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Aegilops is known as the ancestor species of wheat and has a major role in the evolution of wheat. Considering the importance of this species and the fact that Iran is the center of the distribution, fifteen IRAP and REMAP markers were used to evaluate the genetic diversity of Ae. tauschii accessions from different regions of Iran and its relationship with Triticum durum and Triticum aestivum. A high level of polymorphism (99%) was observed for both retrotransposon markers. Polymorphism information content, the effective number of alleles (Ne), Nei’s genetic diversity (H), and Shannon’s information index (I) for IRAP markers were more than REMAP markers. The most genetic diversity was detected in Ae. tauschii accessions. The cluster analysis separated the accessions into three distinct groups. Ae. tauschii accessions from Golestan province grouped in the same cluster with T. aestivum genotypes, indicating that these accessions are probably more like to the progenitor of the bread wheat D genome. Our results revealed that retrotransposon-based molecular markers could be used as the appropriate and reliable marker system to evaluate genetic diversity and relationship in Triticum and Aegilops accessions.

Rice (Oryza sativa L.) is the most important food source for more than half of the world’s population, so determining the best hybrid line to produce hybrids with high grain yield and high cooking quality is important for proper crosses. In this study, 60 microsatellite markers were used in 63 rice genotypes of Central and West Asia to group rice cultivars. Based on data from 60 markers, it was observed that a total of 252 polymorphic alleles were amplified with an average of 4.2 alleles per primer. The mean number of effective alleles was 3.78 which RM490 and RM5423 markers had the lowest and the RM225 and RM246 markers had the highest value for this index. Nei gene diversity and amount of polymorphic information content showed that RM23 and RM212 markers had the highest value and the RM3 marker had the lowest value for these two indices. Genetic similarity and distance between populations revealed that the genetic distance between studied populations ranged from 0.147 to 0.54, indicating high variation among genotypes of these populations. The results showed that the highest genetic distance was between Iran and Uzbekistan and the least distance was between Iran and Afghanistan. The classification of genotypes was performed by cluster analysis. Genotypes were classified into 5 clusters using the Dice similarity coefficient and UPGMA method. Based on the results of cluster analysis and genetic distances, genotypes of Iran, Turkey, and Uzbekistan can be used for hybrid production to increase grain yield and quality.

A pot study was performed to examine the effect of plant growth-promoting rhizobacteria (PGPR) including Azospirillum lipoferum or Azotobacter chroococcum on growth criteria (leaf area and seedlings fresh and dry weight), pigments [chlorophylls (Chl a and b) and carotenoids], osmolytes (soluble sugars, soluble proteins and proline), nutrient uptake, antioxidant enzyme activities, and oxidative stress in maize plants under normal and salt-affected soils. The results showed that salt stress induced a reduction in growth traits, pigments, soluble proteins, K+, and K+/Na+ ratio. On the other side, it increased soluble sugars, proline, Na+, malondialdehyde (MDA), and the activity of peroxidase (POD) and catalase (CAT). Meanwhile, salt stress did not significantly change the activity of ascorbate peroxidase (APX) in maize plants. The inoculation using Azospirillum lipoferum or Azotobacter chroococcum significantly enhanced growth parameters, pigments, K+, osmolytes, K+/Na+ ratio, and the activity of CAT, POD, and APX of the salt-affected maize plants as well as uninoculated control plants. In addition, the results showed that both types of bacteria have attributed to lower MDA and Na+ in maize plants. Interestingly, Azospirillum lipoferum has affected more compared to Azotobacter chroococcum in control and salt-stressed plants. We, therefore, have observed in this study that microbial inoculation significantly improved plant physiological activities and that adding bacteria such as Azospiroillum or Azotobacter to the soil could mitigate the negative effects of salt stress on maize plants.

In this study, the genetic diversity of Thymus collected from Gilan province in Northern Iran was evaluated using AFLP markers and chemical compositions of the essential oil derived from GC/MS. Polymorphic information content varied from 0.26 to 0.37 with an average of 0.31. Estimating Nei’s gene diversity (H) and Shannon’s information index (I) showed that the highest and lowest genetic variation was related to markers E32-M93 (H = 0.32 and I = 0.47) and E33-M39 (H = 0.19 and I = 0.32), respectively. Cluster analysis classified the studied populations in four major groups. Furthermore, essential oil of the studied populations was extracted by hydro-distillation and the chemical compositions of essential oil were identified by capillary GC and GC/MS. In total, 37 compounds were identified in the essential oil of all populations which ranged from 42.786 to 93.337%. Also, the populations of each species had similar chemical compositions. Results of cluster analysis of the chemical compositions grouped the studied populations into four groups. Generally, the observed variation in AFLP markers was associated with the geographical variation.

