Quality losses in wheat caused by the orange wheat blossom midge Sitodiplosis mosellana

In three sets of data pooled over spring wheat varieties and lines a number of grain quality measurements were related to the levels of infestation by Sitodiplosis mosellana larvae. The Hagberg falling number value was negatively correlated with the proportion of damaged grains. The 1000-grain weight, protein content and gluten content were not affected. Differences between cultivars in infestation and damage level were found to depend on the development phenology (timing of ear emergence) and on the percentage of damaged grains remaining in the yield after harvest. The falling number values were reduced most when the attainable values remained low in cultivars prone to sprouting damage, and in seasons with unfavourable weather conditions for quality maintenance. The proportion of damaged grains in relation to the number of larvae was well described by a logit-transformed regression. Sampling for infestation level and preventive measures against quality loss are discussed.     

Differential levels of mite infestation of wheat and barley in Czech grain stores

Abstract  While mites are able to utilize numerous food sources, the suitability of the food strongly influences population growth. The different suitabilities of various stored agricultural products will thus affect the level of infestation. In this study, we compared field mite infestation rates in two stored cereals: wheat and barley. We analyzed mite abundance, frequency and species composition in samples of grain obtained from 79 selected Czech grain stores. Stored barley seemed to be more vulnerable to mite attack than wheat, as we consistently found more infested samples, more species and higher mean and median mite abundance per sample in barley as compared to wheat. The mean mite abundance per sample were 55 and 506 individuals for wheat and barley, respectively. In barley, 10% of samples exceeded allergen risk threshold (i.e., 1 000 individuals per kg of grain). Altogether, 25 species were identified from approximately 35 000 individuals. The most frequently identified species were the same in wheat and barley, that is, Tydeus interruptus Sig Thor, Acarus siro L., Tarsonemus granarius Lindquist, Lepidoglyphus destructor (Schrank) and Tyrophagus putrescentiae (Schrank). Based on principal components analysis, we found a closer association of T. interruptus , T. putrescentiae , L. destructor and Cheyletus eruditus (Schrank) with barley samples, corresponding to the high frequency and abundance values of these mites. The probable reasons for the higher infestation, especially mite abundance in barley, are discussed in relation to the higher proportion of crushed parts, which may release favorable nutrient sources and amplify the abundance values.     

Detection of stored-grain insect infestation in wheat transported in railroad hopper-cars

Levels of insect infestation, insect spatial distribution, and the relationship between the number of insect-damaged kernels (IDK) and the number of insects present in grain samples in three-hopper railcars transporting wheat from country elevators to a mill were studied. Six of eight sampled railcars were infested with more than two species of insects. The most abundant species collected were the lesser grain borer, Rhyzopertha dominica (F.), and rusty grain beetle, Cryptolestes ferrugineus (Stephens), with the larval stage of the two species being the most prevalent (>90%). The spatial distributions of these two species within the grain mass were typically clumped in railcar compartments containing >0.4 insect/2.75-kg sample of wheat, and these foci of high-infestation levels varied in compartments within the railcars and among the sampled railcars. There were no significant correlations between IDK and insect density for any of the different stage-specific insect populations that were collected in the grain samples. Mean numbers of immatures and IDK differed among railcars and compartments within railcars, but not among grain depths. Number of insects in the first discharge sample was not correlated with mean numbers of insects in the entire compartment. This indicates that each compartment of a railcar should be sampled to determine level of insect infestation but that sampling at different depths within a compartment is less important.     

Prairie grasses as hosts of the northern corn rootworm (Coleoptera: Chrysomelidae)

