Fresh Maize Research Articles

Different substrates and starter inocula govern microbial community structures in biogas reactors

ABSTRACTThe influence of different starter inocula on the microbial communities in biogas batch reactors fed with fresh maize and maize silage as substrates was investigated. Molecular biological analysis by Denaturing Gradient Gel Electrophoresis (DGGE) of 16S rRNA gene fragments showed that each inoculum bore specific microbial communities with varying predominant phylotypes. Both, bacterial and archaeal DGGE profiles displayed three distinct communities that developed depending on the type of inoculum. Although maize and silage are similar substrates, different communities dominated the lactate-rich silage compared to lactate-free fresh maize. Cluster analysis of DGGE gels showed the communities of the same substrates to be stable with their respective inoculum. Bacteria-specific DGGE analysis revealed a rich diversity with Firmicutes being predominant. The other abundant phylotypes were Bacteroidetes and Synergistetes. Archaea-specific DGGE analysis displayed less diverse community structures, identifying members of the Methanosarcinales as the dominant methanogens present in all the three biogas digesters. In general, the source of inoculum played a significant role in shaping microbial communities. Adaptability of the inoculum to the substrates fed also influenced community compositions which further impacted the rates of biogas production.

Effects of Husk and Harvesting Time on Provitamin A Activity and Sensory Properties of Boiled Fresh Orange Maize Hybrids

AbstractBoiled fresh maize on the cob is a nutritious food staple among Nigerians. This study evaluated the effect of husk and harvesting time on the β‐carotene, provitamin A (PVA) activity and sensory properties of boiled orange maize hybrids. Eight freshly harvested cobs of orange maize hybrids were boiled with and without husk using an atmospheric cooking method and evaluated for PVA carotenoids. Sensory evaluation was carried out on the boiled samples within 24 h after harvesting. Husk and harvesting time had highly significant effects (P ≤ 0.001) on the carotenoid components. The best harvesting time to boil fresh orange hybrids for higher β‐carotene and PVA is 20 days after pollination (DAP) for boiled maize with husk and 27 DAP for boiled maize without husk. Hybrid variety and harvesting time were very important factors in rating sensory properties of boiled orange maize hybrids, and the sensory properties that determined the acceptance/likeness were found to be aroma, chewiness and taste.Practical ApplicationsThe use of orange maize hybrids with enhanced provitamin A levels will be of value in reducing incidence of vitamin A deficiency (VAD) for low‐income communities in developing countries. The information obtained from this study will not only increase the understanding of the level of retention of these antioxidant phytochemicals after processing but will also help breeders to adjust their germplasm development activities for high content of such phytochemicals. This information can also help researchers in choosing proper cooking methods to increase the retention of high levels of carotenoids in orange maize that can be delivered to consumers through nutrition education.

Assessment of the influence of composts on microbiological and biochemical parameters of substrates and the morphological traits of scarlet sage / Ocena wpływu kompostów na parametry mikrobiologiczne i biochemiczne podłoży oraz cechy morfologiczne szałwii błysz czącej

Abstract The aim of the research was to assess the microbiological (number of heterotrophic bacteria, actinobacteria and moulds) and biochemical (urease and acid phosphatase activity) state of peat with the admixture of composts produced from sewage sludge. An additional aim of the research was to demonstrate the influence of those substrates on the morphological traits of scarlet sage (height, number and length of shoots, number of buds and inflorescences, greenness index (SPAD)). Composts produced from sewage sludge, wheat, maize and lupine straw were mixed with peat, where their percentage varied from 25% to 75%. The substrate which included the composts applied in the experiment had a higher number of heterotrophic bacteria and a higher acid phosphatase activity level than the control substrate (peat). The multiplication of moulds and actinobacteria was more intensive than in the peat only in the combinations with K3 (sewage sludge 50%+sawdust 20%+ lupine straw 30%) and K4 (sewage sludge 50%+sawdust 20%+fresh maize straw 30%) composts, whereas the highest urease activity level was observed in the soils produced from K1 (sewage sludge 50%+sawdust 20%+white straw 30%) compost. The most optimal development of plants was observed in the substrate with compost produced from wheat straw. Composts produced from municipal sewage sludge were found to be suitable for growing scarlet sage. However, their effect depends on the percentage of high peat in the substrate.

