Maize Strains Research Articles

Salicylic acid inducing the expression of maize anti-insect gene SPI: a potential control strategy for Ostrinia furnacalis

BackgroundDue to being rooted in the ground, maize (Zea mays L.) is unable to actively escape the attacks of herbivorous insects such as the Asian corn borer (Ostrinia furnacalis). In contrast to the passive damage, plants have evolved defense mechanisms to protect themselves from herbivores. Salicylic acid, a widely present endogenous hormone in plants, has been found to play an important role in inducing plant resistance to insects. In this study, we screened and identified the insect resistance gene SPI, which is simultaneously induced by SA and O. furnacalis feeding, through preliminary transcriptome data analysis. The functional validation of SPI was carried out using bioinformatics, RT-qPCR, and heterologous expression protein feeding assays.ResultsBoth SA and O. furnacalis treatment increased the expression abundance of SA-synthesis pathway genes and SPI in three maize strains, and the upregulation of SPI was observed strongly at 6 hours post-treatment. The expression of SPI showed a temporal relationship with SA pathway genes, indicating that SPI is a downstream defense gene regulated by SA. Protein feeding assays using two different expression vectors demonstrated that the variation in SPI protein activity among different strains is mainly due to protein modifications.ConclusionsOur research results indicate that SPI, as a downstream defense gene regulated by SA, is induced by SA and participates in maize's insect resistance. The differential expression levels of SPI gene and protein modifications among different maize strains are one of the reasons for the variation in insect resistance. This study provides new insights into ecological pest control in maize and valuable insights into plant responses to SA-induced insect resistance.

Facilitating Growth of Maize (Zea mays L.) by Biostimulants: A Perspective from the Interaction between Root Transcriptome and Rhizosphere Microbiome.

The plant growth-promoting effects of biostimulants have been widely documented, while little is known about the intrinsic mechanism. In our study, a pot experiment was conducted to investigate the effects of biostimulants on maize, and the maize root transcriptome and rhizosphere microbiome were assessed. The physicochemical properties of the soil were significantly altered with various trends, and the growth and yield of maize were promoted by biostimulants. Sampling time and maize strain were the strongest factors that altered the rhizosphere microorganisms. Rhizosphere microbiota with biostimulant application exhibited high community robustness. Root transcriptome analysis suggested an altered expression profile induced by biostimulants and maize strains. An integrated correlation analysis demonstrated that phosphate and nitrate metabolism genes are tightly associated with some rhizosphere microbiota. These results implied the plant growth-promoting effects of biostimulants might act in a rhizosphere microorganism-dependent manner and help to expand the use of biostimulants in sustainable agriculture.

Genetic response of hybrid maize line to downy mildew caused by Peronosclerospora spp. infection

Maize is the second staple food commodity in Indonesia. Apart from being the main source of carbohydrates and protein, the production of maize continues to increase along with the escalation of population growth and animal feed requirements in the last few years. The potential to increase the national production of maize is still feasible because of the yield gap between the potential yields of new superior varieties and the level of yields obtained by farmers. The yield gap caused by biotic stress in maize is mainly caused by pathogens such as downy mildew due to Peronosclerospora spp. Downy mildew distribution is sporadic that can infect a wide area. In Indonesia, it spreads widely and significantly reduces yields in the areas of maize production centres in East Java, Central Java, South Sulawesi, North Sulawesi, Gorontalo, Lampung, and Sumatera. These obstacles can be overcome by integrated pest and disease control technology. One strategy is to discover downy mildew-resistant varieties that can be combined with other control treatments. The phenomenon of resistance to downy mildew infection of several hybrid maize strains began to be detected in the vegetative growth phase, with symptoms beginning at 14 days after planting (DAP), increasing with plant age, and reaching its peak after 28-35 DAP and then the symptoms will gradually disappear until no infection after 42 HST. This study analyses the resistant maize varieties from 2020 to 2022. The data showed the susceptible comparison variety (Anoman) was infected with 88.94% to 100%. In 2020, BMD73 showed a resistant reaction to Philippinensis species, other strains were classified as susceptible in P. maydis except BMD 76. All strains showed highly susceptible and susceptible reactions. In 2021, in P. philippinensis all strains FCP10-FCP16 showed a resistant reaction, but line FCP10-FCP16 had a resistance response that was classified as moderately resistant to P. maydis. The incidence of genetic response in 2022, except BMD86, strains BMD81-BMD85 were classified as resistant, as well as in the P. maydis endemic area all strains showed the same reaction.