We evaluated 27 prairie grass species thought to be among those dominant 200 yr ago in the northern midwest as larval hosts of the northern corn rootworm, Diabrotica barberi Smith and Lawrence. Maize (Zea mays L.), spring wheat (Triticum aestivum L.), and grain sorghum (Sorghum bicolor L.) were included as controls for a total of 30 species. Twenty pots of each species were planted in a randomized complete block design. Each pot was infested 5 wk later with 20 neonate northern corn rootworm larvae. Two pots within each species and block were assigned an extraction date of 7 or 14 d after infestation. The remaining two pots from each block were used to monitor adult emergence. The percentage of larvae recovered, change in larval head capsule width, and change in average dry weights varied significantly among the grass species. The highest percentage of larvae was recovered from slender wheatgrass, Elymus trachycaulus (Link), and this was significantly greater than the percentage recovered from all other species including maize for the 14-d sample date. Several additional species were also relatively good hosts, in that the percentage of larvae recovered from these species was not significantly different from maize. The average dry weight of larvae recovered was significantly greater for larvae recovered from maize than for larvae recovered from all other species except slender wheatgrass, when the two samples dates were combined. Overall, adults were produced from only 6 of the 28 species evaluated, and no analysis was performed because of the low numbers. The results of this study are discussed in relation to the potential of alternate hosts of northern corn rootworm to serve as a bridge to survival on transgenic maize.     

Relative suitability of crested wheatgrass and other perennial grass hosts for the Russian wheat aphid (Homoptera: Aphididae)

The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), reproduces parthenogenetically in North America and must survive year-round on host plants, including in late summer when small grains are not in cultivation. During this time, cool-season perennial wheatgrasses (Poaceae: Triticeae) contribute substantially to aphid survival, crested wheatgrass (Agropyron spp.) particularly. In greenhouse studies, the number of aphids per plant was measured after four infestation periods on unvernalized and vernalized wheatgrasses. Before placement on these test plant species, aphids were reared either on winter wheat or on the grass host species on which aphid progeny were counted. On vernalized plants, aphids reared on wheat resulted in more aphids per test plant than when the aphids were reared on wheatgrasses, but on unvernalized plants the number of aphids per test plant did not differ significantly regardless of rearing host. Aphids on crested wheatgrass were similar in number to the other grasses when plants were unvernalized. However, when plants were vernalized, crested wheatgrass supported significantly more aphids than some of the other hosts. Aphid numbers increased on all test species as infestation period lengthened, and plant growth was largely unaffected by aphid feeding. These results suggest if sufficient moisture is available during summer when small grains are not in cultivation, all host species observed are capable of sustaining aphids. Crested wheatgrass is an abundant and important host of the Russian wheat aphid in its northern range of the western United States, but other less prevalent wheatgrasses also may contribute to aphid survival during late summer when small grains are not in cultivation.     

Voracity of the main stored-product insect pests on wheat grain

The results of an experimental study of voracity of adults and larvae of seven main stored-product insect pests are described. One adult of Sitophilus oryzae, S. granarius, Rhizopertha dominica, Tribolium castaneum, T. confusum, and Oryzaephilus surinamensis consumed 0.38, 0.48, 0.89, 0.15, 0.16, and 0.11 mg of wheat grain per day, respectively. During their development, larvae of these insects consumed 7.60, 13.77, 7.92, 3.32, 3.60, and 2.32 mg of wheat grain, respectively. One larva of Sitotroga cerealella consumed 17.46 mg of wheat grain. The coefficients of harmfulness of these species are calculated, and a method for estimating the “total infestation density” of grain is proposed.     

Hunting for moving hosts: Cephalonomia tarsalis, a parasitoid of free-living grain beetles

The parasitic wasp Cephalonomia tarsalis parasitizes larvae of the saw-toothed grain beetle Oryzaephilus surinamensis, which feed on wheat grains. In contrast to most other host–parasitoid systems studied so far, the grain beetles are highly mobile within their habitat, bulk of grains in grain stores. This should increase the wasps’ problem to locate the hosts. To study the host-finding strategy of C. tarsalis females, the reaction of wasps to different grain and host-derived odour sources was tested in a four-chamber-olfactometer. These experiments revealed that wasps were attracted by healthy grains and mechanically damaged grains. In direct comparison, healthy and mechanically damaged grains are equally attractive. Both potential sources of host-derived odours, host faeces and trail-traces of larvae on filter paper were attractive to the wasps. The response to trail-traces vanished 30 min after larvae had been removed from the filter paper. With respect to the specificity of the odours, it turned out that wasps were attracted to odours from the seed–host complexes from O. surinamensis and Oryzaephilus mercator and the non-host complex of larvae of the granary weevil Sitophilus granarius in wheat grains. Odours from the seed–host complex were preferred. From these results, we hypothesize that host habitat location in C. tarsalis is achieved by using grain-derived odours. Within the habitat, wasps search for kairomones from host faeces and host trails. Following these larval trails finally leads wasps to their hosts.     

