Type of corn endosperm influences nutrient digestibility in lactating dairy cows

An experiment was conducted to evaluate the effect of type of corn endosperm on nutrient digestibility in lactating dairy cows. Near-isogenic variants of an Oh43 × W64A normal dent endosperm hybrid carrying floury-2 or opaque-2 alleles were grown in spatial isolation in field plots and harvested as dry shelled corn. Six ruminally cannulated, multiparous Holstein cows (67 ± 9 d in milk at trial initiation) were randomly assigned to a replicated 3 × 3 Latin square design with 14-d periods; the first 11 d of each period were for diet adaptation followed by 3 d of sampling and data collection. Treatment diets that contained dry rolled vitreous-, floury-, or opaque-endosperm corn [33% of dry matter (DM)], alfalfa silage (55% of DM) and protein-mineral-vitamin supplement (12% of DM) were fed as a total mixed ration. The percentage vitreous endosperm was zero for floury and opaque endosperm corns and 64 ± 7% for the vitreous corn. Prolamin protein content of floury and opaque endosperm corns was 30% of the content found in vitreous corn. Degree of starch access and in vitro ruminal starch digestibility measurements were 32 and 42% greater on average, respectively, for floury and opaque endosperm corns than for vitreous corn. Dry matter and starch disappearances after 8-h ruminal in situ incubations were, on average, 24 and 32 percentage units greater, respectively, for floury and opaque endosperm corns than for vitreous corn. Ruminal pH and acetate molar percentage were lower, propionate molar percentage was greater, and acetate:propionate ratio was lower for cows fed diets containing floury and opaque endosperm corns than for cows fed vitreous corn. In agreement with laboratory and in situ measurements, total-tract starch digestibility was 6.3 percentage units greater, on average, for cows fed diets containing floury and opaque endosperm corns than vitreous corn. Conversely, apparent total-tract neutral detergent fiber (NDF) digestibility was lower for cows fed diets containing floury and opaque endosperm corns compared with vitreous corn. The type of endosperm in corn fed to dairy cows can have a marked effect on digestion of starch and NDF. Feeding less vitreous corn increased starch digestion but decreased NDF digestion.     

Endosperm Structure and Physicochemical Properties of Starches from Normal,Waxy, and Super-Sweet Maize

Maize is a main botanical source used for extraction of starch in the world market. New maize cultivars with different amylose contents and special starch metabolism characteristics have been generated. Three types of maize cultivars, namely, normal maize, waxy maize (wxwx homozygous mutant), and super-sweet maize (sh2sh2 homozygous mutant), were investigated to determine differences in endosperm structures, morphologies, and physicochemical properties of starches. Maize kernels exhibited significantly different contents of total starch, soluble sugar, and amylose. Normal maize kernels contained the largest proportion of floury endosperm, followed by waxy maize and then super-sweet maize. Normal maize starch and waxy maize starch were larger in size than super-sweet maize starch. Normal maize starch and waxy maize starch were spherical and polygonal in floury and vitreous endosperms, respectively. Super-sweet maize starch was spherical both in floury and vitreous endosperms. Waxy maize starch showed the strongest birefringence patterns, the highest crystallinity and the largest proportion of ordered structure in external region of granules, and the largest proportion of double helix components, followed by normal maize starch and then super-sweet maize starch. Waxy maize starch showed the highest peak viscosity, trough viscosity, breakdown viscosity, gelatinization temperatures (i.e., gelatinization conclusion temperature, gelatinization onset temperature, gelatinization peak temperature, and gelatinization enthalpy). By contrast, super-sweet maize starch showed the lowest corresponding values for these parameters.     

Use of High-Resolution X-Ray Micro-Computed Tomography for the Analysis of Internal Structural Changes in Maize Infected with <Emphasis Type="Italic">Fusarium verticillioides</Emphasis>