The LysM receptor-like kinases (LysM-RLKs) play a crucial role in plant symbiosis and response to environmental stresses. Brassica napus, B. rapa, and B. oleracea are utilized as valuable vegetables. Different biotic and abiotic stressors affect these crops, resulting in yield losses. Therefore, genome-wide analysis of the LysM-RLK gene family was conducted. From the genome of the examined species, 33 LysM-RLK have been found. The conserved domains of Brassica LysM-RLKs were divided into three groups: LYK, LYP, and LysMn. In the BrassicaLysM-RLK gene family, only segmental duplication has occurred. The Ka/Ks ratio for the duplicated pair of genes was less than one indicating that the genes’ function had not changed over time. The BrassicaLysM-RLKs contain 70 cis-elements, indicating that they are involved in stress response. 39 miRNA molecules were responsible for the post-transcriptional regulation of 12 Brassica LysM-RLKs. A total of 22 SSR loci were discovered in 16 Brassica LysM-RLKs. According to RNA-seq data, the highest expression in response to biotic stresses was related to BnLYP6. According to the docking simulations, several residues in the active sites of BnLYP6 are in direct contact with the docked chitin and could be useful in future studies to develop pathogen-resistant B. napus. This research reveals comprehensive information that could lead to the identification of potential genes for Brassica species genetic manipulation.

Background Abiotic and biotic stresses induce oxidative processes in plant cells that this process starts with the production of ROSs which cause damage to the proteins. Therefore, plants have increased their antioxidant activity to defend against this oxidative stress to be able to handle stress better. In this research, 14 different tea accessions in a randomized complete block design with two replications were evaluated in two normal and drought stress conditions, and their antioxidant activity was measured by DPPH-free radicals’ assay and gene expression analysis. Results The results of gene expression analysis showed that the 100 and 399 accessions and Bazri cultivar had high values for most of the antioxidant enzymes, ascorbate peroxidase, superoxide dismutase, catalase, and peroxidase under drought stress conditions while the 278 and 276 accessions had the lowest amount of antioxidant enzymes in the same situation. Results showed that the IC50 of the BHT combination was 90.12 μg/ ml. Also, The IC50 of accessions ranged from 218 to 261 μg/ml and 201–264 μg/ml at normal and drought stress conditions, respectively. The 100 and 399 accessions showed the lowest IC50 under normal and drought stress conditions, while 278 and 276 accessions had the highest value for IC50. The antioxidant activity of tea accession extracts under normal conditions was ranged from 25 to 69% for accessions 278 and 100, respectively. While, the antioxidant activities of extracts under drought stress condition was 12 to 83% for accessions 276 and 100, respectively. So, according to the results, 100 and 399 accessions exhibited the least IC50 and more antioxidant activity under drought stress conditions and were identified as stress-tolerant accessions. However, 278 and 276 accessions did not show much antioxidant activity and were recognized as sensitive accessions under drought stress conditions. Conclusions These results demonstrate that total phenol content, antioxidant activity, and the oxygen-scavenging system can be used as a descriptor for identifying drought-tolerant accessions.

Soil contamination with heavy toxic metals is a major environmental problem caused by global industrialization. Conventional soil remediation methods are expensive and not environmentally friendly. The new technology, phytoremediation, is the use of green plants to clean the environment of pollutants and is presented as an affordable and non-destructive alternative to traditional methods. For this reason, phytoremediation is a promising way to improve the soil, which can easily absorb heavy metals and toxic substances and remove them from the soil. In this chapter, phytoremediation, its various methods, its advantages over other methods, and finally its future perspectives are discussed.

