Multi-Location Evaluation of Agronomic Performance and Yield Stability of Select Special Purpose Rice Lines in Luzon, Philippines

Abstract

The increasing demand for high-quality and nutritionally enhanced rice has intensified interest in special purpose rice (SPR) such as aromatic, pigmented, and glutinous types. However, the productivity and adaptability of these rice types across diverse environments remain limited. This study evaluated the agronomic performance, yield, and adaptability of three CLSU-bred SPR lines—CLS1 (aromatic), CLS2 (pigmented), and CLS4 (glutinous)—across three major rice-producing areas in the Philippines (Pangasinan, Nueva Ecija, and Bulacan) during the 2022 wet season and 2023 dry season. Multi-location on-farm trials were conducted under farmer-managed conditions, and data on key agronomic traits and grain yield were collected. Combined analysis across environments was performed to assess genotype and environment effects. Results showed that agronomic performance and grain yield varied across locations and seasons, indicating strong environmental influence on SPR productivity. CLS1 and CLS2 consistently exhibited higher yield performance in irrigated environments, particularly in Nueva Ecija and Pangasinan, with yields reaching up to 6.20 t ha⁻¹ and 7.42 t ha⁻¹. In contrast, all SPR lines showed reduced yield under rainfed conditions in Bulacan. CLS2 demonstrated relatively stable performance across environments, suggesting broader adaptability. These findings highlight the importance of environment-specific varietal selection and support the targeted deployment of SPR lines to enhance diversification and farmer income.