Cultivation of free-living stages of Trichostrongylus colubriformis in media without bacteria, animal tissue extract, or serum

Trichostrongylus colubriformis was cultured from hatched first-stage to third-stage larvae in bacteria-free media in the absence of animal tissue extract or serum. This was achieved for the first time with a nematode, parasitic in vertebrates, whose rhabditiform larvae are food-dependent. The best media contained enzymatic hydrolysed casein (amino nitrogen:total nitrogen ratio 0.39), yeast extract, phosphatidylcholine from soybean, and a number of chemically defined ingredients, which include a salt solution, a sterol, and an iron porphyrin. The yield of third-stage larvae obtained was up to 17% of all the living larval stages present after incubation. When casein hydrolysate with AN:TN ratio of 0.39 was replaced by casein hydrolysate with AN:TN ratio of 0.53, little or no development to third-stage larvae occurred. Development to infective larvae was shown to be possible in media with soy peptone instead of casein hydrolysate, although to a very limited extent. It is proposed that the free-living stages of the parasite require peptides, whose molecular weights all lie within a narrow range.     

Ecology and epizootology of Microsporidia in malarial mosquitoes (diptera: culicidae) from the south of Western Siberia

The ecology and epizootology of Microsporidia were studied in the natural population of malarial mosquitoes from Western Siberia over a 30-year period. Symptoms of the disease, host specificity and character of parasite localization in host tissues were investigated. Microsporidia of 9 species from 4 genera, namely Amblyospora, Crepidulospora, Senoma, and Parathelohania, were found in the malarial mosquito larvae from the territory examined. The mosquito species Anopheles messeae was infested by larger number of the microsporidian species, than A. beklemishevi. Spores and active stages of the microsporidian Senoma sp. from mosquito larvae are localized in epithelial cells of the host's intestine. There are no external signs of the infestation. The infested larvae do not die, and the infection proceeds to the pupal stage. Microsporidians of the genus Parathelohania infest larvae of both male and female mosquitoes. The parasites localized in the fat body cells. Body of the infested host gets an opaque white color in the period of spore maturation. The infested larvae perish at 4th stage. Microsporidian spores are formed in the mosquito larvae of both sexes. However, infection rate is much higher in the male larvae (77.8%), than that in the female larvae (22.2%). Symptoms of the disease under the infestation by the genera Crepidulospora and Amblyospora are similar to those under the infestation by Parathelohania sp. There are no external signs of the infestation in the adult mosquito females. In these hosts microsporidians form large two-nuclear spores with a thin capsule accounted for transovarial transmission. An about two times decrease of fertility in the Anopheles messeae females infested by the Parathelohania microsporidians is revealed. Mean number of eggs laid by the infested females was 121, while that of the noninfested ones was 232. Thus, the cause of the decrease in the mosquito abundance is both the elimination of male larvae and the decrease of fertility in females. In Siberia malarial mosquitoes yield 2 or 3 generations per year. Infested larvae are rarely occurred in the beginning of summer. Maximal extensiveness of the invasion may be observed in the end of summer, because of the accumulation of the infection in water bodies. Number of the peaks of infestation coincides with the peaks of abundance of mosquito larvae of 4th stage. Peaks of infestation are delayed as compared with the peaks of mosquito abundance. It is an evidence of the development delay in the infested larvae. Long-term dynamics of the infestation by microsporidians is studied. The epizooty caused by Parathelohania was observed in the malarial mosquitoes in the eighties (with the infestation rate up to 62 %). In the last ten years the infestation rate was low (from 0.1 to 2.6%).     

