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Giant Foxtail Setaria faberi R.A.W. Herrm. is originally native to E Asia and was introduced to some parts of the European Continent. It has been recorded for the first time in Bosnia and Herzegovina. The paper presents a short morphological description and photographs of the new alien species for Bosnia and Herzegovina, as well as distribution of the taxon. [ABSTRACT FROM AUTHOR]

Weed seeds in and on the soil are the primary cause of weed infestations in arable fields. Previous studies have documented reductions in weed seedbanks due to cropping system diversification through extended rotation sequences, but the impacts of different rotation systems on additions to and losses from weed seedbanks remain poorly understood. We conducted an experiment in Iowa, USA, to determine the fates of Setaria faberi and Abutilon theophrasti seeds in 2-, 3- and 4-year crop rotation systems when seed additions to the soil seedbank were restricted to a single pulse at the initiation of the study. Over the course of the experiment, seedlings were removed as they emerged and prevented from producing new seeds. After 41 months, seed population densities dropped >85% for S. faberi and >65% for A. theophrasti, but differences between rotation systems in the magnitude of seedbank reductions were not detected. Most of the reductions in seedbank densities took place from autumn through early spring in the first 5 months following seed deposition, before seedling emergence occurred, suggesting that seed predation and/or seed decay was important. For S. faberi, total cumulative seedling emergence and total seed mortality did not differ between rotation systems. In contrast, for A. theophrasti, seedling emergence was 71% lower and seed mortality was 83% greater in the 3- and 4-year rotation systems than in the 2-year system. Results of this study indicate that for certain weed species, such as A. theophrasti, crop rotation systems can strongly affect life-history processes associated with soil seedbanks. [ABSTRACT FROM AUTHOR]

Setaria faberi and Digitaria ciliaris are summer annual grass weeds that constitute an orchard weed community in Japan. Species dominance in the weed community shifts from S. faberi to D. ciliaris with an emergence delay. The change in species dominance is assumed to be a clue to how weeds dominate or coexist in shaping the community. Population dynamics and seasonal variations in emergence and competitive ability were studied from this viewpoint. Field monitoring and pot experiments exhibited that the emergence period of the two species overlapped extensively from April to June. The emergence of S. faberi began 2 weeks earlier than that of D. ciliaris in April and declined in June as a result of the induction of secondary dormancy. The plant density of D. ciliaris was high during the whole period. The great mortality of the species was replenished with its great natality. The replacement series experiments revealed that S. faberi that had been planted in April was a better competitor than D. ciliaris, but it lost its competitive superiority in the June plantings, when D. ciliaris became a superior competitor to S. faberi. The level of seed output was greater for D. ciliaris, even when it was an inferior competitor. Therefore, the shift in species dominance appeared to be attributed to a change in competitive superiority between the two species. The early emergence of S. faberi and the high plant density of D. ciliaris might accelerate competitive exclusion. The two species coexist when they are equivalent in competitiveness. [ABSTRACT FROM AUTHOR]

Diversified cropping systems can have high soil microbial biomass and thus strong potential to reduce the weed seedbank through seed decay. This study, conducted in Iowa, USA, evaluated the hypothesis that weed seed decay is higher in a diversified 4-year maize-soyabean-oat/lucerne-lucerne cropping system than in a conventional 2-year maize-soyabean rotation. Mesh bags filled with either Setaria faberi or Abutilon theophrasti seeds and soil were buried at two depths in the maize phase of the two cropping systems and sampled over a 3-year period. Setaria faberi seed decay was consistently greater at 2 cm than at 20 cm burial depth and was higher in the more diverse rotation than in the conventional rotation in 1 year. Abutilon theophrasti seeds decayed very little in comparison with seeds of S. faberi. Separate laboratory and field experiments confirmed differences in germination and seed decay among the seed lots evaluated each year. Fusarium, Pythium, Alternaria, Cladosporium and Trichoderma were the most abundant genera colonising seeds of both species. A glasshouse experiment determined a relationship between Pythium ultimum and S. faberi seed decay. Possible differences in seed susceptibility to decay indicate the need to evaluate weed seedbank dynamics in different cropping systems when evaluating overall population dynamics and formulating weed management strategies. [ABSTRACT FROM AUTHOR]