The rapid growth of the population and the reduction of resources make it necessary to study the ways of optimal use of food production potential for greater productivity in arid and semi-arid environments. Water stress is one of the most important global threats to food production. Also, climate change and population growth in the world are broadening the scope of this problem. On the other hand, in the arid and semi-arid regions, due to the shortage of rainfall and insufficient precipitation as well as the high rate of evapotranspiration, there is always shortage of surface water. Also, since the water resources in these areas are usually saline and of low quality, finding pure water in these areas is a major problem. In such areas, most of the arable lands are affected by salinity stress, either by saline waters or by soil salinity. One of the most effective ways to reduce water stress and salinity damage to plants/crops is to breed the plants to tolerate these stressors. Hence, the breeders are working with various breeding methods to find plant varieties that could tolerate water stress and salinity. Genetic modification of crops to increase their tolerance to water stress and salinity is a very important issue in plant breeding, and the detection and evaluation of drought, flooding, and salinity-tolerant germplasms are very difficult and a time-consuming process. In this chapter, different breeding methods (conventional and molecular) for finding plants/crops tolerant to water stress and salinity are discussed.

Twentieth-century human beings, with all their tremendous advances, are still struggling to provide food due to the growing population. The quality of rice grains plays an important role in consumer satisfaction. After the grain yield, improving the grain appearance, cooking quality, aroma, and taste of rice are other important goals of rice breeding. In this chapter, the traits related to grain quality in rice are discussed physiologically and molecularly, and the works performed in this regard are reviewed.

This study was conducted to investigate the genotype × environment interaction and stability analysis of 14 mutant lines (with their parental lines). The study was designed for two years, 2015-2016, in two environmental conditions, normal and drought stress, in Rasht. Based on the results of combined analysis of variance, genotype, environment, and genotype × environment effects were significant at 1% probability level. The significance of the environmental effect indicates that the environments were different in terms of genotypes performance. Therefore, the stability analysis was performed with different methods of measuring stability. The results of ANOVA for the additive main effect and multiplicative interaction (AMMI) showed the genotype and environment main effects and genotype × environment effects were significant at 1% probability level. Based on the AMMI results, TM6-230-VE-7-5-1, TM6-230-VE-8-4-1, Khazar, and KM5-200-4-2-1 had a positive and negative interaction, respectively. HM5-300-5-1, HM5-250-12-1, TM6-B-19-2 were selected as the stable genotypes. Stability analysis determined through AMMI stability value (ASV) method showed HM5-250-12-1, Tarom, HM5-250-E-1-1, TM6-B-19-2, Hashemi and HM5-300-5-1 with the least stability value were introduced as the most stable cultivars.

Wheat is one of the most important crop among the prime cereals at the global level. In the present investigation, twenty-four bread wheat (Triticum aestivum L.) genotypes were evaluated to estimate the extent of genetic diversity. Analysis of variance revealed that genotypes possess significant genetic variability among all traits at p < 00.1. It was also observed that HPW 447 had recorded the highest value of 35.16 (q/ha) whereas, HPW446 exhibited the lowest value (23.78 q/ha) for the yield. A significant positive correlation was observed among yield and biological yield traits. On contrary, yield and days to maturity revealed a negative correlation. Days to heading revealed a significant positive correlation with plant height (0.40) and a negative correlation with biological yield (-0.45), respectively. Diversity analysis classified the evaluated wheat genotypes into four (4) distinct groups based on an index of similarity and dissimilarity of attributing traits. Group I and II have one genotype each viz., HS637 and HPW447, respectively whereas in third group 6 genotypes including HPW441, HPW444, HPW446, VL2030, HS634, and VL2025 are clustered together. The fourth group had two sub-groups. The first sub-group had five (5) genotypes and the second sub-group had eight (8) genotypes. The first three principal components based on the Euclidean similarity matrix explained 45.13, 17.85 and 14.71 percent of the total variation, respectively. It is concluded that these wheat genotypes (HS631, HPW 442, HPW 447, VL 2027 and VL2028) possess significant genetic variability and requisite potential for use in breeding as candidate wheat genotypes under temperate conditions. It is further suggested that by multivariate methods diverse parents can be identified with a scope in generating transgressive segregants for prospective breeding strategies in the improvement of the wheat crop.

