New and novel genetic tools for improving crops.

Author(s):  
Penna Suprasanna

Abstract The basic tenet of crop improvement is the novel genetic variability that is achieved through selection, hybridization, mutation and recombination. The new technological innovations of plant breeding offer scope for transforming crop improvement with more precision and resolution. Advances in genomic-based tools and high-throughput phenotyping have enabled the analysis of genetic variation and identification of molecular signatures of agronomic traits. Molecular markers and molecular-marker-assisted breeding have facilitated the speedy selection of new, novel genetic combinations in breeding for high-yielding, stress-tolerant and nutritionally enriched crops. Transgenic methods have revolutionized modification for stress tolerance and higher productivity, and several genetically modified crops are under cultivation. Availability of genome sequencing platforms and genomic resources has significantly contributed to accessing novel genes and validating their functions. Genome-editing tools and recent advances of prime editing are now accessible for precise genetic alteration of plant traits. The new plant breeding tools will certainly foster development of highly productive, improved crop varieties for achieving food security and climate resilience.

2020 ◽  
Vol 295 (40) ◽  
pp. 13940-13955 ◽  
Author(s):  
Katrina J. Linden ◽  
Judy Callis

In a single vascular plant species, the ubiquitin system consists of thousands of different proteins involved in attaching ubiquitin to substrates, recognizing or processing ubiquitinated proteins, or constituting or regulating the 26S proteasome. The ubiquitin system affects plant health, reproduction, and responses to the environment, processes that impact important agronomic traits. Here we summarize three agronomic traits influenced by ubiquitination: induction of flowering, seed size, and pathogen responses. Specifically, we review how the ubiquitin system affects expression of genes or abundance of proteins important for determining when a plant flowers (focusing on FLOWERING LOCUS C, FRIGIDA, and CONSTANS), highlight some recent studies on how seed size is affected by the ubiquitin system, and discuss how the ubiquitin system affects proteins involved in pathogen or effector recognition with details of recent studies on FLAGELLIN SENSING 2 and SUPPRESSOR OF NPR CONSTITUTIVE 1, respectively, as examples. Finally, we discuss the effects of pathogen-derived proteins on plant host ubiquitin system proteins. Further understanding of the molecular basis of the above processes could identify possible genes for modification or selection for crop improvement.


1993 ◽  
Vol 44 (4) ◽  
pp. 731 ◽  
Author(s):  
RC Muchow ◽  
PS Carberry

The production potential of rainfed kenaf in the Northern Territory (NT) (latitude 12-15�S.) has been assessed using a growth simulation model for the cultivar Guatemala 4. However, this raises the important question of how well-suited is this cultivar, and what are the likely yield gains which might be obtained by breeding or selecting a different cultivar. Answering these questions with conventional experimentation would be expensive, given the variable yield response among seasons associated with rainfall variability in the NT. Accordingly, the kenaf growth simulation model NTKENAF was used in conjunction with long-term climatic data for two sites in the NT to assess the value of different plant traits relative to Guatemala 4, that are potential selection criteria in plant breeding. Extending the duration from sowing to flowering resulted in relatively small gains in stem yield over Guatemala 4, but substantial yield losses were predicted by using an earlier flowering cultivar. Increasing the efficiency of water use (higher transpiration efficiency) greatly increased yield, and was the most risk-efficient crop improvement strategy. Unfortunately, the prospects for improving transpiration efficiency of kenaf by plant breeding remain uncertain. Increasing the amount of water available for crop growth by greater extent of soil water extraction had little effect on yield in this water-limited environment. Changing the yield potential of kenaf by altering the photosynthetic capacity (higher radiation use efficiency) was risk-efficient in some situations, but the mean yield change was relatively small. It is concluded from the simulation analysis, that the standard cultivar Guatemala 4 is well-suited to the NT environment.


