Tolerant Corn Research Articles

Genome-Wide Association Study Reveals Marker–Trait Associations for Heat-Stress Tolerance in Sweet Corn

Sweet corn (Zea mays var. rugosa Bonaf.) is a crop with a high economic benefit in tropical and subtropical regions. Heat tolerance analysis and heat-tolerant gene mining are of great significance for breeding heat-resistant varieties. By combining improved genotyping using targeted sequencing (GBTS) with liquid chip (LC) technology, a high-density marker array containing 40 K multiple single polynucleotide polymorphisms (mSNPs) was used to genotype 376 sweet corn inbred lines and their heat-stress tolerance was evaluated in the spring and summer of 2019. In general, plant height, ear height and the number of lateral branches at the first level of the male flowers were reduced by 24.0%, 36.3%, and 19.8%, respectively. High temperatures in the summer accelerated the growth process of the sweet corn, shortening the days to shedding pollen by an average of 21.6% compared to the spring. A genome-wide association study (GWAS) identified 85 significant SNPs distributed on 10 chromosomes. Phenotypes in the spring and summer were associated with the 21 and 15 loci, respectively, and significant phenotypic differences between the two seasons caused by the temperature change were associated with the 49 SNP loci. The seed setting rate (SSR) was more susceptible to heat stress. An annotation analysis identified six candidate genes, which are either heat shock transcription factors (Hsfs) or heat shock proteins (Hsps) in Arabidopsis and rice (Oryza sativa), and these candidate genes were directly and indirectly involved in the heat-resistant response in the sweet corn. The current findings provide genetic resources for improving the heat-stress tolerance of sweet corn by molecular breeding.

Conventional corn tolerance to drift‐simulating rates of glyphosate at two growth stages

Core Ideas Conventional corn can tolerate low rates of glyphosate drift. Corn usually recovers from very low drift rates of glyphosate within three to five weeks after exposure. Generally, corn plants become less sensitive to glyphosate drift at later vegetative growth. Corn response to glyphosate drift may vary depending on the weather conditions following the exposure.

Morphophysiological responses and tolerance of various sweet corn (Zea mays convar. saccharata) hybrids to shade stress

Abstract. Utari VF, Chozin MA, Hapsari DP, Ritonga AW. 2023. Morphophysiological responses and tolerance of various sweet corn (Zea mays convar. saccharata) hybrids to shade stress. Biodiversitas 24: 4438-4447. Expanding lands for cultivating sweet corn (Zea mays convar. saccharata) is a strategy to increase its production. Yet, the available lands for sweet corn extensification might be those with existing tree stands with some extent of shading. Planting sweet corn under tree stands affects its growth and productivity since there is a reduction in light intensity, but some superior varieties might tolerate such stress. This study aimed to determine the growth, yield, and shade-tolerance levels of several sweet corn genotypes under shade stress. The experiment adopted a randomized complete block design consisting of two factors, namely shading (i.e. control or 0% shade and 50% shade) and sweet corn genotype (16 genotypes). The observed parameters included morphological traits (plant height, leaf number, leaf length, leaf width, and stem diameter), physiological traits (stomatal density and trichome density), yield attributes (cob weight with husks, cob weight without husks, cob length, cob diameter, and total soluble solid), and stress tolerance index (STI). The tested genotypes responded differently to shading. In general, 50% shade significantly reduced cob production, with an average decrease of more than 50% compared to the control. Commercial varieties, namely Exotic (G13), Talenta (G14), Paragon (G15), and Golden Boy (G16), had relatively higher STI values compared to the hybrids. Among the hybrids, the highest STI values were observed for genotypes resulting from the crosses SM7-8 × SM12-2 (G11) and SM11-6 × SM12-2 (G12). The results of this study recommend that commercial varieties can be cultivated under tree stands or low light intensity and can be used to develop high-yielding shade-tolerant sweet corn varieties.