Thymus vulgaris L. (Lamiaceae), a well-known aromatic medicinal herb, has many important essential constituents in its oil, including γ-terpinene, carvacrol, thymol, and p-cymene. Gibberellins comprise hundreds of components, which regulate several various growths and underlying developmental processes, such as cell division and elongation, shoot elongation, seed germination, and gene expression. In this study, we investigated the influence of sprayed gibberellic acid (GA3) treatments on the internode length, leaf morphology, length of new shoot, expression of monoterpene synthase genes and monoterpenes content during two plant growth stages. Our results showed that increasing of internode length was a clear effect of GA3 that was varied with internode position. The results also showed that all internodes displayed a dramatic increase in the highest concentration of GA3. Also, the foliar application of GA3 resulted in not only an increased expression level of monoterpene synthase genes, but also the improved production of a monoterpene, especially in the moderate concentration of GA3 that they were up-regulated. In the lowest GA3 concentrations, relative expression levels were similar or lower than the control plants and a notable downregulation in those genes was observed in the application of the highest concentration of GA3 rather than the moderate concentrations. Overall, the expression of two out of five monoterpene synthase genes, TPS and CYP71D181, showed a correlation with the level of γ-terpinene and carvacrol, respectively, indicating that they are regulated at the transcriptional levels.

In the general sense, salinity means the amount of salts present in a certain amount of water, but the definition of salinity is the amount of salt present in a kilogram of water, expressed as grams of salt per thousand grams of water. Environmental conditions such as salinity determine the type and biodiversity in it. Therefore it is necessary to know the factors that cause it, identify the saline contaminated environments and their problems, and ways to deal with it. In this chapter the definition of salinity, factors and elements of salinity production, different methods of salinity measurement, types of saline waters and effluents, expression of the need for desalting, environmental effects of salinity, methods of saline wastewater treatment, and advantages and disadvantages of each method are discussed.

Of the consequences of anthropogenic activities, contamination of the pedosphere and biosphere with hazardous heavy metal ions as a growing threat is jeopardizing the human health status through inserting into the food chain, which impairs environmental sustainability. Phytoremediation is one of the environmental friendly bioremediation methods utilized to remove heavy metal contaminants, and it is easy to use, cost-effective, and efficient. The critical part of phytoremediation is to single out the phytoremediator species that allows the removal of these elements from contaminated soils by accumulating heavy metals in aerial parts. Medicinal plants with phytoremediation capabilities owing to the biosynthesis of secondary metabolites in addition to distinctive morphological characteristics are eventually become the preferred choice for effective phytoremediation of heavy metals. In this chapter the main aim is to provide an update on recent studies on renown medicinal and aromatic herbs utilized for phytoremediation of polluted soils with heavy metals.

The necessity of novel technologies to address the long-standing and worsened status of food security and sustainable agriculture is out of the question. Of the most recent promising approaches to alleviate constraints of the increasing occurrence of biotic and abiotic stressors on crop plants in the climate change era is nanobiotechnology involving potent methodologies with a large spectrum of applications covering both biotechnology and agriculture. Versatility of nanotechnology has made possible the establishment of quite a few biosensors that allow not only plant signaling biomolecules to communicate and actuate visually electronic monitoring devices to assess health status in real-time but also facilitates the allocation of resources. These include water and agrochemicals efficiency prior to the occurrence of water-deficit, salinity, extreme temperatures as well as phytopathogen-associated stress in order to maximize crop productivity and, consequently economical gains. Being new to the field of agriculture, achievements may not be commonly accessible worldwide. However, significant steps have been taken and reports are accumulating in relation to the development of nano biosensors for real-time monitoring. Particularly, using genetically encoded sensors that facilitate and accelerate the progress in this field by markedly improving current understanding of communications in stressed plants at the cellular level, the deciphering of which has been the purpose of plenty of recent biological studies. Nevertheless, a significant amount of research is required to optimize the application of nanomaterials to enhance feasibility of sustainable agriculture. This chapter aimed to summarize the most recent approaches to develop nano biosensors to bring worldwide food security into reality as the consequences of climate change become more tangible.

In their life cycle, plants face a range of environmental stresses such as heat, cold, drought, salinity, etc., which greatly affects the performance of the plant and is one of the key factors in the distribution of plant species. Plants use special mechanisms to withstand these stresses. When plants are exposed to stress, the information is transmitted by the signal transduction pathway, and eventually, the response to these signals leads to physiological and biochemical changes in the plants. Usually, one type of stress is accompanied or followed by other stresses. For example, heat stress is followed by drought stress due to physical loss of water, and cold stress is followed by drought stress due to the physiological inaccessibility of water. Due to the large number of environmental hazards that the plant faces at a particular time, abiotic stress signaling is a very complex phenomenon. Plants have tools to avoid and deal with these stressors. On the one hand, they can produce inductive and appropriate responses that lead to a specific desired change for which special stress conditions are specialized. On the other hand, there is a significant overlap between the components of abiotic stress signaling and the starting points in which the pathways for stress signaling are coordinated. In this chapter summarized, how abiotic stresses in plants can be tolerated.

