Evaluación y caracterización de germoplasma de arroz en comparación con variedades comerciales

A trial was conducted at the Paso de la Laguna Experimental Unit of INIA Treinta y Tres during the 2022-2023 growing season. The objectives were to evaluate and characterize imidazolinone-resistant rice materials from the INIA Rice Breeding Program to identify varieties with unique agronomic and milling traits for pre-commercial scale evaluation. Two independent trials were carried out, sown on different dates: early sowing (October 5) and late sowing (November 7). Eleven experimental lines and four commercial checks were assigned to randomized complete block designs with four replicates. The agronomic traits evaluated included grain yield and its components, days to flowering, plant height, and disease incidence. Milling quality parameters included head rice yield, whole grain percentage, and chalkiness percentage. Additionally, seed dormancy was evaluated. The trials had an average yield was 10.9 t/ha, while the reference check (GURI INTA CL) achieved 10.3 t/ha. Some materials exceeded 12 t/ha in productivity, including the hybrids INOV FP and XP 113 FP, as well as the cultivar CL 19244. Promising lines such as CL 19258, CL 19246, and CL 19231 showed significantly higher yields compared to the check, particularly in the late sowing (EP2), with increases of 12%, 14%, and 17%, respectively. Milling quality parameters generally surpassed the commercialization base for head rice yield and whole grain percentage. However, chalkiness levels were generally high, with the cultivar CL 1294 standing out in this parameter. The cultivar CL 19265 demonstrated good overall milling quality values. The material CL 19263 did not differ in yield from the check but showed higher chalkiness in EP2, while CL 19219 exhibited superiority in chalkiness in both sowing periods. The seed dormancy of some materials was short, with germination probabilities at 5 days exceeding 0.8 in materials CL 19220, CL 19246, and CL 19219, while at 14 days, it was 0.14 and 0.34 for the reference check and CL 19265, respectively.