Effect of Methyl Jasmonate and Potassium and Their Combined Action on Drought Tolerance of Fodder Corn

Effect of Methyl Jasmonate and Potassium and Their Combined Action on Drought Tolerance of Fodder Corn

Screening of acid-tolerant hybrid Corn lines and parents using modified acid mineral soil

Screening of hybrid corn parent lines quickly and cheaply compared to hydroponic methods in the laboratory is needed to support the assembly of new high yielding varieties of acid tolerant corn. Addition of CaCO3 as equivalent to 2 t/ha (normal soil), while 0.5 t/ha AlCl3 (acidic). A total of 12 elite maize lines were tested based on relative root growth (RRG). Four sets of experiments were made, namely 2 sets normal soil media (pH 6.5) and 2 sets acid soil media (pH 4.3). Experimental design used in each experimental set was a randomized block with three replications. Results showed that rapid screening of hybrid maize parental lines could be carried out using modified soil acidity method by adding CaCO3 and AlCl3 to acid soil by measuring relative root growth (RRG) as the main variable. Corn obtained by genotypes No.80, MAL03x192, and Bisi-18 were classified as tolerant, MAL03x28, MAL03x182, MAL03x42, MAL03x44, MAL03x107, MAL03x115 were classified as moderately tolerant, while MAL03x100, MAL03x56, classified as sensitive. Screening of hybrid parent lines on acid soil modified to pH 4.3 (acidic) and normal pH 6.5 at seedling age 7 days after planting (dap) was more accurate than at seedling age of maize 14 dap.

Enlist™ corn tolerance to preemergence and postemergence applications of synthetic auxin and ACCase-inhibiting herbicides

AbstractAllowing the use of two additional modes of action (MOAs), Enlist™ corn is a novelty in the continuum of herbicide-resistant crop development efforts that have occurred since the 1990s. Knowledge of Enlist corn tolerance to labeled herbicides and other herbicides within the same MOA for various use and/or exposure scenarios is not well established. Four site-year field experiments for preemergence (PRE) and postemergence (POST) applications were conducted at sites in Fayetteville (2021 and 2022) and Tillar (2020 and 2021), Arkansas, to evaluate Enlist corn response following PRE or POST applications of synthetic auxin herbicides or those that inhibit acetyl-CoA carboxylase (ACCase). A non-Enlist and an Enlist corn hybrid were used for each herbicide treatment to establish differential tolerance. Injury response to PRE application varied among site-years; clethodim was the only herbicide that occasionally caused significant (7% to 17%) injury to Enlist corn. None of the PRE treatments affected plant height, stand, or yield of Enlist corn; these responses were generally similar or better for Enlist corn compared to non-Enlist corn. Enlist corn showed significant injury to POST applications of florpyrauxifen-benzyl (>10%), fluazifop-P-butyl and quizalofop-P-ethyl (>5%), and clethodim and sethoxydim (>75%) 1 wk after application (WAA). These initial injury responses to clethodim and sethoxydim were generally reflected in Enlist corn yield; however, the minimal injury from fluazifop-P-butyl and quizalofop-P-ethyl did not affect yield. Injury to non-Enlist corn with POST-applied ACCase-inhibiting herbicides 2 WAA was >80%, resulting in a proportionate yield reduction. Even though florpyrauxifen-benzyl caused more initial injury to non-Enlist corn, yield reduction in non-Enlist corn was occasionally less than of Enlist corn, with both hybrids experiencing >75% yield reduction. In summary, Enlist corn may occasionally show transient injury even to labeled herbicides when applied POST, and even though the injury from florpyrauxifen-benzyl is initially mild, it nonetheless results in substantial yield loss.

Evaluating and comparing tolerance, nutritional quality and bio-functional activity of bovine-plasma, corn and whey proteins, outcomes of a randomized double blind controlled trial

