Maize Accessions Research Articles

Multiplex-ready PCR assay of SSR marker diversity among quality protein maize inbred parental lines

Phenotypic markers have long been used for classification of maize (Zea mays) cultivars. However, because of shortcomings in detecting differences among closely related genotypes, coupled with sensitivity to environmental conditions, molecular marker techniques have been employed in the determination of relationships among parental genotypes at the DNA level. In this study, simple sequence repeat (SSR) multiplex-ready PCR was used to determine the diversity among 24 quality protein maize (QPM) inbred lines. Analysis of SSR loci of the 24 QPM lines yielded 101 scorable alleles with an average of 5.05 alleles per locus. The highest polymorphic information content (0.77) was observed in di-repeat motifs (Bng 11714) and the least (0.15) in tetra-nucleotide repeat motifs (Phi 053). The expected and observed mean heterozygosities were 0.62 and 0.11, respectively. These values showed deviation from the Hardy–Weinberg equilibrium, an affirmation of genetic diversity among the maize accessions. UPGMA cluster analysis resolved four major clusters with grouping patterns consistent with ancestry information. The results indicate that the multiplex-ready PCR technique could avail breeders in developing countries, especially Africa where research funding is limited, the opportunity of making use of marker techniques in breeding programmes because it is highly economical and time efficient.

Strand-specific RNA-Seq transcriptome analysis of genotypes with and without low-phosphorus tolerance provides novel insights into phosphorus-use efficiency in maize.

BackgroundPhosphorus (P) stress is a global problem in maize production. Although macro/microarray technologies have greatly increased our general knowledge of maize responses to P stress, a greater understanding of the diversity of responses in maize genotypes is still needed.ResultsIn this study, we first evaluated the tolerance to low P of 560 accessions under field conditions, and selected the low P-tolerant line CCM454 and the low P-sensitive line 31778 for further research. We then generated 24 strand-specific RNA libraries from shoots and roots of CCM454 and 31778 that had been subjected to P stress for 2 and 8 days. The P deficiency-responsive genes common to CCM454 and 31778 were involved in various metabolic processes, including acid phosphatase (APase) activity. Determination of root-secretory APase activities showed that the induction of APase by P stress occurred much earlier in CCM454 than that in 31778. Gene Ontology analysis of differentially expressed genes (DEGs) and CAT/POD activities between CCM454 and 31778 under P-sufficient and -deficient conditions demonstrated that CCM454 has a greater ability to eliminate reactive oxygen species (ROS) than 31778. In addition, 16 miRNAs in roots and 12 miRNAs in shoots, including miRNA399s, were identified as DEGs between CCM454 and 31778.ConclusionsThe results indicate that the tolerance to low P of CCM454 is mainly due to the rapid responsiveness to P stress and efficient elimination of ROS. Our findings increase the understanding of the molecular events involved in the diversity of responses to P stress among maize accessions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0903-4) contains supplementary material, which is available to authorized users.

Keragaman Genetik Inbrida Jagung QPM dan Provit-A Berdasarkan Marka SSRs (Simple Sequence Repeats)

Information on genetic diversity of QPM and Provit-A maize germplasm is important to support breeding program, in order to form a high yielding maize hybrid. Simple sequence repeats (SSR) have been extensively utilized as genetic markers to study the genetic diversity, cultivar identification, and gene mapping. The objectives of this research were to investigate the genetic diversity and to obtain information the genetic relationship among 20 maize accessions using 29 SSRs. The research was carried out at the Moleculer Biology Laboratory of Indonesian Cereals Research Institute (ICERI) in Maros, South Sulawesi. Twenty nine polymorphic primers that covered the 10 maize chromosomes were used to fingerprint the genotype of the lines, detecting 83 allels, with an average allel number of 3 allels per locus, ranging from 2 to 6 alleles per locus. The results indicated that polymorphism information content (PIC) ranged from 0.10 (nc133 and phi072) to 0.74 (phi064) with the average of 0.45. Genetic distance based on genetic similarity estimate ranged from 0.39 to 0.92. The high level of PIC values and wide genetic distances indicated the large variability among maize germplasm. Cluster analysis divided the 20 maize accessions into three groups. Coefficient cofenetic value (r) was 0.85 indicated a good fit based on the genetic similarity value. As many as 30 inbred heterotic recombinants were derived by incorporating 20 QPM and Provit-A with genetic distance of ≤0.65. The SSRs proved to be reliable and is practical technique for revealing the relationship among specialty maize genotypes.

