Abiotic Stress Tolerance Traits Research Articles

Genome-wide analysis of the calmodulin-binding transcription activator (CAMTA) gene family in Sesamum indicum L., and its role in abiotic stress tolerance traits

Calmodulin-binding transcription activator (CAMTA) is one of the key transcription factor families possessing calcium receptors (calmodulins, CaM). It modulates the expression levels of genes associated with ontogeny and various biotic and abiotic stress factors. The CAMTA family genes were known to be involved in different abiotic stress in several crop species. However, their functional relevance in sesame remains unexplored. To understand the role of CAMTA in stress tolerance in sesame, we performed a genome-wide analysis to identify the members of the SiCAMTA gene family. We have identified and reported here the five SiCAMTA genes localized on four chromosomes within the sesame genome. In silico analysis of the putative 2-kilobase (kb) promoter regions for these five SiCAMTA genes showed that phytohormone and stress response-related cis-elements were predominated in SiCAMTA2 and SiCAMTA5. Also, we studied its modulated expression levels, with special reference to drought and waterlogging stress. It revealed that the SiCAMTA5 and SiCAMTA2 genes were the most responsive to the studied stress factors. The target prediction and network analysis suggested that SiCAMTAs could bind the CGCG cis element in the target gene promoters and predicted 1202 SiCAMTA target genes in the sesame genome, including abiotic stress-responsive genes viz. LEA, PIP1–2, PPO1, SAP, ARF17, and GA3OX1. These findings were validated using qPCR analysis for five CAMTA and 10 CAMTA target genes and establish a foundation for future functional research of SiCAMTA genes towards sesame stress tolerance.

KASP: a high-throughput genotyping system and its applications in major crop plants for biotic and abiotic stress tolerance.

Advances in plant molecular breeding have resulted in the development of new varieties with superior traits, thus improving the crop germplasm. Breeders can screen a large number of accessions without rigorous and time-consuming phenotyping by marker-assisted selection (MAS). Molecular markers are one of the most imperative tools in plant breeding programmes for MAS to develop new cultivars possessing multiple superior traits. Single nucleotide polymorphisms (SNPs) are ideal for MAS due to their low cost, low genotyping error rates, and reproducibility. Kompetitive Allele Specific PCR (KASP) is a globally recognized technology for SNP genotyping. KASP is an allele-specific oligo extension-based PCR assay that uses fluorescence resonance energy transfer (FRET) to detect genetic variations such as SNPs and insertions/deletions (InDels) at a specific locus. Additionally, KASP allows greater flexibility in assay design, which leads to a higher success rate and the capability to genotype a large population. Its versatility and ease of use make it a valuable tool in various fields, including genetics, agriculture, and medical research. KASP has been extensively used in various plant-breeding applications, such as the identification of germplasm resources, quality control (QC) analysis, allele mining, linkage mapping, quantitative trait locus (QTL) mapping, genetic map construction, trait-specific marker development, and MAS. This review provides an overview of the KASP assay and emphasizes its validation in crop improvement related to various biotic and abiotic stress tolerance and quality traits.

Grafting in Tomato for Improving Abiotic Stress Tolerance, Yield and Quality Traits

Tomato (Solanum lycopersicum L.) is a major vegetable crop worldwide, however, its production is adversely affected by a wide range of abiotic and biotic stresses at various stages of its cultivation. Abiotic stresses, such as drought, salinity, flooding, extreme temperatures and heavy metals can cause morphological, physiological and biochemical changes in the plant, which ultimately affect crop growth, yield and quality. Among various mitigation strategies, grafting technology has emerged as an effective and alternative tool to slow breeding programs to alleviate various biotic and abiotic stresses. Various studies indicated that increased osmolytes accumulation, synthesis of antioxidant enzymes, improved photosynthesis and vigorous root architecture in grafted tomatoes confer tolerance towards abiotic stresses, besides improving plant growth and fruit yields. Moreover, tomato grafting on suitable rootstocks has also a positive effect on the nutritional qualities of fruits, such as, lycopene, β-carotene, ascorbic acid, proteins, etc.). In this review, we have tried to summarize the adverse effects of abiotic stresses in tomatoes and include all possible recent references related to the response of grafted tomatoes using different intra-and/ or inter-specific rootstocks on improving plant growth, yield and quality and alleviation in various abiotic stresses.

