Estimation of Genetic Parameters and Character Associations, and Disease Resistance of Bread Wheat (Triticum aestivum L.) Genotypes

Genetic Variability in Some Local Spring Wheat (Triticum aestivum L.) Genotypes of Bangladesh for Yield and its Attributing Traits

Purpose: Around the globe, wheat is a significant cereal crop, used for food, feed, and raw materials. The study’s main objective was to examine the diversity and variability of yield and its attributing traits among sixty (60) locally cultivated wheat genotypes of Bangladesh based on genetic analyses to formulate appropriate breeding strategies for further improvements.Research Method: A total of sixty wheat genotypes were evaluated in the field using a randomized complete block design (RCBD) with three replications to assess ten yield and yield-related parameters. Statistical analysis was conducted using R-studio software to gauge the genetic variance among these sixty wheat genotypes.Findings and Values: The analysis of variance (ANOVA) results revealed a high degree of genetic variation. The study indicated that grain production per plant exhibited the highest Genotypic coefficient of variation (GCV%) and Phenotypic coefficient of variation (PCV%), along with significant genetic advance and strong heritability. This suggests that selecting for this trait would be an efficient breeding strategy. Additionally, the number of tillers per plant, grains per spike, grains per plant, and grain yield per plant showed significant positive correlations. Shatabdi, SA-8, and PV-79 genotypes were associated with the highest yields. The work selects promising genotypes with a wide genetic diversity for yield and attributing traits, which can be used for further varietal improvement in Bangladesh.

Genetic Variability, Broad-Sense Heritability, and Trait Associations of Bread Wheat (Triticum aestivum L.) Across Multiple Environments in Kenya

Aims: This study evaluated phenotypic variation and genotypic differences, estimated broad-sense heritability for grain yield, and examined associations among agronomic traits in five bread wheat (Triticum aestivum L.) genotypes comprising two parental cultivars and three mutation-derived lines. Study Design: Randomised complete block design with three replications. Place and Duration of Study: The genotypes were evaluated at Kitale, Eldoret, and Njoro, Kenya, during the 2021 and 2022 long-rain seasons, representing six environments. Methodology: Seven agronomic traits were analysed using descriptive statistics, combined analysis of variance, restricted maximum likelihood estimation of variance components, entry-mean broad-sense heritability, and Pearson correlation analysis. Results: Grain yield ranged from 1.80 to 3.50 t ha⁻¹, with a mean of 2.70 t ha⁻¹. Genotype significantly affected all evaluated traits, demonstrating differentiation among the wheat materials, while environmental effects varied among traits. Grain yield was significantly influenced by genotype, location, and season, with a significant genotype × location interaction indicating differential genotypic responses across locations. For grain yield, genotypic variance (σ²G = 0.018) exceeded residual variance (σ²e = 0.012) and genotype × environment interaction variance (σ²GE = 0.006). Entry-mean broad-sense heritability was high (H² = 0.91), indicating strong repeatability of differences among genotype means under the multi-environment testing framework. Grain yield was moderately and positively associated with thousand-kernel weight (r = 0.42), while days to maturity was moderately and negatively associated with thousand-kernel weight (r = −0.53). Days to heading and days to maturity were moderately and positively correlated (r = 0.42). Conclusion: The relatively large genotypic variance and high entry-mean heritability indicate that the evaluated materials could be reliably differentiated for grain yield across the testing framework, although environmental and interaction effects remained relevant. Integrating replicated grain-yield performance with genetic parameters and complementary agronomic traits, particularly thousand-kernel weight, provides a sound basis for identifying promising parental and mutation-derived materials for advancement in bread wheat improvement.

Assessment of Genetic Variability, Heritability and Genetic Advance for Yield and Yield-contributing Traits in Bread Wheat (Triticum aestivum L.)

