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Jauhar Ali Shabir Hussain Wani Editors

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Academic year: 2023

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This book provides a balanced set of chapters after the authors provide an overview of the progress in rice genetics and breeding in the introductory chapter. Chapters cover advances in rice genetics and breeding, as well as deep insights into rice physiology for increasing assimilates and efficient photosynthate partitioning.

1 Introduction

Systematic breeding for the improvement of Asian rice (Oryza sativa L.), although started more than a century ago, has witnessed rapid progress in the last 60 years with breakthroughs in both applied and targeted basic research. In keeping with the objective of this publication, “Molecular and Physiological Breeding Strategies Towards Sustainable Rice Self-Sufficiency”, this introductory chapter provides an overview of the important achievements made during this period.

2 First Breakthrough: The Green Revolution

Thus, the DGWG dwarf gene (sd1) provides short growth in more than 90% of the high-yielding dwarf varieties planted globally in the last 50 years. The dwarf cultivars developed for the relatively risk-free irrigated ecosystem are not adapted to rainfed upland and lowland ecosystems, which constitute more than 45% of the global rice area (Mackill et al. 1996).

3 Second Breakthrough: Hybrid Rice Technology

Among loci causing female sterility in intersubspecific hybrids, S5 is the major locus (Song et al. 2005). Closely linked flanking markers of the S5 gene, RM253 and RM276, have been very valuable in developing suitable parents to produce sterility-free intersubspecific hybrids (Singh et al. 2006; Siddiq and Singh 2005).

4 Next Breakthrough: Strategies

  • Enrichment of the Rice Gene Pool
  • Discovery and Stacking of Yield Genes Hidden in Wild/
  • Designing of Plant Architecture or Ideotype Breeding
  • Designing of Shoot and Panicle Architecture
  • Modification of Root Architecture
  • Green Super Rice for Sustainable Performance
  • Physiological Breeding Approaches
  • Defending Against Biophysical Stresses
  • Selective Modification of Traits by Gene Editing

Expression of two glyoxalase pathway genes, glyI and glyII, preferably together, has been shown to confer salinity tolerance (Singla-Pareek et al. 2006). Constitutive expression of OsNAS2 was reported to result in increased Fe content (19 mg/kg) and Zn concentration (76 mg/kg) in polished rice grains (Johnson et al. 2011).

Table 1  List of wild species/landraces used for trait enhancement in rice
Table 1 List of wild species/landraces used for trait enhancement in rice

5 Conclusions

Transgenic approaches to increase the Fe content of rice grains were first investigated more than ten years ago. Since then, attempts have been made to increase the Fe content of rice endosperm by overexpressing the genes involved in Fe uptake from soil and those involved in translocation from aerial parts to grain.

Hussain AJ, Ali J, Siddiq EA, Gupta VS, Reddy UK, Ranjekar PK (2011) Mapping of tms8 gene for temperature sensitive genetic male sterility (TGMS) in rice (Oryza sativa L.). Karki S, Rizal G, Quick WP (2013) Enhancement of photosynthesis in rice (Oryza sativa L.) by inserting the C4 pathway.

0 10 20 30thgiewyrdtnalplatoT(g/plant)

However, a meta-analysis of several studies on elevated CO2 experiments in different crops has shown that any strategy for increasing photosynthesis can increase crop yield (Ainsworth et al. 2008). Similarly, it has been proposed that altering the rate of photosynthetic electron transport by manipulating the cytochrome b6/f complex can improve the photosynthetic capacity and crop yield of transgenic plants (Yamori et al. 2016a; Fig. 1).

0 10 20 30Grain yield(g/plant)

Some critical reviews suggest that enhancing photosynthesis will not be a useful strategy to improve crop productivity (Gu et al. 2014; Sinclair et al. 2004). Improving photosynthetic capacity in plants is now considered a promising approach to increase crop yield and reduce the atmospheric concentration of CO2, which is the primary component of greenhouse gases.

2 Improving Rubisco Performance 2.1 Rubisco Kinetics

Photorespiration Bypass

At current atmospheric CO2 concentrations and a temperature of 30 °C, the rate of photorespiratory CO2 release from the mitochondria is approximately 25% of the CO2 assimilation rate (Sage et al. 2012). Transgenic plants engineered with this pathway have reduced photorespiration and enhanced photosynthesis, resulting in improved plant growth (Kebeish et al. 2007).

