Not Available

Not AvailableMaize is a versatile cereal crop having the highest genetic potential, production, and productivity. In the past few decades, plant tissue culture and transformation approaches have played an important role in maize improvement via introducing beneficial transgene(s) or modulating the expression of the endogenous gene(s), etc. However, the capability of in vitro regeneration in maize is highly influenced by genotypes, type of explants, media compositions among others. Some genotypes are more amenable to tissue culture producing embryogenic calli, while others are recalcitrant to tissue culture. Genotypic differences in morphogenesis and organogenesis are generally reported that might be possible due to differences in endogenous hormone levels. The in vitro regeneration potential in maize is usually decreased during the channelized path of tissue maturation, therefore embryogenic callus is mostly achieved from immature zygotic embryos. The present article aimed to provide the current state of the art in maize somatic embryogenesis. Further, the article describes the procedure for maize whole plant regeneration from embryogenic callus.Not Availabl

Meta-QTL analysis for mining of candidate genes and constitutive gene network development for fungal disease resistance in maize (Zea mays L.)

Not AvailableThe development of resistant maize cultivars is the most effective and sustainable approach to combat fungal diseases. Over the last three decades, many quantitative trait loci (QTL) mapping studies reported numerous QTL for fungal disease resistance (FDR) in maize. However, different genetic backgrounds of germplasm and differing QTL analysis algorithms limit the use of identified QTL for comparative studies. The meta-QTL (MQTL) analysis is the meta-analysis of multiple QTL experiments, which entails broader allelic coverage and helps in the combined analysis of diverse QTL mapping studies revealing common genomic regions for target traits. In the present study, 128 (33.59%) out of 381 reported QTL (from 82 studies) for FDR could be projected on the maize genome through MQTL analysis. It revealed 38 MQTL for FDR (12 diseases) on all chromosomes except chromosome 10. Five MQTL namely 1_4, 2_4, 3_2, 3_4, and 5_4 were linked with multiple FDR. Total of 1910 candidate genes were identified for all the MQTL regions, with protein kinase gene families, TFs, pathogenesis-related, and disease-responsive proteins directly or indirectly associated with FDR. The comparison of physical positions of marker-traits association (MTAs) from genome-wide association studies with genes underlying MQTL interval verified the presence of QTL/candidate genes for particular diseases. The linked markers to MQTL and putative candidate genes underlying identified MQTL can be further validated in the germplasm through marker screening and expression studies. The study also attempted to unravel the underlying mechanism for FDR resistance by analyzing the constitutive gene network, which will be a useful resource to understand the molecular mechanism of defense-response of a particular disease and multiple FDR in maize.Not Availabl

Role of soluble, cell wall bound phenolics, tannin and flavonoid contents in maize resistance to pink stem borer Sesamia inferens Walker

The pink stem borer Sesamia inferens Walker is an important pest of winter maize which causes significant yieldlosses. In an attempt to identify the biochemical basis of resistance against S. inferens, total soluble phenolics, boundphenolics, cell wall-bound hydroxycinnamic acids-p-coumaric acid (p-CA), ferulic acid (FA), total tannin contentand total flavonoid contents, were measured in leaf at 10, 20 days after germination (DAG); stem at 20, 40 DAG;pith and rind tissues at 60 DAG (stem differentiated). From the present study, it was found that bound phenolics,p-CA, ferulic acid and total tannin contents contribute to the maize defense mechanism against S. inferens. Totalbound phenolic content showed negative correlation with Leaf Injury Rating (LIR). Highly significant strong positivecorrelation (+0.9750) was observed between LIR and total soluble phenolics in leaf tissue at 20 DAG. Similarlyhighly significant strong positive correlation between LIR and total tannins (+0.9354**) and flavonoids (+0.9582**)in pith at 60 DAG was observed. Further, a strong significant positive correlation was also observed between LIRand p-CA (+0.9199*) in pith at 60 DAG and total ferulic acid (+0.9051*) in rind at 60 DAG. The significant strong negativecorrelation between LIR and p-CA (-0.8441*) in stem at 40 DAG was observed. The total bound phenolicsin rind at 60 DAG (0.756), in leaf at 20 DAG (0.681), and total soluble phenolics in the stem at 20 DAG (0.685) showedhigher loadings with PC1, PC2, and PC3, respectively. Genotype-by-biochemical factor biplot showed that thedata of biochemical parameters measured in different tissues and stages could be able to group the genotypesaccording to their reaction to S. inferens

Time course evaluation of provitamin A carotenoids stored under different storage regimens in maize