Development and demographic parameters of Fall Armyworm (Spodoptera frugiperda J.E. Smith) when feeding on rice (Oryza sativa)

Fall Armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), native to the Americas, is a polyphagous insect pest feeding on more than 350 plant species. We studied the developmental and demographic parameters of the maize (Zea mays) strain of FAW on rice (Oryza sativa), and compared the results with its prime host, maize. The developmental period from egg to adult among rice varieties did not differ significantly; however, it did differ significantly between rice and maize, as feeding on rice rather than maize extends development duration of FAW larvae by 15.15%. FAW larvae collected and reared on maize were found to be of significantly higher weight than those reared on rice at two sequential dates of their development; pupal weight however was observed as statistically similar between these two host crops. Regardless of the host, female adults always emerged before males; in maize, female FAW appeared 3.36 days earlier than males. Females derived from rice had longer pre-oviposition periods and shorter oviposition ones than those derived from maize. In rice and maize, the age-specific fecundity rate (mx) peaked at 40 days and 33 days, respectively. When the Fall Armyworm consumed maize instead of rice, there was an increase in the reproduction rate (R0), the intrinsic rate of natural increase (rm), and the finite rate of increase (λ). For instance, when FAW fed on rice, the rm value was 0.121, whereas it rose to 0.173 when FAW fed on maize. Feeding on rice instead of maize resulted in significantly longer mean length of generation (tG) and doubling time (tD) for the fall armyworm (FAW). This suggests that it took a longer time for the FAW population to double when it was fed rice under controlled greenhouse conditions. In summary, our research suggests that FAW can survive and complete its life cycle on rice plants and on multiple varieties of rice in Bangladesh. However, field verification is necessary before drawing strong conclusions as to the risk posed by FAW in rice. This requires additional studies of FAW and associated insect community dynamics under non-controlled conditions and in the context of multi-species interactions in Asian rice fields.

Insect-resistance test of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) on several maize hybrid lines

To reduce the loss because of pest attacks, it is important to select a maize hybrid line resistant to Sitophilus zeamais Motschulsky (maize weevil). This strategy can reduce seed damage during preservation and is safe for the environment. Therefore, the research was conducted to screen the germplasm resistance of maize against the attack of the powdery mildew S. zeamais. Maize strain resistance testing against S. zeamais was carried out in 2018 by testing 30 genetic materials of corn germplasm then the entry was stored in a freezer for 2 weeks which aims to kill warehouse insect pests from the field. Of the thirty accessions/lines of maize germplasm that were tested for resistance to the S. zeamais attack, there were twelve accessions/entries which showed high resistance, namely accession numbers/lines 48, 105, 228, 235, 237, 239, 273, 285, 290, 301, 342, 375. This resilience can be seen in the vulnerability index and the number of F1 progenies S. zeamais produced. The susceptibility index ranged from 0.9 to 3.6 and the number of F1 S. zeamais progeny ranged from 1.5 to 3.5 individuals. The methods and results of this study are useful before the release of the variety to the public.