Evolution has long enabled plants with an adjusted response and tolerance mechanisms in the time facing drought, salinity, extreme temperatures, excessive light, and heavy metals collectively known as abiotic stress, with an accelerated incidence in climate change era owing to a rapid rise in global temperature, which has triggered a domino effect that recent studies announced its destructive influence on agricultural products. These circumstances have exposed crops to an unprecedented level of multi stress that involves a plethora of complicated morphological, physiological and molecular responses as well as survival strategies. The changes assist plants to improve water relations, regulation over oxidative stress and osmotic adjustment and induction of genes that are directly or indirectly initiate networks of signaling to organizational readiness for an arms race in plants against stress-generated harmful products. Its intertwined nature has been the subject of plenty of biological studies to reach a reliable realization of these processes, since this is the safe approach to inject this understanding into selection and breeding programs to create superior cultivars that make a human capacity to provide food to an ever-increasing population on the earth.

The autophagy-related genes (ATGs) play important roles in plant growth and response to environmental stresses. Brassica napus (B. napus) is among the most important oilseed crops, but ATGs are largely unknown in this species. Therefore, a genome-wide analysis of the B. napus ATG gene family (BnATGs) was performed. One hundred and twenty-seven ATGs were determined due to the B. napus genome, which belongs to 20 main groups. Segmental duplication occurred more than the tandem duplication in BnATGs. Ka/Ks for the most duplicated pair genes were less than one, which indicated that the negative selection occurred to maintain their function during the evolution of B. napus plants. Based on the results, BnATGs are involved in various developmental processes and respond to biotic and abiotic stresses. One hundred and seven miRNA molecules are involved in the post-transcriptional regulation of 41 BnATGs. In general, 127 simple sequence repeat marker (SSR) loci were also detected in BnATGs. Based on the RNA-seq data, the highest expression in root and silique was related to BnVTI12e, while in shoot and seed, it was BnATG8p. The expression patterns of the most BnATGs were significantly up-regulated or down-regulated responding to dehydration, salinity, abscisic acid, and cold. This research provides information that can detect candidate genes for genetic manipulation in B. napus.

For the very first time an unsubscribed Humulus lupulus L. germplasm in Hyrcanian forests, N. Iran was carried out to determine its genetic diversity and population structure.

Humulus lupulus L., is an economically and ecologically important plant species, which has suffered habitat degradation throughout the Hyrcanian forests (Northern Iran). Towards conservation and exotic breeding germplasm assessment, we conducted a survey in the Hyrcanian forests: 15 wild populations (WPs) were located and 54 samples collected. Genetic diversity and population structure were assessed by scoring sequence-related amplified polymorphism markers (SSR, ISSR, and RAPD) and morphological features. Molecular marker analysis showed that RAPDs (232) and ISSRs (77) produced more polymorphic bands compared to SSRs (64) per marker. SSRs exhibited a higher PIC average value (0.64), than RAPDs (0.24) and ISSRs (0.54). Cluster analyses based on the SSR markers to a high degree discriminated WPs based on geographical regions and were more congruent with morphologic traits than the ISSR–RAPD-based clustering. The ΔK parameter of structure analysis showed five clusters. The grouping of the WPs based on the structure analysis was congruent with the SSR clustering to some extent. The results confirmed that SSR markers are effective tools to detect the genetic diversity in hops, but employing higher number of molecular markers (more SSRs), which have a higher polymorphism and prevalence in the genome, or application of NGS SNPs in the identification and genetic relationship of hop indigenous populations, is recommended.

Rice (Oryza sativa) is one of the principal cereal crops and is a major source of calories for billions of people around the globe. It has been predicted that rice production will decrease in near future due to the negative effects of global climate change. The increase in temperature and scarcity of irrigation water poses a serious threat to rice cultivation, as rice is very sensitive to heat and drought stress, particularly during the reproduction and grain-filling stages. Individually, the above stressors negatively affect almost all of a rice plants growth and developmental processes, leading to significant impacts on photosynthesis, floral abnormalities, pollen/spikelet sterility, grain yields and quality. Moreover, the combination of drought and heat stress, which commonly occurs under field conditions, can result in deleterious additive effects on the growth, physiology and productivity of rice cultivars. This threat to food security, and the associated economic losses, has increased the need for the development of abiotic stress-resilient rice varieties, with better yield potentials. A comprehensive understanding of the various morphological, biochemical, physiological, and molecular components governing rice yields under a combination of stressors is vital for the development of climate- resilient rice varieties. In this chapter, we provide an overview of the most common combinations of stressors faced by rice plants under field conditions, with special emphasis given to drought and heat stress, and the influence of these stressors, alone and in combination, on the growth, morphology and yields of rice. We also highlighted the potential strategies that can be used to develop rice plants adapted to the multiple abiotic stressors faced by plants under field conditions.