Influence Of Meteorological Factors On Maize Performance In Latvia

Abstract Latvia is recognised as a marginal area for growing of maize (Zea mays L.), as years of high yielding can be broken by years with failures. The aim of this paper is to describe maize yield, dry matter (DM) content in fresh yield, and some other quality indicators in silage maize field trials at the Research and Study Farm “Vecauce” of the Latvia University of Agriculture (56° N), in relation to temperature and moisture conditions. The study was carried out for 15 years (1999–2013). In total, 217 maize hybrids, belonging mainly to the early-maturity group (FAO up to 220), were investigated. Meteorological conditions considerably differed, and, according to heat conditions, only 10 years were suitable for maize production. The mean fresh maize yield varied from 43.01 t ha−1 to 63.39 t ha−1 during the study period, which 1.8 to 2.9 times higher than the average statistical yield in Latvian farms in the respective years. The DM yield ranged between 8.77 t ha−1 (in 2004) and 20.05 t ha−1 (in 2013) and was significantly correlated with temperature in May and June. The study suggested that cold tolerance of hybrids during early development stages should be investigated in future. Fresh and DM yield of maize were significantly (p < 0.001) affected by hybrid and year as factors, as well as by their interaction. DM content in fresh yield was correlated with active temperature sum. Low precipitation was a yield-limiting factor during some years. Ear proportion in yield decreased when moisture stress occurred before and during silking.

Use of Benzimidazole Agar Plates to Assess Fall Armyworm (Lepidoptera: Noctuidae) Feeding on Excised Maize and Sorghum Leaves

The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is an economically significant pest of sorghum and maize. Laboratory bioassays are often conducted for convenience and for fall armyworm confinement but as the number of entries and replications increase, the replenishing of fresh tissue daily and the cleaning of insect diet cups or petri dishes becomes laborious. The current study was conducted to determine if agar plates, used to retain leaf moisture, supplemented with benzimidazole, a fungicide that delays leaf senescence and retards fungicide growth, can be used to assess fall armyworm feeding on fresh maize and sorghum leaf tissue with minimal labor. We conducted 2 trials consisting of 3 cultivars of maize with known resistance or susceptibility to fall armyworm feeding, and 4 cultivars of sorghum that are parents of existing mapping populations. The top 2 (whorl) leaves were removed from 36–37-day old plants, 7.6 cm long pieces of leaf were excised, and each piece was placed on a benzimidazole agar plate. One larva per plate was placed on the leaf tissue; the plate was sealed with Parafilm and placed in an incubator for 7 days. Average larval weights for Trial 1 were significantly different than Trial 2 after 7 days, and thus each trial was analyzed separately. For both trials, the larvae that were fed susceptible maize line ‘AB24E’ had weights that were significantly greater than larvae fed resistant maize lines ‘Mp708’ and ‘FAW1430’. No significant differences in weight were observed for fall armyworm larvae fed on the 4 sorghum lines except for those larvae fed ‘Collier’ in Trial 2, which had weights significantly greater than larvae fed the other 3 sorghum cultivars (Entry 22, ‘Honey Drip’, ‘AN109’). Thus, the benzimidazole agar plate method is an easy and effective method for assessing fall armyworm feeding on maize and sorghum, and thus can be used to identify maize and sorghum germplasm lines with resistance to fall armyworm.