Diversity of Phytosterols in Leaves of Wild Brassicaceae Species as Compared to Brassica napus Cultivars: Potential Traits for Insect Resistance and Abiotic Stress Tolerance.

Phytosterols are natural compounds found in all higher plants that have a wide variety of roles in plant growth regulation and stress tolerance. The phytosterol composition can also influence the development and reproductive rate of strict herbivorous insects and other important agronomic traits such as temperature and drought tolerance in plants. In this study, we analysed the phytosterol composition in 18 Brassica napus (Rapeseed/canola) cultivars and 20 accessions belonging to 10 related wild Brassicaceae species to explore diverse and novel phytosterol profiles. Plants were grown in a controlled phytotron environment and their phytosterols were analysed using a saponification extraction method followed by GC-MS from the leaf samples. The B. napus cultivars showed slight diversity in eight phytosterols (>0.02%) due to the genotypic effect, whereas the wild accessions showed significant variability in their phytosterol profiles. Of interest, a number of wild accessions were found with high levels of campesterol (HIN20, HIN23, HUN27, HIN30, SARS2, and UPM6563), stigmasterol (UPM6813, UPM6563, ALBA17, and ALBA2), and isofucosterol (SARS12, SAR6, and DMU2). These changes in individual phytosterols, or ratios of phytosterols, can have a significant implication in plant tolerance to abiotic stress and plant insect resistance properties, which can be used in breeding for crop improvement.

A fast method to evaluate in a combinatorial manner the synergistic effect of different biostimulants for promoting growth or tolerance against abiotic stress

BackgroundAccording to the most popular definition, a biostimulant is any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrient content. Therefore, a biostimulant can help crops to withstand abiotic stress, while maintaining or even increasing productivity. We have previously designed a sequential system, based on two different model organisms, the baker’s yeast Saccharomyces cerevisiae and the plant Arabidopsis thaliana, to evaluate the potential of different natural extracts as biostimulants employing a blind-test strategy.ResultsIn this report, we further expand this concept to evaluate different biostimulants in a combinatorial approach to reveal the potential additive, synergistic or antagonistic effects of different combinations of biostimulants in order to design new formulations with enhanced effects on plant growth or tolerance to abiotic stress. The method is based on yeast assays (growth tests in solid medium, and continuous growth in liquid cultures) and plant assays (mass accumulation in hydroponic culture) to assess effects on early growth.ConclusionsWith this novel approach, we have designed new formulations and quantified the ability to enhance growth and promote biomass accumulation under normal conditions and in the presence of abiotic stresses, such as drought, salinity or cold. This method enables a fast screen of many different products in a combinatorial manner, in order to design novel formulations of natural extracts with biostimulant potential.

Multi-omics intervention in Setaria to dissect climate-resilient traits: Progress and prospects.

Millets constitute a significant proportion of underutilized grasses and are well known for their climate resilience as well as excellent nutritional profiles. Among millets, foxtail millet (Setaria italica) and its wild relative green foxtail (S. viridis) are collectively regarded as models for studying broad-spectrum traits, including abiotic stress tolerance, C4 photosynthesis, biofuel, and nutritional traits. Since the genome sequence release, the crop has seen an exponential increase in omics studies to dissect agronomic, nutritional, biofuel, and climate-resilience traits. These studies have provided first-hand information on the structure, organization, evolution, and expression of several genes; however, knowledge of the precise roles of such genes and their products remains elusive. Several open-access databases have also been instituted to enable advanced scientific research on these important crops. In this context, the current review enumerates the contemporary trend of research on understanding the climate resilience and other essential traits in Setaria, the knowledge gap, and how the information could be translated for the crop improvement of related millets, biofuel crops, and cereals. Also, the review provides a roadmap for studying other underutilized crop species using Setaria as a model.