Yellow maize is natural source of provitamin A components. However, the provitamin A carotenoids are known to degrade fast as a result of oxidation and isomerization due to exposure to heat and oxygen during storage. Keeping this in view, here, we evaluated the provitamin A carotenoids in maize stored under different storage conditions. For this purpose, F2 grains of six hybrids consisting of two provitamin A rich, two QPM and two normal maize were stored in earthen pot, aluminium box, cotton cloth and jute bag for a period of 6 months under ambient temperature and carotenoid components were estimated at monthly interval. Provitamin A components are found to reduce significantly within two to six months under various storage conditions. However, the samples stored in aluminium box exhibited least degradation of β-carotene (73%) and β-cryptoxanthin (81%), whereas those stored in earthen pot exhibited highest degradation of β-carotene (86%) and β-cryptoxanthin (90%), after six months of storage. The provitamin A rich hybrids especially APH27 retained highest concentration of provitamin A carotenoids after six months of storage. The least losses observed in the samples stored in aluminium box may be attributed to reduced oxidation and least light penetration

Genetic Divergence in Northern Benin Sorghum ( Sorghum bicolor

Sorghum [Sorghum bicolor (L.) Moench] is an important staple food crop in northern Benin. In order to assess its diversity in Benin, 142 accessions of landraces collected from Northern Benin were grown in Central Benin and characterised using 10 qualitative and 14 quantitative agromorphological traits. High variability among both qualitative and quantitative traits was observed. Grain yield (0.72–10.57 tons/ha), panicle weight (15–215.95 g), days to 50% flowering (57–200 days), and plant height (153.27–636.5 cm) were among traits that exhibited broader variability. Correlations between quantitative traits were determined. Grain yield for instance exhibited highly positive association with panicle weight (r=0.901, P=0.000) and 100 seed weight (r=0.247, P=0.000). UPGMA cluster analysis classified the 142 accessions into 89 morphotypes. Based on multivariate analysis, twenty promising sorghum genotypes were selected. Among them, AT41, AT14, and AT29 showed early maturity (57 to 66 days to 50% flowering), high grain yields (4.85 to 7.85 tons/ha), and shorter plant height (153.27 to 180.37 cm). The results obtained will help enhancing sorghum production and diversity and developing new varieties that will be better adapted to the current soil and climate conditions in Benin

Genetic and molecular understanding for the development of methionine-rich maize: a holistic approach

Maize (Zea mays) is the most important coarse cereal utilized as a major energy source for animal feed and humans. However, maize grains are deficient in methionine, an essential amino acid required for proper growth and development. Synthetic methionine has been used in animal feed, which is costlier and leads to adverse health effects on end-users. Bio-fortification of maize for methionine is, therefore, the most sustainable and environmental friendly approach. The zein proteins are responsible for methionine deposition in the form of δ-zein, which are major seed storage proteins of maize kernel. The present review summarizes various aspects of methionine including its importance and requirement for different subjects, its role in animal growth and performance, regulation of methionine content in maize and its utilization in human food. This review gives insight into improvement strategies including the selection of natural high-methionine mutants, molecular modulation of maize seed storage proteins and target key enzymes for sulphur metabolism and its flux towards the methionine synthesis, expression of synthetic genes, modifying gene codon and promoters employing genetic engineering approaches to enhance its expression. The compiled information on methionine and essential amino acids linked Quantitative Trait Loci in maize and orthologs cereals will give insight into the hotspot-linked genomic regions across the diverse range of maize germplasm through meta-QTL studies. The detailed information about candidate genes will provide the opportunity to target specific regions for gene editing to enhance methionine content in maize. Overall, this review will be helpful for researchers to design appropriate strategies to develop high-methionine maize

Not Available

Not AvailableGlobally, maize is an important cereal food crop with the highest production and productivity. Among the biotic constraints that limit the productivity of maize, the recent invasion of fall armyworm (FAW) in India is a concern. The first line of strategy available for FAW management is to evaluate and exploit resistant genotypes for inclusion in an IPM schedule. Screening for resistant maize genotypes against FAW is in its infancy in India, considering its recent occurrence in the country. The present work attempts to optimize screening techniques suited to Indian conditions, which involve the description of leaf damage rating (LDR) by comparing injury levels among maize genotypes and to validate the result obtained from the optimized screening technique by identification of lines potentially resistant to FAW under artificial infestation. Exposure to 20 neonate FAW larvae at the V 5 phenological stage coupled with the adoption of LDR on a 1–9 scale aided in preliminary characterize maize rize maize genotypes as potentially resistant, moderately resistant, and susceptible. The LDR varies with genotype, neonate counts, and days after infestation. The genotypes, viz., DMRE 63, DML-163-1, CML 71, CML 141, CML 337, CML 346, and wild ancestor Zea mays ssp. parviglumis recorded lower LDR ratings against FAW and can be exploited for resistance breeding in maize.ICAR-NAS