Heterosis of yield and its components of maize (Zea mays L.) using factorial mating design


 In this study, ten pure maize strains were introduced in the hybridization program according to the factorial design mating system proposed by Comstock and Robinson (1948 and 1952) and were divided into two groups: a local adapted inbred lines and strain 839 and cv 890 used as parents, (ZM51L, ZP-301, OH, IK-58, IK-8, SH, R-153) were used as females, The seeds of the ten parents and twenty-one hybrids were swon in the field of a farmer in the Zlaya area (south of Tikrit) using a random complete block design with three replicates ( RCBD ). The hybrid vigor was studied in methods (on the basis of the first generation deviation of the average and the best parents) The number of rows in per ear, the number of grains in the row, the number of grains in per ear, the weight of 300 weight and the single plant yield. The results showed significant differences between genotypes (parents and first-generation genotypes) of all characters except the number of ears in the plant at a probability level of 1%. the hybris superior (IK-58 x local strain), (ZP-301 x 839)(IK-58 x 839), (ZM51L x C.V890) and (OH x CV 890) were based on the deviation of the average first generation from the average parents And the best parents of all characters studied.

Biological Control of Fall Armyworm, Spodoptera frugiperda

The fall armyworm (FAW), Spodoptera frugiperda, is one of the most important invasive pests worldwide, resulting in considerable losses in host crops. FAW comprises two genetic strains, such as the “rice strain”, which prefers rice and other grass species, and the “maize strain”, which feeds upon maize and sorghum. Potential control measures are generally more applicable to the farmers who lack financial assets to buy chemical insecticides or costly pure seeds. The adverse effects of pesticides on the ecosystem and human’s health and the development of resistance to insect pests have exaggerated efforts to find an alternative strategy that is cost-effective, low-risk and target-specific. Therefore, biological control is widely considered as one of the most important options for insect pest management. This comprehensive review amasses the information on biological control in all phases of their development, including predators, parasitoids, entomopathogenic fungi, viruses, nematodes, bacteria, and biopesticides, with a special focus on their effectiveness against FAW. The findings regarding biological control are briefly discussed in light of improving management programs of the invasive pest S. frugiperda.

The effect of water hyacinth (Eichhornia crassipes) organic fertilizer on the vegetative growth of Manado strain yellow maize (Zea mays L.)

Introduction: The invasion of water hyacinth (Eichhornia crassipes), a freshwater weed, has been an unsolved problem in many lakes around the world, including in Tondano lake, Indonesia. Since the 2000s, many efforts to eliminate it have turned unsuccessful and uneconomical. Here, we aim to provide a solution and perform a systematic study to utilize water hyacinth as an organic fertilizer for application to local crops, the Manado strain yellow maize. Methods: Water hyacinth was manually harvested and fermented using an effective microbial fermentation for one month. The resulting compost was analyzed chemically and applied to bedding groups of maize at increasing doses: 0, 100, 150, 200, and 250 grams per plant. All beddings were made in triplicate, consisting of 8-10 plants per repeat. At 2 and 12 weeks post plantation, a series of measurements of plant height, leaf length, and leaf width was performed. Data were analyzed using one- or two-way ANOVA. Results: The application of water hyacinth organic fertilizer had readily shown beneficial effects on vegetative growth at 2 weeks of age in terms of plant height, leaves length and leaves width at the dose of 200 and 250 grams of fertilizer per plant. This effect persisted up to 12 weeks of age in terms of plant height, but not in leaves length or width. Conclusion: The application of water hyacinth organic fertilizer is able to increase the vegetative growth of the local Manado strain of yellow maize at the dose of 200 grams per plant.

Nutritional components and protein quality analysis of genetically modified phytase maize

ABSTRACT The nutritional components and protein quality of genetically modified maize expressing phytase gene (GM) were analyzed and evaluated in this study. The nutritional components were analyzed by Chinese national standard methods. The ileostomy Bama miniature pigs were utilized to analyze the true digestibility of protein and amino acids. The digestible indispensable amino acid score (DIAAS) was adopted to evaluate the protein quality of GM, its parental maize (PM) and commercial available maize Zhengdan 958 (ZD). Meanwhile, the widely used protein digestibility corrected amino acid score (PDCAAS) was also calculated and compared with DIAAS. The content of protein, fat, vitamins, and minerals of all the strains of maize are in the normal ranges of OECD and/or ILSI. The DIAAS of GM, PM, and ZD were 54.57, 31.75, and 33.91, respectively, and the first limiting amino acid for GM, PM, and ZD was lysine. In conclusion, the introduction of phyA2 gene in GM maize does not disturb the digestion of protein/amino acid, but has the ability to promote the digestion of amino acids.