To efficiently address the threatened food security worldwide and the gap between supply and demand for agricultural products from a growing population on the earth, novel gene pools are necessities to enable plant breeders to develop crops capable of providing high quality and nutritionally rich food products under the changing climate era with increasing the incidence of environmental abiotic and biotic stresses. Brassica, as an essential source of crops worldwide with extensive gene pool which the close relatives of domesticated species, crop wild relatives, known for highly applicable gene pool have been exploited by plant breeders. While the resistance of current cultivars to the damaging insect pests and pathogens is deteriorating due to constant evolution and favorable environmental requirements for their reproduction of pests, besides increasing in abiotic stresses, hence obtaining the field knowledge on potential resistance wild species, landraces, accessions, and CWR is highly required, since it is a prior step to utilize the current advancements in biotechnological tools that allowing a cost-efficient and reliable screening and sequencing of a large number of plant materials for the gene(s) in target in a time-saving manner. The development of agronomically important traits is mainly time-consuming and laborious because they are multigene-regulated. The gene pool of Brassica crops is narrow, thus exploiting and probing for potential gens among wild genetic resources is inevitable, which in Brassica, Brassica villosa, Brassica incana, and Brassica montana as wild relative of important vegetable crops manifested as a rich source for agronomic traits in particular insect-pest resistance, among amphidiploid species Brassica carinata has been observed to be a promising source of salt and drought tolerance gens and Brassica tournefortii has shown compatible potentials for drought tolerance. Further genome evaluation leads to the identification of urgently needed quantitative trait loci (QTL) and alleles in wild species and CWR, and the large-scale collaborations on the application of genomics to reveal the untapped wild species can greatly contribute in the acceleration of sustainable utilization of genetic resources and reach a balance in agricultural production.

By drastic increment in frequency fluctuation of climatic phenomena worldwide which the consequences majorly negatively have been multifacetedly affecting world’s economy with agriculture section at the pinnacle, is threatening the food security of a large portion of growing population on the Earth to a dangerous level in addition to the percentage that already dealing with food inadequacy. The impacts on this section mainly targeting the productivity and quality of temperate vegetable crops (mainly negative and positive is some cases) and among them Brassicas unquestionably key crops that are an essential source of plant-based protein which increases the incidence of environmental stressors, high temperature, in particular, leads to yield losses to a large quantity since they are vernalization required, a low-temperature period to reach the reproduction phase. In case of the point, Broccoli (Brassica oleracea L. var. italica) a nutritionally and medicinally well-known staple vegetable that in the recent two or three decades has greatly mirrored the devastating effects of global warming owing to its supersensitive crud initiation period and degradation in the salability of heads as a result of heat stress which hopefully with the aim of biotechnology toolbox initial steps toward untwining the complex polygenetically regulated characteristics of heat tolerance and crud quality have been taken and lines of broccoli with non-vernalization requirements have been identified that could expand the broccoli cultivation to tropics. Putative QTLs associated with high-temperature resistance and crud initiation have been detected through gene pyramiding and molecular assistant selection aims to develop commercial cultivars. Gene transformation in broccoli to improve the capability of the current cultivars in addition to elevated CO2 scenario with its influences on broccoli have been studied extensively. The aim of this chapter is to reflect the result of studies concerning reaction and identifying the underlying genetic or protein bases involved in resistance to abiotic or biotic stresses.