X-ray micro-computed tomography (X-ray micro-CT) is a non-destructive, three-dimensional (3D) imaging and analysis technique for the investigation of internal structure of a large variety of materials, including agricultural produce. As a relatively new method in the field of food science, X-ray micro-CT has been applied successfully to obtain micro-structural information of foods undergoing different physical and chemical changes. In this study, high-resolution X-ray micro-CT was used for non-destructive analysis of the internal structure of maize kernels infected with Fusarium verticillioides. The major anatomical features of the maize kernel were identified based on their differences in X-ray attenuation, i.e. the germ, scutellum, vitreous and floury endosperm. Fungal infection caused changes in the internal structure of the kernels over time, which included a decrease in total kernel volume and an increase in total volume of void space, with more voids observed in the germ and floury endosperm regions. No significant (P > 0.05) difference was observed between the control and the infected kernels; it was apparent that the changes observed in the infected kernels were not solely as a result of fungal growth. The grey level histograms of the control and infected kernels shifted to the lower grey value intensity range over time indicating an increase in void space within the kernels. In the 3D images, the increase in total volume of void space with fungal progression was clearer and the effect of fungal damage on the internal structure was evident.     

Starch properties as affected by sorghum grain chemistry

To determine the relationship between sorghum grain polyphenol content, grain structure, and starch properties, starch was isolated from 10 sorghum varieties using an alkali steep and wet‐milling procedure. SV2, a tannin‐free variety with white pericarp, gave a white starch. Varieties having red or white pericarp and higher polyphenol levels gave pink starches. Hunter colour values (L, a, b) of starches were not correlated with grain polyphenol content. Grain appearance in terms of pericarp colour, or presence or absence of pigmented testa, did not relate to the intense pink colouration of sorghum starches. Starch amylose content was significantly negatively correlated (r = −0.88, p < 0.001) to grain floury endosperm texture. Sorghum starches had higher peak viscosity (PV) in pasting than commercial maize starch. The time taken to reach peak viscosity from the initial viscosity rise was less for sorghum starches than maize starch. However, sorghum starches had a higher rate of shear thinning (R_st) than maize starch. There was a significant positive correlation between grain polyphenol content and starch PV (r = 0.75, p < 0.05). Starch gel hardness was negatively correlated to pasting properties of R_st and paste breakdown (r = −0.78 and −0.77 respectively) at p < 0.01. Peak gelatinisation temperature (T_p) occurred over a narrow range from 66 to 69 °C. T_p was negatively correlated to the floury endosperm portion of the grain (r = −0.77) at p < 0.01. It is concluded that sorghum grain polyphenol content and grain characteristics influence its starch properties. © 2000 Society of Chemical Industry     

Distribution of antifungal proteins in maize kernel tissues using immunochemistry

This study examined the distribution of two antifungal proteins, ribosome-inactivating protein (RIP) and zeamatin, in maize kernel tissues. Proteins were extracted from endosperm (including aleurone layer) and embryo tissues of imbibed maize kernels. Western blot analyses revealed that RIP-like protein was present at higher levels in endosperm than in embryo tissues, whereas zeamatin-like protein was more concentrated in embryo tissues than in endosperm tissues. However, there were three protein bands in the endosperm and two bands in the embryo that reacted to anti-RIP antibody in Western blot analyses. Tissue prints were conducted to localize the antifungal proteins. Imbibed kernels were cut longitudinally and transversely and blotted onto nitrocellulose membranes. Using antibodies against maize RIP and zeamatin, RIP was found primarily in the aleurone layer of the endosperm and glandular layer of scutellum, whereas zeamatin was located mainly in the kernel embryo. These results provide insight into the potential functions of these antifungal proteins, especially since the presence of RIP and zeamatin within maize kernels uniquely protects kernels from pathogens.     

Influence of maize kernel state and type on life history of Plodia interpunctella (Lepidoptera: Pyralidae)

The objective of this study was to investigate the influence of different mechanical states (whole, broken and ground kernels) and types (dent, semi-flint and flint) of maize kernels on life history parameters of Plodia interpunctella (Hübner), the Indian meal moth. These parameters included larval development and its dynamics, adult emergence, mean development duration (MDD) and fecundity. Since the larvae are the developmental stage that causes the most damage on maize, additional data on larval development helps identify conditions that promote development. The results of our study indicate that broken maize kernels are the most suitable for P. interpunctella development, where the most successful larval development, the highest number of emerged adults, the shortest MDD and the highest total fecundity were recorded. On the contrary, whole kernels were the least suitable and the most resistant to infestation by P. interpunctella. The type of kernel also significantly affects P. interpunctella developmental parameters. Females reared on flint kernels (the hardest kernel type tested in our study) laid the largest total number of eggs, which implies that kernel hardness, i.e. the type of kernel should be an important parameter when choosing maize hybrids for cultivation and for storage. Our study warrants further investigation of maize types and their susceptibility to P. interpunctella.     