Varietal and harvesting time effects on physical characteristics and sensory properties of roasted fresh yellow maize hybrids

Varietal and harvesting time effects on physical characteristics and sensory properties of roasted fresh yellow maize hybrids

Effects of Different Mixed Ratio of Maize Straw and Cabbage Wastes on Silage Quality

Ensiling, a wet preservation method, is an appropriate method of storing feedstock for biogas production. Fresh maize straw, contain enough water-soluble carbohydrates, is the prevailing material producing biogas, but research on preservation and storage of maize straw as feedstock for anaerobic digestion is still in its infancy. Generally in China, the free sugars are consumed, the water evaporates during wilting and field drying, giving rise to fail to achieve the demand of good-quality silage. In view of strong complementary in terms of physical structure, nutrient/moisture content of maize straw and vegetables, this paper propose a hypothesis of trans-seasonal mixed ensiling for biogas production. The objective of the current work was to evaluate effects of different mixed ratio of maize straw (MS) and cabbage wastes (CW) on silage quality, taking into account the silage quality, chemical composition and structural properties of feedstock. Mixed ensiling of maize straw and cabbage waste were prepared in 1.6-L plastic silos at 25 degrees C. The mixed mass ratios (MMR) of MS and CW were 19:29, 21:27, 23:25, 25:23, 27:21 and 29:19, respectively. The results show that the content of cellulose and hemicellulose after ensiling were increased, achieving the goal of seasonal storage for MS. When the MMR was 27:21, that is, the moist content was 73% (MEMS73), the pH value had a minimum and the content of lactic acid was highest after mixed ensiling for 30 days. Therefore, the optimum MMR of MS and CW was 21:27 for storage of maize straw. The microtoporaghy of SEM indicated that the cracks and ruleless pores were taken on the surfaces of maize straw silage, compared to the compact lignocellulosic matrix before ensiling. The crystalline degree of cellulose was decreased after ensiling. In a word, ensiling is an appropriate feasibly storage method to preserve MS and should be considered a promising method for stable storage of biogas feedstock.

Total aflatoxin level and fungi contamination of maize and maize products

Samples of maize and maize products purchased from selected markets in parts of Kaduna State, Nigeria were analyzed for total aflatoxin and fungi contamination using Enzyme Linked Immunosorbent Assay (ELISA) and mycological procedures. The mean aflatoxin concentration of the maize and maize products obtained from this study shows that one hundred and fifty two (82.70%) of the maize products had aflatoxin contamination above the tolerance level of 20ppb stipulated by World Health Organization).The old maize had a mean aflatoxin level of 177ppb while the new maize had a mean aflatoxin level of 102ppb.The mean aflatoxin level in maize flour was 174ppb while the maize bran had a mean aflatoxin level of 213ppb. Significant differences exists between the mean aflatoxin contaminations of old maize, fresh maize, maize flour and maize bran. Five fungal genera namely: Aspergillus, Penicillium, Rhizopus,, Fusarium and Botrytis were isolated. Aspergillus was the most predominant genera isolated (62%).Among the Aspergillus, three species namely A. niger, A. tamari, and A. flavus were identified. The high level of aflatoxin in maize and maize products highlights the health problem associated with the consumption of these products with the toxin that could lead to adverse health effects such as liver, cervical, breast or oesophageal cancer.

The effect of ensiling on variety rank of maize silage

O variety trials with maize silage determine quality parameters in fresh (i.e., unconserved) samples. However, farmers use silage as daily component of cattle diet. Quality changes (crude protein and starch content, NDF, organic matter (OMD) and cell wall digestibility (DNDF)) during ensiling have been studied extensively. It is as yet unclear if the variety rank based on the quality of fresh maize samples is similar with the variety rank based on the quality of ensiled maize samples. In our research, eight maize silage varieties were monitored at six harvest dates (from 250 to 400 g/kg dry matter content) in Merelbeke (Belgium). At each harvest date, fresh samples were taken and half of the sampled material was ensiled in laboratory silos for three months. We analyzed the data with Analyses of Variance and concluded that the variety rank was stable at any harvest date if the interaction between variety and ensiling was not significant. Quality changes during ensiling resulted in a change of variety rank depending on the dry matter content at harvest. Reporting variety ranks based on fresh material continues to be a good practice for crude protein and starch content. However, changes in variety ranks based on OMD, NDF and DNDF occurred at a higher frequency. For each quality parameter, a stable variety rank was only guaranteed at the first harvest date corresponding with a dry matter content of 250g/kg.