2020 ◽  
pp. 53-66
Author(s):  
Noel Ndlovu

Advances in the fields of genomics and phenomics are currently creating significant foundations for the sustainable intensification of plant breeding initiatives targeting climate resilience. Genomics is a biological study that focuses on architecture, function, editing, mapping, and evolution of genomes. It can be applied extensively in climate resilience breeding for cost-effective, rapid, and high-through put genotyping, phenotyping, and trait mapping. The efficacy of genomics-assisted breeding (GAB) is strongly hinged on the high resolution and robustness of Next Generation Sequencing (NGS) and CRISPR/Cas9-based Gene Editing systems. The integration of genomics and phenomics in crop improvement can upscale the efficiency of breeding systems targeting climate resilience and hasten cultivar release cycle. Phenomics is an interdisciplinary field that focuses on the enhanced measurement of plant performance, growth, and composition. Similarly, phenomics has revolutionized the efficacy of plant breeding off-trial initiatives established to phenotypically characterize and study diversity levels of collected germplasm. Field phenomics tools such as the phenonet, phenomobile, and phenonetwork have proven to be efficient in capturing large sums of multiscale and multidimensional experimental data. The main purpose of this review article is to present a summarized account of the probable applications of integrated systems of genomics and phenomics in plant breeding for climate resilience in major crops.


Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 258 ◽  
Author(s):  
Aakash Chawade ◽  
Joost van Ham ◽  
Hanna Blomquist ◽  
Oscar Bagge ◽  
Erik Alexandersson ◽  
...  

High-throughput field phenotyping has garnered major attention in recent years leading to the development of several new protocols for recording various plant traits of interest. Phenotyping of plants for breeding and for precision agriculture have different requirements due to different sizes of the plots and fields, differing purposes and the urgency of the action required after phenotyping. While in plant breeding phenotyping is done on several thousand small plots mainly to evaluate them for various traits, in plant cultivation, phenotyping is done in large fields to detect the occurrence of plant stresses and weeds at an early stage. The aim of this review is to highlight how various high-throughput phenotyping methods are used for plant breeding and farming and the key differences in the applications of such methods. Thus, various techniques for plant phenotyping are presented together with applications of these techniques for breeding and cultivation. Several examples from the literature using these techniques are summarized and the key technical aspects are highlighted.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mawuli K. Azameti ◽  
Wadzani Palnam Dauda

The ability to create targeted modifications in the genomes of plants using genome editing technologies has revolutionized research in crop improvement in the current dispensation of molecular biology. This technology has attracted global attention and has been employed in functional analysis studies in crop plants. Since many important agronomic traits are confirmed to be determined by single-nucleotide polymorphisms, improved crop varieties could be developed by the programmed and precise conversion of targeted single bases in the genomes of plants. One novel genome editing approach which serves for this purpose is base editing. Base editing directly makes targeted and irreversible base conversion without creating double-strand breaks (DSBs). This technology has recently gained quick acceptance and adaptation because of its precision, simplicity, and multiplex capabilities. This review focuses on generating different base-editing technologies and how efficient they are in editing nucleic acids. Emphasis is placed on the exploration and applications of these base-editing technologies to enhance crop production. The review also highlights the drawbacks and the prospects of this new technology.


Author(s):  
Rajanikanth Govindarajulu ◽  
Ashley N Hostetler ◽  
Yuguo Xiao ◽  
Srinivasa R Chaluvadi ◽  
Margarita Mauro-Herrera ◽  
...  

Abstract Phenotypes such as branching, photoperiod sensitivity, and height were modified during plant domestication and crop improvement. Here, we perform quantitative trait locus (QTL) mapping of these and other agronomic traits in a recombinant inbred line (RIL) population derived from an interspecific cross between Sorghum propinquum and Sorghum bicolor inbred Tx7000. Using low-coverage Illumina sequencing and a bin-mapping approach, we generated ∼1920 bin markers spanning ∼875 cM. Phenotyping data were collected and analyzed from two field locations and one greenhouse experiment for six agronomic traits, thereby identifying a total of 30 QTL. Many of these QTL were penetrant across environments and co-mapped with major QTL identified in other studies. Other QTL uncovered new genomic regions associated with these traits, and some of these were environment-specific in their action. To further dissect the genetic underpinnings of tillering, we complemented QTL analysis with transcriptomics, identifying 6189 genes that were differentially expressed during tiller bud elongation. We identified genes such as Dormancy Associated Protein 1 (DRM1) in addition to various transcription factors that are differentially expressed in comparisons of dormant to elongating tiller buds and lie within tillering QTL, suggesting that these genes are key regulators of tiller elongation in sorghum. Our study demonstrates the usefulness of this RIL population in detecting domestication and improvement-associated genes in sorghum, thus providing a valuable resource for genetic investigation and improvement to the sorghum community.