Registration of tropical populations of maize selected in parallel for early flowering time across the United States

AbstractTropical strains of maize (Zea mays subsp. mays L.) flower very late in temperate environments. This is a barrier to maize diversification and improvement in regions where a large share of the world's corn production takes place. For investigating early flowering time adaptation, a tightly controlled parallel selection experiment spanning a 28° latitudinal range (∼3,100 km) across the United States was conducted. First, a tropical synthetic population (TropicS‐G0) (Reg. no. GP‐605, PI 698625) of maize was created from seven inbred parents. The molecular genetic diversity in TropicS‐G0 is representative of tropical inbreds that are differentiated from the prevailing germplasm used for hybrid production in the United States. Admixture analysis and genome simulation showed that breeding of TropicS‐G0 captured the parental genomes mostly at random, as intended prior to selection. With TropicS‐G0 as a common base population, a standardized protocol was used to recurrently select for early flowering time at eight locations for two generations, giving rise to location‐specific lineages (TropicS‐G1‐PR, Reg. no. GP‐621, PI 698641; TropicS‐G2‐PR, Reg. no. GP‐622, PI 698642; TropicS‐G2‐FL, Reg. no. GP‐620, PI 698640; TropicS‐G1‐cTX, Reg. no. GP‐618, PI 698638; TropicS‐G2‐cTX, Reg. no. GP‐619, PI 698639; TropicS‐G1‐nTX, Reg. no. GP‐616, PI 698636; TropicS‐G2‐nTX, Reg. no. GP‐617, PI 698637; TropicS‐G1‐NC, Reg. no. GP‐614, PI 698634; TropicS‐G2‐NC, Reg. no. GP‐615, PI 698635; TropicS‐G1‐DE, Reg. no. GP‐610, PI 698630; TropicS‐G1‐IA, Reg. no. GP‐608, PI 698628; TropicS‐G2‐IA, Reg. no. GP‐609, PI 698629; TropicS‐G1‐WI, Reg. no. GP‐606, PI 698626; TropicS‐G2‐WI, Reg. no. GP‐607, PI 698627). Additional generations of selection were performed for the DE lineage (TropicS‐G3‐DE, Reg. no. GP‐611, PI 698631; TropicS‐G4‐DE, Reg. no. GP‐612, PI 698632; TropicS‐G5‐DE, Reg. no. GP‐613, PI 698633). The parallel‐selected maize population is a novel resource for breeders and those seeking to investigate adaptation.

Evaluating Artificial Diets for the Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) through Nutritional Indices and an Age-Stage, Two-Sex Life Table Approach

Spodoptera frugiperda (J.E. Smith) is an invasive and key pest of maize, which has been recently introduced to South India. There are two strains reported, viz. rice strain and maize strain. Though several diets were tried in different parts of the world, none of them contained rice leaf powder as a component from natural host. Hence a study was conducted to evaluate the biology, nutritional indices, age-stage and two-sex life table to assess the suitability of the different artificial diets for S. frugiperda larval development. Six differently modified artificial diets were tested to evaluate the following biological parameters: duration of larva and pupae, survival of larvae and pupae, pupal weight, sex ratio, fecundity, adult pre-oviposition period, total pre-oviposition period, adult longevity and total lifespan. The following nutritional indices were determined: growth rate, relative growth rate, consumption rate, consumption index, approximate digestibility, efficiency of conversion of ingested food, efficiency of conversion of digested food and metabolic cost. Larval development showed a significant difference among the diets, in relation to the life table parameters. The results indicated that optimal growth, development and food utilisation by S. frugiperda occurred in the mixture of rice leaf powder and chickpea flour-based diet followed by the mixture of maize leaf powder and common bean powder-based diet. Evaluated diets also had a significant effect on the net reproductive rate, gross reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time and population doubling time. The values of these parameters were higher in the mixture of rice leaf powder and chickpea flour-based diet followed by mixture of maize leaf powder and common bean powder-based diet. Based on the results, the most adequate diet for rearing in the laboratory was the mixture of rice leaf powder and chickpea flour-based diet.