Chapter 3: Double‐Embryo,High‐Protein,High‐Oil Maize Produced Using a Cytokinin‐Based Flower Rescue

ABSTRACT: Maize is an important staple of human diets and animal feed.Improving the nutritional profile for both of these purposes is a desirable research focus and agricultural endpoint. Many mechanisms have been used to improve maize protein and oil content, including selective breeding to introgress desirable traits (Quality Protein Maize), introducing single natural or synthetic genes expressing desired traits, changing signal sequences (high methionine maize), and modifying metabolic pathways (high‐lysine maize, see Chapter 6). A novel approach was used to indirectly increase protein and oil content ( Young and others 2004 ). Maize produces unisexual florets. Within the maize spikelet,the meristem gives rise to an upper and lower floret and male (tassel)‐ and female (ear)‐specific florets are borne on separate inflorescences.The lower floret of each ear spikelet is aborted early in its devel‐opment,leaving the upper floret to mature as the only female floret.Expression of a bacterial cytokinin‐synthesizing isopentenyl transferase (IPT) enzyme,under the control of the Arabidopsis senescence‐inducible promoter SAG 12 (senescence associated gene), blocked the abortion of the lower floret and resulted in 2 functional florets per spikelet.The pistil in each floret was fertile,but the spikelet produced just 1 kernel composed of a fused endosperm with 2 viable embryos.The 2 embryos were genetically distinct, indicating that they had arisen from independent fertilization events. The embryo contains most of the protein and oil in the kernel and kernels that contained 2 embryos have more protein than conventional maize.The presence of 2 embryos in a normal‐sized kernel leads to displacement of endosperm growth, resulting in kernels with an increased ratio of embryo to endosperm content. The end result is maize with more protein and oil and less carbohydrate ( Young and others 2004 ).     

Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 µg kg^?1 (median = 363 µg kg^?1) and in 15% exceeded 1000 µg kg^?1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 µg kg^?1 (median = 24 µg kg^?1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 µg kg^?1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies.     

Effect of oven and forced convection continuous tumble (FCCT) roasting on the microstructure and dry milling properties of white maize

The effect of oven and forced convection continuous tumble (FCCT) roasting on the microstructure of whole maize kernels was characterised and quantified using X-ray micro-computed tomography (μCT). The three-dimensional (3-D) volumes, reconstructed from the two-dimensional (2-D) images, were segmented into regions of interests (ROIs), i.e. air, germ, floury and vitreous endosperm, and each region quantified. Oven roasting was associated with a larger increase in total kernel volume (10.8%) than FCCT roasting (3.4%) as well as a significant (P ≤ 0.05) decrease in whole kernel relative density (oven = 6.3%; FCCT = 1.9%). FCCT roasting had almost no effect on material density, in contrast to a significant (P ≤ 0.05) decrease of 5.0% during oven roasting. Subsequent validation of the dry milling properties, i.e. percentage hominy chop, milling yield and hectolitre mass (HLM), indicated no significantly (P > 0.05) detrimental effect by either of the roasting methods.Industrial relevanceRoasting of maize can improve sensory, shelf life, nutritional and antioxidant properties with subsequent use in ready-to-eat foods and breakfast cereals. Roasting will inevitably affect the structure of maize, which in turn will affect the quality of the end product. This prompted the demand for non-destructive techniques that directly measure microstructural properties of food in order to link structure with quality. X-ray μCT in combination with image analysis uniquely illustrated the microstructural changes occurring during conventional oven and innovative FCCT roasting respectively. Furthermore, dry milling properties are important indicators of quality characteristics for the dry milling industry. The method described in this article can be applied to any food material to investigate structural properties.     

