Evaluation of Advanced Boro Rice Lines for Yield Improvement and Breeding Potential in Bangladesh

Improving Boro rice productivity is critical for food security in Bangladesh. This study evaluated 63 advanced breeding lines and three BRRI check varieties for 13 agro-morphological and yield-related traits to identify superior genotypes and key selection criteria. Genotypic differences were highly significant for all traits, indicating substantial exploitable variability. V57 produced the highest grain yield (8.60 t ha⁻¹), followed by V32 (8.36), V40 (8.23), V54 (8.21), and V44 (8.14 t ha⁻¹), compared with 6.92–7.14 t ha⁻¹ for the check varieties. V57 also combined the highest total and effective tiller numbers (16.50 and 14.10), 92.09% spikelet fertility, 176.70 filled grains panicle⁻¹, and only 15.17 unfilled grains panicle⁻¹. Unfilled grains panicle⁻¹ showed the highest GCV and PCV (18.06 and 18.61%), followed by length–breadth ratio (11.86 and 12.52%) and grain yield (10.21 and 10.77%). Broad-sense heritability was high for all traits (72.35–94.18%); grain yield exhibited 89.82% heritability and 19.92% genetic advance as percentage of the mean, indicating good selection potential. The first two principal components explained 70.7% of total phenotypic variation. Grain yield was strongly and positively correlated with effective tiller number (r = 0.96), total tiller number (r = 0.96), fertility percentage (r = 0.82), thousand-grain weight (r = 0.70), and filled grains panicle⁻¹ (r = 0.61), but negatively with unfilled grains panicle⁻¹ (r = − 0.78). MGIDI identified V38, V35, V31, V47, V8, V54, V5, V63, V62, and V17 as desirable multi-trait genotypes with complementary strengths. These lines, together with the highest-yielding genotypes, represent promising parental and breeding materials, but require multi-environment validation for yield stability, adaptation, grain quality, and stress resilience.