Assessment of genetic diversity of Turkish maize landraces for phytic acid and total phenolic contents

Assessment of genetic diversity of Turkish maize landraces for phytic acid and total phenolic contents

Polyphenol-based nuclear magnetic resonance non-targeted metabolomics of temperature- and time-controlled blue and red maize sprouting

Zea mays L corps apport to human consumption, complex matrices of compounds such as free and bounded phenolics, flavonoids and anthocyanins with high nutritional values and proved health benefits, which are dynamically synthesized since sprouting of grains. This study presents for the first time a Nuclear Magnetic Resonance (NMR) non-targeted metabolomics study of aqueous methanolic extracts of Mexican native blue and red Zea mays L. sprouts, produced with a specific germination scheme, at three different controlled temperatures. The proposed model comprises the rationalization of (poly)-phenolics metabolism dynamics as a function of sprouting time and temperature, which can be identified by more than thirty 1H NMR discriminant resonances at a chemical shift range between 7.7 and 6.3 ppm -mostly comprising typical hydroxyphenyl polyphenolic 1H frequencies- obtained with multivariate statistical analysis. Both principal component (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) reveal a unique maize strain-, temperature- and time-dependent mapping of polyphenolic machinery during sprouting that might serve for optimizing germination schemes. Strengths and limitations of PCA and OPLS-DA analysis of non-targeted (poly)-phenolics NMR data matrix obtained from different blue and red maize sprouts’ methanolic extracts are discussed. Furthermore, a clear inverse correlation between temperature- and time-dependent signal intensity modulation of phenolic resonances and water line widths at half height is observed, suggesting a mechanism of how solvent could participate within the complex metabolomic matrix formation during germination. Finally, non-targeted NMR metabolomics data from sprouts’ methanolic extracts are contrasted with temperature- and time-dependent total phenolic contents obtained with standard quantitative methods.

Tracing the Origin and Evolutionary History of Pyricularia oryzae Infecting Maize and Barnyard Grass.

Blast disease is a notorious fungal disease leading to dramatic yield losses on major food crops such as rice and wheat. The causal agent, Pyricularia oryzae, encompasses different lineages, each having a different host range. Host shifts are suspected to have occurred in this species from Setaria spp. to rice and from Lolium spp. to wheat. The emergence of blast disease on maize in Iran was observed for the first time in the north of the country in 2012. We later identified blast disease in two additional regions of Iran: Gilan in 2013 and Golestan in 2016. Epidemics on the weed barnyard grass (Echinochloa spp.) were also observed in the same maize fields. Here, we showed that P. oryzae is the causal agent of this disease on both hosts. Pathogenicity assays in the greenhouse revealed that strains from maize can infect barnyard grass and conversely. However, genotyping with simple sequence repeat markers and comparative genomics showed that strains causing field epidemics on maize and on barnyard grass are different, although they belong to the same previously undescribed clade of P. oryzae. Phylogenetic analyses including these strains and a maize strain collected in Gabon in 1985 revealed two independent host-range expansion events from barnyard grass to maize. Comparative genomics between maize and barnyard grass strains revealed the presence or absence of five candidate genes associated with host specificity on maize, with the deletion of a small genomic region possibly responsible for adaptation to maize. This recent emergence of P. oryzae on maize provides a case study to understand host range expansion. Epidemics on maize raise concerns about potential yield losses on this crop in Iran and potential geographic expansion of the disease.