Rice is a basic staple food of most countries including developed and less developed nations, and more importantly, 90% of population relies on rice across South Asian countries. Global climate change, increased urbanization, drought, and desertification have resulted in the significant drop in the rice production and also prompted researchers to develop novel varieties with increased productivity. Hence, novel varieties with enriched nutritional composition may offer wide benefits and could be a potential step in eradicating malnutrition among the less developed nations. According to the “International Rice Research Institute (IRRI),” 843 varieties have been developed until now, which have been generated by using both conventional and molecular breeding techniques. Genetic markers are forerunner in the present-day agriculture production system, which has anonymously contributed in the production of novel varieties with additional accuracy, reliability, and rapidity. Thus, it has significantly contributed in precision plant breeding, and dependency on molecular techniques such as marker-assisted selection and quantitative trait loci is inevitable for enhanced crop productivity in the near future. In the present chapter, an elaborate case study involving recent developments in enhancing the nutritional quality of rice crop using marker-assisted selection and quantitative trait loci has been represented.

Global climate change is a man-made phenomenon fueled by ever-increasing population on the Earth which has generated a cascade of unprecedented fluctuations in precipitations almost throughout the world with having agriculture in the target as a highly vulnerable as well as a vital sector for humanity. Agriculture in climate change era means to deal with multifaceted scenario owing to the high frequency of multi-stressed environments in which stress-resilient crop cultivars are recommended as a solution with high reliability to facilitate management. By taking into account the acceleration in climate change-driven impacts and vitality of food security, the conventional methods of plant breeding can no longer meet the challenges; therefore, it is necessary to devote focus and financial resources to novel advancements in plant breeding. Nowadays, agricultural biotechnology is in its heyday and has significantly contributed to this field specifically in major crops. Biotechnology toolkit equipped with precise, efficient, environmentally friendly, and cost-effective tools has enabled researchers to unmask the genes involved in underlying resistant mechanisms against abiotic and biotic stresses and afterward validate and pyramid them into commercial cultivars with simultaneous durable multi-stress resistance. Further, genome-editing approaches have opened a new window to accurately manipulate plant genomes without off-target introgression. Numerous varieties of major food plants that were cultivated by farmers around the world have developed with the help of new methodologies. However, there is a tough road ahead, and these new tools are promising. Many more researches need to be done; the effects of stresses are intertwined which makes breeding projects challenging. Increasing information on plant genome with the aim of novel tools is the key to develop crop varieties that tolerate stress and still provide a reasonable yield and improve food security ultimately.

Among crops, oilseeds are the second largest food source in the world after cereals. Rapeseed is the third most important oil plant in the world and its extracted oil is used for human and industrial purposes due to its fatty acid composition. Its oil is one of the highest quality edible oils due to its good composition of unsaturated fatty acids and low percentage of saturated fatty acids. Rapeseed accounts for 14.7% of total vegetable oil production in the world, and countries such as China, Canada, India, France, England, Germany, Poland, Sweden, Czech Republic, Pakistan, and Bangladesh are the major producers of rapeseed. Most of the rapeseed production in the world is done in dryland conditions, so the plants response to water stress is crucial. In recent years, canola cultivation has declined due to the lack of rainfall and drought. Thus, one of the important factors that threaten the successful development and cultivation of rapeseed in the world is drought stress. This chapter deals with the study of rapeseed and the effect of drought on its morphological and physiological characteristics.

Biotic and abiotic stresses cause special defense reactions in plant organs, which after a series of reactions, these stresses produce secondary metabolites. The effect of ultraviolet radiation on the expression of key genes involved in the biosynthesis of secondary metabolites (Phenylalanine ammonia lyase (PAL), Hydroxymethylglutaryl-CoA reductase (HMG-CoA reductase), GPP synthases, Deoxyribonino heptulosinate 7-phosphate synthase (DAHP), and Deoxy Xylose Phosphate Synthase (DXS)), and the association of these genes with different amounts of secondary metabolites (phenol, terpene, flavonoids, anthocyanins, alkaloids, lycopene, and beta-carotene) was investigated in this study. The results of this study showed that the application of UV-B stress significantly increased the expression of GPPs, HMG-CoA reductase, DXS, DAHPs, and PAL genes compared to the control plants. The expression of two key genes involved in the biosynthesis of phenylpropanoids, including DAHPs and PAL, increased with UV-B stress, and the highest expression was related to the PAL gene. The results revealed that UV-B stress caused a significant increase in total levels of terpenoids, phenols, flavonoids, anthocyanins, alkaloids, beta-carotene, and lycopene. The highest relative expression of all genes was obtained in treatment A (UV-B radiation for 1 h), while in treatment B (UV-B radiation for 2 h), no significant changes were observed in the expression of the genes.