Prospection, Collecte, Nomenclature Paysanne Et Caracterisation Des Variables Qualitatives Des Varietes Locales De Maïs (Zea Mays L.) Cultivees En Cote d’Ivoire

Ivoirian landraces of maize were maintained for several centuries in different ecological conditions, which allowed them to accumulate a large genetic diversity yet little studied. This study aims to make a first inventory of the existing diversity and establish a representative collection of the diversity of this crop in Côte d’Ivoire. Surveys and collection of maize landraces were conducted in three agro-ecological zones of Côte d'Ivoire. Two hundred and forty seven villages were selected and prospect in twentyfour regions. In each village, passport data were collected using the tools and methods of participatory research. A sample of 829 maize accessions were collected. The preliminary characterization of this collection was performed based on the descriptors of maize developed by Bioversity International. The study revealed a significant varietal diversity. Five varieties have been identified based on the color of the grains: yellow maize, white maize, red maize, purple maize and variegated maize. Varieties with yellow grain, with a percentage of 54.16% have been the most prevalent in different areas surveyed. Varieties with purple and red grain have been rare, with respective numbers of 3.38 and 3.62%. Interviews conducted with producers have permitted to inventory 81 local names. The main criteria of farmers to characterize local ecotypes was grains color. The collected accessions are an important gene pool for the present and future generations in the context of plant breeding work.

Morphophysiological Traits Imparting Salinity Tolerance in Maize (Zea mays L.) Hybrids under Saline Water Irrigation in Vertisols

ABSTRACTMaize is categorized as a salt-sensitive crop and identification of fairly salt-tolerant lines is of paramount importance for increasing its production on saline soils. Experiments were conducted in randomized block design with three replications to identify maize accessions showing response to saline water irrigation, traits imparting tolerance, and their effect on yield attributes of maize. Significant variation was present among genotypes for specific leaf area (SLA), potassium (K) content, cob characteristics, yield, biomass, and harvest index. High amount of heritability with large genetic advance indicated the presence of additive gene action for traits like leaf water potential and leaf dry weight. Association analysis revealed high correlation between key traits and direct as well as positive effect of these traits on yield. Principal component analysis resolved three principal components, and high leaf area and water potential were conferring salt tolerance and thus higher yield.

Analysis of Morphological Characteristics for a Core Set of 194 Maize Accessions

Analysis of Morphological Characteristics for a Core Set of 194 Maize Accessions

Genetic architecture of plant height in maize phenotype‐selected introgression families

AbstractThis study aimed at developing, characterizing and evaluating two maize phenotypic‐selected introgression libraries for a collection of dominant plant height (PHT)‐increasing alleles by introgressing donor chromosome segments (DCS) from Germplasm Enhancement of Maize (GEM) accessions into elite inbred lines: PHB47 and PHZ51. Different backcross generations (BC1‐BC4) were developed and the tallest 23 phenotype‐selected introgression families (PIFs) from each introgression library (PHB47 or PHZ51) were selected for single nucleotide polymorphism genotyping to localize DCS underlying PHT. The result shows that most PIFs carrying DCS were significantly (α = 0.01) taller than the respective recurrent parent. In addition, they contained larger donor genome proportions than expected in the absence of selection or random mating across all BC generations. The DCS were distributed over the whole genome, indicating a complex genetic nature underlying PHT. We conclude that our PIFs are enriched for favourable PHT‐increasing alleles. These two libraries offer opportunities for future PHT gene isolation and allele characterization and for breeding purposes, such as novel cultivars for biofuel production.

