**1. Introduction**

Seeds constitute the basic biological input for crop production. The most important potential seed attribute directly affecting crop productivity is the seed vigor, because a good crop stand establishment is required to deliver the genetic and yield potentials of the seed. Thus, seed vigor had been a target trait of economic and ecologic values in crop improvement projects since the green revolution era [1]. Scientific manipulations to innate seed vigor of crops can be a key to increase crop yields per unit area because it can improve crop resilience against

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

climate change effects and biotic impediments to crop yields. More importantly, it will promote low-input agriculture by minimizing crop production inputs e.g. fertilizers, pesticides etc. that increases the environmental footprints of agriculture. However, seed vigor is a complex trait for genetic manipulation since it involves multiple physiological parameters and metabolic events of water uptake by the mature dry seeds to produce morphological events of radicle protrusion (germination) and seedling growth and development [2, 3]. Hence, exploring the fundamental biological processes underlying the trait at the various levels of these events is of intense scientific research interest.

In many recent seed biology literature, seed vigor studies engage modern biology tools using seed deterioration/invigoration experimental models. In the context of seed deterioration, seed vigor is often measured as seed longevity in storage which is relevant to seed conservation and seed bank operation efforts [4, 5]. The processes involved in the loss of seed vigor during seed deterioration elucidate the complex biological phenomenon of seed vigor. Thus, studies on the mechanism of seed vigor involve storing seeds under conditions that accelerate aging, e.g. the accelerated aging (AA) test [6] or the controlled deterioration (CD) tests to simulate the seed aging or seed vigor loss processes. In the context of seed invigoration, seed vigor has been widely studied towards increasing the performance of commercial seed lots. Seed priming is one of the most acknowledged technology-based seed invigoration treatments, which is mainly controlled imbibition of the seeds followed by dehydration back to their initial water content [7–9]. Priming treatments are hypothesized as kick-starting physiological and biochemical processes of seed germination, thus giving the treated seeds, a head-start which should increase resilience, reduce the time it takes seeds to sprout and elicit uniformity of seedling growth. All these can be achieved because primed seeds sort of "memorize" the metabolic signals they acquired from the priming process when stimulated to germinate later [10]. Many studies have proved the phenotypic advantages of priming in terms of early germination, seedling vigor [11] and stress tolerance [12]. The metabolic mechanisms underpinning priming are still been actively investigated, providing veritable data resources for scientific improvement of seed vigor. As will be discussed later in this chapter, many of the published reports suggest that cellular repair, detoxification and induction of protective proteins are the mechanisms underlying the seed vigor process [3, 13–16].

The advances in the science of biology brought a new phrase termed the *-omics* [17]. The *-omics* tools are essentially a hybrid of biological technologies encompassing liquid chromatography-mass spectrometry (LC-MS) and next-generation sequencing (NGS) [18]. They include all genomic and post-genomic approaches which in recent years have been further contributing to identifying genes and understanding their functions [19]. *-Omics* serves as an informal suffix to prefixes of specific biological fields of study such as genomics for genetics *-omics*, proteomics for protein *–omics*, etc. (**Figure 1**). In general, all *-omics* science aim at the collective characterization and quantification of pools of biological molecules that translate into the structure, function, and dynamics of living organisms [19].

With reference to seed vigor, several *-omics* dissections have been reported [20]. Here is a quick run of definitions of key *-omics* sciences that have been applied to seed vigor. *Genomics,* which is the study of the genome of an organism, have been severally used to dissect genomic regions that have significant genetic effects on seed vigor of many crops [21]. *Proteomics* is the study of the entire complement of proteins, modifications made to a particular set of proteins and their functions in the cell. Unlike the genome, which is fixed for most cells, the proteome is known to be dynamic, changing with internal or external (environmental) stimuli. The proteomics of seed vigor of many plant species have been widely reported [22]. Transcriptome involves all set of RNA molecules—mRNA, rRNA, tRNA, and other non-coding RNAs, produced in one or a population of cells, which is important in gene expression. *Transcriptomics* of seed vigor traits has been studied; Soeda et al*.* [12] used the microarrays technique to dissect the expression of seed vigor related genes during the priming of *Brassica oleracea* seed lots while Dinkova et al*.* [23] used the RNA-Seq, method to study translation initiation factors during maize seed germination. *Metabolomics* is the scientific study of chemical processes and metabolites (chemical fingerprinting). A related scientific branch to metabolomics that is well researched for seed vigor traits is *Metabonomics*, the quantitative measurement of the dynamic, multi-parametric metabolic responses to pathological and physiological stimuli or genetic modifications. Examples of metabolomic and metabonomic dissections of seed vigor are the investigations of metabolic pathways and signaling involved in seed vigor. Lipidome is the entire complement of cellular lipids, and *lipidomic*s has been involved in studies of lipids and glycolipids and lipid metabolites during seed deterioration or invigoration [24]. *Glycomics* is the analyses of the glycome—collection of cellular glycans (sugars and carbohydrates) of an organism. A glycomics study that associated seed vigor with sugar metabolites involved has helped to identify carbohydrate and sugar biomarkers for seed vigor [25]. Most of the published studies utilized one or more genomic tools, which explains why so much seed vigor *-omics* references has been categorized under genomics (**Figure 1**).