Varietal and harvesting time effects on physical characteristics and sensory attributes of boiled fresh yellow maize hybrids

Objective : The present study evaluated the effect of varieties and harvesting time on the physical characteristics and acceptability of boiled fresh yellow maize hybrids. Methodology and Results: Freshly harvested cobs from eight biofortified yellow maize hybrids, at three harvesting time (20, 27 and 34 days after pollination (DAP)), were used for the present study. The fresh yellow maize ears at each of the harvesting time were boiled without husk in water at 100 o C for averagely 15mins (20DAP), 25mins (27DAP) and 32mins (34DAP) respectively using atmospheric cooking method. Sensory evaluation was carried out on the boiled fresh yellow maize samples within 24 hours after harvesting. The physical characteristics of the fresh maize grains were also determined. Variety and harvesting time had significant effects (P?0.001) on most of the physical properties, except porosity. The optimum harvest maturity stage to consume boiled maize hybrids was found to be 20DAP. There was negative but significant correlation between the physical characteristics and the sensory properties except colour that showed positive correlation. Conclusions and application of findings : Differences in kernel characteristics caused by genetic inheritance and harvesting time can influence the processing, utilization and consumer appreciation of maize. The information from this study could used by the Maize breeders to further improve the physical characteristics of the maize hybrids and by the maize consumers to know the best harvest time to consume boiled maize hybrids Keywords : yellow maize, hybrids, harvesting time, boiled, physical characteristics acceptability

Biology and Development ofSturmiopsis parasitica(Diptera: Tachinidae) on Different Species and Populations of Maize Stemborers in Zimbabwe and an Assessment of Its Suitability for Redistribution in Africa

The tachinid larval parasitoid Sturmiopsis parasitica (Curran) has a wide distribution in eastern, southern and West Africa where it attacks several species of cereal stemborers. Its development on Busseola fusca Fuller (four populations), Chilo partellus (Swinhoe) and Sesamia calamistis Hampson was evaluated in Zimbabwe in the laboratory. The parasitoid's larviposition patterns and ways to induce its early emergence from diapausing host larvae inside which it overwinters were also studied. Irrespective of the inoculation method used, the four B. fusca populations were equally suitable for parasitoid development. Chilo partellus was a partially suitable host while S. calamistis was completely unsuitable. Mated female parasitoids commenced larviposition at eight days after mating, with a peak being attained on day 15. Placing field-collected diapausing B. fusca larvae in fresh maize stems or in moistened dry stems could bring forward the emergence of S. parasitica from diapausing hosts. The implications of the current findings on the suitability of S. parasitica as a redistribution candidate in Africa are discussed.

Comparative Efficiency of Tillage Practices in Maize

Weed management practices used by small scale farmers determine maize productivity. The trials were executed in Kigumo district during the long and short rains in 2010 to compare effectiveness of glyphosate and hand weeding on weed management in maize (Zea mays L.). Treatments were arranged in a Completely Randomized Complete Block Design replicated three times in a split plot arrangement. The main plots were two maize varieties DUMA SC 41 and DK 8031 and the subplots three weed management practices,(glyphosate, hand weeding and no tillage). Data collected included weed count by species,fresh and dry weed biomass and maize grain yield. Data was subjected to ANOVA using Genstat computer software package at P<0.05. Treatments means were separated by Student-Newman Keuls Test. Results revealed that there were significant differences in weed count among weed management practices (P < 0.05). Weeds, significantly established faster under hand weeding than other weed management practices. There were no significant differences among weed management practices in biomass and maize grain yield (P < 0.05). The two maize varieties significantly differed in grain yield under different weed management practices, DK 8031 under glyphosate had the highest yield among the tillage practices involved.