2021 ◽  
Vol 22 (15) ◽  
pp. 8266
Author(s):  
Minsu Kim ◽  
Chaewon Lee ◽  
Subin Hong ◽  
Song Lim Kim ◽  
Jeong-Ho Baek ◽  
...  

Drought is a main factor limiting crop yields. Modern agricultural technologies such as irrigation systems, ground mulching, and rainwater storage can prevent drought, but these are only temporary solutions. Understanding the physiological, biochemical, and molecular reactions of plants to drought stress is therefore urgent. The recent rapid development of genomics tools has led to an increasing interest in phenomics, i.e., the study of phenotypic plant traits. Among phenomic strategies, high-throughput phenotyping (HTP) is attracting increasing attention as a way to address the bottlenecks of genomic and phenomic studies. HTP provides researchers a non-destructive and non-invasive method yet accurate in analyzing large-scale phenotypic data. This review describes plant responses to drought stress and introduces HTP methods that can detect changes in plant phenotypes in response to drought.


Author(s):  
Pallavi Sinha ◽  
Vikas K. Singh ◽  
Abhishek Bohra ◽  
Arvind Kumar ◽  
Jochen C. Reif ◽  
...  

Abstract Key message Integrating genomics technologies and breeding methods to tweak core parameters of the breeder’s equation could accelerate delivery of climate-resilient and nutrient rich crops for future food security. Abstract Accelerating genetic gain in crop improvement programs with respect to climate resilience and nutrition traits, and the realization of the improved gain in farmers’ fields require integration of several approaches. This article focuses on innovative approaches to address core components of the breeder’s equation. A prerequisite to enhancing genetic variance (σ2g) is the identification or creation of favorable alleles/haplotypes and their deployment for improving key traits. Novel alleles for new and existing target traits need to be accessed and added to the breeding population while maintaining genetic diversity. Selection intensity (i) in the breeding program can be improved by testing a larger population size, enabled by the statistical designs with minimal replications and high-throughput phenotyping. Selection priorities and criteria to select appropriate portion of the population too assume an important role. The most important component of breeder′s equation is heritability (h2). Heritability estimates depend on several factors including the size and the type of population and the statistical methods. The present article starts with a brief discussion on the potential ways to enhance σ2g in the population. We highlight statistical methods and experimental designs that could improve trait heritability estimation. We also offer a perspective on reducing the breeding cycle time (t), which could be achieved through the selection of appropriate parents, optimizing the breeding scheme, rapid fixation of target alleles, and combining speed breeding with breeding programs to optimize trials for release. Finally, we summarize knowledge from multiple disciplines for enhancing genetic gains for climate resilience and nutritional traits.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 564
Author(s):  
Gaetano Distefano

The main challenges for tree crop improvement are linked to the sustainable development of agro-ecological habitats, improving the adaptability to limiting environmental factors and resistance to biotic stresses or promoting novel genotypes with improved agronomic traits [...]


Author(s):  
Daisuke Miki ◽  
Rui Wang ◽  
Jing Li ◽  
Dali Kong ◽  
Lei Zhang ◽  
...  

Abstract Humans are currently facing the problem of how to ensure that there is enough food to feed all of the world’s population. Ensuring that the food supply is sufficient will likely require the modification of crop genomes to improve their agronomic traits. The development of engineered sequence-specific nucleases (SSNs) paved the way for targeted gene editing in organisms, including plants. SSNs generate a double-strand break (DSB) at the target DNA site in a sequence-specific manner. These DSBs are predominantly repaired via error-prone non-homologous end joining (NHEJ), and are only rarely repaired via error-free homology-directed repair (HDR) if an appropriate donor template is provided. Gene targeting (GT), i.e., the integration or replacement of a particular sequence, can be achieved with combinations of SSNs and repair donor templates. Although its efficiency is extremely low, GT has been achieved in some higher plants. Here, we provide an overview of SSN-facilitated GT in higher plants and discuss the potential of GT as a powerful tool for generating crop plants with desirable features.


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