Untargeted Metabolomics to Explore the Bacteria Exo-Metabolome Related to Plant Biostimulants

The control and development of plant growth promoters is a key factor for the agro-nomy industry in its economic performance. Different genera of bacteria are widely used as natural biostimulants with the aim of enhancing nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of their nutrients content. However, the complete exo-metabolome of the bacteria responsible for the biostimulant effect is still unknown and needs to be investigated. Three bacteria with different biostimulant effects were studied by untargeted metabolomics in order to describe the metabolites responsible for this effect. The pentose phosphate pathway, tryptophan metabolism, zeatin biosynthesis, vitamin B6 metabolism and amino acid metabolism were the highlighted pathways related to bacteria biostimulant activity. These results are related to the plant hormones biosynthesis pathway for auxins and zeatins biosynthesis. Fourteen metabolites were identified as biomarkers of the biostimulant activity. The results suggest a greater relevance of auxins than cytokinin pathways due the importance of the precursors identified. The results show a clear trend of using indole-3-pyruvate and 3-Indoleglycolaldehyde pathways to produce auxins by bacteria. The results demonstrate for the first time that 4-Pyridoxic acid, the fructosamines N-(1-Deoxy-1-fructosyl)phenylalanine and N-(1-Deoxy-1-fructosyl)isoleucine and the tripeptides diprotin A and B are metabolites related to biostimulant capabilities. This study shows how untargeted metabolomic approaches can be useful tools to investigate the bacteria exo-metabolomes related to biostimulant effects.

Loss of GSNOR increases abiotic stress sensitivity via regulating MAPK-ethylene cascade signaling in Solanum lycopersicum L.

Nitric oxide (NO), as a redox molecule, played important role in plant response to environmental stress. Here, we found that loss of tomato S-Nitrosoglutathione reductase ( SlGSNOR ), a critical regulator of NO balance, led to global sensitivity to heat, salt, bicarbonate, and paraquat stresses in tomato, suggesting that SlGSNOR was a positive regulator in tomato against abiotic stresses. In addition, under these stresses, loss of SlGSNOR induced excessive NO accumulation in the roots of the transgenic plant. Bicarbonate accumulation has been a limiting factor of tomato production in the north of China, and there were less reports on the regulation of bicarbonate stress compared with other abiotic stress, therefore, in the following experiment, the mechanism of SlGSNOR function focused on investigating bicarbonate tolerance. Proteomes data indicated that loss of SlGSNOR triggered the expression of proteins in MAPK and ethylene signaling pathway under bicarbonate condition. Importantly, loss of SlGSNOR increased ethylene emission under bicarbonate condition, meaning that ethylene signaling participated in SlGSNOR -mediated tomato bicarbonate stress tolerance. Interestingly, under bicarbonate stress, silencing SlMAPK3 or SlACO1 in SlGSNOR -RNAi tomato partially compromised the sensitivity and ethylene emission. Mechanistically, under bicarbonate stress, silencing SlMAPK3 in SlGSNOR -RNAi tomato plants suppressed the transcription of SlACO1 , whereas silencing SlACO1 in SlGSNOR -RNAi tomato activated the transcription of SlMAPK3 . Collectively, these data demonstrated that SlGSNOR -mediated tomato abiotic stress tolerance was depended on SlMAPK3 - SlACO1 cascade signaling, largely. In addition, the incorporation of global abiotic stress tolerance traits into crop plants may succeed by manipulating GSNOR expression. • Tomato GSNOR was a multiple stress-induced gene. • SlGSNOR was positively regulated tomato heat, salt, bicarbonate, and paraquat tolerance. • SlGSNOR -mediated bicarbonate tolerance was depended on SlMAPK3 - SlACO1 cascade signaling.

Genetic diversity analysis and marker-trait associations in Amaranthus species.