Extent of availability of major nutrients from selected Cereal Crop Residues to dairy ruminants as an alternative Dry Season Forage in Northern Uganda.

This work aimed at determining the availability of major nutrients from cereal crop residues (CRs) of maize, rice and sorghum to dairy ruminants in Northern Uganda. The major nutrient composition of the CRs was determined to establish their potential as alternative dry season forage resources for dairy animals. The CRs were selected based on crop economic importance and availability at the on-set of the dry season in randomly selected sub-counties of Lira, Otuke and Kole districts. Five samples of each CR were obtained from 20 farmer’s fields immediately after harvesting of each crop. Chemical analyses measured included Dry matter (DM), Crude protein (CP), Acid detergent fiber (ADF), Neutral detergent fiber (NDF), Digestible energy (DE), Organic matter digestibility (OM dig), Calcium (Ca), and Phosphorous (P). Fresh maize stover (MSF) had the highest CP (70.5g/kg DM), DE (11.3 MJ/kg DM), and lowest lignifications (49g/kg DM). Rice straw (RS) had a CP (42.1g/kg DM), lowest DE (6.9MJ/kg DM) and OM dig (506 g/kg DM). Dry maize stover (MSD) had the highest lignifications (76.0 g/kg DM) and low OM dig (543 g/kg DM) and sorghum stover (SS) had the lowest CP (40.0 g/kg DM) and a very low DE (7.1MJ/kg DM). The low CP levels and high levels of lignification limit the digestibility of the CR. However, their CF digestibility can be improved using an energy rich by-product, molasses (12.7MJ/kg DM) while the CP limitation due to ligfications can be improved through urea treatment.

Effects of ensiling maize and sample conditioning on in situ rumen degradation of dry matter, starch and fibre

High-production ruminants are commonly fed maize silage, which makes accurate evaluation of its nutritive value a key economic issue. However, evaluations of the rate and extent of ruminal degradation of starch and cell wall fractions from maize silage carry uncertainty due to the lack of a standardized method. Here, we investigated the effects of ensiling and sample conditioning on in situ-measured degradation of maize forage. Eight series of maize samples (two hybrids×two maturity stages×two methods of conservation [non-ensiled or fresh and ensiled]) were nylon-bagged in three conditionings: dried and ground to 1mm (D1), dried and ground to 4mm (D4), frozen and coarse-ground (FG). Disappearance of dry matter (DM), starch and fibre (aNDF) was measured in situ in cow rumen after different incubation times (2, 4, 8, 16, 24, 48 and 96h). Effects of ensiling, sample conditioning, genotype, maturity and their interactions on DM, starch and aNDF degradation were analyzed using the SAS MIXED procedure. Effective dry matter degradability (ED4DM) was significantly higher (P<0.001) in silage than in fresh maize due to a significantly higher rapidly degradable fraction (a) (P<0.001). Effective starch degradability (ED6Starch) followed the same trend due to a higher silage degradation rate (P<0.01). Conversely, effective aNDF degradability (ED2aNDF) was lower in silage (P<0.001) than fresh maize due to the longer lag-time to degradation (P<0.001) and lower hemicellulose ((aNDF−ADF)/aNDF) fraction in silage. Effective DM degradability was higher (P<0.001) for D1 samples than D4 and FG samples, mainly due to the higher rapidly degradable fraction (a) (P<0.001) in D1 than D4 or FG samples. In relation to high degradation rate, starch degradability was significantly higher (P<0.001) in FG than D1 and D4 samples, whereas aNDF degradation was lowest in the FG samples. This study shows that ensiling maize increases starch degradability and decreases aNDF degradability compared to fresh plant. Alongside conservation method, fine-grinding samples (as D1) led to high losses through the pores of the nylon bags, and these losses were correlated with high starch degradability, whereas coarse grinding (as FG) led to low aNDF degradability, probably due to insufficiently reduced particle sizes. In conclusion, using ensiled samples dried and ground to 4mm (D4) emerges as the appropriate method for in situ studies of starch-rich forages used as silages.