climate change effects and biotic impediments to crop yields. More importantly, it will promote low-input agriculture by minimizing crop production inputs e.g. fertilizers, pesticides etc. that increases the environmental footprints of agriculture. However, seed vigor is a complex trait for genetic manipulation since it involves multiple physiological parameters and metabolic events of water uptake by the mature dry seeds to produce morphological events of radicle protrusion (germination) and seedling growth and development [2, 3]. Hence, exploring the fundamental biological processes underlying the trait at the various levels of these

In many recent seed biology literature, seed vigor studies engage modern biology tools using seed deterioration/invigoration experimental models. In the context of seed deterioration, seed vigor is often measured as seed longevity in storage which is relevant to seed conservation and seed bank operation efforts [4, 5]. The processes involved in the loss of seed vigor during seed deterioration elucidate the complex biological phenomenon of seed vigor. Thus, studies on the mechanism of seed vigor involve storing seeds under conditions that accelerate aging, e.g. the accelerated aging (AA) test [6] or the controlled deterioration (CD) tests to simulate the seed aging or seed vigor loss processes. In the context of seed invigoration, seed vigor has been widely studied towards increasing the performance of commercial seed lots. Seed priming is one of the most acknowledged technology-based seed invigoration treatments, which is mainly controlled imbibition of the seeds followed by dehydration back to their initial water content [7–9]. Priming treatments are hypothesized as kick-starting physiological and biochemical processes of seed germination, thus giving the treated seeds, a head-start which should increase resilience, reduce the time it takes seeds to sprout and elicit uniformity of seedling growth. All these can be achieved because primed seeds sort of "memorize" the metabolic signals they acquired from the priming process when stimulated to germinate later [10]. Many studies have proved the phenotypic advantages of priming in terms of early germination, seedling vigor [11] and stress tolerance [12]. The metabolic mechanisms underpinning priming are still been actively investigated, providing veritable data resources for scientific improvement of seed vigor. As will be discussed later in this chapter, many of the published reports suggest that cellular repair, detoxification and induction of protective proteins are the mechanisms underlying the seed

The advances in the science of biology brought a new phrase termed the *-omics* [17]. The *-omics* tools are essentially a hybrid of biological technologies encompassing liquid chromatography-mass spectrometry (LC-MS) and next-generation sequencing (NGS) [18]. They include all genomic and post-genomic approaches which in recent years have been further contributing to identifying genes and understanding their functions [19]. *-Omics* serves as an informal suffix to prefixes of specific biological fields of study such as genomics for genetics *-omics*, proteomics for protein *–omics*, etc. (**Figure 1**). In general, all *-omics* science aim at the collective characterization and quantification of pools of biological molecules that translate into the

With reference to seed vigor, several *-omics* dissections have been reported [20]. Here is a quick run of definitions of key *-omics* sciences that have been applied to seed vigor. *Genomics,* which is the study of the genome of an organism, have been severally used to dissect genomic

structure, function, and dynamics of living organisms [19].

events is of intense scientific research interest.

264 Advances in Seed Biology

vigor process [3, 13–16].

With the advent of genomic and post-genomic technologies, high-throughput analyses of molecular profiles have been implemented at the protein, RNA and metabolite levels to dissect the biological processes involved in seed vigor development. The aim of this chapter is to review advances in seed vigor studies in the light of new high precision *-omics* tools. In this

**Figure 1.** References of *-omics* sciences reported on seed vigor related traits in popular library databases as at July 2017. (a) Science Citation Index (expanded web of science), (b) ProQuest, and (c) PubMed.

chapter, I will be discussing some of the major advances made with specific *-omics* technologies towards dissecting the complex seed vigor traits in various crop plant species. I will also focus on the direction to which the current advances in seed vigor *-omics* might be pointing the seed industry in the near future. In discussing all the sections, I will pay attention to seed vigor reports from the experimental perspectives of seed deterioration (aging) and seed invigoration (priming).
