Aflatoxins and ochratoxin A contamination in rice,corn and corn products from Punjab,Pakistan

In present study, a total of 275 retail cereal samples including rice, corn and corn products was analyzed for the presence of aflatoxins and ochratoxin A (OTA) using HPLC equipped with a fluorescence detector. The data has shown that 38 out of 68 samples of rice, 37/105 of corn and 43/102 samples of corn products have been found contaminated with AFs, average level of AFB₁ and total AFs, 8.23 and 19.54, 7.90 and 12.08, and 5.47 and 7.85 μg/kg, respectively. Furthermore, 34, 28 and 26 numbers of rice, corn and corn product samples were found to be contaminated with OTA with an average level of 12.94, 5.29 and 3.69 μg/kg, respectively. The samples of rice, corn and corn products found above the permissible European Union (EU) limit for AFB₁ and total AFs were 18, 13 and 14 and 28, 14 and 20%, respectively; however, the samples of rice, corn and corn products above the EU limit were 40, 14 and 15%, respectively.     

Aflatoxins and ochratoxin A contamination in rice,corn and corn products from Punjab,Pakistan

In present study, a total of 275 retail cereal samples including rice, corn and corn products was analyzed for the presence of aflatoxins and ochratoxin A (OTA) using HPLC equipped with a fluorescence detector. The data has shown that 38 out of 68 samples of rice, 37/105 of corn and 43/102 samples of corn products have been found contaminated with AFs, average level of AFB₁ and total AFs, 8.23 and 19.54, 7.90 and 12.08, and 5.47 and 7.85 μg/kg, respectively. Furthermore, 34, 28 and 26 numbers of rice, corn and corn product samples were found to be contaminated with OTA with an average level of 12.94, 5.29 and 3.69 μg/kg, respectively. The samples of rice, corn and corn products found above the permissible European Union (EU) limit for AFB₁ and total AFs were 18, 13 and 14 and 28, 14 and 20%, respectively; however, the samples of rice, corn and corn products above the EU limit were 40, 14 and 15%, respectively.     

Screening,identification and antagonistic effect of antagonistic bacteria JTFM1001 against aflatoxin contamination in corn

Aflatoxin is a strong carcinogenic and toxic fungal toxin produced by Aspergillus flavus and other Aspergillus species,and can seriously threaten the health of consumers,thus becoming a global concern.Corn,as an important oil and economic crop,is highly susceptible contaminated by aflatoxin.In this study,antagonistic bacteria with strong inhibitory effect on aflatoxin were screened to provide support for the treatment aflatoxin contamination control in corn.Ten strains which have strong antagonistic effects against A.flavus were isolated from healthy corn from different corn producing areas in China.Among them,the antagonistic bacteria JTFM1001 through corn kernels in vivo and field experiment,the inhibition effect of aflatoxin contamination reached above 70%and 55%,respectively.And the strain was identified as Bacillus subtilis based on its morphological,physiological and biochemical characteristics and phylogenetic analysis of 16S rDNA.In addition,our data showed that it can colonize in the rhizosphere and survive for a long time,forming the dominant flora,with broad application prospect.Finally,we were surprised to find that the antibacterial metabolites secreted by the antagonistic bacteria was one of the mechanisms of its inhibition of A.flavus and aflatoxin.This will provide us with new ideas and perspectives on the effective prevention and control of aflatoxin contamination in corn and corn oil.     

