Chemical composition and antioxidant and antimicrobial activity of essential oil of Artemisia annua L. from Bosnia

Hydrodistilled volatile oil obtained from the aerial parts of Artemisia annua L., cultivated near Sarajevo, Bosnia, was analyzed by GC-MS. More than one hundred compounds were identi?ed, representing 95.5% of the total oil. The major constituents of essential oil were oxygenated monoterpenes, artemisia ketone (30.7%) and camphor (15.8%). Isolated essential oil was tested for radical-scavenging ability using the stable DPPH radical, the ABTS radical, for reducing power ability with a test based on the reduction of ferric cations, for reducing ability of hydroxy radical in ORAC assay, and for metal chelating ability using the ferrozine assay. In all tests oil did not show a prominent antioxidant activity, but still comparable with thymol, an already known antioxidant. The screening of antimicrobial activity of oil was individually evaluated against representatives of Gram-positive, Gram-negative bacteria and fungi, using the agar diffusion method. All tested microorganisms were inhibited by essential oil. To the best of our knowledge, this is the first report of antimicrobial activity of essential oil of A. annua against Haemophilus influenzae, Enterococcus faecalis, Streptococcus pneumoniae, Micrococcus luteus and Candida krusei microbial strains. The antioxidant, antibacterial and antifungal activity of essential oil of A. annua from Bosnia is presented here for the first time and extends our knowledge in the range of valuable biological activities and possible roles in therapy associated with this medicinal herb.     

Weed control with pre-emergence herbicides in vegetable soybean (Glycine max L. Merrill)

Field and laboratory experiments were conducted in the early and late rainy seasons in Thailand to evaluate the effect of pre-emergence application of herbicides and determine the herbicide residues on vegetable soybean (Glycine max L. Merrill cv. No. 75) production. No visible crop injury was observed after application of alachlor 469 g a.i./ha, clomazone 1080 g a.i./ha, metribuzin 525 g a.i./ha, pendimethalin 1031.25 g a.i./ha, tank-mixed clomazone 960 g a.i./ha + pendimethalin 928 g a.i./ha, or tank-mixed metribuzin 350 g a.i./ha + pendimethalin 928 g a.i./ha. However, acetochlor 1875 g a.i./ha, isoxaflutole 75 g a.i./ha, and oxadiazon 1000 g a.i./ha caused visible crop injury. Plant bioassay of herbicide residues in the soil after harvest showed no phytotoxic effect on baby corn (Zea mays Linn. cv. Suwan 3), cucumber (Cucumis sativus L. cv. Pijit 1), pak choi (Brassica chinensis Jusl. cv. Chinensis), and soybean (G. max L. Merrill cv. CM 60). Gas Chromatography-Mass Spectrometry (GC–MS) analysis showed no significant herbicide residues on crop yield (or MRLs < 0.01 ppm) for all herbicides used in this study. The application of metribuzin at 525 g a.i./ha was sufficient to provide satisfactory full-season control of several weed species and gave the highest crop yield. In addition, pendimethalin at 1031.25 g a.i./ha, and tank-mixed metribuzin at 350 g a.i./ha + pendimethalin at 928 g a.i./ha can provide a similar level of weed control as an alternative to reduce herbicide dosage thereby increasing food and environmental safety in vegetable soybean production.     

Genetic variability of transpiration response to vapor pressure deficit among soybean (Glycine max [L.] Merr.) genotypes selected from a recombinant inbred line population

Limited observations of soybean plant response of transpiration rate (TR) to vapor pressure deficit (VPD) have indicated the existence of genotypes with nearly constant TR at high VPD. The range of expression of this trait in a given population within a species has not been explored. To initiate study of this possibility, 22 genotypes from a RIL population derived from a cross of PI 416937 and Benning were characterized for their VPD response. Genotype PI 416937 has been shown to reach a maximum TR at a VPD as low as 2 kPa. Surprisingly, Benning was not found to have a continually increasing TR with VPD, but rather it had a two-segment TR response very similar to PI 416937. Unexpectedly, only one of the studied RILs had a TR response similar to the parents. Thirteen RILs had a continually increasing TR with increasing VPD. Eight RILs reached a maximum TR occurring at VPD of about 1.3 kPa, significantly lower value than that of the parents. While the inheritance of the maximum TR trait is clearly complex, these results offer encouragement that the VPD at which plants limit TR might vary so that the trait can be tailored to maximize potential yield increase in different water-deficit environments.     