Effects of genetically modified maize expressing Cry1Ab and EPSPS proteins on Japanese quail

A 49-d feeding study was conducted to evaluate the effects of the genetically modified (GM) maize strain C0030.3.5 on Japanese quails (Coturnix japonica) in terms of body performance and egg quality. Furthermore, the bodily fats of transgenic proteins in the Japanese quails were investigated. The results showed that the parameters body weight, hematology, serum chemistry, relative organ weight, and histopathological appearance were normal in male and female quails that consumed GM diets, and no differences could be attributed to the varying diets in regard to the laying performances or nutrient egg compositions between the groups. Furthermore, the transgenic Cry1Ab and EPSPS proteins were undetectable by Western blot in the blood, organ, fecal, and whole egg samples of quails fed a diet containing GM maize. The results obtained after 49 d suggested that consumption of C0030.3.5 transgenic feed did not adversely affect quail health or egg quality, and there was no evidence of transgenic protein translocation to the blood, tissues, feces, and eggs. Based on the different parameters assessed, C0030.3.5 transgenic maize is a safe food source for quails that does not differ in quality from non-GM maize.

Genetic mapping of northern corn leaf blight-resistant quantitative trait loci in maize.

Northern corn leaf blight (NCLB), a corn disease infected by Exserohilum turcicum, can cause loss of harvest and economy. Identification or evaluation of NCLB-resistant quantitative trait loci (QTL) and genes could improve maize breeds. This study aimed to identify novel QTLs for NCLB-resistance.Two maize strains (BB and BC) were utilized to generate B73 × B97 and B73 × CML322 and constructed the genetic linkage using high-throughput single nucleotide polymorphism (SNP) linkage map analysis of 170 (BB) and 163(BC) recombinant inbred line (RIL) genomic DNA samples. NCLB-resistant QTL was associated with phenotypic data from the field trial of 170 BB and 163 BC strains over two years using these 1100 SNPs to identify high-density NCLB-resistant QTLs.In BB, QTL of the NCLB resistance was on chromosome 1 and 3 (LOD scores between 2.74 and 5.44); in BC, QTL of NCLB resistance was on chromosome 1, 2, 4, 8, and 9 (LOD scores between 2.52 and 8.53). A number of genes or genetic information related to NCLB resistance in both BB and BC were identified with the maximum number of genes/NCLB resistance-related QTL on chromosome 3 for BB and on chromosome 1 for BC.This study successfully mapped and identified NCLB-resistant QTL and genes for these 2 different maize strains, which provides insightful information for future study of NCLB-resistance and selection of NCLB-resistant maize variants.

Standardization of PCR and sequencing-based methods for the detection of the presence of CP4 EPSPS gene in Zea mays

With the rise in planting of transgenic cultivars in Brazil as well as worldwide, the demand for legal regulations has increased. The transgenic event MON88017 is often found in maize cultivars marketed in Brazil. The event contains the CP4 EPSPS and cry3Bb1 genes, which encode tolerance to the herbicide glyphosate and resistance to caterpillars, respectively. Globally, methodologies to track transgenic events are mandatory. The objective of this study was to standardize a method based on qualitative PCR and sequencing for detection of the CP4 EPSPS gene in Zea mays. DNA was extracted from three commercial strains of transgenic maize, containing the MON88017 event, as well as conventional maize. Primers were designed for partial detection of the zein and CP4 EPSPS genes. PCR reactions were performed for detection of partial regions of CP4 EPSPS and Zein (as endogenous marker of Z. mays) genes. The three transgenic maize inbred lines tested positive for zein and CP4 EPSPS, and the two conventional strains tested negative for CP4 EPSPS and positive for the Zein gene. To confirm the presence of the genic regions, PCR products were sequenced and showed 100% identity with sequences of Zein and CP4 EPSPS genes deposited in GenBank. Thus, the results of this study suggest the applicability of an ‘in-house’ method for the qualitative detection of CP4 EPSPS in genetically modified maize cultivars.