Do grains whisper for help? Evidence for herbivore‐induced synomones in wheat grains

Thus far, the release of herbivore‐induced synomones (HIS) has almost exclusively been demonstrated in somatic plant tissue. Here we present evidence for the production of HIS from reproductive tissue, i.e., seeds. The study system consisted of wheat grains (Triticum aestivum L., Poaceae) infested by larvae of the granary weevil Sitophilus granarius L. (Coleoptera, Curculionidae), which in turn are attacked by the parasitic wasp Lariophagus distinguendus Förster (Hymenoptera, Pteromalidae). The use of potential chemical signals from the infested grain for host recognition of L. distinguendus was studied with weevil‐infested grains that had developed under a range of humidity conditions. Wasps always performed longer antennal drumming on infested than healthy grains, demonstrating that they were able to recognize infested grains under all humidity conditions. In grains developed at a high humidity (75% r.h.), host recognition is enabled by chemical signals arising from the host faeces which densely cover infested grains. However, in grains from a low humidity (45% r.h.) almost no faeces are present, indicating that other cues are used by the wasp. Control experiments revealed that these other cues are neither chemical signals from faeces contaminations, volatiles from faeces nor host larvae inside the grain, movement of host larvae, or moisture content of infested grains. Therefore, wasp recognition of infested grains in low humidity conditions is probably based on chemical signals from the grain itself that are induced by the feeding of granary weevil larva. Further experiments revealed that infested grains increase their viability when granary weevil larvae are killed by the idiobiont L. distinguendus. This justifies the categorisation of potential signals from the grain as HIS. To our knowledge, this is the only system where potential HIS in plant seeds have been studied. We discuss whether potential HIS are actively produced by infested grains or are a by‐product of grain metabolism.     

THE FRIT FLY AND ALLIED STEM-BORING DIPTERA IN WINTER WHEAT AND HOST GRASSES

Sampling for stem-boring larvae was undertaken in 1954-56 on ley plots of Lolium perenne, Dactylis glomerata, Festuca arundinacea, F. rubra, Agrostis tenuis and Poa pratensis in randomized experiments at Hurley, Berks. The samples showed infestations by dipterous larvae, mainly species of Oscinella, Meromyza and Opomyza. The larvae showed preferences for specific grass hosts. More larvae were found where plots had been grazed throughout the season than where an early hay cut had preceded grazing. The total numbers of larvae varied between o and 688 per sq.yd. in November.
The larval populations of the leys were reflected in the populations in winter wheat which followed the plough-up of the leys. Populations of up to sixty-five larvae per sq.yd., mostly species of Oscinella , were found in the wheat in March. In 1956 a heavy larval infestation was associated with the death of considerable numbers of wheat plants.     

Efficacy of heat treatment for disinfestation of concrete grain silos

Field experiments were conducted in 2007 and 2008 to evaluate heat treatment for disinfestations of empty concrete elevator silos. A Mobile Heat Treatment Unit was used to introduce heat into silos to attain target conditions of 50 degrees C for at least 6 h. Ventilated plastic containers with a capacity of 100 g of wheat, Triticum aestivum L., held Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Polyvinyl chloride containers with a capacity of 300 g of wheat held adults of Liposcelis corrodens (Heymons) (Psocoptera: Liposcelididae) and Liposcelis decolor (Pearman), which were contained in 35-mm Petri dishes within the grain. Containers were fastened to a rope suspended from the top of the silo at depths of 0 m (just under the top manhole), 10 m, 20 m, and 30 m (silo floor). When the highest temperature achieved was approximately 50 degrees C for 6 h, parental mortality ofR. dominica and T. castaneum, and both psocid species was 98-100%. Progeny production of R. dominica occurred when there was parental survival, but in general R. dominica seemed less impacted by the heat treatment than T. castaneum. There was 100% mortality of L. corrodens at all depths in the heat treatments but only 92.5% mortality for L. decolor, with most survivors located in the bioassay containers at the top of the silo. Results show wheat kernels may have an insulating effect and heat treatment might be more effective when used in conjunction with sanitation and cleaning procedures.     

The nature of the effects of the aphids Sitobion avenae and Metopolophium dirhodum on the growth of wheat

Field-caged, post-anthesis populations of the aphids Sitobion avenae and Metopolophium dirhodum reduced grain weight of wheat by 14 and 7% respectively and induced changes in the senescence of the flag leaf. Spikelet number and grain number were unaffected as they are normally determined by pre-anthesis factors. Percentage grain protein was significantly reduced by both aphid species. The pattern of grain weight reduction within the ear was consistent with known limitations on the distribution of flag leaf assimilates among the grains. The relative effects of the two aphid species apparently resulted from the degree of nutrient drain imposed at particular feeding sites and the reduction in the leaf area duration of the flag leaf.     