Effect of cover crops and mulches on weed control and nitrogen fertilization in tomato (Lycopersicon esculentum Mill.)

Cover crops and mulches are a suitable choice for sustainable agriculture because they improve weed control and crop performance. The aim of this research was to investigate weed control and nitrogen supply by using different winter cover crop species which were converted into mulches in spring. We carried out a 2-year field experiment where a tomato crop was transplanted into four different types of mulches coming from winter cover crops [hairy vetch (Vicia villosa Roth.), subclover (Trifolium subterraneum L.), oat (Avena sativa L.), and a mixture of hairy vetch/oat)] and in conventional treatment (tilled soil without mulch). The mixture of hairy vetch/oat cover crop produced the highest aboveground biomass (7.9 t ha⁻¹ of DM), while the hairy vetch accumulated the highest N in the aboveground biomass (258 kg N ha⁻¹). The oat cover crop was the most effective cover crop for suppressing weeds (on average −93% of weed aboveground biomass compared to other cover crops). After mowing the cover crop aboveground biomass was placed in strips as dead mulch into which the tomato was transplanted in paired rows. Weed density and total weed aboveground biomass were assessed at 15 and 30 days after tomato transplanting to evaluate the effect of mulches on weed control. All mulches suppressed weeds in density and aboveground biomass compared to the conventional system (on average −80% and −35%, respectively). The oat was the best mulch for weed control but also had a negative effect on the marketable tomato yield (−15% compared to the conventional treatment). Amaranthus retroflexus L. and Chenopodium album L. were typical weeds associated with the conventional treatment while a more heterogeneous weed composition was found in mulched tomato. Legume mulches, in particular hairy vetch, gave the best marketable tomato yield 28% higher than the conventional system both with and without nitrogen fertilization. This research shows that winter cover crops converted into dead mulch in spring could be used successfully in integrated weed management programs to reduce weed infestation in tomato crops.     

Cultivation of milk thistle (Silybum marianum L. Gaertn.), a medicinal weed

Milk thistle (Silybum marianum L. Gaertn.) is the most researched plant for the treatment of liver disease. Its therapeutic properties are due to the presence of silymarin, a mixture of three flavonolignans (silybin, silydianin and silycristin). The seeds contain the highest amount of silymarin, but the whole plant is used medicinally. Milk thistle is grown successfully on a range of soil types, from sandy soils to much heavier clay soils. Milk thistle is directly seeded in soils. Sowing occurs in autumn and spring, and row spacing is usually 40-75 cm, with 20-30 cm between plants in the row. Nutrient requirements of this crop are low to moderate since it is adapted to poor quality soils and many different growing conditions. A limiting factor in milk thistle production is weed interference. Pendimethalin and metribuzin herbicides are safe for weed control in milk thistle, both alone and in combination. Milk thistle is considered drought resistant and normal rainfall will often suffice. In a Mediterranean environment, under severe drought conditions, the crops should be irrigated during seed growth and filling. Moreover, a few varieties of milk thistle have been developed. The silymarin content most often ranges from 1.0% to 3.0% of achene dry matter but can exceed 8%. Efforts should be made to develop varieties with high silymarin content.     

Influence of planting date on growth, artemisinin yield, seed and oil yield of Artemisia annua L. under temperate climatic conditions

Artemisia annua L. is an annual aromatic antibacterial herb, with effective antimalarial properties due to the presence of artemisinin. The intention of the present study was to establish plant survival, growth attributes, yield attributes and artemisinin yield of A. annua cv CIM - Arogya with different transplanting months in two cropping seasons (March 2005-February 2006 and March 2006-February 2007) under temperate climatic conditions of Himalaya, India. Artemisinin yield in the dried leaves was found maximum amongst the plants that were transplanted in March (24.39 kg ha⁻¹) and minimum in those transplanted in November (3.39 kg ha⁻¹).     

