the grain yield of winter wheat in the Czech Republic

The response of winter wheat grain yield to four variants of treatment (two input levels, combined with either conventional or reduced tillage) was tested over six seasons at three locations. These experiments with 10 and 12 winter wheat varieties were analysed within three experimental series. The environmental (location and season) effects on grain yield were large in all combinations of input level and tillage type, and the varieties responded differentially to both season and location. However, there was no varietal response either to the tillage system used, or to the level of nitrogen (and other inputs) supplied. The high input reduced tillage system (surface stubble-ploughing to a depth of 8–10 cm) resulted in all series in significantly higher grain yields than the equivalent conventional tillage system. The reduced tillage system combined with high input level delivered a yield advantage for all of the wheat varieties tested.     

Effect of wx genes on amylose content,physicochemical properties of wheat starch,and the suitability of waxy genotype for producing Chinese crisp sticks

The effect of wx genes on amylose content, physicochemical properties of wheat starches, and the quality of Chinese crisp stick were investigated using near-isogenic lines (NILs) with null wx alleles in Yangmai 17 and Yangmai 01-2 backgrounds. wx genes showed significant effects on amylose content and other traits. The triple-null genotype had the lowest amylose content among eight genotypes, followed by double-null, single-null, and wild-type genotypes. The triple-null also showed lower flour yield, higher percentage of type B-granules on a volume basis and higher crystallinity than non-waxy genotypes, and showed significant differences in all pasting and thermal transition parameters compared to non-waxy genotypes, except for degree of retrogradation at day 14. For the quality of Chinese crisp stick, the hardness, crispness, fracturability, and specific volume of waxy genotype were 3.91 kg, 11.0, 1.85 mm and 104.4 ml, whereas the corresponding ranges for non-waxy genotypes were 5.39–5.70 kg, 0.5–0.9, 0.69–0.86 mm and 49.5–57.6 ml, respectively, in Yangmai 17 background. This indicates that waxy genotypes showed significantly better crisp stick quality than non-waxy genotypes. A similar trend was also observed in Yangmai 01-2 background. This indicated the potential utilization of waxy wheat for producing traditional products.     

Association of Puroindoline b-B2 variants with grain traits,yield components and flag leaf size in bread wheat (Triticum aestivum L.) varieties of the Yellow and Huai Valleys of China

A total of 169 wheat (Triticum aestivum L.) varieties (landraces and cultivars) were used to asses the relationship between Puroindoline D1 alleles and Puroindoline b-B2 variants and grain hardness, other grain traits, yield components, and flag leaf size. Results indicated that the average SKCS hardness of Pinb-B2v3 varieties was significantly greater than that of Pinb-B2v2 varieties within the soft Puroindoline D1 haplotype sub-group. Conversely, no statistically significant difference was obtained for SKCS hardness between varieties with the Pinb-B2v3 vs. Pinb-B2v2 alleles within the two hard Puroindoline D1 haplotypes (Pinb-D1b and Pinb-D1p sub-groups). Therefore, the Puroindoline b-B2 gene may have a bigger impact on soft wheat varieties than hard. Across all varieties, thousand-kernel weight, grain weight per spike, grain diameter, grain number per spike, flag leaf width and area of Pinb-B2v3 varieties were significantly greater than those possessing Pinb-B2v2. These results indicated that the Pinb-B2v3 allele was associated with preferable grain yield traits compared to the Pinb-B2v2 allele in bread wheat. This study provides evocative information for better understanding the molecular and genetic basis of wheat grain yield.     

