Study of Genetic Diversity for Rust Resistance and Yield Related Traits in F5 and F6 Populations of Bread wheat (Triticum aestivum L.)

Abstract

Aims: To study the variability for morphological traits and yellow rust resistance in the bread wheat. Study Design: Randomized block design (RBD) at a 5% level of significance. Place and Duration of Study: The study was undertaken in the Department of Genetics & Plant Breeding, CCS Haryana Agricultural University, Hisar during the 2018-2019 and 2019-2020 cropping seasons. Methodology: A total of 210 F5 and F6 progenies from the cross WH711 (susceptible) x PBW698 (resistant) including parents were evaluated in a single row of 1m length and 11 different morphological traits were included in the study. Infector rows were planted and artificial inoculation (using spray method) was carried out under field conditions using Pst (Puccinia striformis) isolate as a source of inoculums. Results: The analysis of variance was highly significant (P<0.01) for yield and its related components. In F5 and F6 generations, high to moderate PCV and GCV were recorded for harvest index, biological yield/plant, 1000-grain weight, grain yield/plant, number of spikelets/spike, and number of grains/spike. High heritability coupled with high genetic advance as a percent of mean was observed for the number of grains/spike, number of spikelets/spike, 1000-grain weight, biological yield/plant, harvest index, and grain yield/plant in F5 and F6 generations. The correlation coefficient studies revealed that grain yield/ plant is significantly correlated with all yield-attributing characters except with days to heading in F5 and plant height in F6 generation. The path analysis recommended that all the traits had maximum positive direct contribution towards grain yield/plant except plant height and days to heading in F5 and F6 generations. The 135 and 148 progenies showed no infection in F5 and F6 generations. Conclusion: The presence of substantial variability has existed among the tested wheat lines and possibility of improving yield and other desirable traits through selection or hybridization. Phenotypic and genotypic correlation analysis showed a positive correlation of grain yield with important quantitative characters. Hence, improving one or more of these traits could result in a high grain yield/ plant.