Chemical composition of solid waste and effect of enzymatic oil extraction on the microstructure of soybean (Glycine max)

The solid wastes were obtained from enzymatic extraction of soybean oil using four enzyme systems (Alcalase/Celluclast or Alcalase/Viscozyme L) each with two pH conditions: controlled or not controlled. This last option gave a better oil extraction, regardless of the enzymes used. The ash levels were higher for the enzyme systems subjected to controlled pH, depending on the buffer solutions used. The others constituents presented similar values between each other. The monosaccharides with highest concentrations were galactose, followed by glucose and arabinose. The physical analysis showed that the waste residues had good oil binding capacity. The SEM and epifluorescence microscopy revealed the microstructure of the beans and raw materials, as well as the changes caused by the extraction procedures.     

Insect-mediated cross-pollination in soybean [Glycine max (L.) Merrill] : I. Agronomic performance

In soybean, manual cross-pollination to produce large quantities of F₁ hybrid seed for yield trials is difficult and time-consuming. Conversely, insect-mediated cross-pollination has been shown to produce large quantities of hybrid seed in soybean and could facilitate the identification of heterotic patterns. The objective of our study was: (1) evaluate F₁ hybrid soybean plants from single crosses for yield and agronomic traits over several environments and (2) compare hybrid performance of the single crosses to lines developed from three-way crosses and backcrosses. In 2003, F₁ seed of single-crosses and their parent lines were evaluated in replicated experiments at three locations. Also in 2003, three-way crosses, and BC₁F₁ seed were produced. In 2004, three-way crosses, BC₁F₁ crosses, and their parent lines were evaluated at one location. High-parent heterosis (HPH) in single-crosses for grain yield ranged from −41.11% to +11.19%; for protein content from −4.34% to +3.53%, and for oil content from −13.22% to −0.84%. In three-way crosses, HPH for yield ranged from −25.21% to −4.50%, for protein from −2.72% to +1.92%, and for oil from −5.87% to −1.20%. For BC₁F₁ crosses, HPH for yield ranged from −15.65% to +41.97%, for protein from −2.57% to +1.69%, and for oil from −2.47% to +2.22%. Although positive heterosis levels were observed across all populations tested to determine the economic feasibility it is imperative that more tests of more cross-combinations be evaluated in replicated environments. Extensive research in different environments must be conducted to determine what parental combinations will produce the highest heterosis levels, and to develop criteria for selecting the parents with the best combining ability. This will be important to maximize agronomic performance that can economically justify the use of hybrids in soybean production.     

Screening of three sweet potato (Ipomoea batatas L.) cultivars for resistance to different virulence groups of root-knot nematodes (Meloidogyne spp.) under controlled conditions

The susceptibility of three sweet potato cultivars (Ipomoea batatas L.) C4, TIS 3290 and TIS 9162 was evaluated against 156 isolates of Meloidogyne spp. with the aim to include resistant/tolerant sweet potato cultivars in a crop rotation scheme for the management of root-knot nematodes. The nematode isolates corresponded to races 1, 2 and 3 of Meloidogyne arenaria (n = 7), races 1, 2, 3 and 4 of M. incognita (n = 131) and Meloidogyne javanica (n = 18). Also, the isolates of M. incognita were differentiated in virulence groups: Pepper (n = 35), Pepper-Mi (n = 25), Tomato (n = 41) and Tomato-Mi (n = 30), depending on their ability to parasitize resistant pepper and tomato cultivars. The tested isolates of M. javanica parasitized C4 and TIS 3290, but not TIS 9162, whereas M. arenaria parasitized C4 and TIS 9162, but not TIS 3290, and M. incognita was able to parasitize the three sweet potato cultivars tested. C4 was the most susceptible cultivar to all nematode species tested, especially M. incognita, TIS 3290 was the most resistant and TIS 9162 was in between (7.2, 62.9 and 26.9% of resistant plants, respectively). Susceptibility of the sweet potato cultivars showed slight variations depending on the race or virulence group of M. incognita. The results suggest that sweet potato cultivars TIS 3290 and TIS 9162 may be used as rotation crops in fields where root-knot nematodes are present, their selection depending on the Meloidogyne isolates present. The use of resistant sweet potato cultivars would be preferably combined with other management practices to avoid virulence selection in nematode isolates.     