Fig. 3  Schematic diagram of photorespiration in plants (black), with three bypasses to minimize  photorespiratory expenses engineered in plants (red, blue, green)
Fig. 3 Schematic diagram of photorespiration in plants (black), with three bypasses to minimize photorespiratory expenses engineered in plants (red, blue, green)

3 Improving Thermotolerance of Rubisco Activase

Facilitating photorespiratory flux through overexpression of glycine decarboxylase (GDC) subunits, which produces CO2 from the photorespiratory process, may be another approach to improve photorespiration (Timm et al. 2016). Furthermore, overexpression of GDC-H contributed to greater plant growth in tobacco (Nicotiana tabacum) both in a controlled environment and under field conditions (Lopez-Calcagno et al. 2018).

Cyanobacteria have evolved a CCM in which Rubisco is encapsulated in a cellular compartment known as the carboxysome (Price et al. 2011). Currently, considerable efforts are being made to incorporate features of the C4 complex pathway into C3 crops such as rice (Covshoff and Hibberd 2012; von Caemmerer et al. 2012).

Fig. 4  Schematic diagram of mechanisms for concentrating CO 2  around Rubisco. The diagram  shows CO 2  transfers from the outside to the intercellular air space through the stomatal pore and  the CO 2  diffuses through the cell wall and plasma membrane i
Fig. 4 Schematic diagram of mechanisms for concentrating CO 2 around Rubisco. The diagram shows CO 2 transfers from the outside to the intercellular air space through the stomatal pore and the CO 2 diffuses through the cell wall and plasma membrane i

5 Enhancing Activity of Calvin–Benson-Cycle Enzymes

Moreover, the disruption of the chloroplastic FBPase was also shown to negatively affect the rate of photosynthesis (Kossmann et al. Evidence supporting this hypothesis was provided by transgenic tobacco plants overexpressing SBPase (Lefebvre et al.

6 Enhancing Electron Transport Rate in Thylakoid Membranes

There is a strong linear relationship between chloroplast electron transport rate and cytochrome b6/f complex content at any leaf temperature (Yamori et al. 2011). In plant cells, NADP is mainly located in the chloroplast, where NADP + acts as the final electron acceptor in the photosynthetic electron transport chain (Wigge et al. 1993).

Fig. 5  Schematic diagram of electron transport in thylakoid membranes. Electron transport,  driven by the excitation of photosystem I (PS I) and photosystem II (PS II), results in the reduction  of NADP +  to NADPH and the accumulation of protons in the t
Fig. 5 Schematic diagram of electron transport in thylakoid membranes. Electron transport, driven by the excitation of photosystem I (PS I) and photosystem II (PS II), results in the reduction of NADP + to NADPH and the accumulation of protons in the t

7 Improving Photosynthetic Performance Under Fluctuating Light in Natural Environments

Electron Transport

PGRL1-dependent and NDH-dependent cyclic electron transport have physiological roles for photoprotection in maintaining photosynthesis and plant growth in rice under repeated light fluctuations (Yamori et al. 2016c). In cyanobacteria, pseudocyclic electron transport by flavodiiron protein (Flv) mediates the photoreduction of O2 to H2O and is essential for photosystem-I photoprotection in fluctuating light (Allahverdiyeva et al. 2013).

Fig. 7Strategies for engineering steady-state and non-steady-state photosynthesis. The possible targets would be (1) Rubisco catalysis; (2) Rubisco activase;  (3) photorespiratory bypass; (4) stomatal opening; (5) introduction of C 4 cycle; (6) introductio
Fig. 7Strategies for engineering steady-state and non-steady-state photosynthesis. The possible targets would be (1) Rubisco catalysis; (2) Rubisco activase; (3) photorespiratory bypass; (4) stomatal opening; (5) introduction of C 4 cycle; (6) introductio

Activation of Calvin-Cycle Enzymes, Especially Rubisco

The overexpression of KEA3 accelerates the relaxation of photoprotective energy-dependent quenching after transitions from high to low light in Arabidopsis and tobacco (Armbruster et al. 2016). The overexpression of the endogenous NTRC gene in Arabidopsis also increased plant growth under moderate light intensity (Toivola et al. 2013).