Amaranth (Amaranthus spp.) is a highly nutritious, underutilized vegetable and pseudo-cereal crop. It possesses diverse abiotic stress tolerance traits, is genetically diverse and highly phenotypically plastic, making it an ideal crop to thrive in a rapidly changing climate. Despite considerable genetic diversity there is a lack of detailed characterization of germplasm or population structures. The present study utilized the DArTSeq platform to determine the genetic relationships and population structure between 188 amaranth accessions from 18 agronomically important vegetable, grain, and weedy species. A total of 74, 303 SNP alleles were generated of which 63, 821 were physically mapped to the genome of the grain species A. hypochondriacus. Population structure was inferred in two steps. First, all 188 amaranth accessions comprised of 18 species and second, only 120 A. tricolor accessions. After SNP filtering, a total of 8,688 SNPs were generated on 181 amaranth accessions of 16 species and 9,789 SNPs generated on 118 A. tricolor accessions. Both SNP datasets produced three major sub-populations (K = 3) and generate consistent taxonomic classification of the amaranth sub-genera (Amaranthus Amaranthus, Amaranthus Acnida and Amaranthus albersia), although the accessions were poorly demarcated by geographical origin and morphological traits. A. tricolor accessions were well discriminated from other amaranth species. A genome-wide association study (GWAS) of 10 qualitative traits revealed an association between specific phenotypes and genetic variants within the genome and identified 22 marker trait associations (MTAs) and 100 MTAs (P≤0.01, P≤0.001) on 16 amaranth species and 118 A.tricolor datasets, respectively. The release of SNP markers from this panel has produced invaluable preliminary genetic information for phenotyping and cultivar improvement in amaranth species.

CRISPR-Cas9 based stress tolerance: New hope for abiotic stress tolerance in chickpea (Cicer arietinum).

Plants are subjected to biotic and abiotic stresses regularly, which irreparably harm agricultural production. Eco-friendly and sustainable technology to deal with this challenge is to breed abiotic stress tolerant cultivars. To generate crop plants conferring resistance against stresses, conventional breeding was used in the past, but because of the complex heredity of abiotic stress tolerance traits, such techniques remain insufficient in making greater enhancement. Genome-engineering based on CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats-CRISPR associated protein9) has shown enormous potential in developing climate-resilient cultivars. Likewise, the development of chickpea transgenic lines by knockout of 4CL and REV7 genes exhibits drought tolerance which establishes a foundation for future studies in chickpea. In addition, the CRISPR-Cas9 system can boost yield potential under abiotic stress situations by producing non-transgenic plants having the required characteristics. This review article discusses the validation of gene function based on the CRISPR-Cas9 for the development of abiotic stress-tolerant crop plants, emphasizing the chickpea to open the new ventures of generating abiotic stress-tolerant chickpea varieties.

Expanding Gene-Editing Potential in Crop Improvement with Pangenomes.

Pangenomes aim to represent the complete repertoire of the genome diversity present within a species or cohort of species, capturing the genomic structural variance between individuals. This genomic information coupled with phenotypic data can be applied to identify genes and alleles involved with abiotic stress tolerance, disease resistance, and other desirable traits. The characterisation of novel structural variants from pangenomes can support genome editing approaches such as Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR associated protein Cas (CRISPR-Cas), providing functional information on gene sequences and new target sites in variant-specific genes with increased efficiency. This review discusses the application of pangenomes in genome editing and crop improvement, focusing on the potential of pangenomes to accurately identify target genes for CRISPR-Cas editing of plant genomes while avoiding adverse off-target effects. We consider the limitations of applying CRISPR-Cas editing with pangenome references and potential solutions to overcome these limitations.

Construction of a collection of introgression lines of “Texas” almond DNA fragments in the “Earlygold” peach genetic background