Influence of undersowing annual forage legumes in early-maturing maize on grain yield and quality of their forage mixtures

An experiment was carried out to investigate the effects of date of undersowing different legume species on maize grain yield and forage quality. Early-maturing maize (Zea mays L. cv. Suwan1) and Tephrosia bracteolata Guill. and Perr. (tephrosia), Lablab purpureus (L.) Sweet (lablab) and Mucuna pruriens (L.) DC. (mucuna) monocultures as well as their mixture at three planting times—same day, 2 weeks after planting (WAP) and 4 WAP of maize—were arranged in a randomised complete block design with three replications. After harvesting fresh maize cobs, herbage samples (maize stover and legumes) from each plot were mixed together in ratios of 50:50 and 70:30 (maize:legume) for chemical analysis. Legume type and time of undersowing significantly affected (P < 0.05) the height and spread of maize from 4 to 6 WAP maize. Legume type and time of undersowing influenced fresh cob weight with the highest (P < 0.05) cob weight and grain yield recorded from maize undersown with tephrosia 2 WAP maize. Undersowing affected dry matter yield, crude protein, neutral detergent fiber and acid detergent fiber concentrations. It is concluded that intercropping of early-maturing maize and legumes can substantially increase forage quantity and quality compared with maize monocultures.

Seed germination and viability of herbicide resistant and susceptible Chenopodium album populations after ensiling, digestion by cattle and manure storage

SummaryChenopodium album became a problem weed in sugar beet production, due to resistance to metamitron, a key herbicide in this crop. Dispersal of the seeds from resistant biotypes may occur due to spread by wind, animals, agricultural machinery or manure. This study examined the effect of ensiling, digestion by cattle and storage in slurry and farmyard manure on the germination and viability of the seeds of one susceptible and three resistant C. album populations. After 4 weeks in a maize silo, seed viability of C. album populations was reduced drastically to 0–5%. Incubation for 24 h in the rumen followed by a post‐ruminal digestion in vitro of intact seeds only resulted in a small reduction in viability in one C. album population. Storage in a slurry cellar for 16 weeks reduced the viability of intact seeds of the C. album populations to 25–60%. Only 0–1% of the seeds remained viable after storage in a farmyard manure heap for 4 weeks. An accelerated ageing experiment showed seed persistence to be population specific and less related to seed weight. Keeping a fresh maize silo closed for at least 4 weeks and heaping farmyard manure are excellent preventive measures to limit the spread of resistant C. album seeds between fields.

Employment of maize silage in non-liquid fermentation for biogas production

This paper deals with the optimization of the anaerobic fermentation process of maize silage using the non-liquid technology. The aim of the paper is to increase the knowledge necessary for more efficient running of biogas stations using batch technology of non- liquid fermentation. The preferable ratio of initial materials, fresh maize silage and maize silage after partial fermentation, was verified within this experiment. Dynamics of the process, especially the quantity and quality of produced biogas has been monitored during the experiment. All the experiments have been done in the batch-system fermentors of volume of 0.48 m3 equipped with an independent and indirect circuit of water heating, the heat has been transferred to the material throught the steel wall of the fermentor. The material has been tested in the mesophilic conditions with the temperature of the 38 °C. The retention time of material in fermentors has been 27 days. The results of our experiments reveal the fact that the maize silage of lower mix ratio produced about 22.8 % more of biogas counted to one kilogram of dry matter than the maize silage of higher mix ratio.

Conversion of Carbohydrates in Herbaceous Crops during Anaerobic Digestion

The methane yields and conversion of pentoses (xylose) and hexoses (cellulose) in hemp, maize, and white lupin were studied over 30 days of anaerobic digestion. Preservation of hemp increased the methane yield by 23% compared with the fresh hemp. The increased methane yield of hemp was verified by the enhanced conversion of C6 sugars, increasing from 48% to about 70%, whereas the conversion of C5 sugars increased from only 9% to nearly 50%. The consumption of all carbohydrates in fresh maize was almost complete in the 30 days of anaerobic digestion. Hence, there was no major difference in carbohydrate consumption between fresh and preserved maize during biogas production. Fresh white lupin produced the highest methane yield (343 ± 33 dm(3) kg(-1) TS) in this work, mainly due to its highest amount of proteins. Conversion of C6 sugars was 80%, but that of C5 sugars was notably less at 46%.