Marker-assisted identification of maize genotypes with improved protein quality

Currently, more than 70% of maize is used for food and fodder; therefore, an improvement in grain quality can increase its nutritive and energy value. A deficiency of two essential amino acids (lysine and tryptophan) significantly reduces the nutritional quality of maize proteins. However, in comparison to conventional maize varieties, opaque2 (o2) mutants have greater contents of lysine and tryptophan in their endosperm proteins and their bioavailability is better. The aim of the study was to identify the maize accessions with high-quality protein. A collection of maize accessions of various ecogeographical origins was studied by molecular methods. This approach was expected to improve the maize’s breeding efficiency. We collected 54 maize genotypes differing in grain quality performance. Amplification with three specific markers for the opaque-2 gene (phi057, phi112, and umc1066) revealed homozygous recessive o2 genotypes associated with an improved nutritional quality of the protein. UREA-PAG electrophoresis of zein proteins was used for Quality Protein Maize (QPM) identification. In addition to the mutant o2 allele, QPM contains genetic modifiers that convert the starchy endosperm of the o2 mutant to the hard vitreous phenotype. The selected QPM accessions are of interest for maize breeding programs aimed at improving grain quality. The use of the markers for o2 and modifier genes accelerates the development of QPM varieties and significantly reduces the labor and financial costs of their production.

Interception of Wheat mosaic virus (WMoV) in Brazil in maize seeds from the United States

Abstract: The objective of this work was to evaluate the phytosanitary aspect of two accessions of maize (Zea mays) seeds from the United States introduced to Brazil, regarding the presence of Wheat mosaic virus (WMoV). Two to three weeks after sowing, symptomatic leaves were tested by Elisa using specific antiserum to WMoV. The reaction was positive, and leaf samples were analyzed by real-time PCR and amplified PCR products were sequenced. The WMoV isolates had 99 to 100% nucleotide identity with isolates from Australia and the United States. Until now, there is no report of the presence of this virus in Brazil. According to the federal law on plant protection, the plants were burned to avoid the introduction of this exotic pest in the country. The obtained results show WMoV interception in Brazil.

Genetic Diversity and Structure of Maize Accessions of North Western Himalayas Based on Morphological and Molecular Markers

Genetic diversity among 48 maize genotypes was determined using 11 morphological traits, 4 biochemical traits and 29 SSR primers. To assess the genetic diversity, data on morphological traits were recorded during the year 2013–2014 using standard maize descriptors. Eleven morphological traits observed across the 48 maize genotypes showed wide variation and grouped various test genotypes into two clusters. Based on the mean performance of genotypes, LM-19-07 and HKI-1348 were found superior for grain yield/plant, cob length, cob girth, kernel row/ear among all the genotypes. Protein content of LM-02-08 was the highest among all the genotypes. CML193 was found superior for iron and zinc content. Carotenoid content of LM-19-07 was higher as compared to checks. At molecular level, 29 SSR primers amplified 96 polymorphic alleles with an average of 2.16 alleles per primer. Size of amplified alleles ranged from 50 to 500 bp. Mean polymorphic information content was 0.43 showing high level of SSR polymorphism. Cluster analysis based on SSR data differentiated 48 maize genotypes into two major clusters. Bayesian model-based structure analysis assigned genotypes into two clusters and also showed the extent of admixture within individuals. Clustering pattern of maize genotypes based on SSR marker profiles was different from that of morphometric traits. Based on the pooled analysis at morphological, biochemical and molecular level, genotype LM-19-07 was found superior as well as most distant among all the accessions under study. So the genotype LM-19-07 could be used in future breeding programmes for genetic improvement in maize.