Important considerations in the choice of future sustainable protein sources for human application are tolerance, nutritional quality, and potential health benefits. We evaluated, in a double-blind cross-over intervention trial, tolerance, nutritional quality, and potential health effects of two sustainable protein sources. Thirty-six apparently healthy older adults (age 62.3 ± 7.2yrs, BMI 25 ± 3 kg/m2) received 40 g/day bovine-plasma protein (BP), corn protein (CP) or, as a benchmark, whey protein (WP) for one week with a washout period of one week in-between. In 12 participants, we also determined postprandial amino acid (PAA) uptake kinetics upon consumption of 20 g BP, CP, or WP. Changes in self-reported gastrointestinal complaints and intestinal permeability assessed using a multi-sugar acetylsalicylic acid test did not differ between the interventions. Clear differences in PAA responses were observed after consumption of the different proteins, but clear essential amino acid responses were observed for all proteins. BP consumption resulted in a small but significant increase in blood pressure outcomes, and CP consumption resulted in a small but significant decrease in insulin levels when compared to the other interventions. In conclusion, alternative protein concentrates and isolates studied here can be consumed in relative high quantities without experiencing unwanted GI complaints or gut barrier dysfunction and they can be a good source of essential amino acids. The rise in blood pressure observed during the BP intervention, potentially linked to the elevated salt content of the BP, constitutes a potential health issue. Future studies with longer intervention periods might however be recommended.

Distribution and genetic characterization of bird rape mustard (Brassica rapa) populations and analysis of glyphosate resistance introgression.

The introgression of a transgene conferring glyphosate resistance from Brassica napus (rapeseed, canola) to Brassica rapa weeds (bird rape) was documented at a single location in 2007. In 2015, several cases of glyphosate resistant mustard were reported by growers in areas where rapeseed was seldom grown. Survey result indicated glyphosate resistant bird rape mustard is present in areas where glyphosate tolerant corn and soybean are often grown in rotation. Genetic analyses reveal that hybridization followed by introgression and progressive loss of chromosome is the likely mechanism for the horizontal gene transfer (HGT) of glyphosate resistance. Introgression of the glyphosate-resistance conferring transgene in the populations studied appears to have occurred several times, consistent with the ease for B. rapa to form hybrids with B. napus. The introduction of a transgene into a crop should therefore take into account the weediness of the species that share a common genome and their ability to form hybrids. We provide here such an example between B. napus and B. rapa, and potentially between B. napus and Raphanistrum raphanistrum. © 2022 Her Majesty the Queen in Right of Canada. Pest Management Science © 2022 Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

Bacillus thuringiensis-Based Bioproduct: Characterization and Performance Against Spodoptera frugiperda Strains in Maize Under Different Environmental Temperatures.

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an important pest in several regions being the use of Bacillus thuringiensis-based bioproducts an alternative for its control. Firstly, 3 L of an aqueous bioproduct suspension was produced and characterized. Its 50% lethal concentration against molecularly identified corn and rice S. frugiperda strains using an artificial diet were 77.01% (95% CL, 68.16-90.47) and 2.22% (95% CL, 0.01-6.68), respectively. The next objective of this work was to evaluate the performance of this bioproduct in maize against S. frugiperda strains under different simulated agrological regions mimicking their corresponding periodic day/night temperatures. Thus, the impact of environmental temperature on the bioproduct efficacy (E) was studied. It was observed that a warmer scenario (35°Cday/30°C night) could favor the tolerance of corn S. frugiperda strain to the bioproduct (E = 56.36 ± 0.61%) maintaining a high efficacy (92.44 ± 6.55%) when it was tested against rice S. frugiperda strain. Conversely, under temperate conditions, efficacy values ranged from 84 to 95% for both S. frugiperda strains. On the other hand, based on a foliar feeding damage analysis, our bioproduct displayed a significant foliar protection in maize plants infested with either corn or rice S. frugiperda strains.

Plant growth regulators affecting corn (Zea mays L.) physiology and rab17 expression under drought conditions