Learning pays off: influence of experience on host finding and parasitism in Lariophagus distinguendus

Abstract. 1. The influence of experience on egg maturation, parasitism rate, and behaviour during host searching was investigated for Lariophagus distinguendus (Först.) (Hymenoptera: Pteromalidae) parasitizing larvae of the granary weevil Sitophilus granarius (L.) in grains of wheat Triticum aestivum L.
2. Dissection of female parasitoids and parasitism bioassays at high host density revealed that experience with hosts (e.g. by oviposition or by host feeding) is not required either for triggering oogenesis or for oviposition.
3. In parasitism experiments at low host density, when single host-infested grains were offered within a bulk of healthy grains, host finding and parasitism rate were increased by experience.
4. Behavioural observations revealed that searching time required for finding an infested grain was shorter for experienced parasitoids than for naive parasitoids, because travel time from grain to grain is shorter for experienced parasitoids, and because experienced parasitoids spend less time than naive parasitoids on non-infested grains.
5. In conclusion, experience due to host exposure increases parasitism and thereby the fitness of the parasitoids. It is discussed that this increase is more likely due to learning than to different egg load dynamics of experienced parasitoids.     

Simulation of generation times of the rusty grain beetle,Cryptolestes ferrugineus, in farm-stored grain in the canadian prairies, 1952-1990

The number of potential annual generations of the rusty grain beetle,Cryptolestes ferrugineus, was simulated in wheat stored in granaries for all crop districts in the prairie provinces of Canada each year from 1952 to 1990 using a population dynamic model driven by ecological variables. Granary size was assumed to be 6 m in diameter. Historical data for temperatures at harvest and times when storage began were used in the simulation model. A second model, which predicted the rate of temperature change at the centre of a 6-m-diameter bulk of wheat, determined environmental parameters for the population dynamic model. (Grain moisture content was assumed constant at 14.5% wet mass basis.) The combined model shows that the initial storage temperature is the most important factor responsible for predicting the number of generations and levels of infestation ofC. ferrugineus. This finding was largely validated by historical grain storage and infestation data. For various years initial grain temperature ranged from 17.7 to 37.4 °C and harvest dates were between 1 August and 20 October. The number of generations annually in simulations based on field conditions ranged from 0.35 to 6.77 with a mean of 3.29. Three or more generations result in a severe infestation and every year at least three simulated generations were completed in some crop districts. In one year, at least three generations were completed in every crop district. Harvest temperature and date permit prediction of crop districts that will potentially have the largest populations of C.ferrugineus so that early monitoring of wheat for infestations can be targeted to areas most at risk. Cereal Research Centre Contribution No. 1660     

Evaluation of mercury resistance and accumulation characteristics in wheat using a modified membership function

Mercury pollution in fields has become a potential threat to human health. Planting wheat cultivars with low mercury accumulation in slight or medium mercury-polluted fields is an efficient solution to ensure food safety. Therefore, this study evaluated the mercury resistance and accumulation characteristics of 30 generalized wheat cultivars in major wheat-producing areas of China. A modified membership function that considers the weight of each trait was used.Results demonstrated that the plant height of wheat significantly increased under both low mercury and high mercury stresses. The uppermost internode length significantly increased while the spikelet number significantly decreased under low mercury stress. Yield-related traits, including total grain number, fresh grain yield, and dry grain yield, significantly decreased under high mercury stress. The mercury concentrations in wheat grains presented a significant negative correlation with the mercury resistance coefficients of plant height (−0.38*), spike length (−0.39*), and fresh grain yield (−0.38*) under high mercury stress. The heritability of all traits reached medium to high levels, ranging from 0.31 to 0.68. This finding suggested that the investigated traits are stable and suitable for the assessment system. Selection criteria for wheat mercury resistance were established using discriminant analysis, which integrated the mercury resistance coefficients of effective tiller number, fresh grain yield, and dry biomass into the discriminant function under low mercury stress and the mercury resistance coefficients of dry grain yield and dry biomass under high mercury stress. Ultimately, Liangxing-99, Nongda-3163, and Gaocheng-8901 were screened for high mercury resistance and low mercury accumulation. These wheat cultivars could be planted in fields with low or medium mercury pollution to obtain safe grains.     