Prevalence of Helicoverpa zea (Lepidoptera: Noctuidae) on late season volunteer corn in Mississippi: Implications on Bt resistance management

The southern United States has a long growing period between corn, Zea mays L., harvest and first winter frost, so volunteer corn which germinates after harvest has a growing period sufficient for corn earworm, Helicoverpa zea (Boddie) and fall armyworm, Spodoptera frugiperda (J. E. Smith) to feed on these plants. However, lower air temperatures can limit larval development on late season volunteer corn and thereby successful pupation. Here we explore the suitability of late season volunteer corn for larval development and the potential contribution of H. zea larvae to the overwintering population. Our survey revealed the occurrence of volunteer corn in high densities, with monthly mean densities ranging from 56,000 to 143,000 plants ha⁻¹. H. zea larvae were found feeding on both vegetative and reproductive stage plants while S. frugiperda were only found on vegetative stage plants. An analysis of H. zea growing degree day (GDD) accumulations based on Mississippi weather data from 1980 to 2010 revealed that sufficient GDD to reach prepupation would always be accumulated before first frost if oviposition occurred by 9 September, with the probability of successful pupation decreasing rapidly thereafter. However, most of the H. zea larvae were oviposited after this, and could not reach pupation. Because S. frugiperda cannot overwinter in Mississippi, their ability to pupate was not examined. Low suitability of whorl stage corn for H. zea development coupled with low larval densities during this stage effectively diminish the number of larvae that complete development on late season volunteer transgenic corn expressing genes from the soil bacterium, Bacillus thuringiensis (Bt). This limits the Bt resistance risk posed by larvae developing on late season volunteer corn in all but the most southern locations in the US.     

A preliminary study on the effects of a transgenic corn event on the non-target pest Dalbulus maidis (Hemiptera: Cicadellidae)

The inclusion of the cry gene in corn may produce direct effects on non-target pests. Our research was focused on the relationship between Bt corn germplasm, expressing the cry1F protein to control the fall armyworm [Spodoptera frugiperda (Noctuidae)], and a non-target pest, the corn leafhopper [Dalbulus maidis (Cicadellidae)]. The aim of this contribution was to elucidate if Bt corn plants have influence on the oviposition preference of the leafhopper and to evaluate the effect of the transgenic plant on the hatching rate of egg. Female corn leafhoppers were released in cages each containing two potted plants in the V2 stage: a Bt germplasm and the corresponding isogenic hybrid. Laid eggs were counted and the number of hatched nymphs recorded. D. maidis females oviposited and laid more eggs in Bt plants. The egg hatching rate was negatively affected by the Bt germplasm. In addition, a field study was conducted in order to determine the abundance of D. maidis adults in Bt corn and the corresponding non-Bt isoline. Two corn plots sown with the same germplasms as used in the laboratory bioassays were sampled weekly. In the field, the population of the corn leafhopper was higher in the Bt corn plot than in the non-Bt isoline. Possible hypotheses for the differences in abundance of the vector in the field are: a) that pleiotropic effects of Bt corn could attract adults; b) the existence of a possible direct competition between the corn leafhopper and the target pest in order to utilize the whorls of corn plants as refuge and feeding sites, so the high populations of the vector could be due to the large supply of healthy whorls in the transgenic plot; and/or c) a differential attack of natural enemies occurring in non-Bt plots.     

The nutritional properties of extruded and non-extruded corn fiber isolate

The feed efficiency and selected organ weights of rats fed diets containing 3 or 7% corn fiber, extruded corn fiber or silica were compared to rats fed a fiber-free diet. No significant differences were found in feed efficiency, spleen, lung or liver weights for any of the treatments relative to the fiber-free control diet.     

耐荫型大豆与紧凑型玉米间作模式与推广前景分析

耐荫型大豆与紧凑型玉米采用6：4或6：2的方式间作种植,比单作玉米可提高综合效益4500元／hm^2以上,同时对化解玉米、大豆种植相互争地的矛盾和大豆面积的恢复以及振兴中国大豆产业具有重要的意义,推广前景十分广阔。     

不同光照条件下大豆体内异黄酮的含量与分布

用ＨＰＬＣ检测了不同光照处理大豆组织中异黄酮的含量。结果显示：幼苗子叶异黄酮含量大大高于叶片和根中的含量;光照处理后,子叶中异黄酮的含量降低,而叶片和根中的异黄酮含量上升;异黄酮含量较低的品种,幼苗光照后子叶中异黄酮含量上升较多。幼苗子叶中的异黄酮以大豆甙和染料木甙及其丙二酰衍生物为主,叶片中主要含有染料木甙及其丙二酰衍生物,根中异黄酮组分以丙二酰大豆甙为主;异黄酮组分因品种不同显示出一定差异。     

