The present research consists of 12 rice (Oryza sativa L.) genotypes and the experiment was conducted during June- November 2017 in Randomized Block Design with three replication at NARC, Kumaltar. The data were recorded for ten quantitative characters to study genetic variation, heritability, genetic advance and correlation coefficient analysis. Analysis of variance among 12 genotypes showed a significant difference for all characters studied except non-effective tillers.
Grain yield had a positive significant correlation with SPAD and positive correlation with 1000 grain weight, flag leaf area, days of 50% flowering, plant height, a number of effective tiller and panicle length whereas negative significant correlation with a number of a non-effective tiller and negative correlation with days of 90%maturity. A moderate genotypic coefficient of variation (GCV) and phenotypic coefficient variation (PCV) was observed for flag leaf area and followed by grain yield and number of effective tiller, that these characters could be used as a selection for crop improvement.
High estimates of heritability were observed for days of 50% flowering and followed by panicle length, flag leaf area, test weight and days of 90% maturity. A high genetic advance was found in a number of non-effective tillers, grain yield per meter square, no of an effective tiller and flag leaf area indicating pre-dominance of additive gene effects and possibilities of effective selection for the improvement of these characters.
Table of Contents
1. INTRODUCTION
2. MATERIALS AND METHODS
2.1 Experimental details
2.2 Statistical analysis
2.3 Genotypic and phenotypic coefficient of variation
2.4 Broad sense heritability (H2bs)
2.5 Genetic advances (GA)
3. RESULTS AND DISCUSSION
3.1 Genotypic and phenotypic variance
3.2 Genotypic and phenotypic coefficient of variation
3.3 Heritability
3.4 Genetic Advance and Genetic Advance as percentage of mean
3.5 Correlation
4. CONCLUSION
5. REFERENCES
Research Objectives and Focus Areas
The primary objective of this research is to investigate the nature and magnitude of genetic variations and the interrelationships between yield and various agronomic traits in twelve selected rice genotypes grown under rainfed conditions in Nepal.
- Analysis of genetic variability among diverse rice genotypes.
- Evaluation of heritability and genetic advance for key quantitative traits.
- Examination of phenotypic and genotypic correlations between grain yield and yield-contributing characters.
- Identification of suitable selection criteria for future crop improvement breeding programs.
- Assessment of the influence of environmental factors on genotype performance.
Excerpt from the Book
INTRODUCTION
Rice (Oryza sativa L.) 2n=24 (Hooker,1979), is monocot, annual, semi aquatic cereal crop and a member of family Poaceae. Thiamine, riboflavin, niacin and dietary fibre are good source in rice(FAO 2004). Global production of rice is about 740 million ton with 4,539 kg/ha productivity and habitable in 117 country covering a total area of 163 million hectares (FAOSTAT, 2014) and in Asia for 100 million household it is main source of income and employment (Singh.,et al.,2015).
Rice contributes 33.91% to GDP and 48.8% to AGDP in Nepal (MOF, 2016). Rainfed rice, based grown in Asia about 46 million hectares (Haefele and Hijmans,2007) and has alone around 23 million hectares prone to drought Reyes (2009) and affects regularly, out one in five year (Pandey et al.,2005). NARC(2004) indicates still 79% of rice is grown under rainfed condition of which 70% under rainfed lowland and 9% is under upland condition .Pantuwan, et al., (2000) observed that grain yield of rice genotypes under rainfed condition was reduced from 18 % to 54 % as compare to irrigated condition. According to United Nation’s report world population is going to cross 8 billion in 2030 and 9.6 billion by 2050.For rice production, water is critical and important factor. So, to meet future demand resulting from population growth and limited water condition, plant breeders have to identify genotypes with optimal reproductive capacity with high yield potential under stress condition.
Summary of Chapters
INTRODUCTION: Provides background on the importance of rice in Nepal, the challenges of rainfed agriculture, and outlines the research objectives regarding genetic variation.
MATERIALS AND METHODS: Details the experimental design, including the use of 12 rice genotypes in a Randomized Complete Block Design, and the specific statistical formulas used to calculate variance and heritability.
RESULTS AND DISCUSSION: Presents the analysis of variance, genotypic and phenotypic variance, heritability estimates, and the correlation coefficients between yield and yield-contributing traits.
CONCLUSION: Summarizes the findings, highlighting traits that show sufficient variability and heritability for effective selection in crop improvement programs.
Keywords
Correlation, Heritability, Genetic Advance, Genetic Variability, Rice, Oryza sativa, Genotypes, Rainfed, Breeding, Yield, Agronomic traits, ANOVA, Phenotypic, Genotypic, Selection.
Frequently Asked Questions
What is the core focus of this research study?
The study focuses on evaluating the genetic variability, heritability, and character associations of twelve rice genotypes grown under rainfed conditions in Nepal to assist in breeding for improved grain yield.
Which quantitative characters were analyzed in the study?
The research recorded data on ten characters, including days to 50% flowering, plant height, flag leaf area, chlorophyll content (SPAD), panicle length, days to 90% maturity, effective and non-effective tillers, 1000 grain weight, and total grain yield.
What is the primary objective of this paper?
The main objective is to determine the nature and magnitude of genetic variations and the interrelationships between grain yield and its contributing components to identify effective selection criteria for rice improvement.
What scientific methodology was employed?
The study used a Randomized Complete Block Design with three replications and utilized ANOVA for genotypic effects, alongside statistical methods suggested by Burton and De vane for calculating variance, heritability, and genetic advance.
What is the main finding regarding grain yield correlation?
Grain yield showed a significant positive correlation with SPAD values, while exhibiting highly negative significance with the number of non-effective tillers per square meter.
Which traits are identified as key selection criteria?
Based on moderate to high GCV, PCV, and heritability, flag leaf area, grain yield, and the number of effective tillers are highlighted as critical traits for selection in future breeding programs.
Why are environmental factors significant in this study?
The results show that phenotypic variance is generally higher than genotypic variance, indicating that environmental conditions in rainfed environments significantly influence the expression of yield-related traits.
How does water deficit affect rice production according to the text?
The study notes that under rainfed conditions, grain yield can be reduced by 18% to 54% compared to irrigated conditions, necessitating the identification of genotypes with optimal reproductive capacity under stress.
- Arbeit zitieren
- Narayan Neupane (Autor:in), 2019, Genetic Variation and Correlation of Spring Rice Genotypes in Mid-Hill's Rainfed Condition of Nepal, München, GRIN Verlag, https://www.grin.com/document/454179