Peach [Prunus persica L. Batsch] is one of the major temperate fruit tree species, the commercial materials of which have a low level of genetic variability. Almond [P. dulcis (Mill) DA Webb], a close relative of peach cultivated for its kernels, has a much higher level of diversity. The species are inter-compatible and often produce fertile hybrids, almond being a possible source of new genes for peach that could provide biotic and abiotic stress tolerance traits. In this paper we describe the development of a collection of peach-almond introgression lines (ILs) having a single fragment of almond (cv. Texas) in the peach background (cv. Earlygold). Lines with few introgressions were selected with markers from successive generations from a “Texas” × “Earlygold” F1 hybrid, initially using a set of SSRs and later with the 18 k peach SNP chip, allowing for the final extraction of 67 lines, 39 with almond heterozygous introgressions covering 99% of the genome, and 28 with homozygous introgressions covering 83% of the genome. As a proof of concept, four major genes and four quantitative characters were examined in the selected ILs giving results generally consistent with previous information on the genetics of these characters. This collection is the first of its kind produced in a woody perennial species and promises to be a valuable tool for genetic analyses, including dissection of quantitative traits, positional cloning, epistasis and as prebreeding material to introgress almond genes of interest into the peach commercial gene pool.

Improvement of grain yield under moisture and heat stress conditions through marker-assisted pedigree breeding in rice (

Enhancement of rice (Oryza sativa L.) productivity under rainfed ecosystems is important to food security. Efforts to increase yield have had little success, mainly due to the complexity of inheritance of abiotic stress tolerance traits and the technical challenges of phenotyping these traits. The study was conducted to pyramid quantitative trait loci (QTLs) governing tolerance to moisture and heat stress from cv. Nagina22 and QTLs for high yield traits from variety IR64, with the aid of marker-assisted pedigree breeding. From the IR64/N22 cross, we identified 14 pyramided lines with various combinations of targeted QTLs (5–11 QTLs). The three best lines that performed well under moisture stress conditions were PL76 with two water-use efficiency (WUE) QTLs (Mr19a, SLA 9.1), three drought-tolerant yield (DTY) QTLs (qDTY1.2, qDTY3.2, qDTY6.1), one heat-tolerance (HT) QTL (qSSPF10) and four yield QTLs (qFLW4.1, qFLL9, LP1, GW5); PL476 with two WUE QTLs (%N11.1, qWue7a), two DTY QTLs (qDTY6.1, qDTY12.1), two HT QTLs (qSSPF10, qHT6) and three yield QTLs (qFLW4.1, qFLL9, LP1); and PL130 with two WUE QTLs (Mr19a, qWue7a), four DTY QTLs (qDTY1.2, qDTY3.2, qDTY4.1, qDTY12.1), two HT QTLs (qSSPF10, qHT6) and two yield QTLs (qFLW4.1, LP1). These three lines shown a yield advantage of 51.93%, 55.93% and 60.30%, respectively, over high-yielding IR64. Under heat stress, PL457 and PL130 with HT QTLs qSSPF10 and qHT6 showed 85.02% and 61.55% yield advantage, respectively, over IR64. In conclusion, we have demonstrated that the systematic combination of important QTLs from two contrasting parents through marker-assisted pedigree breeding is an outstanding approach to supplement conventional phenotype-based pedigree breeding, especially to improve complex traits such as yield and tolerance to moisture stress and heat.

Evolutionary innovations driving abiotic stress tolerance in C4 grasses and cereals.

Grasslands dominate the terrestrial landscape, and grasses have evolved complex and elegant strategies to overcome abiotic stresses. The C4 grasses are particularly stress tolerant and thrive in tropical and dry temperate ecosystems. Growing evidence suggests that the presence of C4 photosynthesis alone is insufficient to account for drought resilience in grasses, pointing to other adaptations as contributing to tolerance traits. The majority of grasses from the Chloridoideae subfamily are tolerant to drought, salt, and desiccation, making this subfamily a hub of resilience. Here, we discuss the evolutionary innovations that make C4 grasses so resilient, with a particular emphasis on grasses from the Chloridoideae (chloridoid) and Panicoideae (panicoid) subfamilies. We propose that a baseline level of resilience in chloridoid ancestors allowed them to colonize harsh habitats, and these environments drove selective pressure that enabled the repeated evolution of abiotic stress tolerance traits. Furthermore, we suggest that a lack of evolutionary access to stressful environments is partially responsible for the relatively poor stress resilience of major C4 crops compared to their wild relatives. We propose that chloridoid crops and the subfamily more broadly represent an untapped reservoir for improving resilience to drought and other abiotic stresses in cereals.