Methylated seed oil (MSO) is a recommended adjuvant for the newly registered herbicide topramezone in China and also in other countries of the world, but the mechanism of MSO enhancing topramezone efficacy is still not clear. Greenhouse and laboratory experiments were conducted to determine the effects of MSO on efficacy, solution property, droplet spread and evaporation, active ingredient deposition, foliar absorption and translocation of topramezone applied to giant foxtail (Setaria faberi Herrm.) and velvetleaf (Abutilon theophrasti Medic.). Experimental results showed that 0.3% MSO enhanced the efficacy of topramezone by 1.5-fold on giant foxtail and by 1.0-fold on velvetleaf. When this herbicide was mixed with MSO, its solution surface tension and leaf contact angle decreased significantly, its spread areas on weed leaf surfaces increased significantly, its wetting time was shortened on giant foxtail but not changed on velvetleaf, and less of its active ingredient crystal was observed on the treated weed leaf surfaces. MSO increased the absorption of topramezone by 68.9% for giant foxtail and by 45.9% for velvetleaf 24 hours after treatment. It also apparently promoted the translocation of this herbicide in these two weeds. [ABSTRACT FROM AUTHOR]

M ohler CL, D ykeman C, N elson EB & D itommaso A (2012). Reduction in weed seedling emergence by pathogens following the incorporation of green crop residue. Weed Research. 52, 467-477. Summary Because tillage promotes the germination of many weed species and freshly killed plant material favours the growth of microbial pathogens, we hypothesised that the incorporation of green crop residue should temporarily reduce weed seedling emergence relative to unamended soil. Soil with field-incorporated green crop residue was compared with non-amended soil in glasshouse experiments by sowing several weed species at different times after incorporation. Species included Abutilon theophrasti, Chenopodium album, Amaranthus powellii, Setaria faberi, Echinochloa crus-galli and, in one year, lettuce and red clover. Soils with green crop residue reduced seedling emergence for 0-4 days after incorporation by an average of 30%. Comparison of emergence in non-sterilised soil with that in sterilised soil, with and without fresh crop residue, indicated that a biological agent caused the depressed emergence. In the third year of the study, the fungi Fusarium oxysporum and F. chlamydosporum were isolated from seeds exposed to soil amended with green crop residues, and their pathogenicity to seeds and seedlings was confirmed in bioassays. This study indicated that incorporation of fresh crop residue reduces the first flush of weed seedlings following tillage and that this depression in emergence is probably caused by pathogen attack on seeds and seedlings before emergence. [ABSTRACT FROM AUTHOR]

Foxtail millet is well-suited to climatic conditions in semi-arid tropic regions where it is cultivated using both agro-ecologic and conventional cultivation practices. This study evaluated the nutritional value, digestibility, and physiological effects of agroecologic and conventionally cultivated foxtail millet in comparison with corn. Chemical and TME analysis of foxtail millet cultivated conventionally and agro-ecologically indicated similar nutritional value. In total, 432 eight-day-old Ross 308 broiler chicks, using a 2 x 3 factorial arrangement, were randomly assigned to 4 replicate pens for each of 6 isonitrogenous and isoenergetic diets. Experimental diets were formulated by replacing corn with conventional or agro-ecologic millet at 3 levels (33, 66, or 100% of corn replacement). Body weight at 21 and 42 d of age was higher (P < 0.05) at 100% millet inclusion versus the lower inclusion levels. At 42 d of age, feed intake and feed conversion ratios were also improved (P < 0.05) at the 100% millet inclusion level. Similarly, the apparent ileal digestibility of CP increased (P < 0.05) for 100% millet diets. There were no differences in ileal digestibility of nutrients between millet growth conditions. Millet inclusion level significantly affected small intestinal morphology such that crypt depth was lowest (P < 0.05) in the 100% inclusion group for duodenum, jejunum, and ileum at 28 d of age, and for duodenum and ileum at 42 d of age. The villus crypt ratio was also highest (P < 0.05) in the 100% millet inclusion group for jejiinum and ileum at 28 d of age, and duodenum, jejunum, and ileum at 42 d of age. Millet growth condition did not markedly affect small intestinal morphology. Serum antibody responses to Gumboro and Newcastle diseases were not affected by millet inclusion level or growth condition. In conclusion, foxtail millet could be considered as an alternate cereal for inclusion in the diet of broiler chickens. Broiler chicken performance and physiological responses to foxtail millet were similar whether grown conventionally or using agro-ecologic practices. [ABSTRACT FROM AUTHOR]