Effects of soil compaction in the sub-humid cropping environment in Pakistan on uptake of NPK and grain yield in wheat (Triticum aestivum): II: Alleviation

Alleviation of soil compaction can be achieved through application of appropriate measures which will vary from soil to soil and with the socio-economic factors of the farmers. The effects of alleviation measures applied to artificially compacted soil on yield components, grain yield, dry matter and nutrient uptake by wheat was studied at the Agriculture Research Institute, Mingora, Pakistan, in two separate experiments in 2002–2003 and 2003–2004. The improvement measures included deep ploughing (DP), farmyard manure (FYM) and gypsum (GYP), and comprised a compacted control and four treatments T1 (control), T2 (DP), T3 (DP + FYM), T4 (DP + gypsum) and T5 (DP + FYM + GYP), arranged in completely randomized block design replicated four times. Improvement measures applied to compacted soil significantly decreased soil bulk density and increased total porosity. Bulk density decreased in the range of 12–15% while total porosity showed an increase of 16–23% over the control. Improvement measures significantly increased concentration and uptake of NPK in both years. Higher concentration and uptake was recorded during the second year as compared to the first year, probably as a result of higher seasonal rainfall in the second year. The uptake of NPK by wheat plants increased in the range of 43–51, 25–94 and 11–28%, respectively, over plants in the compacted control. Similarly, improvement treatments increased grains spike⁻¹, thousand grain weight, dry matter accumulation and grain yield in the range of 14–21, 5–14, 3–10 and 21–37% respectively, over the control. This work demonstrates that it is possible to overcome the deleterious effects of compaction induced by wheeled traffic, and improve crop yields and nutrient uptake in intensive cropping systems in rainfed environments in Pakistan and similar environments.     

Effect of soil compaction in the sub-humid cropping environment in Pakistan on uptake of NPK and grain yield in wheat (Triticum aestivum): I. Compaction

Soil compaction is a major cause of decrease in crop yield. The most serious cause of soil compaction is continuous ploughing at the same depth which affects bulk density, porosity and root proliferation, consequently affecting concentration and uptake of nutrients by plants. The effects of soil compaction on concentration and uptake of Nitrogen, Phosphorus and Potassium (NPK) by wheat were studied at the Agriculture Research Institute, Mingora, Pakistan in two separate experiments, conducted during 2002–2003 and repeated in 2003–2004. The treatments in each experiment consisted of four compaction levels arranged in a randomized complete block design replicated four times. Subsoil compaction affected soil bulk density and total porosity. With increasing compaction, bulk density increased in the range of 15–26% while total porosity decreased in the range of 15–27%. Compaction treatments significantly and progressively decreased concentration and uptake of NPK in both years of the experiments. Higher nutrient concentration and uptake was recorded during the second year as compared to first year, probably as a result of higher seasonal rainfall. Concentration of NPK showed reductions of 5–20%, 10–53% and 9–21%, respectively, due to the compaction treatments over control. The uptake of NPK decreased due to the compaction treatments in the range of 7–26%, 11–54% and 11–28%, respectively, over control. Compaction treatments decreased the dry matter accumulation in the range of 2–9% whereas grain yield showed a reduction of 5–48%. Inverse relationships between bulk density, and concentration and uptake of NPK, dry matter accumulation and grain yield were recorded. The implications of these findings for intensive agricultural systems in Pakistan and similar environments are discussed.     

Influence of the cultivar,environment and management on the grain yield and bread-making quality in winter wheat

The genotype, environment and their interaction play an important role in the grain yielding and grain quality attributes. The main aim of this study was to determine the contributions of the genotype, environment and their interaction to the variation in bread-making traits. The data that were used for the analyses performed in this study were obtained from 3 locations in Poland from post-registration multi-environment trials with winter wheat in 2009 and 2010. The experimental factors were the cultivar (7 cultivars) and the crop management level (low input and high input). In the multi-environment trials, 17 traits were investigated that characterize grain, flour and dough quality. Most of the traits were affected much more strongly by environmental factors (i.e., year and location) than by genotype. The variance components revealed an especially strong effect of the year on the baking score, loaf volume and water absorption, as well a strong effect of the location on dough development and protein content. The obtained results demonstrate that the grain quality as measured by the parameters based on the protein content and quality may be substantially improved by crop management practices, especially by N fertilization level.