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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

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

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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

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

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Not AvailableSorghum acts as a dietary staple for millions of people living in about 30 countries in the subtropical and semi-arid regions of Africa and Asia. It is a source of food and fodder, mostly in the traditional, smallholder farming sector. It also finds a place in the high-input commercial farming sector as a feed crop, and is fast emerging as a biofuel crop. More than 80 % of the global sorghum area is characterized by low yield levels contributing to slightly above half of total grain output whereas the rest comes from the developed world with high yield levels. Though sorghum cultivation is reported from more than 100 countries, only eight countries have over 1 million ha area under sorghum, which together contribute more than 60 % of world sorghum production. In Africa, although only a few countries contribute a major share of area, sorghum is widely distributed and is a major staple food grain in large parts of the continent. In spite of its economic importance, sorghum cropped area around the world has declined over the last four decades at a rate of over 0.15 million ha per year. However, in some countries including Brazil, Ethiopia, Sudan, Australia, Mexico, Nigeria, and Burkina Faso it is expanding, mainly because of new land brought under sorghum cultivation or diversion of a portion of area planted to other crops such as maize and wheat. Global sorghum production peaked during the mid-1980s, and thereafter it declined by about 13–15 %, but not steadily. In almost all the sorghum growing regions except Africa yield levels have been enhanced over the years as a result of improved cultivars, higher input use, better resources, and crop management. Most of the sorghum is consumed in the countries where it is produced and world trade is mainly linked to demand for livestock products, which is governed by the feed requirements and prices in developed countries. Consumption of sorghum for food purposes is declining because of a change in food habits and consumer preference brought about by economic status, whereas use for animal feed and other industrial purposes is increasing. Under a changing climate regime sorghum would assume renewed importance as a food and industrial crop, and therefore concerted focus is necessary on such marginalized crops to ensure food and nutritional security in a sustainable manner in the years to come.Not Availabl

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Not AvailableCereals are members of grass family and play an important role in providing food security to billions of people across the globe since the beginning of agriculture. Cereal crops differ considerably from each other in terms of morphology, adaptation and genetic architecture. This has motivated researchers across the world to study their evolution, genetics and development. During the last few decades, phenomenal progress in genomics research has paved the way for comparative genomic studies across crop species, especially the cereals due to their economic importance. These studies together have revealed a good level of conservation across cereals both at macro and micro level. However, most of the comparative studies in cereals prior to genome sequencing projects have been performed at genetic map level. Large-scale genome sequencing projects during the beginning of the twenty-first century, especially in rice, sorghum, maize, barley, wheat and foxtail millet, led to better understanding of the conservations of genes/genomic regions at sequence level. This chapter reviews the status of cereal comparative genomics prior to genome sequencing and progress post-genome sequencing of major cereals. The genomic organization of major cereals has been discussed in detail. The chapter also describes the distinguishing features and the mechanism of evolution of cereal genomes. The advancement in genome sequencing technologies, especially the next-generation sequencing technologies and its effectiveness in performing genomic studies across crops, is also discussed. The various genomic tools, databases and resources for performing comparative genomic studies are reviewed here. The chapter presents the opportunities on how the knowledge gained from comparative genomics of cereals can be used for gene discovery programmes, functional genomics and subsequently genetic improvement of cereal crops.Not Availabl