Finding methods, which may improve corn ( Zea mays L.) growth and physiology under drought stress, is of significance. Accordingly, the effects of different plant growth regulators (PGRs) including benzyl adenine (BA6), gibberellins (GA 3+7 ), proline (Pr), and BA6 + GA 3+7 + Pr (sub plots), at different drought levels including control (S1), moderate (S2) and severe (S3) (main plots) on the physiology and genetic contents of corn (Single Cross 704) plants were investigated. A two-year field research, as a split plot on the basis of a randomized complete block design with four replications, was conducted in the Research Field of Islamic Azad University, Isfahan, Iran in 2015–2016. Corn physiological parameters including carotenoids (Car), total chlorophyll (Chlt), chlorophyll a (Chla), chlorophyll b (Chlb), plasma membrane resistance (PR), and rab17 expression were determined. Analysis of variance and comparison of means indicated the experimental treatments significantly (P ≤ 0.01) affected the measured parameters. The combination of PGRs and drought stress was not significant on PR, and just drought stress had a significant effect on rab17 expression at P ≤ 0.01. The year parameter significantly affected corn Car and PR. Although stress decreased plant Car, and Chl contents, it increased PR. The tested PGRs significantly improved corn physiology and rab17 expression, and interestingly their effectiveness enhanced with increasing the level of stress (significant interaction of PGRs and drought stress). The role of proline as an RNA binding protein affecting RNA activity and rab17 expression and subsequent corn tolerance under drought stress has been suggested. • Plant growth regulators (PGRs) affecting corn physiology and genetic under drought. • Proline and its combination with benzyl adenine and gibberellins the most effective. • Suggesting proline as and RNA binding protein in the alleviation of drought stress. • The possibility of alleviating drought stress in corn plants using the tested PGRs.

Significance of application timing, formulation, and cytochrome P450 genotypic class on sweet corn response to dicamba

AbstractSweet corn (Zea mays L.) tolerance to dicamba and several other herbicides is due to cytochrome P450 (CYP)-mediated metabolism and is conferred by a single gene (Nsf1). Tolerance varies by CYP genotypic class, with hybrids homozygous for functional CYP (Nsf1Nsf1) being the most tolerant and hybrids homozygous for mutant CYP alleles (nsf1nsf1) being the least tolerant. The herbicide safener cyprosulfamide (CSA) increases tolerance to dicamba by stimulating the expression of several CYPs. However, the extent to which CSA improves the tolerance of different sweet corn CYP genotypic classes to dicamba is poorly understood. Additionally, the effect of growth stage on sweet corn sensitivity to dicamba is inadequately described. The objective of this work was to quantify the significance of application timing, formulation, and CYP genotypic class on sweet corn response to dicamba. Hybrids representing each of the three CYP genotypes (Nsf1Nsf1, Nsf1nsf1, nsf1nsf1), were treated with dicamba or dicamba + CSA at one of three growth stages: V3, V6, or V9. Across all timings, the nsf1nsf1 hybrid was the least tolerant to dicamba, displaying 16% higher crop injury levels 2 wk after treatment and 2,130 kg ha−1 lower ear mass yields compared with the Nsf1Nsf1 hybrid. The V9 growth stage was the most susceptible time for dicamba injury regardless of genotypic class, with 1.89 and 1,750 kg ha−1 lower ear mass yields compared with the V3 and V6 application timings, respectively. The addition of CSA to dicamba V9 applications reduced the injury from dicamba for all three genotypic classes; however, it did not eliminate the injury. The use of Nsf1Nsf1 or Nsf1nsf1 sweet corn hybrids along with herbicide safeners will reduce the frequency and severity of injury from dicamba and other CYP-metabolized herbicides.

Titanium dioxide nanoparticles (TiO2-NPs) enhance drought tolerance and grain yield of sweet corn (Zea mays L.) under deficit irrigation regimes

Titanium dioxide nanoparticles (TiO2-NPs) enhance drought tolerance and grain yield of sweet corn (Zea mays L.) under deficit irrigation regimes

Physiological and transcriptomic analyses of the effects of exogenous melatonin on drought tolerance in maize (Zea mays L.)