Not Available

Not AvailablePhytic acid (PA) is an important antinutritional component in maize that affects the availability of major micro-nutrients like di- and multivalent mineral cations like iron (Fe) and zinc (Zn). The long-term consumption of maize as a staple food crop leads to micronutrient malnutrition especially iron and zinc deficiency in the human population. In addition, it also acts as a storehouse of a major part of mineral phosphorous (P), approximately 80% of the total P stored as phytate P is not available to monogastric animals like humans and poultry birds, and it gets excreted as such, leading to one of the major environmental pollution called eutrophication. Of the various low phytic acid (lpa) mutants, lpa2-2 generated through mutagenesis reduces PA by 30%. BML 6 and BML 45, the parents of the popular maize hybrid DHM 121 with high PA were selected to introgress lpa2-2 through marker-assisted backcross breeding (MABB). The percent recurrent parental genome (RPG) in the selected BC2F2 plants ranged from 88.68 to 91.04% and 90.09–91.51% in the genetic background of BML 6 and BML 45, respectively. Based on the highest percentage of RPG, best five BC2F2 plants, viz., #3190, #3283, #3230, #3263 and #3292 with RPG 88.68–91.04% in the genetic background of BML 6 and #3720, #3776, #3717, #3828 and #3832 with RPG 90.09–91.51% in the genetic background of BML 45 were advanced to BC2F3. The newly developed near-isogenic lines (NILs) possessed low phytate content (2.37 mg/g in BML 6 and 2.40 mg/g in BML 45) compared to 3.59 mg/g and 3.16 mg/g in recurrent parents BML 6 and BML 45, respectively thereby reducing the phytate by an average of 34 and 24 per cent, respectively. These newly developed progenies were similar to their recurrent parents for various morphological traits. These inbreds assume great significance in alleviating Fe and Zn deficiencies in worldwide.Not Availabl

Genetic trends in CIMMYT’s tropical maize breeding pipelines

Fostering a culture of continuous improvement through regular monitoring of genetic trends in breeding pipelines is essential to improve efficiency and increase accountability. This is the first global study to estimate genetic trends across the International Maize and Wheat Improvement Center (CIMMYT) tropical maize breeding pipelines in eastern and southern Africa (ESA), South Asia, and Latin America over the past decade. Data from a total of 4152 advanced breeding trials and 34,813 entries, conducted at 1331 locations in 28 countries globally, were used for this study. Genetic trends for grain yield reached up to 138 kg ha−1 yr−1 in ESA, 118 kg ha−1 yr−1 South Asia and 143 kg ha−1 yr−1 in Latin America. Genetic trend was, in part, related to the extent of deployment of new breeding tools in each pipeline, strength of an extensive phenotyping network, and funding stability. Over the past decade, CIMMYT’s breeding pipelines have significantly evolved, incorporating new tools/technologies to increase selection accuracy and intensity, while reducing cycle time. The first pipeline, Eastern Africa Product Profile 1a (EA-PP1a), to implement marker-assisted forward-breeding for resistance to key diseases, coupled with rapid-cycle genomic selection for drought, recorded a genetic trend of 2.46% per year highlighting the potential for deploying new tools/technologies to increase genetic gain

Not Available

Not AvailableRapid generation of genome and transcriptome data from various research projects across the globe resulted in the accumulation of enormous amounts of data of various crop species or groups of crops. These data are organized and stored in different databases, which offers userfriendly search and retrieval of the desired information for further analyses and use. The information in these databases is used to develop DNA-based markers such as SSRs and SNPs, which are the most popular genomics resources applied for QTL mapping and marker-assisted selection. Several bioinformatics resources such as algorithms, stand-alone software, as well as web-based tools are developed by several research groups and made available in the public domain or sold commercially for the rapid and systematic analysis of DNA sequence or gene expression data. Genetic resources such as biparental, multi-parental, natural, as well as mutant populations for various target traits were developed by researchers, which are utilized for the mapping of QTLs as well as identifi cation of candidate genes associated with the traits of interest by the application of genomics tools developed using bioinformatics resources in these mapping populations. This review discusses the most relevant databases useful for sorghum, development of genomics resources such as DNA markers using various bioinformatics tools, and the genetic resources available in sorghum.Not Availabl