Exploration of wheat wild relative diversity from Lahaul valley: a cold arid desert of Indian Himalayas

Climate change is causing a huge loss in biodiversity throughout the globe and the rate has accelerated in recent years. Plant diversity of temperate regions has continuously suffered due to this. The importance of conservation of wild relatives/species of staple crop such as Elymus, Leymus, Thinopyrum, Lolium either in situ or ex situ is essential to sustain these resources for future use due to their ability to withstand in a stressful environment. Thus plant researchers are always in a quest to explore novel species to enhance the genetic diversity of wild crop relatives to improve the resilience of staple crops to a wide range of stress conditions. Keeping these viewpoints in mind, in 2016–2018, we have explored the Lahaul valley, a cold arid region of District Lahaul and Spiti, Himachal Pradesh. A total of 230 accessions of four different species belonging to genus Elymus viz-E. semicostatus (Nees ex steud.) Meld., E. repens Gould, E. dahuricus Turrcz Ex Griseb. and E. longiaristatus (Boiss.) Tzvelev subsp. Canaliculatus (Nevski) Tzvelev belonging to the family Poaceae, tribe Triticeae were taken into consideration. Wide-range of variability was observed at an inter-and intraspecific level among these species. The variations in morphological characters at different ecological amplitudes were recorded. The presence of variation in abiotic stress tolerance traits such as spike pigmentation, low seed shattering, dense pubescence, waxiness was observed. Forty traits were recorded during field evaluation to ease wheat breeders and researchers to identify germplasm during the collection at an in situ level. The population of these four species had a variation for qualitative and quantitative traits at different ecological regimes at their native habitat suggesting their adaptability to a particular niche. Pre-breeding on these germplasm resources could be initiated for introgression novel alleles in wheat to mitigate environmental constraints posed by changing climate.

Maize spermosphere bacterial endophytes and their biotic and abiotic stress tolerance traits

In the present study, 12 bacterial endophytes (C1 to C12) were isolated from three different genotypes of maize seed (COH6). Seed endophytes are considered as pioneers of plant microbiome and enhance the plant defense response at an early stage of crop growth and later stages of seedling development. The seed-associated endophytes exhibit the antagonistic property against the fungal pathogen (Fusarium oxysporum and Macrophomina phaseolina) of maize. Among 12 isolates, C11 suppressed the mycelial growth of both the tested pathogens. Furthermore, the selected isolates were subjected to in vitro abiotic stress tolerance such as salt, drought and temperature stress. The isolates C3, C5, C7, and C12 showed increased tolerance to drought, salt and temperature stress and might assist the host plant in alleviating the ill-effects of abiotic stress on maize. On a whole, microbial isolates associated with the seeds could be a better candidate in biotic and abiotic stress tolerance and would develop those isolates as consortia for obtaining desirable growth in maize.

Agromorphological Characterization of Introgression Lines Derived from Wild and Exotic Sorghum Germplasm to Climate Change Challenges

Sorghum (Sorghum bicolor (L.) Moench) is vitally important for food security in semi-arid West Africa. The introgression of wild- and high transpiration efficiency genotypes may contribute genes for abiotic stress tolerance or novel traits. Characterizing the introgressed lines can help researchers in the process of varietal improvement. The objectives of this study are (i) To learn if introgression of wild sorghum (CWR) and high transpiration efficiency (HTE) lines into a very early maturing (photoperiod insensitive) local land-race variety can create useful variation for grain yield in drought-prone Sahelian environments, (ii) To determine if grain yield advantages (and putative drought tolerance traits) obtained from introgression of CWR and HTE germplasm are expressed differently in moderately to highly moisture-limited environments, and (iii) To understand the relationship between putative drought tolerance traits. These populations were developed from crosses between the CSM63E (Jakumbe, a high grains quality variety) and two wild parents (accessions) and five high transpiration efficiency (TE) sorghum accessions. Phenotyping was conducted using an alpha lattice design with three replications in two environments for agronomic traits (grain yield and components), flowering time and physiological traits (stay-green, chlorophyll content and lodging). A total of 669 BC1F5 progenies were developed. Genetic variation for grain yield and putative drought tolerant traits were evaluated. Both populations derived from wild parents exhibited in Cinzana a grain yield (>300 g/m2) greater than CSM63E (245 g/m2). In Bema, more than 75% of the progenies of all populations indicated a chlorophyll content at physiological maturity (>30 SPAD) higher than CSM63E (20 SPAD) chlorophyll content. The estimated broad sense heritability was generally high (≥0.50) for all traits. The results also showed a very significant interaction between genotype and environment for grain yield, flowering time, chlorophyll content, stay green and lodging. There was a strong correlation between stay green and chlorophyll content (0.60) on the one hand and between stay green and lodging (0.48) on the other. This great variability could help improve the grain yield of sorghum for farmers in the Sahelian zone.