Management, Analyses, and Distribution of the MaizeCODE Data on the Cloud

MaizeCODE is a project aimed at identifying and analyzing functional elements in the maize genome. In its initial phase, MaizeCODE assayed up to five tissues from four maize strains (B73, NC350, W22, TIL11) by RNA-Seq, Chip-Seq, RAMPAGE, and small RNA sequencing. To facilitate reproducible science and provide both human and machine access to the MaizeCODE data, we enhanced SciApps, a cloud-based portal, for analysis and distribution of both raw data and analysis results. Based on the SciApps workflow platform, we generated new components to support the complete cycle of MaizeCODE data management. These include publicly accessible scientific workflows for the reproducible and shareable analysis of various functional data, a RESTful API for batch processing and distribution of data and metadata, a searchable data page that lists each MaizeCODE experiment as a reproducible workflow, and integrated JBrowse genome browser tracks linked with workflows and metadata. The SciApps portal is a flexible platform that allows the integration of new analysis tools, workflows, and genomic data from multiple projects. Through metadata and a ready-to-compute cloud-based platform, the portal experience improves access to the MaizeCODE data and facilitates its analysis.

Production and evaluation of antifungal stilbenoids in Dracaena cochinchinensis elicited by fungal inoculation

Plants infected by fungal elicitors produce phytoalexins. As one of the most valuable traditional medicines, dragon’s blood is harvested from the trunks of Dracaena cochinchinensis elicited by fungal species. However, the functional metabolites exhibiting antifungal activity in dragon's blood remain unclear. In the current study, three new stilbenoids (1―3), one new chalcone (4), and one new flavane (5), together with one known compound (6), were identified from dragon’s blood of D. cochinchinensis elicited by Fusarium graminearum. Among these compounds, compound 3, (7E)-2,4-dihydroxy-1-methylstilbene, exhibited a broad-spectrum inhibitory activity against four pathogenic fungal strains of maize, including Exserohilum turcicum, Bipolaris maydis, Curvularia lunata, and F. graminearum. Inspiringly, compound 3 showed a stronger inhibitory activity (half-maximal inhibitory concentration, IC50: 11.02 ± 1.12 μg/mL) against the elicited fungus F. graminearum than that of a commercial fungicide, nystatin (IC50: 16.23 ± 3.10 μg/mL). Additionally, a dramatically low electron density was observed in the cell walls of F. graminearum, suggesting that compound 3 might exert its function by directly targeting cell walls. Compound 3 also showed potent antioxidant activities, which was validated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical inhibition assays. Collectively, our findings highlight that stilbenoids in dragon’s blood of D. cochinchinensis have promising potential for the future development of natural fungicides for organic farming.

Identification of maize (Zea mays L.) progeny genotypes based on two probabilistic approaches: Logistic regression and naïve Bayes

We used two probabilistic methods, Gaussian Naïve Bayes and Logistic Regression to predict the genotypes of the offspring of two maize strains, the BLC and the JNE genotypes, based on the phenotypic traits of the parents. We determined the prediction performance of the two models with the overall accuracy and the area under the receiver operating curve (AUC). The overall accuracy for both models ranged between 82% and 87%. The values of the area under the receiver operating curve were 0.90 or higher for Logistic Regression models, and 0.85 or higher for Gaussian Naïve Bayes models. These statistics indicated that the two models were very effective in predicting the genotypes of the offspring. Furthermore, both models predicted the BLC genotype with higher accuracy than they did the JNE genotype. The BLC genotype appeared more homogeneous and more predictable. A Chi-square test for the homogeneity of the confusion matrices showed that in all cases the two models produced similar prediction results. That finding was in line with the assertion by Mitchell (2010) who theoretically showed that the two models are essentially the same. With logistic regression, each subset of the original data or its corresponding principal components produced exactly the same prediction results. The AUC value may be viewed as a criterion for parent-offspring resemblance for each set of phenotypic traits considered in the analysis.