Davis AS & Raghu S (2010). Weighing abiotic and biotic influences on weed seed predation. Weed Research 50,402–412. Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. Current knowledge of weed seed predation focuses on biotic mechanisms, with less undersatanding of the relative impact of abiotic variables. In order to quantify relative contributions of abiotic and biotic variables to weed seed predation rates, a field study was made within a maize crop in central Illinois, USA, in 2005 and 2006. From late July through to mid-October, weekly measurements of Abutilon theophrasti, Ambrosia trifida and Setaria faberi seed removal rates by invertebrate and vertebrate granivores, and seed losses because of abiotic processes were recorded. Weed seed rain was measured concurrently in contiguous plots, as were air temperature, precipitation, wind speed, thermal units and invertebrate activity-density. Statistical models supported the possibility that higher-level trophic interactions were contributing to variation in seed predation rates. Approaching granivory in agroecosystems as a food web may help future attempts to regulate this ecosystem service. [ABSTRACT FROM AUTHOR]

• Premise of the study: Climate change models predict increasing variability in precipitation across the globe, with an increase in the incidence of large precipitation events but decreasing overall event frequency. Research with annual species in arid and semiarid ecosystems has demonstrated that precipitation variability can influence plant community dynamics; however, less is known about the impact of precipitation variability in less water-limited ecosystems, including economically important agricultural systems. • Methods: We conducted three greenhouse experiments to determine how variation in total precipitation and the interval between precipitation events affected emergence and growth of two common annual midwestern weed species, Chenapodium album (Chenopodiaceae) and Setariafaberi (Poaceae). • Key results: Both species responded to precipitation variability; however, the effect depended on life stage and precipitation amount, indicating that responses are highly context-dependent. Emergence of both species increased with longer intervals between precipitation events at low total precipitation, but species' responses varied under typical precipitation amounts. Individual seedling biomass of both species depended on interactions between total water and interval, but species' responses differed; Setaria faberi biomass was reduced with longer intervals, but Chenopodium album had either a positive or no response. • Conclusions: Our results suggest that changes in precipitation variability likely will affect the composition and relative abundance of agriculturally important weeds. These results are important for understanding how changes in the temporal variability of precipitation due to global climate changes could impact plants in non-arid communities. [ABSTRACT FROM AUTHOR]