Wet Milling Comparison of Quality Protein Maize and Normal Maize

Quality protein maize (QPM) experimental hybrids and normal maize possessing different physical and chemical properties were studied as the raw material for wet milling. Maize samples were steeped for 36 h in a 600-ml solution containing 15 g kg⁻¹ lactic acid and 0·5 g kg⁻¹ SO₂ followed by 12 h in a second 600-ml solution containing 5 g kg⁻¹ lactic acid and 1 g kg⁻¹ SO₂. The steeped grain was then wet milled and the yields and purity of fractions were analysed. Water-soluble solids, kernel size, quality protein, total dietary fibre and ash content were higher in QPM samples than in normal maize. Water-soluble solids were positively correlated to kernel size ( r =0·97, P< 0·05), test weight ( r =0·83, P< 0·05) and density ( r =0·57, P< 0·05). Total fraction recovery for the five hybrids tested ranged from 921 to 955 g kg⁻¹, with the highest values corresponding to QPM hybrids. QPM hybrids yielded slightly higher starch content than normal maize. Gluten yields of QPM-HO (high oil) presented the highest values. The lysine contents of kernel, gluten and milling solubles were highest for QPM hybrids. QPM contained more palmitic acid than the other hybrids. The H-137 normal maize and QPM yellow dent-HO contained more oleic and linolenic acids than the other samples, and the QPM white-C (corneous) contained more linoleic acid than QPM-HO and normal maize.     

Localisation of antinutrients and qualitative identification of toxic components in Jatropha curcas seed

BACKGROUND: Jatropha curcas seed oil is a promising feedstock for biodiesel production. The seeds contain major toxic (phorbol esters, PEs) and antinutritional (phytate and trypsin inhibitor) factors. In the present study the localisation of antinutrients and a rapid qualitative method for detecting the presence of PEs were investigated. RESULTS: Kernels were separated into cotyledon, hypocotyl, kernel coat and endosperm. The majority of phytate (96.5%), trypsin inhibitor (95.3%) and PEs (85.7%) were localised in the endosperm. Based on PEs, a qualitative method was developed to differentiate between toxic and non‐toxic Jatropha genotypes. In this method, PEs were easily detected by passing methanol extracts of kernels (Jatropha toxic and non‐toxic genotypes) through a solid phase extraction (SPE) column and measuring the absorption of the resulting eluates at 280 nm. For raw kernels, SPE eluates with absorbance ≥ 0.056 were considered as toxic and those with absorbance ?0.032 as non‐toxic. For defatted kernel meals, SPE eluates with absorbance ≥ 0.059 were considered as toxic and those with absorbance ?0.043 as non‐toxic. CONCLUSION: The majority of antinutrients/toxic compounds are localised in the endosperm of the kernel. The qualitative method developed for rapid identification of toxic PEs could be useful in screening the toxicity of Jatropha‐based products in the biodiesel industry. Further confirmation of PEs should be established by high‐performance liquid chromatography. Copyright © 2011 Society of Chemical Industry     

Effects of maize grain size,shape and hardness on drying rate and the occurrence of stress cracks

The effects of maize (Zea mays L) grain hardness, morphological factors (grain size and shape), drying rate and the development of stress cracking over time were investigated for four hybrids (Hmv565 ? 3 × E1386, CF06, CF05 and Furio). The re‐parametrised Morgan–Mercer–Flodin (MMF) model successfully predicted the rate (κ) and maximum value (α) of percentage checked stress cracking (checking) in various sizes, shapes and hardnesses of grains with time after drying. The maximum percentage checking (α) was significantly correlated with grain length (r = ?0.707), thickness (r = 0.620), roundness (r = 0.703) and the shortest diffusion pathway (r = 0.627). The rate (κ) of percentage checking with time after drying was significantly correlated with grain bulk density (r = ?0.564), hardness ratio (r = ?0.611) and drying rate (r = 0.551) and, to a lesser extent, with grain size parameters including hundred‐grain weight, grain length and width. Removing small and round grains could reduce checked stress cracking by up to 50% in some dent maize hybrids. © 2002 Society of Chemical Industry     

Interactions between the kernel N sink, grain yield and protein nutritional quality of maize