CO 2 Diffusion into the Chloroplast

Furthermore, a recent study showed that both ferredoxin-dependent thioredoxin m, one of the thioredoxin families, and NADPH-dependent NTRC are indispensable for photosynthetic acclimation in fluctuating light intensities (Nikkanen et al. 2016; To what extent mesophyll conductance) limits photosynthesis under fluctuating light is largely unknown, although it has been reported that mesophyll conductance could impose a significant limitation on photosynthesis during the steady state.

8 Future Prospects

Kossmann J, Sonnewald U, Willmitzer L (1994) Reduction of chloroplastic fructose-1,6-bisphosphatase in transgenic potato plants impairs photosynthesis and plant growth. Yamori W, Shikanai T (2016) Physiological functions of cyclic electron transfer around photosystem I in the maintenance of photosynthesis and plant growth.

However, these two main factors, GCV and NRS, will have direct or indirect effects on crop growth and significantly reduce crop yield (Pandey et al. 2017). Multiple abiotic stresses greatly affect crop productivity and have adverse effects on plant growth and development (Fahad et al. 2017; Cohen and Leach 2019).

Fig. 1  Estimated growth of population in the top 10 rice-producing countries
Fig. 1 Estimated growth of population in the top 10 rice-producing countries

2 Green Super Rice

GSR Breeding and Population Development

These early efforts helped in the development of the GSR breeding strategy to breed varieties with multiple biotic and abiotic stress tolerance. 25 DP OM 997 Vietnam Drought tolerance, resistance to blast 26 DP Basmati-385 Pakistan Tolerance of zinc deficiency.

Fig. 3  IRRI-Green Super Rice early backcross breeding strategy to develop rice varieties with  multiple-stress tolerance, resource-use efficiency, and high yield with market-required grain  qual-ity
Fig. 3 IRRI-Green Super Rice early backcross breeding strategy to develop rice varieties with multiple-stress tolerance, resource-use efficiency, and high yield with market-required grain qual-ity

3 Genetics of Green Traits

  • Drought Tolerance
  • Salinity Tolerance
  • Submergence Tolerance
  • Nutrient-Use Efficiency
  • Weed-Competitive Ability Traits
  • Low-Temperature Stress Tolerance at Different Crop Growth Stages
  • Grain Quality
  • Biotic Stress Tolerance

Globally, more than $100 billion is lost annually to weed control (Appleby et al. 2002). Improving the tolerance of LTS in the reproductive phase is necessary through a method of selective introgression (Liang et al. 2018).

Table 2List of QTLs and putative candidate genes for green traits in the Green Super Rice breeding program TraitsGenotypingParents (RP/DP)Breeding strategyPolymorphic SNPsNumber of QTLs
Table 2List of QTLs and putative candidate genes for green traits in the Green Super Rice breeding program TraitsGenotypingParents (RP/DP)Breeding strategyPolymorphic SNPsNumber of QTLs

4 Molecular Genetics and Breeding Strategies to Combine Multiple Stresses

Dissecting the Stress-Regulated Mechanisms for Multiple Stress Tolerance

They also connect with the multiple stress signaling pathways to regulate stress-responsive gene expression (Vemanna et al. 2019). In the GSR breeding strategy, Murugaiyan et al. 2019) identified a robust QTL for arsenic tolerance on chromosome 1 and found a multidrug resistance-associated protein (OsMRP2) belonging to the subfamily of ABC transporters.

Breeding Products Combining Tolerance of Multiple Stresses

For example, Yorobe et al. 2016) assessed the impact of GSR varieties and evaluated farmers' income per acres. One GSR line (IRIS in data from two seasons for 2 years showed a 10% yield advantage over the local control variety and also had tolerance to drought, salinity and submergence (Ali et al. 2013a).

Fig. 5  Achievements of GSR breeding program and released GSR varieties across the globe
Fig. 5 Achievements of GSR breeding program and released GSR varieties across the globe

Development of Rice Hybrids with Multiple-Stress Tolerance

Ali J, Xu JL, Gao YM et al (2013a) Breeding for yield potential and increased productivity across different rice ecologies through green super rice (GSR) breeding strategy. Guojun P, Shuqiang C, Chengyan S et al (2009) Study on the relationship between resistance to blast and yield traits in early japonica rice in cold region [J].

Hybrid rice technology is a viable approach to increase rice production with limited resources and climate change. The increased production of hybrid rice provides food to more than 70 million people annually (Yuan 2014).