Genetic Diversity of Gora Rice (Oryza sativa L.) Landraces of Chotanagpur Plateau Region in Eastern India

The rice cultivars grown in the uplands of the state of Jharkhand, India are traditionally known as gora rice. These cultivars possess many important traits such as high seedling vigour, deeper roots and drought tolerance. In this study, a collection of gora landraces were assessed for morpho-genetic diversity using SSR markers. Morpho-agronomic analysis indicated that although seed morphological features are traditionally used for differentiating landraces, based on overall morpho-agronomic features also the cultivars could be differentiated as found in case of black gora. A genetic diversity analysis using 39 SSR markers detected considerable gene diversity (0.52) within gora cultivars. The white gora accessions were classified as indica, and rest including black gora, brown gora and other gora accessions belonged to aus group. This germplasm set provides scope for further genetic studies on multiple abiotic stress tolerance traits such as drought, submergenece and phosphorus starvation and traits for aerobic adaptation.

Molecular markers : An uprising tool for crop improvement

Molecular marker is a DNA sequence in the genome of any organism which can be located and identified. Plant breeders always prefer to remark the gene as the molecular marker, although this is not always possible. A molecular marker is nothing but a small region of DNA that shows sequence polymorphism in different individuals within a species or different species. The utility of molecular marker is based on naturally occurring DNA polymorphism and its growth in utility has greatly modified genetics and plant breeding. The DNA markers are most widely used in plant breeding programmes such as in the assessment of genetic variations within cultivars, gene mapping, transferring desirable genes for biotic and abiotic resistance. Marker-assisted selection (MAS) proves to be the most fascinating approach of molecular markers. An ideal DNA marker should be polymorphic in nature and it can be expressed in all tissues, organs, at various developmental stages. When comparing between conventional breeding approaches and molecular markers, the efficiency and effectiveness of breeding programs can be increased by molecular markers. Due to the presence of different types of molecular markers, and the variation in their principles, methodologies and mode of application, they require careful consideration in selecting one or more of such methods. With advancement in the availability of types of molecular markers, they can be used for the assessment of genetic diversity in cultivars, germplasm collection and advanced breeding material, identification of homokaryonand hybrid selection. This review article attempts to consider the current resources and novel examples where the MMs have been developed and used for the improvement of cereal crops for agronomic, food quality, disease resistance, abiotic stress tolerance traits and cytogenetic studies.

MAGIC - Multi-parent Advanced Generation Inter-Cross

The development of Multi-parent Advanced Generation Inter-Cross populations (MAGIC) in rice and discusses potential applications for mapping quantitative trait loci (QTLs) and for rice varietal development. The 4 multi-parent populations: indica MAGIC (8 indica parents); MAGIC plus (8 indica parents with two additional rounds of 8-way F1 inter-crossing); japonica MAGIC (8 japonica parents); and Global MAGIC (16 parents – 8 indica and 8 japonica). The parents used in creating these populations are improved varieties with desirable traits for biotic and abiotic stress tolerance, yield, and grain quality. The purpose is to fine map QTLs for multiple traits and to directly and indirectly use the highly recombined lines in breeding programs. These MAGIC populations provide a useful germplasm resource with diverse allelic combinations to be exploited by the rice community.