Genetic variability is the foundation of effective selection and crop improvement in wheat breeding programmes. Therefore, the present investigation was conducted during the Rabi season of 2023–24 at the Crop Research Centre, Jigyasa University, Dehradun, Uttarakhand, to evaluate genetic variability, heritability and genetic advance for yield and yield-contributing traits in bread wheat (Triticum aestivum L.). Thirty wheat genotypes were evaluated in a randomized block design with three replications. Observations were recorded for fifteen quantitative characters, including phenological traits, plant height, flag leaf area, productive tillers per plant, spike traits, grains per spike, 1000-grain weight and grain yield per plant. Analysis of variance revealed significant differences among genotypes for plant height, flag leaf area, grains per spike, 1000-grain weight, grain filling period, days to maturity and days to 50% heading, indicating the presence of substantial genetic variability for these traits. The phenotypic coefficient of variation was slightly higher than the corresponding genotypic coefficient of variation for all characters, suggesting a limited influence of environmental factors on trait expression. High heritability estimates were observed for plant height, flag leaf area, grains per spike, 1000-grain weight, spike weight per plant and grain yield per plant. Among these, plant height and flag leaf area also exhibited comparatively higher genetic advance as percent of mean, indicating their potential for effective improvement through selection. The findings suggest that these traits may serve as reliable selection criteria for developing high-yielding bread wheat genotypes under the agro-climatic conditions of the study area.

Analysis of Genetic Variation, Correlation and Path Effects for Grain Yield Enhancement in Bread Wheat (Triticum aestivum L.) under Rainfed and Irrigated Conditions

Drought constrains wheat productivity, making the identification of genetically variable and yield-associated traits important for selection under contrasting moisture regimes. This study evaluated 50 advanced bread wheat genotypes, including five standard checks, under rainfed and irrigated environments during the Rabi season of 2022–23 using a randomised block design with three replications. Two physiological and fourteen yield-related morphological traits were assessed using analysis of variance, phenotypic and genotypic coefficients of variation, broad-sense heritability, genetic advance, correlation, and path coefficient analyses. The phenotypic coefficient of variation exceeded the genotypic coefficient of variation for all traits in both environments. Canopy temperature depression at 14 days after heading (CTD 2) showed the highest PCV/GCV values, at 39.90/33.42% under rainfed and 34.26/29.45% under irrigated conditions. Productive tillers per plant and CTD 2 combined high heritability with comparatively large genetic advance in both environments. Under rainfed conditions, grain yield per plot was strongly and positively correlated with harvest index (r = 0.721), productive tillers per plant (r = 0.698), and biological yield per plot (r = 0.626). Under irrigation, the strongest positive associations were with peduncle length (r = 0.611), spike length (r = 0.606), flag leaf length (r = 0.563), and biological yield per plot (r = 0.552). Path analysis identified harvest index as the largest positive direct contributor under rainfed conditions (0.8029) and biological yield per plot under irrigated conditions (0.8620). These findings support consideration of these traits in selection across contrasting moisture regimes.

Genetic Variability, Correlation and Path Coefficient Analysis for Grain Yield and its Component Traits in Rice (Oryza sativa L.)

The present investigation was undertaken to assess genetic variability among thirty rice (Oryza sativa L.) genotypes and to identify reliable indirect selection criteria for grain yield through correlation and path coefficient analysis. Thirty genotypes were evaluated in a randomised block design with three replications during Kharif 2025 at the Field Experimentation Centre, Naini Agricultural Institute, Prayagraj, Uttar Pradesh, for thirteen quantitative traits. Analysis of variance showed highly significant genotypic differences for twelve of the thirteen characters, confirming substantial genetic variability in the material. High heritability coupled with high genetic advance as a percentage of the mean was recorded for number of spikelets per panicle (98.4%; 41.1%), biological yield per plant (71.2%; 23.6%) and grain yield per plant (69.9%; 22.8%), indicating predominantly additive gene action and good scope for direct phenotypic selection for these traits. Grain yield showed a strong positive genotypic correlation with test weight (1.09), biological yield (0.871) and harvest index (0.715), and path analysis confirmed biological yield and harvest index as the traits with the largest positive direct effects on grain yield at both genotypic and phenotypic levels; test weight, despite its strong correlation with yield, acted mainly through indirect effects channelled via these two traits. The genotype DRRH2 combined the highest grain yield with high biological yield, harvest index and test weight and, together with 72-Dhan-59, 80-NLR-40024 and Vikramarya, is proposed as a promising donor for future hybridisation programmes aimed at raising grain yield in rice.

Multi-trait model-based assessment of selection efficiency and stability in soybean germplasm.