Variability in essential oil content and composition of Origanum hirtum L., Origanum onites L., Coridothymus capitatus (L.) and Satureja thymbra L. populations from the Greek island Ikaria

Plants belonging to four “oregano” plant species (Origanum hirtum L., Origanum onites L., Coridothymus capitatus L., and Satureja thymbra L.) were collected during flowering from 33 sites located in the eastern part of the Greek island of Ikaria in the Eastern Aegean during April, May and July 2008. C. capitatus and O. hirtum were mostly observed in higher altitudes, whereas O. onites and S. thymbra in lower ones. The spatial distribution of all species was depicted on a GIS map. All four species exhibited essential oil concentrations higher than those reported in earlier literature, namely O. onites 3-4.3%, S. thymbra 4-6.5%, C. capitatus 3.7-5.6% and O. hirtum 5.5-10.0% (v/w). Carvacrol was the main constituent of the essential oils of all species, followed by γ-terpinene, p-cymene and caryophyllene, while thymol was not detected. All constituents varied remarkably among the four species, with carvacrol exhibiting the lowest variation. Carvacrol content varied between 72.3 and 89.2% in O. onites; 46.5 and 58.0% in S. thymbra; 82.9 and 90.9% in C. capitatus; and 84.4 and 93.8% in O. hirtum. By applying hierarchical cluster analysis on the basis of the essential oil constituents two main groups, divided into four subgroups of the taxa were evident. The first group consisted of O. onites and S. thymbra, while the second one of C. capitatus and O. hirtum. The results are discussed in terms of topography and climatic variation.     

Weed control and sesame (Sesamum indicum L.) response to preplant incorporated herbicides and method of incorporation

Field studies were conducted at two sesame-growing regions of Texas in 2004 and 2005 to determine weed control and sesame response to four dinitroaniline herbicides and their method of incorporation. Ethalfluralin, pendimethalin (formulated as Prowl EC), and trifluralin were applied at the X, 1X, and 2X of the suggested label dose for Gossypium hirsutum L. Pendimethalin (formulated as Prowl H₂O) was applied at the X, 1X, and 1X rate. Two methods of incorporation included rolling cultivator mixing wheels and spring tooth harrow. With rolling cultivator mixing wheels, all herbicides controlled Amaranthus tuberculatus (Moq.) J.D. Sauer at least 74% regardless of dose. The X dose of ethalfluralin and pendimethalin (formulated as Prowl EC), or the X and 1X dose of pendimethalin (formulated as Prowl H₂O) controlled Brachiaria platyphylla (Griseb.) Nash no better than 73% while all other doses of the herbicides controlled B. platyphylla at least 80%. The use of mixing wheels to incorporate the herbicides resulted in better sesame stands and less stunting than the use of the spring tooth harrow; however, sesame stands were reduced as herbicide rate increased when using mixing wheels. Ethalfluralin at the 1X dose, pendimethalin (formulated as Prowl H₂O) at the X dose, and trifluralin at the X dose produced the highest sesame yield while ethalfluralin at the 2X dose produced the lowest yield.     

Evaluation of non-fumigant alternatives to methyl bromide for weed control and crop yield in California strawberries (Fragaria ananassa L.)