Carotenoid composition and antioxidant activity of tortillas elaborated from pigmented maize landrace by traditional nixtamalization or lime cooking extrusion process

Mexican pigmented maize (Zea mays L.) landrace kernels have been scantily evaluated regarding potential as functional food. In this study, eight Mexican pigmented (yellow and red) maize accessions of Tuxpeño, Tabloncillo and Chapalote landraces collected in the northwestern region of Mexico were processed into tortilla to determinate carotenoid profiles, as well as their Oxygen Radical Absorbance Capacity for Lipophilic extract (ORAC-L). The total carotenoid content ranged from 3.66 to 5.56 mg LE/kg DW in the yellow maize and from 1.49 to 3.49 mg LE/kg DW in the red maize among all raw genotypes. Lutein and zeaxanthin were major carotenoids in all pigmented maize, accounting for ∼85% of total carotenoids. The traditional nixtamalization and lime-cooking extrusion process significantly (p < 0.05) decrease total carotenoid and ORAC-L assays when compared to raw kernels. Traditional tortillas retained among 72.0–87.6% and 65.1–78.8% of total carotenoids and ORAC-L levels respectively, compared to 68.8–79.5% and 60.3–75.5% assayed in extruded tortillas. Interestingly, traditional and extruded tortillas maintained more 72.7 and 60%, respectively; of the lutein concentration associated with raw grains. Our results suggest that yellow maize landrace could be considered for the elaboration of nixtamalized food products with nutraceutical potential.

Genetic diversity of maize accessions for maizelethal necrosis disease resistance

Maize is among the most preferred crop in Tanzania and other parts of the world. However, its production has been facing a number of challenges. Maize Lethal Necrosis Disease (MLND) is a new challenge in Eastern Africa. The control of MLND is said to be complicated as it is caused by a combination of more than one virus viz. Maize Chlorotic Mottle Virus (MCMV) and Sugarcane Mosaic Virus (SCMV). Stakeholders agree that the priority is to identify MLND resistant maize varieties. Genetic diversity provides the source of traits required against maize production challenges such as MLND. The study of genetic diversity in maize accessions often involves characterizing morphological plant characteristics as well as molecular marker techniques to study variation at DNA level. This review explores different literatures that address the importance of genetic diversity and the possibility of generating information towards obtaining potential materials against maize challenges and MLND in particular.

Identification of maize-derived dominant gametophyte factors

The use of gametophyte factors to protect specialty-type maize has long been advocated, but as of yet, they have made very little impact on preventing pollen contamination due to the complications associated with breeding with these materials, mainly the additive nature of the alleles. A dominant gametophyte factor (DGF) overcomes this problem, allowing for less time consuming production of gametophytic hybrids, but effectively utilized sources do not exist. Tcb1-s, a known DGF, is a teosinte introgression into maize and the leading candidate for utilization, however, it has several issues that limit its effective use in expediting the breeding process for gametophytic hybrids. The use of maize for a source of DGFs may overcome this problem; with the idea years of selection by farmers would likely have minimized any segregation for yield associated with these alleles, making their use for production of gametophytic hybrids an appealing option for modern breeders. Through screening and backcrossing selected maize accessions, we identified DGFs in seven accessions from race Maiz Dulce, which we document here as a starting point for identification of additional maize-derived DGFs. These accessions did not appear to segregate for yield, a marked improvement over existing DGFs. Additionally, we assessed the compatibility of identified maize-derived DGFs from one accession, and showed that, while lines are generally compatible, they are not obligately so since a single accession may segregate for multiple gametophyte factors. There is, therefore, a need to consider the compatibility of pairs of DGFs early in the inbreeding process. Maize-derived DGFs provide a more effective method of producing gametophytic hybrids, making their production economical enough to be brought to market. The use of DGFs has wider potential to benefit any producers interested in preventing pollen contamination with gametophytic hybrids through the same benefits provided to breeders for organic and other specialty systems. In combination with Ga1-m resistance, maize-derived DGFs provide a long-term gametophytic solution to pollen contamination, in a more expeditious way.