Development of biodegradable films based on blue corn flour with potential applications in food packaging. Effects of plasticizers on mechanical,thermal, and microstructural properties of flour films

In the present study, blue corn flour films were developed. The cereal grain’s total composition (excluding the pericarp) is used to obtain the films. The plasticizing effects of two different polyols such as glycerol and sorbitol on the mechanical, thermal, and microstructural properties of flour films were researched. The results showed that films plasticized with sorbitol had better mechanical properties and less affinity for water than those plasticized with glycerol. The sorbitol-plasticized films were more rigid and did not lose their integrity when immersed in water. The ATR-FTIR spectra of blue corn flour plasticizer with sorbitol showed the presence of the additional band at 1745 cm⁻¹ characteristic of the vibrational carbonyl peak, which confirms the chemical linkages between sorbitol and a polymeric matrix. The effect of the plasticizer on the glass transition temperature (T_g) was characterized using differential scanning calorimetry (DSC). T_g decreased as the plasticizer content increased. Plasticized glycerol films showed lower T_g values than those with sorbitol. SEM observations showed that it was necessary to add plasticizer to maintain film integrity. The sorbitol-plasticized flour films revealed better adhesion between phases, and these films showed a compact structure.     

Trichoderma harzianum seed treatment controls Fusarium verticillioides colonization and fumonisin contamination in maize under field conditions

In northern Italy, the most frequently occurring class of mycotoxins in maize are fumonisins, mainly those produced by Fusarium verticillioides. Currently, good agricultural practices (GAPs) represent the best line of defense for controlling the contamination of maize by Fusarium-toxins. Annual fluctuations in weather conditions can strongly reduce the advantages conferred by GAPs, and thus integration with biological control strategies can be a sustainable way to achieve reliable control of Fusarium colonization and toxin contamination. Trichoderma harzianum is a good biocontrol agent against a wide range of plant pathogens, and previous studies have reported its ability to reduce F. verticillioides colonization under greenhouse conditions. Field trials were conducted in two locations to assess the effect of seed treatment with T. harzianum strain T22 on F. verticillioides kernel colonization and on fumonisin contamination under various natural conditions. An average reduction of 58% in fungal infestation and 53% in mycotoxin contamination was observed during our three-year experiments. This research suggests that seed biopriming with T. harzianum T22 can be a promising and environmentally friendly way to control F. verticillioides kernel colonization and fumonisin accumulation.     

Formulation and characterization of dry mixes based on dehydrated fresh high-lysine corn

Fresh sweet corn pulp from high-lysine corn was dehydrated in a drum-dryer and utilized in the formulation of creamy instant soups. Studied formulas contained 27.5 to 67% dehydrated high-lysine corn pulp. The sensory profiles of the formulas improved with increasing proportion of dehydrated fresh corn pulp. Formula with 27.5% fresh corn pulp was rated lowest by the tasters on the basis of poor appearance, low characteristic fresh corn flavor and low overall impression. Formulas with 60 and 67% corn pulp rated highest in sensory quality and were nutritionally adequate. The PER for these formulas did not differ from casein control diet but nitrogen absorption and nitrogen retention was inferior for the formulas protein as compared to casein.     

Preparation and nutritional quality of high protein food extracts from immature corn,whole soybean and dry whole milk

Five foods have been prepared from water extracts of immature corn (IC), immature corn-milk (CM) and immature corn-whole soybean (CS). The method of preparation followed either the common practice used for the immature corn drink or with certain modifications to increase yield. The protein quality of the three foods (IC, CM and CS) were evaluated and compared with that of casein. They had same digestibility (87–88%) but differed in protein quality. Two other foods, CS-1 and CS-2 were prepared using mechanical pressing of solubles. The corn-soy foods, CS-1 and CS-2, had almost the same digestibility as that of casein. An analysis of costs of materials indicated that the production of corn-soy food will be cheaper than the corn-milk food.     