In California, USA, agricultural fumigant use regulations hinder the complete transition from methyl bromide (MB) to alternative fumigants. Alternative fumigants such as 1,3-dichloropropene (1,3-D) and chloropicrin (Pic) are being used on approximately half of California conventional strawberry production fields. Geographic use limits and buffer zones set by the California Department of Pesticide Regulation for 1,3-D + Pic restrict a more complete replacement of MB. Due to the regulatory constraints and public resistance to fumigant use, it is necessary to develop fumigant-free strawberry production systems. Trials were conducted during the 2007/2008 and 2008/2009 strawberry growing seasons at Salinas and Watsonville, California. Non-fumigant treatments including steam, mustard seed meal (MSM), Muscodor albus, and furfural, fertilizers including Mustard Products & Technologies fertilizer and stabilised urea, and fungicide treatments including AG3(NP), fludioxonil + mefenoxam (mfx), and mfx + thiophanate-methyl were evaluated for weed control and strawberry fruit yield, and compared to MB + Pic (MBPic) standard soil fumigation and an untreated control. Steam treatment applied pre-plant to achieve soil temperature of ≥70 °C for 20 min up to 25 cm soil depth consistently provided weed control similar to the MBPic standard soil fumigation. Use of oxyfluorfen herbicide prior to fungicide applications in 2008/2009 also controlled weeds similar to the MBPic standard soil fumigation. Strawberry yields in steam-treated plots with the exception of steam alone in 2007/2008 at Salinas, were comparable to MBPic. At Watsonville in 2008/2009, treatment effect on strawberry yields was insignificant. Yields in furfural and MSM treatments were comparable to MBPic only in some years or sites. With the exception of steam, none of the treatments can be considered viable replacement to MB.     

大豆种子抗老化鉴定的方法研究

选用遗传差异相对较大的皖豆24、皖豆25(杂交品种)及合豆3号的种子,在温度为40℃、湿度为85％的条件下老化处理4、8和12 d,研究加速老化过程中不同基因型大豆种子成苗率、发芽率、电导率及单株幼苗干重的变化规律.结果表明:随着加速老化时间的延长种子活力下降;加速老化处理8d,3个品种的各项鉴定指标均发生改变:品种的成苗率、发芽率及单株幼苗干重显著降低,电导率明显升高,且品种间有显著差异;发芽率和成苗率的变化在品种间具有一致性,电导率、单株幼苗干重的变化和成苗率品种间一致性较差;成苗率和发芽率的相关性最高(r=0.972**).利用国家大豆微核心种质中的91份资源对老化鉴定方法进行验证,结果在温度为40℃,湿度为85％条件下老化8d的种子发芽率及老化指数与在自然条件下老化15个月的发芽率及老化指数极显著相关(r=0.943**,0.716**).综合分析认为,温度为40℃,湿度为85％条件下老化处理8d,以种子发芽率为活力鉴定指标可作为大豆种子抗老化性的鉴定方法.     

Comparative chemistry and insect antifeedant action of traditional (Clevenger and Soxhlet) and supercritical extracts (CO2) of two cultivated wormwood (Artemisia absinthium L.) populations

A comparison between traditional extraction techniques (hydrodistillation and organic solvent extraction) and supercritical fluid extraction was made for two different populations and crops of Artemisia absinthium L., cultivated in the field and aeroponically. The composition of the extracts, volatile and non volatile oils, was analyzed by GC-MS and HPLC-DAD, respectively. The antifeedant and phytotoxic activity of the extracts was tested on insect pests (Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi) and plants (Lactuca sativa and Lolium perenne). The supercritical extracts exhibited stronger antifeedant effects than the traditional ones (up to 8 times more active) with moderate selective phytotoxic effects on L. perenne root growth (<50% inhibition).     

Improvement of essential oil yield of oil-bearing (Rosa damascena Mill.) due to surfactant and maceration