The timing that dying root tissues of Setaria faberi R.A.W. Herrm. and maize, Zea mays L., no longer support growth and development of neonate and second-instar western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), larvae was evaluated to enhance our understanding of the basic ecology of this pest. Three separate greenhouse experiments were conducted. In the first experiment, glyphosate was used to kill S. faberi. In the second experiment, glyphosate was used to kill maize, and in the final experiment, maize was killed by severing it below the growing point. These experiments evaluated western corn rootworm larvae for survival and growth parameters among living control plants, plants severed or sprayed on the day they were infested, plants severed or sprayed 5 and 10 d before they were infested, and plants planted 5 and 10 dearly and severed or sprayed 5 and 10 d before they were infested (the last two treatments were controls for root size). Larvae were sampled from each of these treatments 5, 10, and 15 d after infestation, and beetle emergence was recorded from the remaining pots. When infested on the day of glyphosate spray, significantly fewer larvae were recovered from S. faberi than from living S. faberi. Overall, when infested 5 or 10 d after being sprayed with glyphosate or being severed below the growing point, no significant larval weight gain was recorded from any treatment. Host plant tissue apparently becomes unsuitable for larval growth within the first 5 d after glyphosate spray and severing below the growing point. The implications of these data toward current work involving alternate grassy hosts sprayed with herbicide, the increasing occurrence of volunteer corn, related studies on rootworm-host interactions, and certain adult emergence techniques are discussed along with possible mechanisms as to why the tissue becomes unsuitable so quickly. [ABSTRACT FROM AUTHOR]

Twenty-eight Pyricularia isolates from two wild foxtails—green foxtail ( Setaria viridis) and giant foxtail ( S. faberii)—in Japan were taxonomically characterized by DNA analyses, mating tests, and pathogenicity assays. Although most of the isolates failed to produce perithecia in mating tests with Magnaporthe oryzae, a diagnostic polymerase chain reaction-restriction fragment length polymorphism phenotype of M. oryzae was detected in the beta-tubulin genomic region in all isolates. The pathogenicity assays revealed that host ranges of the isolates were similar to those of isolates from foxtail millet ( S. italica), which were exclusively pathogenic on foxtail millet. In addition to the 28 isolates from wild foxtails, 22 Pyricularia isolates from 11 other grasses were analyzed by RFLP using single-copy sequences as probes. In a dendrogram constructed from the RFLP data, isolates that were previously identified as M. oryzae formed a single cluster. All the wild foxtail isolates formed a subcluster with foxtail millet isolates within the M. oryzae cluster. From these results, we conclude that Pyricularia isolates from the wild foxtails are closely related to isolates from foxtail millet and should be classified into the Setaria pathotype of M. oryzae. [ABSTRACT FROM AUTHOR]

Soil nitrogen (N) is considered an important driver of crop-weed interactions, yet the mechanisms involved have been only partially explored, especially with respect to early-season growth, when competitive hierarchies are formed. This study characterises the effects of different N levels on biomass accumulation and plant morphology for maize ( Zea mays), and four important weed species ( Amaranthus retroflexus, Abutilon theophrasti, Setaria faberi, and Chenopodium album). Under glasshouse conditions, plants were grown in separate pots and irrigated with nutrient solution at four N concentrations (0.2, 0.5, 2, 5 μm L−1) until 57 days after emergence. Except for S. faberi, which was unresponsive to N, the relative biomass growth rates (RGR) of maize and the broad-leaved weeds were positively and similarly affected by increasing nitrogen. At all N levels, maize had a height advantage by virtue of its larger seed size, which conferred early growth benefits independent of RGR. At low N, biomass growth was instrumental to S. faberi’s improved competitive position, whereas height development per unit biomass improved the competitive position of A. theophrasti, C. album and A. retroflexus. The approach presented could be applied to other crop-weed systems to evaluate environmental impacts on competitive outcomes. [ABSTRACT FROM AUTHOR]

