Genetic variability and agronomic performances of rice genotypes in different growing seasons in Bangladesh

Genetic variability is a key factor in the selection of suitable genotypes in rice breeding programs. To evaluate the genetic variability of 11 rice genotypes, a study was carried out in the field of agronomy at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, during 2019–2020. These genotypes were characterized for 11 traits and analyzed to determine the level of genetic and agronomic diversity as well as the degree of association existing between grain yield and its related component traits. The results revealed significant differences (P ≤ 0.001 and 0.05) among the rice genotypes for the studied traits in all growing seasons. Furthermore, it was noted that the phenotypic coefficient of variation was more pronounced than the genotypic coefficient of variation, highlighting the environmental impact on each trait. The majority of the traits had moderate to high heritability and genetic advance across the three seasons, showing additive gene action. The principal component analysis showed that the first three principal components accounted for the greatest variability, with the majority of the evaluated traits significantly influencing the genetic variability. The mean value of studied traits exhibited that there was seasonal variation of grain yield by the genotypes, such as BU-R-ACC-08 and BU-R-ACC-11 genotypes, which produced higher yield in Aus, BU-R-ACC-05 and BU-R-ACC-06 in Aman, and BU-R-ACC-07 and BU-R-ACC-06 in Boro season, where several genotypes mature earlier in all growing seasons, viz., BU-R-ACC-05, BU-R-ACC-01, BU-R-ACC-10, and BU-R-ACC-11. The correlation analysis revealed that there were significant, strong positive or negative correlations among the traits. The results suggest that agronomical traits that were positively correlated with grain yield could be useful in selecting desired rice genotypes.