The isogenic opaque-2 (o2) and its normal counterpart of maize (Zea mays L.) hybrid ‘B14 × B37’ were used as a model system and grown under different levels of nitrogen fertility to test the importance of the kernel N sink (zein accumulation) relative to kernel osmotic potential, dry matter accumulation, grain yield and protein nutritional quality. Self-pollination and reciprocal crosses were made with seven o2 hybrids and their normal counterparts in order to determine the effect of the kernel N sink and/or vegetative characteristics on kernel dry weight accumulation. The results indicate that with a small supply of nitrogen, both normal and o2 kernels produced only small amounts of zein, and kernel weights and grain yields were comparable. As the level of nitrogen increased, zein accumulated preferentially in normal, but not in o2, and differences in kernel weight and grain yield between these two genotypes became greater. The reduction of dry matter accumulation in o2 kernels relative to normal kernels when grown under high N levels may result from the accumulation of free amino acids and their catabolic products in the kernel as a consequence of a small N sink. These osmotica contributed to a more negative osmotic potential which may favour water movement, but reduce solute movement into the kernel. Increased zein accumulation in normal kernels enhanced kernel weight and grain yield but reduced protein nutritional quality. The concentration of lysine and tryptophan as a percentage of protein decreased as the level of N fertiliser and kernel protein in the normal kernel increased. On the other hand, the o2 mutant failed to deposit additional N as zein; therefore, the concentration of these two essential amino acids remained constant regardless of N levels. However, when lysine and tryptophan were expressed on an area (kg ha^?1) basis, the amino acid yields of these two genotypes were comparable.     

Inverse relationship between oil content and specific gravity of groundnut kernels

Thirty-two samples of groundnut kernels were analysed for oil content by the standard Soxhlet extraction procedure. The oil content ranged between 425.6 and 549.5 g kg^?1. The specific gravity of groundnut kernels was determined both for the whole kernels and the split kernels (cotyledons with testa). The specific gravity of whole kernels varied between 0.9358 and 1.0730 while that of split kernels between 1.0547 and 1.1227. A highly significant correlation (r = -0.9459) was found between oil content and specific gravity of split kernels. It should, therefore, be possible to predict the oil content of the groundnut samples on the basis of specific gravity of split kernels.     

Developmental Changes in Starch Properties of Several Endosperm Mutants of Maize

The properties of starches during development of several endosperm mutants of maize were investigated. Starch contents of normal and waxy (wx) kernels were higher than those of dull (du), sugary-2 (su₂), and amylose-extender (ae) kernels, and in general the greater increase in starch contents occurred earlier in kernel development. The normal, du, su₂, and ae mutants in that order, respectively, increased the apparent amylose concentration of the starches as measured by the “blue value” method. Within each of these genotypes, absorption intensity increased and λ max. of absorption curves shifted to a longer wavelength region with increasing maturity. Waxy starches did not change in either of these properties at any of the developmental stages. Few detectable differences were observed in X-ray diffraction intensity, gelatinization temperature, heat of gelatinization, and the photopastegrams within these genotypes during development. Exhaustive degradation of starch granules by glucoamylase showed that ae starches were more resistant to amylase than the other starches. Except for wx, the starches tended to be more resistant to amylase with increasing maturity.     

基于高光谱图像光谱变量和颜色特征的霉变玉米籽粒识别

目的:准确识别霉变玉米籽粒。方法:基于高光谱图像光谱变量和颜色特征建立霉变玉米籽粒识别的新方法。先对玉米籽粒图像进行图像分割和光谱变量、颜色特征提取,并根据颜色特征生成颜色直方图;将光谱变量和颜色直方图特征组成特征集合;通过距离函数对特征集合中所有特征的分析确定霉变玉米籽粒所属类别。结果:所提方法对霉变玉米籽粒类别的最大平均识别偏差为1.12,最佳平均识别准确率为97.59%;与基于高光谱图像+随机蛙跳+极限学习机的方法、基于高光谱图像+稀疏自动编码器+卷积神经网络的方法、基于高光谱图像+蚁群优化+BP神经网络的方法相比,研究所提方法对霉变玉米籽粒类别的识别准确率明显提高。结论:该方法可实现被测玉米籽粒样品是否霉变以及霉变程度的准确判断。     

Influence of commodity on the population growth of the larger grain borer,Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae)

In this study, we compared different amylaceous commodities for their suitability for population growth of the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae), which is an important pest of stored maize in the tropics. In this context, we conducted three different series of tests. In the first test, we compared whole grains: whole barley, peeled barley, maize, whole oats, peeled oats, peeled rice, rough rice, rye, triticale, and wheat. Only maize was found suitable for P. trunctatus to reproduce and significantly increase its population, but there were certain commodities where surviving adults were found. In the second series of tests, we evaluated the percentage of cracked maize kernels on P. truncatus population growth. In this test, we found that the numbers of alive P. truncatus adults in the vials that contained 100% cracked kernels was higher than these with lower percentages of cracked kernels (5–50%) or no cracked kernels (0%). Finally, in the third series of tests, we compared eleven different types of amylaceous commodities with maize. These commodities were: whole maize (whole kernels), whole oat flakes, maize flour, whole barley flour, pasta, white soft wheat flour, whole soft wheat flour, white hard wheat flour, whole hard wheat flour, whole rye flour, and semolina. The results indicated that only whole maize and maize flour were suitable for P. truncatus population growth. Nevertheless, in some of the other commodities tested, there was a low number of adults and immatures that were able to survive 60 days after the incorporation of the parental adults. The results of the present study indicate that from the commodity range tested here, only maize was suitable for P. truncatus population growth. Nevertheless, the marginal numbers of surviving individuals in the non-maize commodities and the role of these substrates as potential “non-preferred food vehicles” that may contribute to further spread of this species should be tested in more detail.     