Water deficit inhibits maize (Zea mays L.) seedling growth and yield. Application of exogenous melatonin can improve drought tolerance of corn, but little is known regarding the transcriptional mechanisms of melatonin-mediated drought tolerance in maize. Increased understanding of the effects of melatonin on maize plants under drought stress is vital to alleviate the adverse effects of drought on food production in the future. The aim of this investigation was to use physiological and transcriptome analyses for exploring the possible mechanisms of exogenous melatonin against drought stress in maize. In this study, maize seedlings were subjected to drought stress and some were treated with exogenous melatonin. The physiological results showed that melatonin inhibited H2O2 accumulation and promoted the scavenging of excessive reactive oxygen species to reduce oxidative damage in maize leaves. Transcriptomic analysis identified 957 differentially expressed genes between melatonin and non-melatonin treatment groups. Further detailed analyses suggested that melatonin-regulated genes are mainly related to glutathione metabolism, calcium signaling transduction, and jasmonic acid biosynthesis. Some transcription factor families, such as WRKY, AP2/ERF-ERF, MYB, NAC, and bZIP, were also activated by exogenous melatonin. Moreover, crosstalk between melatonin and other hormones that mediate drought tolerance was observed. In conclusion, the combination of physiological and transcriptome analyses revealed some mechanisms underlying the role of melatonin in alleviating drought; knowledge of these mechanisms may assist in successful maize cultivation under drought stress.

Metabolic Pathways for S-Metolachlor Detoxification Differ Between Tolerant Corn and Multiple-Resistant Waterhemp.

Herbicide resistance in weeds can be conferred by target-site and/or non-target-site mechanisms, such as rapid metabolic detoxification. Resistance to the very-long-chain fatty acid–inhibiting herbicide, S-metolachlor, in multiple herbicide-resistant populations (CHR and SIR) of waterhemp (Amaranthus tuberculatus) is conferred by rapid metabolism compared with sensitive populations. However, enzymatic pathways for S-metolachlor metabolism in waterhemp are unknown. Enzyme assays using S-metolachlor were developed to determine the specific activities of glutathione S-transferases (GSTs) and cytochrome P450 monooxygenases (P450s) from CHR and SIR seedlings to compare with tolerant corn and sensitive waterhemp (WUS). GST activities were greater (∼2-fold) in CHR and SIR compared to WUS but much less than corn. In contrast, P450s in microsomal extracts from CHR and SIR formed O-demethylated S-metolachlor, and their NADPH-dependent specific activities were greater (>20-fold) than corn or WUS. Metabolite profiles of S-metolachlor generated via untargeted and targeted liquid chromatography–mass spectrometry from CHR and SIR differed from WUS, with greater relative abundances of O-demethylated S-metolachlor and O-demethylated S-metolachlor-glutathione conjugates formed by CHR and SIR. In summary, our results demonstrate that S-metolachlor metabolism in resistant waterhemp involves Phase I and Phase II metabolic activities acting in concert, but the initial O-demethylation reaction confers resistance.

Stem Density, Productivity, and Weed Community Dynamics in Corn-Alfalfa Intercropping

Intercropping legumes with cereals for forage production is a practical multi-cropping technique to increase yield and improve land use efficiency. In a 3-year cropping sequence, alfalfa (Medicago sativa L.) intercropped with corn (Zea mays L.) may increase overall economic yield and land sustainability over either crop alone. The objective of this study was to assess overall productivity of a corn-alfalfa intercropping system and its effect on weed community. The study was conducted near Boone, IA, USA, from 2016 to 2018 and repeated from 2017 to 2019 to assess the effect of five treatments: alfalfa only, corn only, corn intercropped with alfalfa, corn intercropped with alfalfa with prohexadione (PHX) applied to alfalfa at the V8 corn stage, and spring-seeded alfalfa (corn in the seeding year followed by planting alfalfa the following year) on system productivity. Corn grain yield decreased by 23 to 26% when intercropped with alfalfa; PHX application did not affect corn or alfalfa yield. Alfalfa stand density under corn was reduced by 36 to 68% compared with alfalfa alone in the seeding year. Alfalfa forage yield in the first production year was the same among intercropped treatments and sole alfalfa. However, spring-seeded alfalfa had two to three times less yield than other treatments. Alfalfa stem density was greater in sole alfalfa than the intercropped studies in the seeding year, with fewer stems in successive production years. Alfalfa forage yield strongly correlated with stem density, stem height, and stage at harvest in the seeding year and first harvest of the first production year. Weed density inconsistently correlated with alfalfa biomass. In conclusion, establishing alfalfa in intercropping with corn can skip alfalfa low-yielding seeding year. Based on the findings of our experiment, future research on corn-alfalfa intercropping should focus on screening drought tolerant corn hybrids with vigorous root systems. Using an early-maturing corn hybrid, coupled with management practices such as appropriate N fertilization, may improve corn yield and the chances of success for this intercropping system.