1. Post-dispersal seed predation is an important source of mortality for arable weed populations that can potentially contribute to ecologically based management strategies. The extent to which cropping practices influence rates of seed predation is not well established. 2. Removal of Abutilon theophrasti and Setaria faberi seeds by predators was measured in 2-year (maize/soyabean), 3-year (maize/soyabean/triticale + red clover) and 4-year (maize/soyabean/triticale + lucerne/lucerne) crop rotations in Iowa, USA, during 27 48-h sampling periods conducted during the 2003 and 2004 cropping seasons. 3. Predation of S. faberi seeds was equal (eight sampling periods) or greater (19 sampling periods) than predation of A. theophrasti seeds, but the influence of crops on seasonal predation patterns was generally similar for the two weeds. 4. Seasonal patterns in seed predation were crop-specific and complementary. In maize and soyabean, seed predation was low in spring, high in summer and low in autumn. In triticale–legume intercrops, seed predation was high in spring, low in summer and moderate in autumn. In lucerne, seed predation fluctuated from high to low, matching the periodic harvest and regrowth cycle of the crop. 5. Measurements of crop canopy light interception taken in 2004 were positively correlated with rates of seed removal for both A. theophrasti ( r = 0·54, P < 0·001) and S. faberi ( r = 0·25, P < 0·001), suggesting that vegetative cover promotes weed seed predation. 6. Synthesis and applications. The results indicate that crop vegetation can be managed to promote weed seed predation. Diversified farming systems that include a range of phenologically dissimilar crop species are likely to provide the greatest opportunities for weed seed destruction by predators. [ABSTRACT FROM AUTHOR]

For mechanical weeding, the uprooting force of whole seedlings and the shearing force of basal stems were measured in two grass weeds ( Setaria faberi and Echinochloa crus-galli var. crus-galli) and two broad-leaved weeds ( Chenopodium album and Amaranthus patulus), using balance-type equipment and a pair of scissors, respectively. Seedlings were grown in plastic pots. Uprooting and shearing experiments were carried out on the 11th, 16th, 21st, and 26th days after sowing. The uprooting force, the shearing force required to fracture the specimen, plant dry matter weight and cross-sectional area exponentially increased as seedlings grew, but the uprooting stress and shearing toughness maintained similar values after the 2nd sampling time, except for the 3rd and 4th sampling times in C. album. The increases in uprooting force and the shearing force required to fracture the specimen were supported by an expansion of the cross-sectional area of stems of the broad-leaved weeds or pseudostems of grass weeds. The higher values of uprooting stress and shearing toughness in C. album were related to an increased area of lignified organs in the basal stems. There was a significant correlation between uprooting and shearing forces. The shearing force was always higher than the uprooting force, so that most seedlings were uprooted and not fractured at the basal stems or pseudostems. The mean ratio of uprooting force to root dry matter weight after the 2nd sampling time suggested a high uprooting resistance at an extremely low amount of root dry matter weight. [ABSTRACT FROM AUTHOR]

The article presents a study on the use of periodic matrix population model to determine the effects of legume green manure and tillage timing on the demography of giant foxtail (Setaria faberi). Prospective and retrospective perturbation analysis were employed in the study. It was observed that stochastic population growth rate depended upon an interaction between legume green manure and tillage-timing effects.

Greenhouse and field experiments were conducted to evaluate the efficacy of various combinations of imazethapyr (0, 23, 46, and 70 g ai/ha) with glyphosate (0, 210, 420, 630, and 840 g ae/ha) on Setaria faberi, Amaranthus rudis, Abutilon theophrasti, and Ipomoea hederacea control. Additivity was the most frequently observed interaction and no synergistic interaction occurred throughout this study. The combination of imazethapyr with glyphosate at 210 g/ha caused an antagonistic response on Setaria faberi. Glyphosate at 420 g/ha with or without imazethapyr provided at least 95% control of Setaria faberi. The interaction between glyphosate and imazethapyr was additive on Amaranthus rudis control. Eight of the twenty-one herbicide combinations were antagonistic on Abutilon theophrasti control. Antagonistic interactions occurred when 46 or 70 g/ha of imazethapyr was added to 420 or 630 g/ha of glyphosate; while no antagonistic interactions were noted when glyphosate rate was 840 g/ha. The interactions on Ipomoea hederacea control were additive when the glyphosate rate was at least 420 g/ha. Glyphosate at 210 g/ha plus imazethapyr at 46 or 70 g/ha caused antagonistic interactions on Ipomoea hederacea control. Weed control tended to be more variable when the glyphosate rate was 210 g/ha and the imazethapyr rate was 46 or 70 g/ha. In general, the addition of imazethapyr to low rates of glyphosate improved control of Amaranthus rudis and Ipomoea hederacea and did not improve control of Setaria faberi and Abutilon theophrasti. [Copyright &y& Elsevier]