Evolution of DUF1313 family members across plant species and their association with maize photoperiod sensitivity

Proteins of the DUF1313 family contain a highly conserved domain and are only found in plants; they play important roles in most plant functions. In this study, 269 DUF1313 genes from 81 photoautotrophic species were identified; they were classified into three major types based on the amino acid substitutions in the conserved region: IARV, I(S/T/F)(K/R)V, and IRRV. Phylogenic tree constructed from 51 DUF1313 genes from graminoids revealed three clades: A, B1, and B2. Clade B1 was found to have undergone episodic positive selection after a gene duplication event and included four amino acid sites under positive selection. The association between DUF1313 family members and traits investigated in maize indicated that three of four genes (GRMZM2G025646, GRMZM5G877647, GRMZM2G359322, and GRMZM2G382774) were associated with the target traits such as days to silking, days to tasselling, and plant height. The nucleotide diversity of the most primitive and highly conserved DUF1313 gene, ELF4-like4, was the highest in Tripsacum and the lowest in maize. Tajima's D and Fu and Li's D tests revealed that significant purifying selection had occurred in the coding sequence region of this DUF1313 gene in teosinte and maize. No significant signal was detected in the 5′-untranslated region of this gene in each of the three species (maize, teosinte, and Tripsacum) or in any gene regions of Tripsacum. Phylogenetic analyses revealed that the 103 accessions of maize, teosinte, and Tripsacum can be grouped into four clades based on the ELF4-like4 gene sequence similarity. Thus, this gene can be used to determine the relationships between maize and its relatives, and the DUF1313 family members and alleles identified in this study might be valuable genetic resources for molecular marker-assisted breeding in maize.

Effect of traditional nixtamalization on anthocyanin content and profile in Mexican blue maize (Zea mays L.) landraces

Mexican blue maize (Zea mays L.) grains have been poorly evaluated regarding their potential as functional food ingredients. The aims of this research were to identify and quantify anthocyanins from fifteen Mexican blue maize accessions of Elotero Sinaloa landrace recollected in the northwestern region of Mexico. Additionally, the effect of traditional nixtamalization processing on these compounds was evaluated. The acyl type anthocyanins, such as cyanidin-3-(6″-succinylglucoside) (Cy-Suc-Glu) and cyanidin-3-(6″-disuccinylglucoside) (Cy-diSuc-Glu) were the most abundant compounds in blue maize, accounting for 52.1% and 15.6% the total anthocyanins, respectively. Other predominant anthocyanins included cyanidin-3-glucoside (Cy-3-Glu), pelargonidin-3-glucoside (Pg-3-Glu), pelargonidin-3-(6″-malonylglucoside) (Pg-Mal-Glu) and cyanidin-3-(6″-malonyglucoside) (Cy-Mal-Glu). The raw blue maize presented a similar anthocyanins profile dominated by cyanidin derivatives on (86.9% on average). Nixtamalization processing increased the relative percentage of glycosylated anthocyanins (Cy-3-Glu, and Pg-3-Glu) and decreased the acylated anthocyanins (Cy-Suc-Glu, and Cy-diSuc-Glu) when compared to raw kernels. Results obtained indicate that the studied Mexican native blue maize contained anthocyanin patterns predominated by acylated cyanide derivatives. This information could be useful to select the best pigmented maize for the derivation of food products with nutraceutical potential.

Genetic Diversity of Maize Accessions (&amp;lt;i&amp;gt;Zea mays&amp;lt;/i&amp;gt; L.) Cultivated from Benin Using Microsatellites Markers

Maize (Zea mays L.) is the major cereal cultivated in Benin and it is important to know its genetic diversity to improve the yield. The genetic markers of important traits are evaluated in order to improve the maize inbred lines. The aim of this study was to evaluate the genetic diversity of Benin’s maize accessions by SSR marker. Thus, one hundred eighty seven maize accessions from three areas (South, Center and North) were analyzed using three SSR markers. A total of 227 polymorphic bands were produced and showed high genetic diversity (Shannon index = 0.51). The polymorphic information content (PIC) values for the SSR loci ranged from 0.58 to 0.81, with an average of 0.71. Genetic distance-based UPGMA dendrogram showed a genetic differentiation between accessions and they were grouped into four clusters in each area. This work provides necessary information that can be used not only to improve the maize production and conservation but also to better manage genetic species resources in Benin.