2 The Emergence of Two-Line Hybrid Rice Technology with a Historical Perspective

Currently, the annual planting area of ​​two-line hybrid rice in China has exceeded 5 million ha, while heterosis in rice is fully exploited (Chen et al. 2020). With recent research advances, TGMS-based two-line hybrid rice breeding is poised to replace three-line hybrid rice technology over the next decade (Ali et al. 2018).

Table 1Origin and fertility-sterility transformation behavior of photoperiod-thermosensitive and temperature-sensitive male sterile sources in rice SourceEcotypeOrigin of genePlace of development
Table 1Origin and fertility-sterility transformation behavior of photoperiod-thermosensitive and temperature-sensitive male sterile sources in rice SourceEcotypeOrigin of genePlace of development

3 Advantages and Disadvantages of the TGMS System in the Tropics

In this regard, to address the tropical Asian markets, IRRI is refocusing on the development of two-line hybrid rice technology and usable TGMS parent lines. The two-line hybrid rice approach via TGMS is promising because it eliminates the need for an outcrossing step of parental line production, directly reducing seed costs.

4 Physiological Characterization of the TGMS Trait

  • Determination of CSTP and CFTP
    • Characterization Under Controlled-Temperature Screening Conditions
    • Field Screening Through Sequential Seeding
  • Determination of the Critical Stage for Fertility-Sterility Alteration
  • Evaluation of TGMS Lines for Sterility-Fertility Alteration in Different Environments
  • Improvement of Outcrossing Traits in TGMS and Pollen Parental Lines

Based on the tracking method (Ali et al. 1995), CSTP and sensitivity can be determined. Visual phenotypic selection can be used efficiently to identify the highest seed potential (Ramakrishna et al. 2006;

Fig. 2  Physiological characterization of TGMS lines in (a) plant growth facility bay, (b) cold- cold-water facility, and (c) reach-in chamber
Fig. 2 Physiological characterization of TGMS lines in (a) plant growth facility bay, (b) cold- cold-water facility, and (c) reach-in chamber

5 Genetics of TGMS Lines

Identification of Genes Governing the TGMS Trait

In this context, it is essential to understand the molecular function of the TGMS trait (Ding et al. However, the first genetic study to confirm the location of the TGMS gene was initiated by Wang et al.

Table 2Molecular markers associated with EGMS genes in rice (modified from Ali et al. 2018) TraitGeneSourceChromosomeClosest flanking markersDistance (cM)Reference TGMStms 15460S8RZ562-RG9786.7Wang et al
Table 2Molecular markers associated with EGMS genes in rice (modified from Ali et al. 2018) TraitGeneSourceChromosomeClosest flanking markersDistance (cM)Reference TGMStms 15460S8RZ562-RG9786.7Wang et al

Molecular Mechanisms of the TGMS Trait

However, few studies have attempted to pyramid these alleles, which have been studied to improve the stability of TGMS lines (Nas et al. 2005). The TGMS trait is governed by a single master gene and may have multiple modifier genes that exist in different backgrounds.

Fig. 4  Current breeding approaches for TGMS followed at IRRI
Fig. 4 Current breeding approaches for TGMS followed at IRRI

6 Breeding of TGMS and Pollen Parental Lines

  • Different Available Approaches to Breed TGMS Lines
    • Mutation Breeding for the Identification of TGMS Mutants
    • Pedigree Breeding
    • Transfer from a Known TGMS Gene Source to Elite Lines
    • Pyramiding TGMS Genes for Better Stability
  • Rapid Fixation of Segregating TGMS Lines
  • Breeding Pollen Parents
  • Two-Line indica/japonica Hybrids

Regardless of the fixation method, marker-assisted selection (MAS) is an integral part of the generation promotion of TGMS lines. MAS ensures the integrity of the tms gene and the genetic purity of the TGMS lines across generations.

Fig. 5  New IRRI stable TGMS lines with low critical sterility temperature point at 24 °C
Fig. 5 New IRRI stable TGMS lines with low critical sterility temperature point at 24 °C

7 Breeding Two-Line Hybrids

  • Combining Ability Nurseries
  • Breeding Trials
  • Insect Pest and Disease Resistance
  • Grain Quality Considerations Addressing Market Needs

Two-line rice hybrid yield potential can be fully realized by including resistance to major diseases and insect pests (bacterial leaf blight (BLB), blast (BL), false smut (FS), sheath blight (SHB), tungro, green. leafhopper ( GLH), brown leafhopper (BPH), stem borer, leaf folder and gall midge IRRI's two-line rice hybrid Mestiso 61 with good grain quality suited the market needs of the Philippines.