Summary Populations of Setaria faberi and Digitaria sanguinalis cross-resistant to sethoxydim and fluazifop-P-butyl were identified in a vegetable cropping system in Wisconsin, USA, in 1991 and 1992 respectively. Experiments were conducted with partially purified acetyl-CoA carboxylase (ACCase) to determine whether resistance to sethoxydim and other ACCase inhibitors in S. faberi and D. sanguinalis resulted from altered enzyme activity. Based on I50 values (the herbicide dose that inhibited ACCase activity by 50% compared with untreated ACCase), ACCase of the resistant accession of S. faberi was 4.8-, 10.6- and 319-fold resistant to clethodim, fluazifop-P acid and sethoxydim, respectively, compared with that of the susceptible accession. Similarly, ACCase of the resistant accession of D. sanguinalis was 5.8-, 10.3- and 66-fold resistant to clethodim, fluazifop-P acid and sethoxydim respectively. These results indicated that resistance to ACCase inhibitors in these accessions of S. faberi and D. sanguinalis resulted from an altered ACCase enzyme that confers a very high level of resistance to sethoxydim. [ABSTRACT FROM AUTHOR]

Genomic in situ hybridization (GISH) was used to investigate genomic relationships between different Setaria species of the foxtail millet gene pool (S. italica) and one interspecific F[sub 1] hybrid. The GISH patterns obtained on the two diploid species S. viridis (genome A) and S. adhaerans (genome B), and on their F[sub 1] hybrid showed clear differentiation between these two genomes except at the nucleolar organizing regions. Similar GISH patterns allowed differentiation of S. italica from S. adhaerans. However, GISH patterns did not distinguish between the genomes of S. italica and its putative wild ancestor S. viridis. GISH was also applied to polyploid Setaria species and enabled confirmation of the assumed allotetraploid nature of S. faberii and demonstration that both S. verticillata and S. verticillata var. ambigua were also allotetraploids. All these tetraploid species contained two sets of 18 chromosomes each, one from genome A and the other from genome B. Only one polyploid species, S. pumila, was shown to bear an unknown genomic composition that is not closely related either to genome A or to genome B.Key words: Setaria, genomic in situ hybridization, genome analysis.L'hybridation in situ génomique (GISH) a été utilisée pour étudier les relations génomiques entre différentes espèces de Setaria au sein du complexe d'espèces du millet à grappe (S. italica) et chez un hybride interspécifique F[sub 1] . Les profils GISH obtenus sur les espèces dipoïdes S. viridis (génome A) et S. adhaerans (génome B) ainsi que sur leur hybride F[sub 1] nous ont permis de séparer de façon nette les deux génomes, bien différenciés à l'exception des régions organisatrices des nucléoles. Des profils GISH similaires nous ont permis aussi de séparer S. italica de S. adhaerans. Par opposition, la GISH n'a pas permis d'observer de différenciation entre S. italica et son ancêtre putatif S. viridis. La GISH a été aussi appliquée aux espèces polyploïdes. Elle nous a permis de confirmer la nature allotétraploïde de S. faberii et de démontrer que S. verticillata et S. verticillata var. ambigua sont aussi allotetraploïdes et contiennent 18 chromosomes originaires du génome A et 18 autres chromosomes originaires du génome B. Seule une des espèces polyploïdes, S. pumila, possède une composition génomique inconnue n'ayant de relation proche ni avec le génome A ni avec le génome B.Mots clés : Setaria, hybridation in situ génomique, analyse du génome. [ABSTRACT FROM AUTHOR]