黑玉米杂交种“黑糯玉米941”的选育及应用研究

通过突变黑粒种质的纯化、筛选，采用回交转育法，将黑粒种质导入到白糯玉米育种材料中再选系或转育成黑粒同型系，组配黑糯玉米杂交种。根据育种目标．经籽粒色泽、品质、抗逆性鉴定和产量配合力的测交试验决选出适合作母本系和适合作父本系组成“黑糯玉米941”杂交种．经初步生产检验和示范获较好结果。     

Agronomic assessment of Bt trait and seed or soil-applied insecticides on the control of corn rootworm and yield

Corn rootworm (Diabrotica spp.) has become the most concern and widespread insect pest of corn (Zea mays L.) production in North America. Two field experiments were conducted to assess the agronomic and yield performance of transgenic rootworm trait, Bacillus thuringiensis (Bt) Cry3Bb, seed-coating treatment, and a soil-applied insecticide under natural corn rootworm infestation. Experiment 1 compared a conventional corn hybrid with and without insecticide (Force 3G) with its near isoline Bt hybrid from 2003 to 2005, on a clay loam soil. Experiment 2 investigated the same treatments as in Experiment 1 plus an additional seed-coated Poncho treatment on a sandy loam in 2004 and 2005. Rootworm population before the crop anthesis, root node injury and root:shoot dry weight ratio during the early grain filling stage, and stalk lodging and grain yield were determined. Our data showed that rootworm population diminished over the 3 years owing to rootworm displacement and adverse weather conditions. At the clay loam site, both Force 3G and the Bt hybrid significantly reduced the larval populations, root injury and lodging score, and increased root:shoot ratio. Over the 3 years, grain yields of the Bt hybrid were 11–66% greater than the untreated non-Bt isoline hybrid; yield of the non-Bt hybrid treated with Force 3G was also significantly greater than the same untreated non-Bt hybrid in 2 of 3 years. Despite less root node injury in the first rows of non-Bt plants adjacent to the Bt plots was observed, yield benefit of this effect remained to be proven. On sandy loam soil, the larval population was very low and there were no differences in root node injury and plant lodging among all the four treatments in either 2004 or 2005. The yield of the Bt hybrid was up to 10% greater than its non-Bt isoline hybrid treated or not with an insecticide in 1 year. Our data showed that Bt rootworm seed technology was effective to control the rootworm larvae and protected grain yield under severe infestation. Furthermore, our data suggest that some of the gain in Bt hybrid yield may be attributed to the genetic transformation as observed in sandy loam soil experiment. In all cases, corn producers should be aware of the pest history, rootworm pressure in relation to economic threshold, soil type and the expected cost-to-benefit ratio before deciding to adopt any protective measures.     

锌对夏玉米生长发育及产量影响的研究

采用小区试验的方法,研究了不同锌肥用量对夏玉米诸多生育性状及产量的影响。结果表明,增施锌肥能明显提高玉米产量,２年平均,增锌区分别比对照增产３５５６５、８１１３５、１０９４５５、１２２７９０、１３８３６０、１６３９０５ｋｇ;增产率分别为４３１％、９８３％、１３２６％、１４８７％、１６７６％、１９８５％。同时,增施锌肥还能有效地增加玉米次生根条数和单株干物重等     

夏玉米不同种植方式生长发育规律研究

1998－1999年以掖单22号为材料，采取塑盘育苗带土移栽与麦田套种，麦收后直播3种不同种植方式，研究了夏玉米的生长发育进程，植株高度，田间生长整齐度和叶面积系数，根系发育，干物质积累以及产量情况，明确了夏玉米塑盘育苗带土移栽的方式比麦田套种和麦后直播具有明显的生长发育优势和增产效果，为今后夏玉米改进种植方式提供了依据。     

Physical properties of dry-heated octenyl succinylated waxy corn starches and its application in fat-reduced muffin