Occurrence of different trichothecenes and deoxynivalenol-3-β-d-glucoside in naturally and artificially contaminated Danish cereal grains and whole maize plants

Fusarium mycotoxins such as deoxynivalenol (DON) can occur in cereals conjugated to glucose and probably also to other sugars. These conjugates, which are often referred to as "masked mycotoxins", will not be detected with routine analytical techniques. Furthermore, it is suspected that the parent toxin may again be released after hydrolysis in the digestive tracts of animals and humans. Today, our knowledge of the occurrence of these compounds in cereal grains is limited. In this paper, a LC-MS/MS method for the simultaneous determination of DON, deoxynivalenol-3-β-D-glucoside (DON-3-glucoside), 3 acetyl-DON, nivalenol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin in naturally (n = 48) and artificially (n = 30) contaminated cereal grains (wheat, barley, oat, rye triticale) is reported. The method has also been applied to whole fresh maize plant intended for production of maize silage (n = 10). The samples were collected from the harvest years 2006-2010, The results show that DON-3-glucoside and DON co-occurred in cereal grains and, especially in several of the highly contaminated samples, the concentration of the glucoside can be relatively high, corresponding to over 37% of the DON concentration. The DON-3-glucoside levels in both the naturally and in the artificially grain inoculated with Fusarium were second only to DON, and were generally higher than those of the other tested trichothecenes, which were found at low concentrations in most samples, in many cases even below the detection limit of the method. This argues for the importance of taking DON-3-glucoside into account in the ongoing discussion within the European Community concerning exposure re-evaluations for setting changed values for the tolerable intake for DON. Our results indicate that, in the naturally contaminated grains and in the Fusarium infested cereal grains (winter and spring wheat, oat, triticale), the concentration level of DON-3-glucoside is positively correlated to the DON content. When the DON concentration is high, then the content of DON-3-glucoside will most probably also be high and vice versa.

Identification of glutinous maize landraces and inbred lines with altered transcription of waxy gene

Waxy maize has little or very low content of amylose (<5 %) in grain starch and carries null mutations of the waxy (Wx) gene. With important uses as fresh maize or as an ingredient in food, textile, adhesive, and paper industries, two types of wx allele, wx-D7 and wx-D10, had been identified. In the present study, 10 accessions carrying neither wx-D7 nor wx-D10 allele were identified from a collection of 325 waxy maize accessions. The Wx locus of these 10 accessions was sequenced, but no potential causative mutation was detected. Further sequencing of the full-length complementary DNAs revealed that 6 of the 10 accessions had alternative splicing patterns while the other 4 had wild-type Wx transcripts. Among the six accessions, one generated transcripts identical to the wx-D7 allele, two had the same transcripts as the wx-D10 allele, another two generated transcripts with deletion of the 10th and the 11th exon, yet the other one produced transcripts of various lengths due to deletions from part of the 2nd exon to part of the 12th exon. The wx alleles with the above alternative splicing modes are referred to as wx-tD7, wx-tD10, wx-tD10-11, and wx-tD2-12, respectively. Real-time quantitative reverse-transcription polymerase chain reaction analysis of two waxy accessions that produced Wx transcripts showed significantly decreased expression, having only 47.3 and 3.6 % transcription level compared with B73. Sequence analysis of deletions in the transcripts with comparison with wild one showed short direct repeats at deletion endpoints, similar to reported signatures of DNA deletions. The waxy accessions present unique wx alleles for waxy maize breeding as well as for transcriptional regulation studies in plants.