The essential oil content of the oil-bearing rose (Rosa damascene Mill.) is relatively low, around 0.3-0.4 mL kg⁻¹ in fresh flowers. There is a need to increase essential oil yield of oil-bearing rose. The objective was to examine the effect of Tween 20 (polyoxyethylene sorbitan monolaurate) applied with, or without, maceration of flowers on oil content and composition of oil-bearing rose harvested at beginning of flowering, full bloom, and end of flowering. Addition of Tween 20 at 1000 mL L⁻¹ and 2500 mL L⁻¹ increased essential oil yield by 26% (to 0.44 mL kg⁻¹) and 54% (to 0.54 mL kg⁻¹) respectively relative to the untreated control that gave 0.35 mL kg⁻¹ yield. Maceration, in combination with the addition of Tween 20 at 1000 mL L⁻¹ and Tween 20 at 2500 mL L⁻¹, increased oil yield by 69% (to 0.59 mL kg⁻¹) and 94% (to 0.68 mL kg⁻¹) respectively. Among the three phenological phases of harvest, harvesting at the beginning of flowering gave the highest yield followed by the full bloom and then by the end of flowering phases. Since the interaction effect was not significant, the differences obtained among the treatments were regardless of the phase, and vice versa. Treatments did not significantly alter composition of the essential oil. Postharvest pre-extraction application of Tween 20 in combination with maceration could be used in the rose industry for increasing the essential oil yield.     

Response of spring planted barley (Hordeum vulgare L.), oats (Avena sativa L.) and wheat (Triticum aestivum L.) to mesotrione

There is little information on the response of spring planted barley (Hordeum vulgare L.), oats (Avena sativa L.) and wheat (Triticum aestivum L.) to mesotrione under Ontario environmental conditions. Four field studies were conducted in Ontario, Canada over a two-year period (2008 and 2009) to evaluate the sensitivity of spring planted cereals (barley, oats, and wheat) to pre-emergence (PRE) and post-emergence (POST) applications of mesotrione at 50, 100, and 150 g ai ha⁻¹. Mesotrione applied PRE caused minimal visible injury at 3, 7, 14 and 28 days after emergence (DAE) and had no adverse effect on plant height or yield of barley, oats and wheat. Mesotrione applied POST caused as much 11% injury and reduced plant height as much as 6% in spring planted cereals. Injury was higher in wheat compared to barley or oats. Mesotrione applied POST had no adverse effect on the yield of barley or oats but decreased the yield of wheat as much as 14%. Based on this study, mesotrione applied PRE at 50, 100 or 150 g ai ha⁻¹ can be safely used in spring planted barley, oats, and wheat. Mesotrione applied POST at the proposed dose of 50, 100 or 150 g ai ha⁻¹ can also be safely used in spring planted barley and oats. However, mesotrione applied POST results in unacceptable injury in spring planted wheat.     

Factors that modify early and late reproductive phases in oilseed rape (Brassica napus L.): Its impact on seed yield and oil content

Oilseed rape yield potential could be improved lengthening the duration of the late reproductive phase by increasing the number of grains per unit area. Photoperiod sensitivity could be used as a tool to manipulate the reproductive phase and thereby the number of grains. The aim of this study was to assess (i) the effects of different combinations of photoperiod on the duration of different phases and (ii) analyze how the changes in that duration affect yield (and its components) as well as oil seed content in oilseed rape. Field experiments were conducted in a factorial combination of three cultivars and three photoperiod regimes: natural photoperiod (NP) which represents the control and extended photoperiod of 6 h over NP (NP + 6) during emergence (E)-flower buds visible (FBV) and FBV-maturity (M) arranged in a randomized complete block design with three replicates, during two years representing three environments. Results showed that oilseed rape evidenced photoperiod responses during vegetative and early reproductive phases. Due to the lack of correlation between the duration of the vegetative and reproductive phases, it is possible to speculate the vegetative period may be altered independently of the modification of the rest of the phases. The positive relationship between grain number per m² and the duration of the late reproductive phase suggests that yield could be increased by lengthening the duration of that phase. Thus, regardless of the effect on the previous phase, the photoperiod sensitivity found in the early reproductive phase opens the possibility to manipulate the relative durations of vegetative and reproductive phases. Therefore, the length of the reproductive phase will be increased at the expense of a reduction in the duration of the vegetative phase, but without changing the whole duration of the crop cycle. This strategy could increase yield in oilseed rape in the future. Variations in yield were mostly explained by changes in the grain number per unit area without significant correlation with grain weight. However, a negative relationship between grain weight and grain number was found, showing a slight counterbalance in yield, by decreasing the grain weight. Since oil concentration appeared to be a more conservative attribute, increases in crop yield through a higher grain number per unit area would be a suitable strategy for improving oil yield as no reductions in oil concentration can be expected.     