Table 4Performance of hybrids over the best inbreds and hybrids at IRRI-South Asia Hub, Hyderabad, in WS 2018, and at ISARC-Varanasi in kharif 2019 DesignationIRRI-South Asia Hub, Hyderabad (WS2018)ISARC Varanasi (kharif 2019)Days to flowering
Table 4Performance of hybrids over the best inbreds and hybrids at IRRI-South Asia Hub, Hyderabad, in WS 2018, and at ISARC-Varanasi in kharif 2019 DesignationIRRI-South Asia Hub, Hyderabad (WS2018)ISARC Varanasi (kharif 2019)Days to flowering

8 Seed Production Challenges

Identification of Ideal Locations for Self-Seed

Almost 800 ha of sandy soils are available for commercial multiplication of promising TGMS lines (Soundararaj et al. 2002). In the Philippines, Lucban, Nueva Vizcaya and Benguet have all been identified as very suitable for the propagation of TGMS lines.

9 Wide-Scale Adoption and Use of Two-Line Hybrid Rice Technology

IRRI will continue to invest in this critical technology to provide rice farmers in South Asia with the benefits of two-line rice hybrids. The success of two-line hybrid rice technology in tropical Asia would shift the focus from hybrid rice development in China to South Asia, sparking widespread adoption of two-line rice hybrids.

10 Future Directions and Conclusions

Latha R, Thiyagarajan K (2010) Fertility change behavior of thermosensitive genetic male sterile lines in rice Oryza sativa L. Li RB, Pandey MP, Sharma P (2005) Inheritance of thermosensitive generic male sterility in rice (Oryza sativa L.).

Productivity by Decreasing Water Demand

Such conditions further complicate rice genetic improvement programs, which increases the pressure on the irrigated ecosystem (He et al. 2020). This forces us to develop new water management techniques for rice cultivation that specifically improve production in different ecosystems (Carracelas et al. 2019).

2 Current Rice Cultivars/Varieties Grown Under Water-Limiting Conditions

आईआरआरआई ने 17 अधिक उपज देने वाली सूखा-सहिष्णु चावल की किस्मों को सफलतापूर्वक विकसित और जारी किया है, जिसमें सहोद उलान और कटिहान (फिलीपींस), हरदीनाथ और सूखा धन (नेपाल), सहभागी धन (भारत), बीआरआरआई धान (बांग्लादेश), इनपागो लिपि गो 1 शामिल हैं। /2 (इंडोनेशिया), एम'ज़िवा (मोज़ाम्बिक) और यूपीआईए3 (नाइजीरिया) (कुमार और अन्य 2014)। इसी तरह, नेपाल में, सूखा-सहिष्णु किस्म सूखा धान 2 ने 1000-1600 मसल (ढाकल एट अल. 2020) की ऊंचाई से अधिक उपज दिखाई।

3 Existing Rice Cultivation Practices Under Water-Deficit Conditions

Plant-Based Strategies

  • Selection of Cultivars/Varieties
  • Date of Planting
  • Decreased Stand Density

Due to early maturity (105 days) and low irrigation requirements, farmers can save up to USD 60 per crop (Basu et al. 2017). Similarly, taking 15 rice cultivars commonly grown in Mississippi (USA), early season drought tolerant cultivars were selected by analyzing the total drought response index (TDRI) (Singh et al. 2017).

Fig. 1  Different strategies to improve rice productivity by decreasing water demand
Fig. 1 Different strategies to improve rice productivity by decreasing water demand

Soil- and Irrigation-Based Strategies

  • Alternate Wetting and Drying
  • Saturated Soil Culture
  • Aerobic Rice Development
  • Decreasing Non-beneficial Water Depletions and Water Outflows A decrease in evaporation during different stages of development is achieved by
  • System of Rice Intensification
  • Sprinkler Irrigation

In this system, rice cultivars were sown in weak and unsaturated (vibrant) soils (Bouman et al. 2007). These measures also increase crop competitiveness by reducing weed transpiration (Korres et al. 2016).