Small-scale gaps are often colonized by more than one plant, yet few individuals. We examined interactions among co-invading plants within small gaps in an old-field community as a function of the size of the gap being invaded. Several colonizing annual species were grown, as single individuals or in conspecific or heterospecific pairs, in artificially created gaps of 10, 20, and 40 cm diameter in a Poa pratensis L. background in two successive years. The identity of the neighbor influenced plant survivorship for one of the two years studied, but had no effect on the probability of becoming reproductively mature, or on levels of seed production. In contrast, vegetative growth was influenced by neighbor identity in both years. Both positive and negative plant-plant interactions were found; the presence of a neighbor did not always result in competitive reduction in the target individual. Conspecific neighbors were found to reduce vegetative biomass to a greater extent than heterospecific neighbors for one of the two years studied, primarily due to the sensitivity of one species, Setaria faberii, to conspecific neighbors. We found no evidence of a consistent competitive hierarchy present in this system. Finally, although increasing gap size had significant, positive effects on survivorship, growth, and reproduction, the size had being colonized had no effect on plant-plant interactions between co-invading individuals. In this system the number and identity of invading individuals, as well as the characteristics of the gap itself, interact to dictate the composition of the invading community and the relative performance of each individual colonist. This complexity may contribute to increased diversity in plant communities in which small-scale disturbances provide opportunities for earlier successional species to persist in localized patches within later successional vegetation. [ABSTRACT FROM AUTHOR]

Assesses the germinability states in giant foxtail or Setaria faberii, as well as surrounding tissues using germination assays. Results of qualitative and quantitative morphological observations of the hull; Germinability phenotypes; Panicle growth, development and flowering.

Setaria faberi (giant foxtail) is a major grass weed of maize in North America and can prove difficult to control using selective herbicides. In grasses, tolerance to the chloro-s-triazine and chloroacetanilide classes of selective herbicides is associated with their rapid detoxification by glutathione conjugation catalysed by glutathione transferases (GSTs, EC 2.5.1.18). We were therefore interested in characterising the GSTs in S. faberi and comparing them with the corresponding enzymes in maize. Four S. faberi GST isoenzymes (SfaGSTs 1 to 4) with activities toward the triazine herbicide atrazine, the chloroacetanilide herbicides metolachlor and alachlor and the diphenyl ether herbicide fluorodifen were purified from the foliage of young plants. These GSTs detoxified herbicides with similar efficiencies to those determined for GST isoenzymes from maize, but their levels of expression in the leaves were 20-fold lower than those reported in the crop. All SfaGSTs were composed of two subunits and the 28 kDa subunit of the isoenzyme SfaGST1 reacted strongly to an antiserum raised to the maize theta-type GSTZm GSTI-II. SfaGST1 also appeared to be very similar in substrate specificity to the major maize GST ZmGSTI-I. The similarity of SfaGST1 and ZmGSTI subunits was confirmed by RT-PCR using primers specific to ZmGSTI, with a 370 bp DNA amplification product from S. faberi showing 88% identity at the nucleotide level to the corresponding sequence of ZmGSTI. However, SfaGSTs also differed significantly from ZmGSTs. Unlike maize, only one isoenzyme, SfaGST2, detoxified chloroacetanilides. Also, SfaGST3 and SfaGST4 resembled tau-type GSTs from maize in showing high activities toward fluorodifen, but these SfaGSTs were not recognised by an antiserum raised to the maize tau-type GST ZmGSTV-VI. SfaGST4 also differed from the ZmGSTs described to date in showing high activities toward atrazine. Our results demonstrate that while some GSTs are conserved in grass crops and weeds, others are quite different. [ABSTRACT FROM AUTHOR]