Characteristics, composition and thermal stability of Acacia senegal (L.) Willd. seed oil

The chemical composition, main physicochemical properties and thermal stability of oil extracted from Acacia senegal seeds were evaluated. The oil, moisture and the ash contents of the seeds were 9.80%, 6.92% and 3.82%, respectively. Physicochemical properties of the oil were iodine value, 106.56 g/100 g of oil; saponification value, 190.23 mg KOH/g of oil; refractive index (25 °C), 1.471; unsaponifiable matter, 0.93%; acidity, 6.41% and peroxide value, 5.43 meq. O₂/kg of oil. The main fatty acids in the oil were oleic acid (43.62%) followed by linoleic acid (30.66%) and palmitic acid (11.04%). The triacylglycerols (TAGs) with equivalent carbon number ECN 44 (34.90%) were dominant, followed by TAGs ECN 46 (28.19%), TAGs ECN 42 (16.48%) and TAGs ECN 48 (11.23%). The thermal stability analysed in a normal oxidizing atmosphere showed that the oil decomposition began at 268.6 °C and ended at 618.5 °C, with two stages of decomposition at 401.5 °C and 576.3 °C. According to these results, A. senegal seed oil has physicochemical properties, fatty acids composition and thermal characteristics that may become interesting for specific applications in several segments of food and non-food industries.     

Analysis of host plant resistance to multiple Fusarium species associated with stalk rot disease in sorghum [Sorghum bicolor (L.) Moench]

Fusarium spp. is among the largest and most important pathogen groups that attack major grain crops including sorghum. The objectives of this study were to compare the virulence of Fusarium spp. associated with sorghum and examine the mode of resistance of genotypes to the disease. Eight Fusarium species – F. verticillioides, F. thapsinum, F. andiyazi, F. proliferatum, F. nyagamai, F. pseudoanthophilum, F. brevicatenulatum, and F. pseudonygamai – were studied using three sorghum genotypes under greenhouse condition. Three of these pathogens (F. verticillioides, F. thapsinum, and F. andiyazi) were selected for genetic analysis of resistance under field conditions. Sorghum genotypes with contrasting stalk rot reactions were selected for use in both the greenhouse and field experiments. Two weeks after flowering, plants were inoculated with liquid inoculum culture (5 × 10⁴ conidia ml⁻¹) of the different pathogens. Plants were harvested 4 weeks after inoculation and rated for disease severity on the basis of lesion length and number of nodes crossed by the lesion. Among the pathogens, F. thapsinum resulted in consistently higher disease scores in all genotypes under all environments. Likewise, genotype SC599 showed the greatest and most stable resistance as inbred as well as in hybrid combinations as shown by consistently high GCA for resistance to all pathogen species. We recommend that future screening exercises for Fusarium stalk rot resistance utilize F. thapsinum as the causal organism and include the resistant genotype SC599 as a control.     

Wheat (Triticum aestivum L.) puroindoline functionality in bread making and its impact on bread quality

Wheat puroindolines (PINs) spontaneously adsorb at air/water interfaces and show excellent foaming properties. They can positively impact bread quality, in which the formation of stable foam is important for product quality. The impact of endogenous PINs on bread quality was studied by preparing gluten–starch blends from isolated gluten and starch fractions with different PIN levels, which allowed largely retaining the interaction between PINs and flour components. Our results indicate that blends with high PIN levels yielded more homogeneous crumb structures with fine gas cells than bread made with blends containing medium or low PIN levels. However, the mechanism by which PINs exert this crumb improving effect is not clear. Varying PIN levels impacted neither dough extensibility nor did it result in different PIN levels in dough liquor. Lipid removal yielded bread with a less homogeneous crumb gas cell distribution, indicating that lipids also are required to obtain good crumb structure.