Improving Capacity of Yellow Corn Tolerance to Water Stress by Foliar Application of Ascorbic Acid and Hydrogen Peroxide

Two field experiments were conducted in a new soil conditions in the extension field in El Qantra- West, Ismailia Governorate, Egypt (300 58/ N, 320 23/ E, and 10m above mean sea level) during 2016 and 2017 summer seasons. The study aimed to find out the effect of five exogenous application levels of AsA and H2O2 on yellow corn hybrid 352 (three way cross) under three amounts of irrigation water (1.00. 0.80 and 0.60 of the estimated crop evapotranspiration) using surface irrigation system. A randomized complete block split-plot design with three replications was used in each season. The irrigation treatments and the levels of AsA and H2O2 were randomly allocated in the main and sub-plots, respectively. The most important findings could be summarized as follows: Irrigation by 2250 m3/fad (severe water stress) instead of 3750 m3/fad (full irrigation) reduced ear leaf blade area, total chlorophyll and relative water content in both seasons. Increasing the level of AsA up to 350ppm/fad increased ear leaf blade area, total chlorophyll and relative water content followed by the highest level of H2O2 (60mM H2O2). Decreasing irrigation water significantly reduced ear length, 100-grain weight and grain yield/fad. Meanwhile, ear length, 100-grain weight and grain yield/fad were significantly obtained from the highest level of AsA followed by the highest levels of H2O2 compared with their untreated analogues. The interaction between the both studied factors showed that application of 350ppm AsA and 60mM H2O2 treatments protected about 920 and 320 kg/fad grains from collapse under moderate water stress (3000 m3/fad). Meanwhile, under severe water stress, treatments by same levels of AsA and 30mM H2O2 protected about 670 and 330kg/fad grains from lose. Application of 350ppm AsA saved approximately 750m3/fad of irrigation water without yield reduction.

Evaluation of induction of sethoxydim tolerance in maize (Zea mays L.) using salicylic acid as a safener

Introduction Herbicide safeners are chemical compounds used in combination with herbicides to make them safer that is, to reduce the effect of the herbicide on crop plants, and to improve selectivity between crop plants versus weed species being targeted by the herbicide. Herbicide safeners can be used to pretreat crop seeds prior to planting, or they can be sprayed on plants as a mixture with the herbicide. Salicylic acid (SA) and other salicylates are known to affect various physiological and biochemical activities of plants and may play a key role in regulating their growth and productivity. This hormone is synthesized by many plants and is accumulated in the plant tissues as the impact of unfavorable abiotic factors, contributing to the increase of plants resistance to stress. The aim of this study was to evaluate the efficacy of salicylic acid as a safener in corn tolerance to non-selective herbicide; sethoxydim, and the response of two weed species of johnsongrass (Sorghum halepense (L.) Pers.) and junglerice (Echinochloa colona (L.) Link) to it. Materials and methods The effect of sethoxydim (0.5, 22.5, 45, 94, 187 and 375 grams of active ingredient per hectare), and salicylic acid (in concentrations of 0, 1 and 2 mM) as factorial experiment in a completely randomized design were investigated to evaluate the response of fresh weight of corn, johnsongrass and junglerice. Salicylic acid treatment was used in seed priming form also. Pre-treatment of salicylic acid was done three days before herbicide spraying. Spraying different doses of sethoxydim herbicide in a complete five-leaf stage, was done using a mobile rail sprayer (Matabi, Spain) equipped with a flat-fan nozzle (8002), a delivery of 220 L ha-1 and a spray pressure of 200 kPa. To investigate the changes in photosynthesis in the treated plants, chlorophyll fluorescence of the leaves was evaluated on the sixth day after application of herbicides by PEA model fluorometer. Three weeks after spraying the herbicide, the shoots of the plants were removed from the surface of the pot and their fresh weight was measured. Analysis of variance was performed using generalized linear models (GLM) in SAS 9.2 software environment. Before performing analysis of variance to determine the normality of the data from Anderson-Darling test in Minitab ver. 17 were used, and in cases of non-normal data, Box-cox two-way power transformation was used in the same software. Analysis of variance, was performed as a factorial experiment for each plant to investigate the effect of the herbicide dose of sethoxydim and the concentration of salicylic acid and their interaction. The trend of wet weight changes of different species under the influence of different amounts of herbicide sethoxydim was investigated using the four parameters log-logistic equation.Results and discussion Dose-response curves of fresh weight of the treated plants showed that weeds were significantly affected by sethoxydim compared to corn. In all species, by increasing the concentration of salicylic acid, the ED50 increased. For all three levels of salicylic acid treatment, this parameter was the greatest in salicylic acid treatment as seed priming than others, and the lowest values of this parameter were observed for jungle rice. The highest amount of ED50 was 210 gram of active ingredient per hectare for corn sown with 2 mM / L salicylic acid treatment, and the lowest value was 31.5 gram of active ingredient per hectare for non-salicylic acid treatment in jungle rice. Kutsky’s curves for corn and weeds showed that Fluorescence chlorophyll was increased with the use of steroids herbicide, but salicylic acid treatment could reduce the rate of chlorophyll fluorescence, so that weed and corn after weeding the control without grass was observed at the lowest salicylic acid treatment (2 mM / L).Conclusions: In general, the results of this experiment showed that under the influence of sethoxydim, all three species of maize, johnsongrass and junglerice showed a positive response to salicylic acid foliar application. Therefore, in order to use salicylic acid as a safener, its seed treatment in corn should be used. Overall, the results showed that salicylic acid can be used as a stress reducer due to the use of sethoxydim in narrow-leaved plants. But as a safener we cannot use it universally and foliar spraying, because there is no differentiation in the response of crops and weeds. Therefore, in the use of salicylic acid as an immunizer for the sethoxydim, its seed treatment will give better results.

