Genetic and Molecular analysis of yield and physiological traits in three line hybrids in rice (Oryza sativa L.) under aerobic condition

Table of Contents

I. INTRODUCTION

II. REVIEW OF LITERATURE

2.1. DROUGHT AND DROUGHT TOLERANCE IN RICE

2.2. NEED FOR AEROBIC RICE AND ITS IMPORTANCE

2.2.1. Aerobic rice breeding and its improvement

2.3. GENETICS OF DROUGHT TOLERANCE AND YIELD

2.4. DROUGHT TOLERANT TRAITS

2.5. ROLE OF SECONDARY TRAITS AND PUTATIVE TRAITS FOR DROUGHT TOLERANCE

2.5.1. Secondary traits

2.5.1.1. Days to 50 per cent flowering

2.5.1.2. Plant height

2.5.1.3. Number of productive tillers per plant

2.5.1.4. Panicle number per plant

2.5.1.5. Panicle length

2.5.1.6. Filled grains per panicle

2.5.1.7. Spikelet fertility

2.5.1.8. Total dry matter production (TDMP)

2.5.1.9. Hundred grain weight

2.5.1.10. Harvest index

2.5.1.11. Single plant yield

2.5.2. Putative traits

2.5.2.1. Root characters

2.5.2.1.1. Root length, dry root weight and dry shoot weight

2.5.2.1.2. Root – Shoot Ratio

2.5.2.1.3. Relative water content (RWC)

2.5.2.1.4. Chlorophyll stability index (CSI)

2.5.2.1.5. Proline content

2.5.2.1.6. SPAD chlorophyll meter reading

2.6. COMBINING ABILITY AND GENE ACTION

2.6.1. Gene action for different biometrical and physiological traits

2.7. VARIABILITY STUDIES

2.7.1. PHENOTYPIC AND GENOTYPIC CO EFFICIENT OF VARIATION

2.8. HERITABILITY AND GENETIC ADVANCE

2.9. HETEROSIS

2.10. ASSOCIATION ANALYSIS

2.10.1. Correlation studies

2.10.1.1. Correlation of grain yield with component traits

2.10.1.2. Inter correlation among yield components

2.10.2. Path analysis

2.10.2.1. Direct effects of different characters on grain yield

2.10.2.2. Indirect effects of different characters through other characters

2.11. GENETIC DISSECTION FOR DROUGHT TOLERANCE THROUGH MOLECULAR MARKERS

III. MATERIALS AND METHODS

3.1. MATERIALS

3.2. METHODS

3.2.1. HYBRIDIZATION PROGRAMME

3.2.2. Evaluation of F1 hybrids and parents for yield traits under aerobic condition

3.3. CHARACTERS STUDIED

3.3.1. YIELD AND ITS COMPONENTS

3. 3. 1.1. Days to 50 per cent flowering (DF):

3. 3.1.2. Plant height (PH):

3. 3. 1.3. Number of Productive tillers per plant (PT):

3.3.1.4. Number of panicles per plant (PP):

3. 3. 1.5. Panicle length (PL):

3. 3. 1.6. Filled grains per panicle (FG):

3. 3. 1.7. Spikelet fertility (SF):

3. 3. 1.8. Hundred grain weight (HGW):

3.3.1.9. Proline content (PC):

3.3.1.10. SPAD chlorophyll meter reading (SCMR):

3.3.1.11. Chlorophyll stability index (CSI):

3.3.1.12. Relative water content (RWC):

3. 3. 1.13. Biomass yield (BMY):

3. 3.14. Dry shoot weight (DSW):

3. 3. 15. Dry root weight (DRW):

3. 3. 16. Root / shoot ratio (RS):

3. 3. 1.17. Root length (RL):

3. 3.1.18. Harvest index (HI):

3.3.1.19. Single plant yield (YLD):

3.4. STATISTICAL ANALYSIS

3. 4. 1. Line x Tester analysis

3. 4. 1. 1. Analysis of variance

3.4.1.1.1. Phenotypic and genotypic variances

3.4.1.1.2. Phenotypic and genotypic co-efficient of variability (PCV and GCV)

3.4.1.2. HERITABILITY

3.4.1.3. GENETIC ADVANCE

3. 4. 1. 4. ANALYSIS OF COMBINING ABILITY AND GENE ACTION

3. 4. 1. 4. 1. ANOVA for combining ability

3. 4. 1. 4. 1.1. Estimation of combining ability effects

3. 4. 1. 4. 1.2. General combining ability effects

3. 4. 1. 4. 1.3. Specific combining ability effects

3. 4. 1. 4. 1.4. Test of significance of combining ability effects

3. 4. 1. 4. 2. ESTIMATION OF HETEROSIS

3. 4. 1. 4. 2.1. Heterobeltiosis (dii)

