Agronomic and yield performance of two rice (Oryza sativa L.) Azucena bi-parental mutant population grow under conventional and field rapid generation advance conditions in Los Baños, Laguna, Philippines

Abstract

Rice breeding is constrained by prolonged generation cycles, limiting the rapid development of improved cultivars. To accelerate breeding, the Field Rapid Generation Advance (FRGA) approach was employed. This study assessed and compared the agronomic traits, yield performance, and associated costs of Azucena bi-parental mutants under conventional and FRGA setups. In the F₂ generation, MON 329 × Azucena (P1) and Azucena × MON 329 (P2) headed at 81 days and matured at 104 days, with P1 producing taller plants, more tillers, and higher yield, while P2 had longer panicles. In the F₃ generation under conventional conditions, P1 headed earlier at 75.68 days, matured at 105.18 days, produced more tillers and longer panicles, and yielded 2,840.89 kg ha⁻¹. Under FRGA, plants matured 5–10 days earlier but showed reduced height, tiller number, panicle length, and yield, with P1 producing 977.08 kg ha⁻¹ and P2 587.09 kg ha⁻¹. Correlation analysis showed a strong relationship between heading and maturity and identified tiller number as the trait most associated with yield. Scatter plots indicated wider trait dispersion under FRGA, reflecting stronger environmental influence. Selected lines P1 (C-11784-3, C-11784-30) and P2 (C-11785-30, C-11785-6) showed stable expression for advancement. Although FRGA shortened the generation cycle, partial budget analysis indicated higher costs and lower yield, resulting in a net loss of ₱193,849.12. Thus, FRGA is not economically feasible under the evaluated conditions but provides technical advantages for rapid line assessment and functions as a breeding acceleration platform rather than a cropping system.