Interaction of the temperature with the parasite mite Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) on the development of Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae)

The objective of this study was to evaluate the effect of different temperatures with the association of the mite Acarophenax lacunatus (Cross & Krantz) on the population suppression of Rhyzopertha dominica (Fabricius). The experimental units were petri dishes containing 40 g of whole wheat grains (13% moisture content) infested with 10 adults of R. dominica, under the temperatures of 20, 25, 30 and 35 masculineC, with or without A. lacunatus, in five replicates. Relative humidity of 60 +/- 5% and escotophase of 24h were used for all temperatures. Five days after the infestation, five mites were inoculated in each experimental unit. The evaluations were carried out at 20, 40, 60, 80, 100 and 120 days after R. dominica infestation. The interaction of the temperature with the parasite A. lacunatus was an important tool for the population suppression of R. dominica. In temperatures higher than 25 masculineC, however, despite the reduction of the immature stages of R. dominica, there was a high grain weight loss after 120 days. The maintenance of the temperature of the wheat grains stored at 20 masculineC can be used to complement the biological control of R. dominica with A. lacunatus.     

A rapid and sensitive method for the evaluation of cereal grains in bioethanol production using near infrared reflectance spectroscopy

The potential of near infrared spectroscopy (NIRS) for determining fermentable substance and also ethanol yield in wheat, rye and triticale grains as a feedstock for fuel ethanol production was investigated. The total sample set contained 480 samples of 10 types of wheat, 24 types of triticale and 6 types of rye, which were grown on 10 locations in Germany from 2006 to 2008. Samples were scanned by NIRS as whole or ground grains, and their reference values regressed against different spectral transformations by partial least squares regression (PLS-1). Ground grains were scanned on a dispersive NIR-Spectrometer. Whole grains were scanned on a diode array NIR-Spectrometer. Principal Component Analysis (PCA) revealed that samples could be classified by crop season, growth location and species. It is shown that near infrared spectroscopy is an appropriate and useful tool for prediction of biofuel yield for both industry and research.     

Insect fragments in flour: relationship to lesser grain borer (Coleoptera: Bostrichidae) infestation level in wheat and rapid detection using near-infrared spectroscopy

We determined that the number of insect fragments, quantified using the standard flotation method, in flour milled from wheat infested with larvae, pupae, or preemergent adults of the lesser grain borer, Rhyzopertha dominica (F.), was proportional to infestation level. Wheat infested with a single preemergent adult contributed 28 and 10x as many fragments as wheat infested with a single larva or pupa, respectively. Using regression models that were developed from these data, we predicted that the maximum infestation level that would result in flour with fragment counts below the Food and Drug Administration defect action level (75 fragments/50 g of flour) was 0.95 and 1.5% (380-640 infested kernels/kg of wheat) for pupae and larvae, but it decreased to 0.05% (20 infested kernels/kg) when the grain was infested with preemergent adults. We also reexamined the accuracy and sensitivity of near-infrared spectroscopy (NIRS) for detecting insect fragments in flour by testing three different NIR spectrometers. NIRS-predicted numbers of insect fragments were correlated with the actual number of fragments. NIRS is less precise than the standard flotation method, but it is rapid, nondestructive, does not require extensive sample preparation, and could easily be automated for a more sophisticated sampling protocol for flour based on prescreening samples with NIRS followed up by use of the standard flotation method when necessary.     

Identification of quantitative trait loci for rice grain element composition on an arsenic impacted soil: Influence of flowering time on genetic loci

Elements in grain crops such as iron, zinc and selenium are essential in the human diet, whereas elements such as arsenic are potentially toxic to humans. This study aims to identify quantitative trait loci (QTLs) for trace elements in rice grain. A field experiment was conducted in an arsenic enriched field site in Qiyang, China using the Bala × Azucena mapping population grown under standard field conditions. Grains were subjected to elemental analysis by inductively coupled plasma mass spectroscopy. QTLs were detected for the elemental composition within the rice grains, including for iron and selenium, which have previously been detected in this population grown at another location, indicating the stability of these QTLs. A correlation was observed between flowering time and a number of the element concentrations in grains, which was also revealed as co‐localisation between flowering time QTLs and grain element QTLs. Unravelling the environmental conditions that influence the grain ionome appears to be complex, but from the results in this study one of the major factors which controls the accumulation of elements within the grain is flowering time.