3. 4. 1. 4. 2.2. Standard heterosis (diii)

3. 4. 1. 4. 2.3. Test of significance

3. 4. 1. 4. 3. ASSOCIATION ANALYSIS

3. 4. 1. 4. 3.1. Correlation studies

3. 4. 1. 4. 3.2. Path coefficient analysis

3.5. Molecular characterization

3.5.1. Extraction of DNA

3.5.2. Quantification of DNA

3.5.3. Agarose gel electrophoresis

3.5.4. Molecular marker analysis

3.5.4.1. PCR amplification for SSR marker

3.5.4.2. Electrophoresis analysis

3.6. Scoring and statistical analysis of SSR data

3.6.1. Data scoring

3.6.2. Data analysis

3.6.3. Cluster analysis

IV. EXPERIMENTAL RESULTS

V. DISCUSSION

VI. SUMMARY

Research Objectives & Key Topics

The primary research objective of this thesis is to perform a comprehensive genetic and molecular analysis of various rice hybrids to identify the best parental combinations and genotypes that exhibit superior yield performance and drought tolerance under aerobic conditions.

• Line x Tester mating design for estimating combining ability and gene action.
• Assessment of heterosis for physiological, yield, and yield-contributing traits.
• Correlation and path analysis to determine the interrelationship between drought tolerance and yield.
• Molecular marker analysis using SSR markers to assess genetic polymorphism and similarity among parents.

Excerpt from the Book

Summary of Chapters

INTRODUCTION: Provides an overview of the global importance of rice, the challenges of water scarcity, and the rationale for developing aerobic rice varieties.

REVIEW OF LITERATURE: Examines existing research on drought tolerance in rice, secondary traits, combining ability, heterosis, and molecular markers.

MATERIALS AND METHODS: Details the materials, hybridization techniques, characterization of traits, and statistical approaches used in the investigation.

EXPERIMENTAL RESULTS: Presents the statistical findings regarding variance, mean performance, combining ability, and heterosis of the rice genotypes studied.

DISCUSSION: Interprets the experimental results in the context of breeding strategies for yield improvement and drought tolerance in aerobic environments.

SUMMARY: Recaps the main findings of the research, emphasizing the effectiveness of specific hybrids and parental lines for future breeding programs.

Keywords

Aerobic rice, drought tolerance, Line x Tester analysis, combining ability, gene action, heterosis, SSR markers, genetic diversity, yield components, harvest index, SPAD chlorophyll meter, proline content, correlation analysis, path analysis, grain yield.

Frequently Asked Questions

What is the primary focus of this research?

The research focuses on the genetic and molecular improvement of rice for aerobic cultivation, specifically aiming to enhance yield and drought tolerance.

What are the core thematic areas covered in the thesis?

The thesis covers plant breeding methodologies, genetic variance estimation, heterosis exploitation, correlation and path analysis of yield components, and the use of molecular markers for genetic diversity assessment.

What is the main research objective?

The goal is to identify superior parental lines and hybrid combinations that maintain high productivity while using less water under non-flooded, aerobic conditions.

Which scientific method is utilized for breeding analysis?

The study employs a 'Line x Tester' mating design to estimate combining ability (GCA and SCA) and gene action in rice hybrids.

What topics are discussed in the main body chapters?

The main body chapters discuss experimental results related to mean performance, combining ability variance, heterosis, and association studies between various physiological and yield-related traits.

What keywords characterize the research?

The research is characterized by terms such as aerobic rice, drought tolerance, combining ability, heterosis, and molecular marker analysis.

What specific role does the 'Line x Tester' analysis play?

It provides critical information about the general combining ability (GCA) of parents and specific combining ability (SCA) of crosses, helping identify which parents contribute desirable traits for drought and yield.

How is molecular marker analysis applied in this study?

Molecular markers (SSRs) are used to screen 21 parents to determine genetic similarity and construct a dendrogram, which aids in selecting genetically diverse parents for cross-breeding.