Microbiota and Mycotoxins in Trilinear Hybrid Maize Produced in Natural Environments at Central Region in Mexico

Mycotoxigenic fungi and mycotoxins in 3 inbred lines (hybrids resistant to corn ear rot) were identified in twenty samples. The maize (Zea mays) accessions were collected in five plots of two municipalities in High Valley, state of Hidalgo. The fungal population was determined with a microbiological dilution method used two culture media (PDA and ELA), for the detection of mycotoxins with thin layer chromatography with visual inspection in UV light and a direct competitive enzyme-linked immunosorbent (ELISA). The results showed high moisture content in all hybrids evaluated on an average of 38.3% and a 1.8 × 103 UFC/g fungus, values within the permitted limits by the Mexican legislation; however the most prevalent fungi were Fusarium sp. (76%), Alternaria sp. (14%), Penicillium sp. (4%) and Aspergillus sp. (5%), and the species Aspergillus nidulas, Aspergillus flavus, Fusarium verticillioides, Fusarium poae, and Penicillium ochraceum. The aflatoxin concentration was observed in a range from 2 to 13 ng/g and 370 to 660 ng/g to fumonisins. It is concluded that trilinear corn hybrids have a variety of pathogenic potential fungi. The two genetic hybrids showed levels of aflatoxins and fumonisin safe for human consumption, contrary to one hybrid, with a content not suitable for human consumption. A better understanding of genetic hybrids corn will improve predictive mycotoxin contamination.

Genetic studies for drought related traits in temperate maize

Under the INSA Fellowship Programme (2015), thirty genotypes of Maize which included twenty eight inbred lines and two checks maintained at D(K)ARS, SKUAST-K were used for a Comprehensive Assessment of Drought Tolerance in the Department of Crop Physiology, University of Agricultural Sciences, GKVK Bangalore. In this programme the genetic variability for Roots, Water Use Efficiency and Photosynthesis related traits studied to identify contrasts for trait based introgression for drought tolerance. Maize accessions revealed a significant genetic variability for roots, WUE (∆13C). Further significant genetic variability in WUE at single level was also observed. Significant genetic variability in drought tolerance traits was revealed among the maize germplasm lines. The promising lines identified like KDM-932A for root length, KDM-1095 for root volume, KDM-918A for root weight, KDM-954 for epicuticular wax content and KDM- 944A for WUE can be used as trait donor lines to transfer specific traits into a recipient genotype.

Retraction: Cluster and principle component analyses of maize accessions under normal and water stress condition, published in Journal of Agricultural Sciences, 2015, vol. 60, issue 1, pp. 33-48

We would like to inform you that the paper ?Cluster and principle component analyses of maize accessions under normal and water stress condition? by Hafiz Saad Bin Mustafa, Jehanzeb Farooq, Ejaz-ul-Hasan, Tahira Bibi and Tariq Mahmood, published in Journal of Agricultural Sciences, 2015, Volume 60, Issue 1 (pp. 33?48), has been retracted, that is, refuted and is no longer in the archives of this journal. &lt;br&gt;&lt;br&gt;&lt;font color="red"&gt;&lt;b&gt; Link to the retracted article &lt;u&gt;&lt;a href="http://dx.doi.org/10.2298/JAS1501033M"&gt;10.2298/JAS1501033M&lt;/a&gt;&lt;/b&gt;&lt;/u&gt;

Characterization of Maize Collections from Nagaland State of North Eastern Himalayan Region

Traditional cultivars and primitive landraces of maize ( Zea mays L.) are invaluable treasure for humankind. These need to be collected, evaluated, conserved and utilized for increasing agricultural production and quality enhancement. Based on extensive survey, 58 diverse maize accessions were collected from Nagaland state of the North Eastern Himalayan region during year 2011. These collections were evaluated under two different agro-ecological regions located at New Delhi and Shillong using twelve quantitative variables during kharif 2012 and 2013 and nine qualitative traits. Significant variability was observed for the traits studied. The trait mean performance and variability were compared for both the environments and superior collections were identified. This study clearly demonstrated that despite environment-specific adaptations, several accessions are capable of showing high adaptability at region outside their habitat and could be utilized for diversifying the pools and deriving inbred lines with diverse features.