Tillage and maize (Zea mays L.) residues ai up to four times the base level had variable effects on the emergence of lour annual weed species in the field. Environmental conditions varied during the three years of the research and interacted with residue and tillage to govern seedling emergence. When tillage affected Setaria fabari Herrm., emergence was greater in untilled than tilled plots. The effect of residues varied among years. Abutilon theophrasti Medik, emergence from tilled soil was greater than from untilled soil in two of three years. Maize residue at two or four times the base Ievel reduced emergence. Amaranthus retroflexus L. emergence was often greater from untilled than tilled soil. The effect ot maize residues on this species was dependent on tillage and precipitation. Chenopodium album L. emergence was affected by tillage and residues but differences over the three years were inconsistent. Results of this research indicate that tillage and residues interact with weed species, precipitation and other factors to regulate seedling emergence. The reduced soil disturbance and minimal weed seed burial associated with the elimination of tillage appear to have a greater impact on weed population dynamics than surface residues in non-tillage maize production systems. [ABSTRACT FROM AUTHOR]

We performed a field experiment to test whether the presence of litter produced by the dominant species in the first successional year affects the plant community structure in the following year. We removed the litter of Setaria faberii (the first-year dominant) in midfall, early spring, mid-spring, or late spring. Both the fall and early spring removal increased the biomass of Erigeron annuus, which became dominant, and reduced the biomass of S. faberii. In the fall-removal treatment more plants of E. annuus flowered, while early spring removal increased the biomass of rosettes (non-flowering individuals) at the end of the growing season. In the other treatments and in the control S. faberii retained dominance, but its biomass was the highest in mid-spring removal plots. The removal of litter of S. faberii in the fall and in early spring allowed E. annuus to pre-empt the site and dominate the community. When litter was not removed, it strongly hindered the growth of E. annuus, favoring S. faberii. These results highlight the importance of litter as a historical factor linking interactions across successive generations, and controlling the community structure. [ABSTRACT FROM AUTHOR]

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This study was carried out to evaluate genetic diversity, phenolic compound composition, and biological activity of Setaria italica L. collected from different parts of South Korea. Antioxidant potential of seeds was estimated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and antimicrobial activity was determined by evaluating the minimum inhibitory concentration (MIC). Eight phenolic acids and 3 flavonoids were identified and quantified, among which myricetin and salicylic acid were the most dominant phytochemical compounds detected in the majority of accessions. The antioxidant potential of the leaf extracts of all the accessions was significantly higher (ranging from 32.33 ± 1.53 µg mL−1 in SI-03 to 87.87 ± 1.63 µg mL−1) in SI-10 than that of the root, stem, or seeds. Among the 15 accessions, methanolic extracts of the SI-15 accession strongly suppressed the growth of Escherichia coli (250 µg mL−1). Accessions SI-14 and SI-15 showed positive antimicrobial activity against all gram-positive bacteria. Interestingly, extracts of all accessions were more sensitive towards E. coli and Staphylococcus aureus, with MICs ranging from 250 to 1000 µg mL−1. Three phenolic acids, namely chlorogenic acid, catechin, caffeic acid, naringin, hesperetin, and myricetin, were found to be moderately positively correlated with antioxidant activities. A wide range of diversity was observed in morphological traits, namely plant height (99.33 to 201.33 cm), culm length (67.10 to 160.00 cm), spike length (12.80 to 24.00 cm), 1000 seeds weight 1.44 to 2.91 g), bloom beginning (93.67 to 128.00 days), and full bloom (99.67 to 135 days). A dendogram generated from unweighted pair group method with arithmetic mean clustering (UPGMA) cluster analysis based on the morphological traits and inter simple sequence repeat (ISSR) marker data revealed three major groups. However, no clear correlation between these two different approaches was found. The average Shannon's information index value (I) was 0.492, and it ranged from 0 to 0.693. The average expected heterozygosity (He) was 0.335, and it ranged from 0 to 0.499. The substantial variation in the morphological traits, bioactive properties, and genetic diversity among the accessions may provide useful information for breeding programs attempting to obtain S. italica with improved bioactive properties. [ABSTRACT FROM AUTHOR]