4 Molecular Breeding for Rice Improvement

  • QTL Mapping
  • Marker-Assisted Selection
  • Marker-Assisted Backcrossing
  • Marker-Assisted Pyramiding
  • Marker-Assisted Recurrent Selection
  • Genomic Selection

Marker-assisted recurrent selection (MARS) essentially increases the frequency of beneficial alleles with additive and small individual effects (Bankole et al. 2017). During the implementation of MARS, the frequency of favorable alleles increases, reducing genetic drift (Bankole et al. 2017).

Table 1  Drought tolerance QTLs mapped and used for rice breeding programs QTL/gene QTL/gene
Table 1 Drought tolerance QTLs mapped and used for rice breeding programs QTL/gene QTL/gene

5 Transgenic Strategies

Similarly, overexpression of the gene trehalose-6-phosphate synthase (OsTPS1), which expresses an enzyme in trehalose biosynthesis, showed improved drought tolerance in transgenic rice (Li et al. 2011). The expression of stress-responsive genes increased, resulting in greater drought tolerance (Kim et al. 2010).

6 Future Prospects

Dixit S, Singh A, Sandhu N, Bhandari A, Vikram P, Kumar A (2017) Combination of drought and submergence tolerance in rice: marker assisted breeding and QTL combination effects. Li HW, Zang BS, Deng XW, Wang XP (2011) Overexpression of the trehalose-6-phosphate synthase gene OsTPS1 enhances abiotic stress tolerance in rice.

Traits, Physiology, and Genetics

Although it was beneficial to increase grain yield, the effects of the Green Revolution came at an environmental cost. This review aims to summarize crop establishment practices in rice in relation to climate change and water scarcity.

Fig. 1  2017 worldwide (a) milled rice production (tons) and (b) total rice consumption
Fig. 1 2017 worldwide (a) milled rice production (tons) and (b) total rice consumption

2 Climate Change and Water Scarcity

Economic water scarcity is due to the lack of ability to withdraw water given that there is a sufficient amount of reserve (Molden 2007; OCHA 2010). An estimated four billion people worldwide are limited by extreme water scarcity for blue water (fresh surface water and/or groundwater that is extracted from the ground and not returned due to evaporation into the atmosphere or incorporation into a product). of which more than half are from China and India (Mekonnen and Hoekstra 2016), two of the highest rice-producing Asian countries.

Fig. 2  Average yearly precipitation (cm) across different countries. (Image retrieved from https://
Fig. 2 Average yearly precipitation (cm) across different countries. (Image retrieved from https://

3 Rice Establishment Methods

Puddled Transplanted Rice

Although 1432 L of water is needed to produce 1 kg of rough rice (Rice Knowledge Bank 2017), only about 10% of the total absorbed water is used by the plant for its development (Chavarria and dos Santos 2012). In today's water scarcity scenario, the transplanted rice paddy system is becoming increasingly unsustainable.

Direct-Seeded Rice

4 Traits, Physiology, Genetics, and Breeding 4.1 Anaerobic Germination

  • Physiology and Molecular Mechanisms of AG
  • Genetic Factors Underlying the AG Trait
  • Seed Longevity
    • Physiology and Molecular Mechanisms Affecting Seed Longevity Seeds battle aging through protection and repair. The seed protection mechanism
    • Genetic Factors Affecting Seed Longevity
  • Early Seedling Vigor
    • Physiology and Molecular Mechanisms of Early Seedling Vigor

Expression analysis through RNA-seq (RNA-seq) revealed that RAMy3D was highly expressed in tolerant genotypes under anoxia (Ismail et al. 2009). During starvation, a glucose and sucrose receptor, RAMy3D, is activated by protein kinase SnRK1A (Lu et al. 2007).

Fig. 4  Mean shoot and  root lengths of five  flooding-tolerant and five  flooding-sensitive  genotypes of rice measured  21 days after sowing under  control and flooded  (10 cm) conditions
Fig. 4 Mean shoot and root lengths of five flooding-tolerant and five flooding-sensitive genotypes of rice measured 21 days after sowing under control and flooded (10 cm) conditions

Hình ảnh

Table 1  List of wild species/landraces used for trait enhancement in rice
Table 2  Targeted editing of important genes employing genome editing techniques
Fig. 1 Relationship  between CO 2  assimilation  rate at a CO 2  concentration  of 390  μ mol/mol, total  plant dry weight at the  final stage, and grain yield  in rice
Fig. 3  Schematic diagram of photorespiration in plants (black), with three bypasses to minimize  photorespiratory expenses engineered in plants (red, blue, green)
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