Drought test resistance of maize varieties through PEG 6000

Abstracs. The germination phase is a very critical time for corn plants against water stress. Corn resistance to water stress in this phase is very different between cultivars. This initial test has been carried out in the Laboratory to determine the resistance level of some varieties of corn to water stress during the germination phase by using Poly Ethylene Glycol (PEG) 6000. There are nine corn varieties tested at three levels of PEG 6000 concentration of 0 % (0.00 MPa), 10 % (-0.19 MPa), and 20 % (-0.67 MPa). The experiment used a completely randomized 9 × 3 factorial design with 2 replications. The nine varieties tested were: Anoman 1 (V1), Lamuru (V2), Gumarang (V3), Srikandi Kuning (V4), Sukmaraga (V5), Bisma (V6), Arjuna (V7)), Lagaligo varieties (V8), and NK-Jumbo varieties (V9). Selection of maize varieties on water stress during the germination phase of 9 selected varieties into 3 varieties consisting of one tolerant variety, one moderately tolerant variety and one sensitive variety through prediction of a PEG 6000 osmoticum solution in the germination phase. The experimental results showed that the concentration of PEG 6000 affected the response of nine corn varieties to germination and seed vigor. The most tolerant (resistant) corn varieties are NK-Jumbo (V9) and the moderately resistant varieties (medium) are Srikandi Kuning (V4) while the intolerant (sensitive) varieties are Lamuru (V2).

Nutritive value of ensiled Italian ryegrass and winter cereal mixture

Nutritive value of ensiled Italian ryegrass and winter cereal mixture

Biotech Crops, Input Use and Landslides Case Study of Herbicide Tolerant Corn in the Philippine Highlands

Improved seeds varieties have led to an increase in agricultural production as well as to a change in agricultural practices and input use. While some of these new practices can be more environmentally sustainable, others may lead to a higher level of environmental degradation. In a case study using an original survey method of farming households on the Philippine island of Mindanao covering the past ten years, this paper finds a very robust positive correlation between herbicide tolerant corn cultivation and landslide occurrence. This effect is robust to the inclusion of plot fixed effect, indicating that physical characteristics of the farm do not explain the results. Instead, more aggressive weed control via broad-spectrum herbicide appears as a likely mechanism.