Waxy corn starch was modified by dry heating (130 °C, 2 h) in the presence of octenyl succinic acid (OSA) at different pHs (4, 6, and 8), and the physicochemical properties of the modified starch were evaluated. The dry-heated octenyl succinylated (DH-OS) starch was also evaluated as a partial fat substitute in a muffin. Dry heating of starch under a more acidic condition resulted in lower degree of polymerization (DP_n) but lower degree of substitution (DS). The pasting viscosity of the DH-OS starch prepared under basic conditions was higher than that of the unheated counterparts, whereas that under acidic conditions was lower. It was because the substitution favored basic conditions, and thermal degradation was accelerated by acids. The gelatinization characteristic was not significantly altered by OSA substitution and dry heating. The muffin containing the DH-OS starch had a higher specific volume and a softer texture than the muffin containing maltodextrin. Among the DH-OS starches tested, the starch prepared under acidic conditions produced muffins that had a greater volume, which was most likely due to its low molecular size. The muffin prepared with DH-OS starch at pH 6 was the softest in texture and had characteristics that were relatively close to the full-fat muffin.     

Effect of the Lactiplantibacillus plantarum and Lentilactobacillus buchneri on corn and sorghum silage quality and sheep energy partition under tropical conditions

This study aimed to evaluate the silage quality, ingestive behaviour, and sheep energy partition fed corn and sorghum silages, with or without inoculation with Lactiplantibacillus plantarum and Lentilactobacillus buchneri. Whole plants of one dent corn hybrid (DCS), one flint corn hybrid (FCS), and one forage sorghum hybrid (SS) were ensiled with or without an inoculant containing L. plantarum and L. buchneri (4 × 10⁵ CFU g⁻¹), totalling six treatments (3 × 2 factorial scheme). The treatments were ensiled in metal drums with 200 L capacity. The lactic acid concentrations in the inoculated FCS and DCS were higher by 13.4% and 12.8%, respectively, than those in the non-inoculated plants. In contrast, the lactic acid concentration in the inoculated SS was 23.1% lower than that in the non-inoculated SS. Furthermore, there were differences in pH and acetic acid concentrations only in SS, which were 2.3% and 45.2% higher, respectively, in inoculated silage than in non-inoculated silage. In inoculated DCS and SS, propionic acid concentrations were 1.7 times higher (for both silages), and 1-propanol was 3.7 and 1.8 times higher compared than those in non-inoculated silages. There was a main effect of the inoculant on 1,2-propanediol concentrations, which were 37.5% higher in inoculated silages than in non-inoculated silages. However, ingestive behaviour, heat and methane production, and silage net energy concentrations were not affected by inoculant use. Fermentative modifications caused by inoculation with L. plantarum and L. buchneri in whole plant corn or sorghum silage did not modify sheep energy partition.     

小麦 玉米轮作区西农979不同器官氮素转运及对籽粒贡献率的影响

为了解华北地区小麦玉米轮作模式下小麦不同器官氮素吸收、分配及转运的差异,采用田间试验方法,以西农979为供试品种,于小麦的分蘖期、越冬期、返青期、拔节期、抽穗期、灌浆期和成熟期采集植株样品,对其叶、叶鞘、茎、穗轴、颖壳和籽粒的干物重及氮含量进行了测定和分析。结果表明,小麦成熟时,不同器官氮含量从大到小依次为：籽粒＞叶＞叶鞘＞颖壳＞茎＞穗轴,氮积累量从大到小依次为：籽粒>叶鞘>叶>茎>颖壳>穗轴,即氮在籽粒中分配和积累量最大,叶是最大的氮素“源器官”。在不同生育阶段,拔节至抽穗期的氮吸收量和吸收速率最大。在华北小麦玉米轮作区,籽粒氮收获指数达到68.48%,而叶对籽粒的氮转运贡献率达到54.52%;拔节至抽穗期氮素吸收比例占全生育期的48.07%,故而底施氮肥与拔节期追氮的比例控制在5∶5为好。