Effect of the addition of calcium hydroxide on some characteristics of extruded products from blue maize (Zea mays L) using response surface methodology

The aim of this research was to study the effects of calcium hydroxide (0–0.2%) and screw speed (100–180 rpm) on the expansion index (EI), bulk density (BD), penetration force (PF) and specific mechanical energy (SME) values of blue maize meal extrudates. Blue maize meal was extruded using a commercial extruder (Brabender 20DN/8‐235‐00) with a compression screw ratio of 3:1. A second‐order, central composite experimental design was used. It was found that the EI and SME values decreased and the BD and PF values increased when the calcium hydroxide concentration was increased. The screw speed had a significant effect only on the SME and PF values. Quadratic model fitness was shown for all responses, with values of R² > 0.74, p of F (model) <0.01 and variability coefficient <13.3% (except for PF, 29.18%), and for almost all cases there was no lack of fit (p > 0.055). Calcium hydroxide concentration showed good correlation (p < 0.01) with EI (r = ?0.81), PF (r = 0.60), SME (r = ?0.76) and BD (r = 0.83). However, screw speed was marginally or not correlated (r < 0.36, p > 0.14) with the responses. The results suggest that it is possible to produce appropriate extruded products from blue maize fortified with calcium in an optimised calcium hydroxide concentration and screw speed range of 0.02–0.078% and 117–180 rpm respectively. © 2001 Society of Chemical Industry     

Effects of short-term feeding by adults of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) on shelled maize

Laboratory tests were performed to determine the damage caused by adults of Prostephanus truncatus (Horn) feeding on shelled maize. Adults when fed at densities of 25, 50, or 100 on 200 maize kernels for 10–40 days did not preferentially feed on the endosperm or the germ and damaged both. Fifty or 100 adults of P. truncatus feeding on 100 g of maize for 10–40 days caused substantial damage resulting in decreased weight and kernel germination. Kernel damage, grain weight loss, and germination after 40 days of adult feeding was about 5–8, 6–8, and 68–72%, respectively. Adult survival during the 40-day period decreased linearly with time at the rate of 1.5 and 1.3% of adults/day at adult densities of 50 and 100, respectively.Fifty adults of P. truncatus when fed on 100 g of maize for 20 days at 75% r.h. caused significantly greater kernel damage and grain weight loss at 30°C than at 25 or 35°C. However, adult survival at the three temperatures was similar. Though P. truncatus develops less effectively on shelled maize than maize on the cob, our results suggest that a short period of adult feeding could result in substantial grain damage.     

Investigations on Fusarium spp. and their mycotoxins causing Fusarium ear rot of maize in Kosovo

After wheat, maize (Zea mays L.) is the second most important cereal crop in Kosovo and a major component of animal feed. The purpose of this study was to analyse the incidence and identity of the Fusarium species isolated from naturally infected maize kernels in Kosovo in 2009 and 2010, as well as the mycotoxin contamination. The disease incidence of Fusarium ear rot (from 0.7% to 40% diseased ears) on maize in Kosovo is high. The most frequently Fusarium spp. identified on maize kernels were Fusarium subglutinans, F. verticillioides/F. proliferatum and F. graminearum. Maize kernel samples were analysed by LC-MS/MS and found to be contaminated with deoxynivalenol (DON), DON-3-glucoside, 3-acetyl-DON, 15-acetyl-DON, zearalenone, zearalenone-14-sulphate, moniliformin, fumonisin B₁ and fumonisin B₂. This is the first report on the incidence and identification of Fusarium species isolated from naturally infected maize as well as the mycotoxin contamination in Kosovo.